any experienced deviter lobbying with a spare minut read me - WarmGlass.com

any experienced deviter lobbying with a spare minut read me

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Tyler Frisby
Posts: 75
Joined: Tue Dec 02, 2003 8:27 pm
Location: Canada

any experienced deviter lobbying with a spare minut read me

Postby Tyler Frisby » Sat Apr 10, 2004 5:34 pm

I've been asked to make some 4' and 2 inch square tiles for a washroom
from tempered chunks devitrified. I have come to the conclusion that the amount of devit I get may depend where the float came from.

-Does a "cloudier" tinside mean your going to have more/less devit ?

-Can anyone tell me a top working temperature for them on inducing devit on temperd chunks at a 1/4'' thickness ?

(im going to try 1550 for 20 minutes, the point where glass begins to level out)

-will regular float devit as much as tempered float chunks it seems to me that tempered devits ALOT more ?

-do u think I could get six full 20'' shelves ful of tempered chunks to devit in my kiln if I stacked them with 1'' 1/2 posts only using side elements to prote even heater throughout?

-is there any windex with or without amonia that help induce this Devit ? lol kinda like a reverse borax or something ?

hmm any help here would be sooo amazing, probably save me a hole week of testing. I will share my resluts with anyone who wants it.

charlie holden
Posts: 260
Joined: Thu Mar 13, 2003 8:26 pm
Location: Atlanta

Postby charlie holden » Sat Apr 10, 2004 7:51 pm

I have not actually done this but I understand that if you mix some whiting in water and paint it on your glass, then soak at a high temperature for a couple of hours you will get plenty of devit. Devit likes to grow on dust and the whiting provides just that. Cool slowly from 1450 to 1300 F and it should be even thicker.

Search the old archives for Brian Blanthorn secret cheatin technology on devit.

Tempered float is no different from regular float once you get it above 800 F or so, other than that it used to be tempered, so has had one more run up to the annealing point. This might make it a little more prone to devit but I doubt by much. Tempered may be deviting more because it picks up some microscopic dust in the tempering process.

The question about six shelves in a kiln is mostly a question of whether your kiln has enough power to get that much mass up to temp. You just have to test it.

ch

skin_mechanic
Posts: 35
Joined: Fri Mar 26, 2004 10:42 pm
Location: Birmingham, AL

Postby skin_mechanic » Sun Apr 11, 2004 12:32 pm

I found this message in the archive. Kinda hard to read, almost like a foreign language :? I'm intrested in doing patterned devit in combination with textural applications on the underside(float glass). I like the vit's iridescent sheen under strong directional lighting, and the velvety feel, especially over oxidized foil with plenty of seeding... Ok, I admit I'm a flake, but somebody's gotta go out on a limb here :lol: :lol: :lol:

PDXBarbara
Posts: 292
Joined: Sun Mar 09, 2003 4:09 pm
Location: Portland, OR

Postby PDXBarbara » Sun Apr 11, 2004 2:59 pm

Skin_Mechanic wrote:I found this message in the archive. Kinda hard to read, almost like a foreign language :? I'm intrested in doing patterned devit in combination with textural applications on the underside(float glass). I like the vit's iridescent sheen under strong directional lighting, and the velvety feel, especially over oxidized foil with plenty of seeding... Ok, I admit I'm a flake, but somebody's gotta go out on a limb here :lol: :lol: :lol:

Without even checking the link, sounds like it's a message from Brian Blanthorn. We've all had to learn to translate. Translating his messages and applying his advice has paid off for me.
best,
BB
Barbara Bader

Tyler Frisby
Posts: 75
Joined: Tue Dec 02, 2003 8:27 pm
Location: Canada

Postby Tyler Frisby » Sun Apr 11, 2004 3:00 pm

Thank you soo much for all the replay guys , it think I read some ol archives thanks for the direction :)

I'll post some results

Tyler,

Brian and Jenny Blanthorn
Posts: 353
Joined: Mon Mar 10, 2003 5:25 pm
Location: UK
Contact:

Re: any experienced deviter lobbying with a spare minut read

Postby Brian and Jenny Blanthorn » Mon Apr 12, 2004 6:10 am

Tyler Frisby wrote:I've been asked to make some 4' and 2 inch square tiles for a washroom
from tempered chunks devitrified. I have come to the conclusion that the amount of devit I get may depend where the float came from.

-Does a "cloudier" tinside mean your going to have more/less devit ?

-Can anyone tell me a top working temperature for them on inducing devit on temperd chunks at a 1/4'' thickness ?

(im going to try 1550 for 20 minutes, the point where glass begins to level out)

-will regular float devit as much as tempered float chunks it seems to me that tempered devits ALOT more ?

-do u think I could get six full 20'' shelves ful of tempered chunks to devit in my kiln if I stacked them with 1'' 1/2 posts only using side elements to prote even heater throughout?

-is there any windex with or without amonia that help induce this Devit ? lol kinda like a reverse borax or something ?

hmm any help here would be sooo amazing, probably save me a hole week of testing. I will share my resluts with anyone who wants it.


Never noticed any diferebce tin side or not

If U dont want a carpet of devit try spot painting a tiny bit of china clay on Just the tynyest ammount

Without checking my secret archives dont know the melt temp of whiting if it not melt that will B OK

U can get a pattern by using anty devit stuff in places

As 2 the temp best 2 watch glass as soon as it starrts 2 move soak

Remove test peices 2 C how devit is doing

U can refire devit n get more

Very high temps will disolve it but the glass will B very runny

One thing U gotta do with devit is remember that most of the technology is develpoed 2 avoid it

So take care what U read

There R many unbelevers out there who will take U way from UR quest

As far as devit goies more glass in kiln is better

N any unevenivity is usually a good thing

If U got any more devit Qs stick em on this thread n I will get back 2 U

Onglaze + flux will act as a anti devit

If U go 2 thick it will crack

This tolerance will varie whith the glass

The cracks will continue as there is actual strain there, use

Destruct n Go tm

This revolutionary technology was develped by my technitions toiling 24 / 7 in there secret labs

In brief

Best 2 use a known glass

Devit it over a number of firings till it cracks

Work back from that divide hours by 2 or 3

So 3 hours = 1 1/2 or 1 hours soak

Some glass will be Ok at 1-2 mm devit at the interface

Below is devit stuff I got which is more up 2 date than the link given

This is not the complete works of the Global Lab Research team but there is a lot there

Enjoy Brian

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

From "Dictionary of Glass: Materials and Techniques" by Charles Bray

Devitrification. Glass is a material with a randomly distributed structure which, on cooling from a molten state, tries to regain a more regular crystalline lattice. It is restricted from doing so because of the viscosity of the material. If, however, the glass is held at its liquidus temperature for any length of time, the network modifiers can help to form crystals, of, for instance, devitrite. These localised crystals have a changed composition from that of the glass resulting in a different coefficient of expansion. This creates areas of strain and tends to promote cracks. For those responsiblie for large scale production, devitrification is something of a nightmare and as far as is reasonably possible, both glass composition and the coolong rates are designed to aviod it happening. Because of this, the normal procedure is to cool the glass as quickly as possible to a temperature at which it can be annealed.

A glass that has a high lime content tends to devitrify easily. An increase in the lime content also reduces the working time so a manufacturere who wishes to produce a glass which hardens quickly to suit his forming process may decide to increase the amount of calcia in the batch. If he overdoes this he increases the risk of producing crystals of devitrite. Devitrification can occur in the furnace, particularly if there are parts of the tank or pot which remain cool. this can cause the production of devitrification stones and/or cords and create a subsequent loss of material.

The danger of devitrification in studio glass is exactly the same as in the factory. It often occurs in kiln-cast glass where the cooling of the material in a mould tends to be slow. If the result is one in which there is uniform transulcency or opacity then this may well be caused by some other factor such as glass to glass phase separation or silmply the effect of dust on the pieces being fused or cast. The studio glassmaker has always taken a rather wide, and often incorrect, interpretation of devitrification and anything which in the process of creating cast or kiln-formed work has become opaque or traslucent tends to be labelled as being affected by this. Experience would suggest that anything which has developed individual patches of what could possibly be crystalline material is likely to be suspect and should be discarded whilst glass which has become evenly opaque or transucent throuthout will probably be safe provided that there has been adequate annealing and if all the pieces of glass involved are compatible.

Studio glassmakers producing kiln-formed pieces need to be particularly careful when trying to re-melt or fuse to gether glass which contains areas of devitrification with glass which is clear (meaning glass that is doesen't contain areas of devitrification). The devitrified areas of glass will not melt as readily as the normal glass and as a result will not move into the required form. Even if the two materials become incorporated to any extent the result will inevitably be unstable an will probalby crack or simply fall into pieces.

This definition of devitrification doesn't give an answer to "why devit on the upside but not the kiln side?", but might offer some groundwork to make some suppositions from.


XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Devit is glass molecules arranged in ordely fashion micro cristaline or larger cristals or both

In our normal glass the molecules R arranged in a random manner ( with some glasses this is not true )

Anti devit stuff works by making the glass 2 liquid so the cristal cant grow, also it will tend 2 disolve any neucleation points, so again it cant grow

Devit will only grow within a certain viscosity range

To stiff or 2 liquid n it cant grow

It aslso needs something 2 grow from like dirt or a scratch ( neucleation point )

It is this reason that devit usually only grows at an interface

Anty devit applied 2 light devit will mask it as it will B shiny n there may B a little disolving going on depending on temps

Brian


XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXx

Yo David

I belive devit is incompatabble

But it only cracks in a particular glass at a certain thicness of growth

So I put samples in a firing over a number of firings

Keeping 1 back each time

So I have a selection of same glass with different soak times

I break the glass or just look

When the tests start 2 crack I work back from that thickness by 2/3

So if the devit cracks at 3mm I grow to about 1mm

So 2 UR Q

I do hold some old bowls / tests from about 1975 onwards

The ones that cracked strait away badly, kept cracking

These were small neumerous incompatablilty cracks that grew

The ones that cracked only a little got no worce

These with just a few small cracks and that were only tiny have not got worce over the last 25 + years

Some of these R full sized finished bowls

I have had no returns or complaints on any of this devit work

One test back about 1981 which was nearly completaly devitrified cracked very badly

Every time I look at it it got worce last time I looked about 2000 it was beggining 2 fall appart

Further tests on this glass showed it would crack with very little devit

So 2 sum up

It is all 2 do with the spacing of the devit

How thick it is

How tolerent the glass is of it

Glass varies from batch 2 batch

Glass 2 glass

When cold devit will not grow

But if the cracks R bad they will very likely grow

If very tiny cracks spaced out few and small they R unlikely 2 grow

http://www.blanthorn.com/bowls/bowls_19 ... _large.htm

U can C a few tiny cracks in this, as the devit is spread out they will not grow K12B

I have not seen this bowl since 1980 or so but a similar one 1979 with tiny cracks is OK as of last week


http://www.blanthorn.com/bowls/bowls_19 ... 0_1989.htm

K35A is mine is OK as 2001

SB10 looked 1997 OK

The other devit bowls I have R OK

Bert

The vitrolite I belive is completaly devitrified

And no glass left

The Artist Formaly Known As

11/12/02



i just got out a load in which i used borax to illiminate devit, and it worked great, but im wondering if the borax accelerates the action of the glass, i fired at 1425, but it made the glass seem more blobby than would be usual at 1425,

did the borax make the glass more blobby at 1425 than would be normal at 1425 with NO BORAX

thanks

rodney



rodney

: probably yes. Borax as a flux lowers the melting temp of
: the surface.

: Bert

In addition

What UR doin is using Cheetin technology

What happens is the glass surface becomes softer so cannot devit

Also the suface tension is reduced allowing the glass 2 flow a little more

Devit can only grow when the glass is soft but not runny

In addition and most importantly it cannot start 2 grow

Devit once grown is difficult 2 stop unless U go high or refire + flux

Devit stops the glass from moving - increaces surface tension

Formaly Vit Boy




OT Brian+Jenny Blanthorn UK <warm@blanthorn.com> -- Thursday, 5 September 2002 at 15:29

: Read this post:
: http://www.warmglass.com/cgi-bin/wgarch ... ?read=7179

: And this:
: http://www.warmglass.com/cgi-bin/wgarch ... read=10006

: A lot of the info in those threads is from Brian
: Blanthorn. If you're interested in devit, take the
: time to figure out what he's saying (easier said than
: done). Without a doubt, Brian is the world's expert on
: devit and float. To do devit well, it's more
: complicated than just a simple soak.

: According to Graham Stone, float anneals at 1030 F.
: According to Bert Weiss, float anneals at 1000 F.
: According to Shand's Glass Engineering Handbook, the
: right annealing temp is 1025 F. Take your pick.

Well lookin at it from my side I supose I should B an expert but

I would say I am begginning 2 learn

When I hear or meet an expert in any field it does concern me that they probably know as little about there subject as I know about mine

I do have masses on devit in my top secret private archives

If U want not all mine

One thing SLS does devit differently batch 2 batch

n the colour is enhanced by it

Some of it yukky smooth some lovely cristals

Lappsed Vit Boy

http://www.blanthorn.com

Post Response


NEW: Re: Float devit
Paul Stevenson <studio5@btopenworld.com> -- Thursday, 5 September 2002 at 16:43

Useful bookmark;

http://www.primaryglass.org/specguide/01.htm

is chapter one: Float Glass Manufacturing Process

HTH,

Paul





: I realize this has been beat to death but I could not
: find info in the archives on the temp that float glass
: devits The Most. I am looking to fire some with the
: purpose of getting it really foggy.

: Also, could not find the annealing temp for float. Seen
: lots of numbers but nothing specific.

: Thanks, Tim

Realy foggy OK

Best 2 sandblast, clean but not 2 well

Fuze till start 2 move soak

If U not got blaster use any high temp stuff such as china clay

+ gum arabic + water paint on realy thin an atom or 3 will B OK

If thick will act a seporator

If U want thick devit dont bother with any of this just soak

Crystal Boy









The tendency to devit in float is largely a result of the high lime content. The high lime confers reasonable chemical durability (important for glass that has to withstand considerable weathering) but the down side is the devit. -Graham ( from handmade ) http://handmade-glass.com/cgi-bin/bbs/b ... l?read=361

:

Brian, I have always understood that glass, per se, is
: not a crystalized material...although the materials
: that make up "glass" are crystalline in
: nature. The composition changes when
: high-heat-combined. Are you saying that the composite
: materials return to their original crystaline
: form?...That it is this phenomenom, rather than
: impurities or oxides in the glass that surface, that
: create devit? I really want to understand this.

Dear Boggled Girl

Glass is actualy a very large subject area

But I will stick with glass as we know it.

I have a working knowledge of this I am not a scientist

On the whole glass we use is not cristalized it is liquid but if U read Hugo's post U will C this is not always true

OK I will now talk about none devitrified ( normal glass ) without solid bits ( neucleation points ) inside

This exists at room temp's as a liquid in its molecular state

This is called a super cooled liquid

Will not devitrify as it needs something 2 grow from

However there is lots of solids ( neucleation points ) on any surface

But none inside the glass

That glass wants 2 devitrify and given the right conditions it will do so

But it can only grow from a neucleation point

So in this example in the kiln it will only grow from the surface

If its laminated there R lots of surfaces

In this example

http://www.blanthorn.com/bowls/bowls_19 ... _large.htm

The glass is laminated from some 50 or so strips of SLS

Fuzed

Then sawn up + more glass added then devitrified

Then the top + bottonm devit ground off

Note every surface has devit on it

But none inside the glass strips

So 2 answer UR Q glass cannot devitrify unless it has something 2 grow from

In our case this is dirt / scratches / smoke

The anti devit stuff U put on the glass stops the growth as the glass is 2 liquid

It possibly disolves the dirt

It realy is a sneeky way of stopping devit

If U R using a coloured glass as long as the stuff is desolved U have no neucleation points

If its some kind of solid bits such as cristaline then U got lots of neucleation points

Hugo

I would say that in the ( normal ) glass I discused there R no neucleation points within the glass

Well not any that affect us at our temps

In actual glass making this could well B a different story

When reading stuff remember that various technologies R not all " true " 4 us

As we lie inbetween a lot of them

I have been given lots of problems from looking at other technologies

But also a lot of Cheetin Technology as well

Its an inbetweeny world we live in my friend

Deep Boy
: Hi all!

: On reading literature with regard to devit, I learned
: that devit is crystallization and crystals (devit)
: disolve over the "liquidus" temperature.

: Thinking of a piece of ice the concept is clear and easy,
: in fact, the "liquidus" temperature is 32°F,
: isn't it?. That's when a crystalline solid melts, the
: "melting point".

: Since devit is crystal silica, I thought the
: "liquidus" temperature for glass must be
: silica melting point. Is that true?. What temperature
: do you think it is?.

: DevitpunisherBoy ( Hugo )


I cant give U an exact temp

But I did a post arroud this recently

The cristals R the actual glass I dont recon pure silica

The glass can exist in 2 states liquid ( normal )

And cristaline

The temp is probably not specific

I guess it grows faster at a certain temps slower either side

And disolving higher up

In my experience with SLS

Moving slightly but not runny - devit grows fast

At this temp the glass will bead up

Runny IE off the shelf the devit will disolve

Soaking will alter the temp

With SLS a soak arround 950 c / 1000 c will disolve devit

Arround these temps oxides will tend 2 go into the glass as well

With SLS bubbles come where the devit was

My guess is any glass will behave in a similar way

But some glass devits less that others n has different crystals

Did U C the devit epic story I have ??

Formaly Boy
: hi there brian, thanks as always for you insight,

: i have a followup on the neucleation, since this is a
: solid in the liquid glass, does this cause a problem
: with incompatibility, making for stress

: can this material that is the neclei be so small that it
: doesnt cause stress, can you tell me what i can add to
: the glass that will act as the neclei

: amigo, you are the best of the best

Rodney

Its a case realy of how much do U want 2 know

I am only a begginer myself so am not a expert

The neucleation points in themselves if tiny R of no consiquence

The devit is incompatabble in my experience

As it gets bigger this is a problem

This depends on its thickness

Densivity

n How compat it is

Some R more or less

U could add a 1000 or so things 2 get devit

But the problem if using say sheet glass is U already have the neucleation points already

So in that sence U cant add anything as U already got it

OK

Heres something U can try

Put on some anti devit stuff so U get the control

Add a few grains or more of quartz / sand / whatever where U want it

Then take it up 2 pre runny temps

Soak

Formaly Boy

: The crystallisation of a melted substance which
: generally takes place when the temperature falls below
: the melting point. Devitrification does not occur with
: glass either because the rapidly increasing viscosity
: of molten glass as it cools impedes crystal growth or
: because of an insufficient number of nuclei for
: crystallite formation. Devitrification can be
: stimulated for the production of opaque
: glass-ceramics.

: FROM THE Illustrated Glass Dictionary

: can someone tell me what is the nuclei in the glass that
: causes the crystals to form, and how do you increase
: the number of nuclei

: and

: what are opaque glass-ceramics

: thanks

Rodney

U also asked about growing large cristals

UR Qs although simple R realy complex

Did U get the big epic devit post I sometimes put out ??

Anyway neucleation as far as we R concerned is anything solid when the glass is liquid

Specificaly arround the sofening point

Go 2 high so it is runny n it will disolve

Time is also a factor

So this is dirt / scratches and realy any oldish surface

Even a new surface

2 get big cristals

U can take thick glass n pool it out so reducing the surface (old) area

And or put on anty devit stuff n leave small spots 2 grow

Hi Bert
Welcome to the SDS

Secret Devitrification Society

U can do a number of things to remove devit

I will tell U them U will have to dicide if any are suitable

there are lots of views on how to avoid devit

there is the low temp soak method

method I use is

after aneal realy fast climb to fuze

do not open door look through bung, bung hole is tapered kiln side

crash cool to above aneal

the thinking with this method is to flash heat the surface to melt it so it cant devit

this is all assuming the glass was clean ??

ok so to remove it use the above fire method

U will need to take up slower to above aneal then

the enamel idea should work well

4 enamel take it as high as u can

to use the flux method take it as high as u can

another method is to sand blast then do the above

If U wana search the site there is lots of info on this

SDS Boy

i hase redone this post a bit - some is repeated in other prts of your summery

Hi I see a lot of quiries on devit so here is my bit
glass is unusual in that when when it cools quickly it does not crystalise as most materials do like say water / ice
: when normal glass is cool it is a liquid the molicules are arranged in a random manner
and is transparent (usualy) calleed a supercooled liquid as the molicules did not have time to crystalise

devitrification is glass which
: has changed from a liquid in the molecular level to a
: cristaline organised structure which is white scummy /
: opaque in clear glass can be nice when they get big
: did a lot of it myself if u want to see? look on
: blanthorn.com
: http://www.blanthorn.com/bowls/bowls_19 ... _4:+40.htm

the two can exsist side by sie in the same peice of glass

: It actualy grows from something a solid a nucleation point in our
: case usually dirt on the glass scratches etc but
: because it needs something to grow from it dosent grow
: within the glass grows from a surface
it grows when glass starts to move
: remember glass can be hot on the surface from the
: elements so get localised heat

: so to prevent it clean glass heat glass after about 400
: dC as fast as possible to melt surface of glass I have
: seen other methods of heat rise this is specificaly to
: prevent devit do not open kiln peek through bung hole
: mine is made like what they have in castles small out
: big in so can see a lot but not loose heat U can dig
: out brick carefully to extend existing hole the
: concept is to get glass hot but not cool by opening
: kiln

if u open kiln get surface cooling and devit will start to grow

as soon as fuzed open door to cool to say
: 700 d C open / close so not crack shelves Or / as well
: as use some anti devit spray these work in a very
: sneaky way it is a low temp flux which makes the
: surface liqiud so preventing devitrification It has to
: grow from a solid bit for devit spray see :
: : http://www.warmglass.com/making_your_ow ... IT%20SPRAY

: I have not tried this

U can disolve /remelt devit take to temp where glass is realy runny
about 950 /1000 dc

: To grow it Dont clean glass to well soak at sottening
: temp just as start to move but not so run off shelf I
: can be incompatable in some glass growth rate and type
: of cristal varies greatly from glass to glass / batch
: to batch I cut / grind mine to show cristals
Brian

----- Original Message -----
From: Brian Blanthorn
To: bcb
Sent: Friday, December 28, 2001 10:07 PM
Subject: Secret Devit Stuff


Pablo

Anti Devit Cheatin Technology explained

The way it works is

Glass is a liquid with no solids

Devit grows ( neucleates ) from a solid bit

It is a cristaline growth

The anti devit stuff is simply a low melt flux which melts the solids

Or does not allow them 2 form

Solids 4 us is dirt finger prints dust scratches rough areas

There is much related technology 2 this

Such as

Baffle n Go

Zap n Blastem

These R in the archives

Devit growth is very similar 2 rain and frost

Formaly Devit Boy


All the best

Brian and Jenny

bcjs@blanthorn.com
http://www.blanthorn.com

Hi Bert
Welcome to the SDS

Secret Devitrification Society

U can do a number of things to remove devit

I will tell U them U will have to dicide if any are suitable

there are lots of views on how to avoid devit

there is the low temp soak method

method I use is

after aneal realy fast climb to fuze

do not open door look through bung, bung hole is tapered kiln side

crash cool to above aneal

the thinking with this method is to flash heat the surface to melt it so it cant devit

this is all assuming the glass was clean ??

ok so to remove it use the above fire method

U will need to take up slower to above aneal then

the enamel idea should work well

4 enamel take it as high as u can

to use the flux method take it as high as u can

another method is to sand blast then do the above

If U wana search the site there is lots of info on this

SDS Boy

i hase redone this post a bit - some is repeated in other prts of your summery

Hi I see a lot of quiries on devit so here is my bit
glass is unusual in that when when it cools quickly it does not crystalise as most materials do like say water / ice
: when normal glass is cool it is a liquid the molicules are arranged in a random manner
and is transparent (usualy) calleed a supercooled liquid as the molicules did not have time to crystalise

devitrification is glass which
: has changed from a liquid in the molecular level to a
: cristaline organised structure which is white scummy /
: opaque in clear glass can be nice when they get big
: did a lot of it myself if u want to see? look on
: blanthorn.com
: http://www.blanthorn.com/bowls/bowls_19 ... _4:+40.htm

the two can exsist side by sie in the same peice of glass

: It actualy grows from something a solid a nucleation point in our
: case usually dirt on the glass scratches etc but
: because it needs something to grow from it dosent grow
: within the glass grows from a surface
it grows when glass starts to move
: remember glass can be hot on the surface from the
: elements so get localised heat

: so to prevent it clean glass heat glass after about 400
: dC as fast as possible to melt surface of glass I have
: seen other methods of heat rise this is specificaly to
: prevent devit do not open kiln peek through bung hole
: mine is made like what they have in castles small out
: big in so can see a lot but not loose heat U can dig
: out brick carefully to extend existing hole the
: concept is to get glass hot but not cool by opening
: kiln

if u open kiln get surface cooling and devit will start to grow

as soon as fuzed open door to cool to say
: 700 d C open / close so not crack shelves Or / as well
: as use some anti devit spray these work in a very
: sneaky way it is a low temp flux which makes the
: surface liqiud so preventing devitrification It has to
: grow from a solid bit for devit spray see :
: : http://www.warmglass.com/making_your_ow ... IT%20SPRAY

: I have not tried this

U can disolve /remelt devit take to temp where glass is realy runny
about 950 /1000 dc

: To grow it Dont clean glass to well soak at sottening
: temp just as start to move but not so run off shelf I
: can be incompatable in some glass growth rate and type
: of cristal varies greatly from glass to glass / batch
: to batch I cut / grind mine to show cristals
Brian

----- Original Message -----
From: Brian and Jenny Blanthorn
To: Brian and Jenny Blanthorn
Sent: Tuesday, January 30, 2001 10:08 PM
Subject: collection devit


: The many causes of devit I am aware of are as follows: *
: Chemical composition. Lime content, in particular, is
: a factor. Different glasses vary considerably, also

: Brian's probably sleeping in the UK, but if you want to
: get more devitrification, try the following: 1. Don't
: clean the glass. Devit likes surface contamination. 2.
: Soak it at softening temperature. (full fuse or a
: little higher, but not so high that it becomes runny)
: According to Brian, the type of devit crystal varies
: greatly by type of float or even from batch to batch.
: To show the crystals off best, you need to cut the
: glass and polish edges. Brad The negative press for
: devit is well founded It is difficult toit make look
: good. Additional information: Devit increases colour
: of glass: i.e. green - more green The more you soak,
: the more it devits If you go too far it is
: incompatible Some glasses are more tolerant than
: others It’s best to find when it cracks, then work
: back from that If it does crack the cracks tend to get
: worse and grow. One of my test pieces had so much
: devit that it continued to crack and bits fall of
: years. The devit was about 5mm thick Consider
: colouring layers. The colour then tends to stay in
: interface and devit then grows over it The anti devit
: stuff the unbelievers use is useful for stopping devit
: in places This can be mixed in colour For suggestions
: of colour do a search on body stains / flux, metal
: powders. Pure copper powder is good and a bit of flux
: can but go brown through. Oxides tend to bubble

: Strange things happen when you soak . One time the copper
: moved into the glass away from the devit about 1.5 mm
: into the glass. A really good devit method would be
: what Ron has recently done . It’s very difficult to
: give a temp for this as it depends on the kiln, but
: try 1760 + /- f soak 1 - 5 hours. It could be redone
: using this method. The higher you go the more your
: colours dissolve. I suggested metals and body stains =
: flux as they don’t bubble., I took one to 1830f for
: few hours and it really dissolved . I feel i have to
: confess I stoped devit due to impending poverty due to
: lack of devit sales. My customer was so overawed by
: the opalescent glass they stopped buying it !! If that
: was not bad enough I have further to confess that I
: avoid devit in my current work Be kind to the
: unbelievers Lapsed Member SLS Boy

: Rosanna: You only need to apply divit spray for your high
: temp fusing..above 1400. One application will be
: sufficient to take you through the subsequent slump
: cycle. Spray A needs to mature and it will not do so
: at slumping temps. This is why you now have a matt
: finish. There are certain divit sprays that are meant
: to mature at slumping temps and will give you a glossy
: surface, but Spray A isn't one of them. Hope this
: helps.

: Mary, Spectrum suggests using the Clear cap to avoid
: devit problems and I swear by it. I also soak
: somewhere between 1100 and 1200 it get rid of the
: bubbles. Spectrum has a site about fusing with their
: glass which may be helpful. Robin

: http://wwwspectrumglass.com/fuseset.html

: As Boyce Lundstrom used to say, "never refuse to
: re-fuse" . Yes, you can sandblast the piece and
: fire polish it by refiring (this works best with
: Bullseye glass...not so well with Spectrum), or you
: can apply Spray A (prefered method is with an
: airbrush), and refire. Avery

: By the way, Spray A is not food safe, so don't use it on
: surfaces intended for food. Geri

: I get two different etching creams...one from C&R Loo
: called P-ETCH16. It works in about 2 minutes and is
: not resusable. C&R Loo has a website. (They are in
: Richmond, CA). I am impressed with the owner's
: committment to his customers. The other cream I get
: from Franciscan Glass in Mountain View, CA. It is
: reusuable. Franciscan doesn't have a website yet that
: I know of, but they do mail order, I think. (I buy
: from them on a walk-in basis.) Whichever you use, make
: sure you don't get etching cream on porcelain sinks or
: ceramic tile because it etches them, too. I prefer the
: cream from C&R Loo because it works faster. The cream
: from Franciscan is reusuable, so it is more cost
: effective. I'm sure there are other etching products
: that will probably work fine, too. Just follow the
: instructions. I always apply them on glass resting on
: an old towel to protect the surface underneath. I use
: a brush or squeegee. I don't have a sandblaster in my
: home studio, which is why I tried this approach.
: Sometimes, I have to etch a piece twice to get all of
: the devit off. Geri

: My two sense: When using any acid, ALWAYS have a base (I
: use baking soda Baking Soda) to stop or neutralize it.
: Prevents any accidental spillage from causing any
: damage and saves your brushes. Hot Regards, Andy

: I have had a similar problem with Spectrum transparents
: showing a haze around the edges when fused and each
: time I can tell it came from a ground edge that I
: didn't polish. It seems that an edge fresh from the
: grinder will not flow out like the rest of the glass,
: for some reason the frosty surface never fires clear.
: I have started to finish ground edges with a small
: hand diamond sharpening stone from 3M and the edges
: look much better. Even the score line from the cutter
: will leave a small line on a finished piece if you
: look real close. Ron

: Bullseye glass does not require ANY anti devit spray for
: most any firing program. Stop using any anti devit
: spray. Spray A is NOT food safe but Superspray is.
: There is no need to use any alcohol to clean your
: pieces. Good old sink dishwashing detergent is fine.
: Rinse well and dry with a clean towel. I do not use
: oil in my cutter when cutting most glass for fusing.
: Helps on the clean up. You can fire some test pieces
: to demonstrate the worth of this information. Or
: better yet, just follow these guidelines and your
: devit problems will be no more. Bob

: I occassionally have devit problems, but then I just etch
: the surface and refire. That usually works. I have
: only used isopropyl alcohol and I use a coffee filter
: to apply the alcohol. That way you don't get any
: fibers on the glass. I have never used Spray A or
: borax. Just clean the glass and fire away. Good Luck
: Mary Anne

: The only time I encountered a devit problem with bullseye
: similiar to what you describe was when I allowed too
: much overglaze to accumulate in one spot..and then dry
: on the piece prior to firing. This could especially
: accumulate around the edges of any piece and would
: result in a whitish splotch. Also allowing the
: overglaze to dry (even a little) and then trying to
: rework or cover with more glaze caused an inconsistant
: shine. Glassbird

: After I put Super Spray on, I spread it around with a
: small foam brush until I cannot see any puddles or
: other buildup on the piece. then to the kiln. LynnB

: Are you cutting your pieces on a diamond band saw? I had
: big problems with devit (or maybe just fused in dirt)
: along the edges of bandsaw cuts. My guess is that the
: blade picks up residue from the rubber wheels. No
: amount of cleaning cured the problem. I have to grind
: the edges with a fine grit diamond wheel before
: firing. As the Ron said, do some tests to see if the
: devitfrified edges are cut, ground or bandsaw cut.
: Charlie

: When cleaning glass (any glass), you should never use
: denatured alcohol. Use isopropyl alcohol if you must,
: but no stronger than a 70% alcohol solution. Some of
: the commercial cleaners will work well for fusing,
: some won't -- if you go that route, you just have to
: experiment to find the brand that works for you. As
: for me, I use ordinary tap water (or sometimes just
: dishwashing detergent and water). I rarely oil my
: cutter. I rarely use a devit spray (either borax
: solution or a commercial preparation), and I can't
: remember the last time I had a devitrification
: problem. Try what you will, but don't try denatured
: alcohol. I'm not a chemist, so I can't explain why it
: doesn't work, but I know it doesn't. Brad W

great Lynn

in addition

for no devit a alternative to the low temp method u can also go up realy fast and let the elements realy flash heat the glass so devit cannot grow cos the surface is to melted then flash cool if u use this method it is essencial not to open the kiln till fin as the surface cools and devit realy starts to grow

make your peep hole tapered so can look in better

glass is unusual in that when when it cools quickly it does not crystalise as most materials do like say water / ice
: when normal glass is cool it is a liquid the molicules are arranged in a random manner
and is transparent (usualy) calleed a supercooled liquid as the molicules did not have time to crystalise

devitrification is glass which
: has changed from a liquid in the molecular level to a
: cristaline organised structure which is white scummy /
: opaque in clear glass can be nice when they get big

the two can exsist side by sie in the same peice of glass

: It actualy grows from something a solid a nucleation point in our
: case usually dirt on the glass scratches etc but
: because it needs something to grow from it dosent grow
: within the glass grows from a surface
it grows when glass starts to move
: remember glass can be hot on the surface from the
: elements so get localised heat

: so to prevent it clean glass heat glass after about 400
: dC as fast as possible to melt surface of glass I have
: seen other methods of heat rise this is specificaly to
: prevent devit do not open kiln peek through bung hole
: mine is made like what they have in castles small out
: big in so can see a lot but not loose heat U can dig
: out brick carefully to extend existing hole the
: concept is to get glass hot but not cool by opening
: kiln

if u open kiln get surface cooling and devit will start to grow

as soon as fuzed open door to cool to say
: 700 d C open / close so not crack shelves Or / as well
: as use some anti devit spray these work in a very
: sneaky way it is a low temp flux which makes the
: surface liqiud so preventing devitrification It has to
: grow from a solid bit

U can disolve /remelt devit take to temp where glass is realy runny
about 950 /1000 dc

: To grow it Dont clean glass to well soak at sottening
: temp just as start to move but not so run off shelf I
: can be incompatable in some glass growth rate and type
: of cristal varies greatly from glass to glass / batch
: to batch I cut / grind mine to show cristals

devit is more stiff than normal glass and cristaline texture when polished

: According to Brian, the type of devit crystal varies
: greatly by type of float or even from batch to batch.
: To show the crystals off best, you need to cut the
: glass and polish edges.

: Happy crystal making.

I have been known to sleep on occasion

did a post on devit I think it now in archives or hopefully Brad has added a society page on site and put it in ??

The negative press 4 devit is well founded

it is difficult to make look good

some further info 4 members in addition to Brads recent

sls is probably best

devit increaces colour of glass ie green - more green

the more u soak the more it devits

if u go to far it is imcompatable

some more tolerant than others

best to find when crack then work back from that

if it does crack they tend 2 get worce and grow {the cracks) one of my test peices had so much devit that it continued to crack and bits fall of years later the devit was about 5mm thick

consider colouring layers the colour then tends to stay in interface and devit then grow over it

the anti devit stuff the unbelivers use is usefull 4 stopping bevit in places

this can be mixed in colour

4 sugestions of colour do search on body stains / flux

oxides tend to bubble

search 4 metal powders

pure copper powder is good + bit of flux can but go brown though

strange things happen when u soak one time the copper moved into the glass away from the devit about 1.5 mm into the glass

a realy good devit method would be what Ron has recently done very difficult to give a temp 4 this as depends on kiln but try 1760 + /- f soak 1 - 5 hours could re do using this method the higher u go the more ur colours disolve i suggerted metals and body stains = flux as they dont bubble i took one to 1830f for few hours realy disolved

I feel i have to confess I stoped devit due impending poverty due to lack of devit sales my coustomer was so overawed by the opalesent glass they stoped buying it !!

If that was not bad enough I have further to confess that I avoid devit in my current work

Be kind to the unbelivers

Lapsed Member SLS Boy

All the best

Brian
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