wiring mold

jerry oliver · Post by **jerry oliver** » Thu May 22, 2003 9:43 am

i have used steel wire to wrap my investment molds, used in the lost wax process, as a little insurance to retain some degree of mold integrity if it were to crack while in the kiln. steel wire expands with high heat and seems to be of limited value for this purpose. is there a better type of wire to use and if it's hard to find, where can it be purchased?

jerry oliver

Colin & Helen · Post by **Colin & Helen** » Thu May 22, 2003 10:58 am

I use two types of wire around the core mould , I start by wrapping galvanized bird wire around the mould this is held in place with 2mm copper wire finally covered with the outer mould mix...Colin

charlie · Post by **charlie** » Thu May 22, 2003 12:26 pm

Colin & Helen wrote:I use two types of wire around the core mould , I start by wrapping galvanized bird wire around the mould this is held in place with 2mm copper wire finally covered with the outer mould mix...Colin

one shouldn't use galvanized anything in a kiln. it produces both deadly gases, and probably does damage to elements.

when i was building a cage, i found spools of wire in the fence building section of home depot. a couple bucks for 100', about 1/16". it's either iron or soft steel, but since it rusts i think it's iron.

Dani · Post by **Dani** » Thu May 22, 2003 1:05 pm

jerry oliver wrote:i have used steel wire to wrap my investment molds, used in the lost wax process, as a little insurance to retain some degree of mold integrity if it were to crack while in the kiln. steel wire expands with high heat and seems to be of limited value for this purpose. is there a better type of wire to use and if it's hard to find, where can it be purchased?

jerry oliver

I wonder why you're having problems with the wire.... isn't jeweler's wire steel? It holds up to torch temperatures and holds pieces of silver in place without them shifting. Hmmm.... I'm gonna go look what's special about that wire.

Dani · Post by **Dani** » Thu May 22, 2003 1:11 pm

Well, Rio only carries stainless steel binding wire, but I could swear some of my rolls are iron binding wire, now that I think about it. They're packed up though.... can any of the other jewelers comment?

sadiesjewels · Post by **sadiesjewels** » Thu May 22, 2003 1:52 pm

My old binding wire is definitely made of iron - we all know the woes of placing it in the pickle! Stainless steel is much less labor intensive since it can be placed directly into the pickle along with the work in progress.

I purchased some stainless steel binding wire from Rio sometime last year and it's all I use now.

It's very possible to burn through the iron binding wire when soldering, so I wonder if that is what is happening around the mold in the kiln? The stainless steel wire seems less prone to this, so maybe it would be a better option.

Sadie

PaulS · Post by **PaulS** » Thu May 22, 2003 2:45 pm

When you build up the mould, you build up the tickness by coating the wax with your mould in paste form, right?

Is it possible to use fibre glass in strands between the layers, to give it strength?

I was just reading something in Keith Cummings' book today about something similar. He mentioned fibreblanket in the mix, I'm sure it was. But these were big (to me anyway) moulds, maybe 0.5 metre deep.

Paul

jerry oliver · Post by **jerry oliver** » Thu May 22, 2003 2:49 pm

sadie and dani both mentioned "rio" as a source of stainless steel wire. can you provide me with contact info?

jerry oliver

Dani · Post by **Dani** » Thu May 22, 2003 4:03 pm

http://www.riogrande.com.... and the iron wire shouldn't be any problem for you since you're not going to put your glass in pickle, right?

Whether it holds up any better in the kiln, I don't know. I haven't had alot of troubling burning through it with the torch which is probably a bit more intense heat than your firing... what temp are you firing?

jerry oliver · Post by **jerry oliver** » Thu May 22, 2003 6:53 pm

thanks for all the comments about my question regarding wire binding the mold. i want to respond to a couple of posts to clarify what i'm doing and what i want.

i'm casting 3 dimensional organic abstract shapes using a lost wax process and an investment mold of 1/2 r & r 910, 1/4 fgr 95 and 1/4 silica flour (325 mesh) - by weight - plus water. i'm not building up a mold from the wax original, rather i'm putting the wax original into a wooden box frame into which i pour the investment so it completely engulfs the wax original with a minimum of an inch investment around all parts of the wax original. so far my normal mold size doesn't exceed 10"x10"x10". i seldom have cracking, but the investment mix is expensive enough that i want the insurance of binding the mold with wire so that in case the mold does crack there will be minimal if any seepage of the molten glass.

i take the temp up gradually as high as 1550 f and usually do 2 or 3 recharges at 1550 f to refill the sprue with frit as it condenses and fills out the mold interior. then i take the temp down very slowly, depending on the size, shape and thickness of the mold.

i've used chicken wire within the investment mold to provide the mold insurance i want and it has worked fine, but it is much harder to remove the investment from the finished cast glass pieces. so i prefer wire binding the mold with a wire that doesn't expand while in the kiln - otherwise it's not much insurance because a crack in the mold could expand and let molten glass seep out of the mold.

i've been binding my molds with regular cheap wire from the hardware store, which i think is steel, but i'm not sure - i know it's not stainless steel. i thought stainless steel wire would not stretch or expand and therefore it would provide the insujrance i want, but i haven't been able to find it in the guage i want (16 guage).

hope that clarifies and answers some questions in some of the posts

thanks again

jerry oliver

Colin & Helen · Post by **Colin & Helen** » Thu May 22, 2003 7:24 pm

charlie wrote:
Colin & Helen wrote:I use two types of wire around the core mould , I start by wrapping galvanized bird wire around the mould this is held in place with 2mm copper wire finally covered with the outer mould mix...Colin
one shouldn't use galvanized anything in a kiln. it produces both deadly gases, and probably does damage to elements.

when i was building a cage, i found spools of wire in the fence building section of home depot. a couple bucks for 100', about 1/16". it's either iron or soft steel, but since it rusts i think it's iron.

Point taken, as the process of galavnization is acid coating iron with zinc oxide...is the residual acid the problem ?as for the zinc its used in many pottery glazes with out any problems.Colin

charlie · Post by **charlie** » Thu May 22, 2003 7:41 pm

Colin & Helen wrote:Point taken, as the process of galavnization is acid coating iron with zinc oxide...is the residual acid the problem ?as for the zinc its used in many pottery glazes with out any problems.Colin

google is your friend. from http://www.chaingang.org/faq.html:

Why don't you use galvanized steel?

In short, zinc oxide is bad for you.

Heating galvanized steel can result in an unpleasant condition called welder's fever. Caged animals can develop illness brought on by swallowing or licking galvanized parts. We've known many people in the metal working profession forced to take extended sabbaticals due to various kinds metals poisoning. We work intimately with our construction materials and avoid galvanized steel out of concern for both our own health and that of our customers.

Additionally, the zinc coating on galvanized steel, used as a rust deterrent, is by no means permanent. The coating will often corrode into white rust which then results corrosion of the steel underneath. Due to the nature of the process the steel used in galvanizing is rarely of premium quality.

For those interested in the nature of galvanizing process, here is a description from Intl. Chemtex Corp: In the galvanizing process, the steel to be coated is first cleaned in a caustic bath followed by pickling in a dilute hydrochloric or sulfuric acid bath. The steel is then subjected to a fluxing operation with a zinc ammonium chloride solution.

Colin & Helen · Post by **Colin & Helen** » Thu May 22, 2003 8:35 pm

Charlie

Thanks for the link...Many things we fire are bad one ceramic company in Australia has done a lot in listing all the toxic nastes... the two at the top of the ( I believe) list have now been banned for use in schools and the like.they are cadmium and chrome..so now at the top of the list is manganese di-doide ( used in blacks and purple) other listed as toxic when fired include nickel vanadium copper cobalt zinc the list goes on ...for some reason lead is not there.....non toxic iron ilmenite lithium magnesium tin ect ect ..

Col

PS..I did read about the effect of lead fishing weights poisoning swans on some rivers in England...the swan would swallow the weights while feeding then some time later show all the signs of lead poison .. rocking back and forward

Tim Lewis · Post by **Tim Lewis** » Wed Jun 04, 2003 8:32 am

If you must use wire why not copper. It is soft enough to move with the mold but provide some support. Talk to an electrician or go to your local metal recycler. The smaller the better.

But the best solution is fiberglass "shorts" in the mold outer mold added after the plaster mix is wet. Get it from a concrete supplier. It really works well.

Kevin Midgley · Post by **Kevin Midgley** » Wed Jun 04, 2003 8:55 am

Fiberglass boat builders too for fiberglass chop to add to molds.
Tried Vermiculite as a matrix? I like it but don't use it for a glass contact area.
Another source for stainless wire is fishing line, long spools and cheap.
Kevin in Tofino where people go fishing.

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