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i've got a 16" disk, 5/16" thick, made from 3mm BE white base sheet, then frit and glass elements on top. it has been fully fused. i made this in one of matt hoppes's stainless steel rings, and the outside edge was in need of just a little cleaning up. i had this done at a tile shop. the disk was trimmed and the now-vertical edge polished up, but not to a high shine. it's very smooth to the touch. hindsight being 20/20, i probably should have asked the guy who trimmed it for me to put a higher polish on it than i asked for. phooey on me.

initially i planned to fire polish for the benefit of the outside edge. i read a little bit about fire polishing, and now i wonder if the slumping cycle would be sufficient to give the edge enough shine?

i could take it back to the tile man and ask him to polish it higher, or if you think the slumping would be enough, i could just do that. i am not looking for a typically rounded edge.

it would be nice to not ruin this project.

also -- final thought -- it seems like a slower dph schedule would be wise, eh?

thanks for your help and expertise. kitty.

this is what a wet belt sander is for. if he's willing to do this for you, take him up on it.

a fire polish is in the 1300F range or so will start to slump the edges of a 5/16" blank and they won't be vertical anymore. a slump temp won't do much for polishing.

yes, you want to go really slow on the way up, and REALLY slow on the way down. if the temp of the outside and inside of the glass aren't close, it'll go ping.

any alteration of the shape of the outside edge is OK with me. i'll have him polish it higher, charlie. and thanks for the remarks about the firing schedule. i'll post a proposed one later today, and see what you think. i'm not at all experienced with these kinds of decisions, so i thank you for your help.

i live in a condo, so i can't use certain kinds of messy or noisy tools. however, the beginning of 2004 will see me back in a house, with real studio space and also a couple of areas with electricity to do things that i can't possibly do indoors. really looking forward to it.

one of the neat things about the guys at the tile and stone yard is being able to look at some of their tools, and see what they do. because i don't know any other fusers around here, much less people who know the secrets of finishing, it's hard to imagine the tools and their uses without seeing them. more reasons why this WG board is so great. kitty.

visit places that do stone countertops and headstones. they have the same requirements for polishing that we do. i saw some amazing stuff done in granite when i was on vacation in st martin last month.

yes, charlie, that's what i mean. the guys at the tile and stone yard cut and finish marble and granite tub and sink surrounds, counters, tables, etc. they have many of the tools and techniques that i've read about here and elsewhere. luckily for me, they are interested in what i'm up to, so we've been having 4:30 pm get-togethers which are "show and tell" and a few beers. i bring the brews -- it's the price of admission to the stone yard. i feel very lucky to have stumbled onto these guys ... they're proving to be excellent teachers for me, and new friends as well.

Kitty wrote:i've got a 16" disk, 5/16" thick, made from 3mm BE white base sheet, then frit and glass elements on top. it has been fully fused. i made this in one of matt hoppes's stainless steel rings, and the outside edge was in need of just a little cleaning up. i had this done at a tile shop. the disk was trimmed and the now-vertical edge polished up, but not to a high shine. it's very smooth to the touch. hindsight being 20/20, i probably should have asked the guy who trimmed it for me to put a higher polish on it than i asked for. phooey on me.

initially i planned to fire polish for the benefit of the outside edge. i read a little bit about fire polishing, and now i wonder if the slumping cycle would be sufficient to give the edge enough shine?

i could take it back to the tile man and ask him to polish it higher, or if you think the slumping would be enough, i could just do that. i am not looking for a typically rounded edge.

it would be nice to not ruin this project.

also -- final thought -- it seems like a slower dph schedule would be wise, eh?

thanks for your help and expertise. kitty.

Hi Kitty,

Almost all of my current work is 3/8" with a vertical edge that I want to maintain. I can give you my observations, but you'll have to take into account that all kilns will fire differently.

If you have the edge brought up to a much finer polish, then slumping will give you a fairly good shine, but depending on the temp of your slump, this will vary quite a bit. People slump anywhere between 1150 and 1300, so obviously this will make quite a difference.

If I have ground or blasted a piece and want to keep a matte finish, not return to a shine, a low temp around 1175 - 1200 will do it. If I were slumping (lately I don't) I would probably do it at about this temp, especially because most of my work is large so it requires a lower temp/less time to slump. So if matte is what you're after, you can easily slump and firepolish together.

It seems to me that you would like to return the edges to a shine. Also, you mentioned you used white. This is going to be tougher to do if you want to maintain your vertical edge, and you are far better off to have it polished as high as they can for you. Especially given that white glass will take longer (or higher temp) to polish than black, for instance.

I am working on a piece that has 9 panels each finished differently - some blasted, some polished by hand, some ground, some carved and one that is sandblasted, surface ground, then firepolished to a high gloss. All are trimmed in black. One of the matte pieces was surface ground up to a 600 grit then firepolished at 1175 and held for 10 minutes. It's smooth and most importantly - matte.

The one with the high gloss was firepolished first up to 1350 with a 10 minute hold. Looking in, I observed that the black edge and design elements in black had glossed up at this point, but not the rest, so I shot up to 1375 quickly, and right back down. This gave me a nice wet looking gloss, and amazingly didn't ruin my edges - here's why:

I agree if you are firing under almost all circumstances, slow and low is the way to go. But, in a circumstance like this where you want to keep your edge work in tact, go slow up to 1000, maybe 200 or 250 degrees per hour, but then shoot up as fast as you can to your top firepolish temp and just as fast back down to annealing. This should give you the shine you want without distorting your edge.

Also, I baffeled the piece with cut up kiln shelves to protect the edges from direct heat from the elements - probably only important if you have side and top (or only side) elements.

I just went through using several different schedules to acheive different degrees of firepolishing and also, like you, needed to keep the edgework in tact, so if you have any other questions or want to see photos of the different effects, just let me know.

Good luck -
Jackie

jackie -- many thanks. i will go back to the stone yard this afternoon and ask my new best friend there to bring the outside edge up to a higher shine.

the top surface is shiny, and will remain shiny. the white bottom, however, will ultimately have a satin finish.

after i get the piece back from The Polishing Man, i'll post a proposed firing schedule. the kiln is a Paragon GL22, top elements only, so no baffles necessary.

once again, many thanks for the great tips. i'm so glad i posted this inquiry.

okay, i am back from the stone yard, and had the rim of the plate polished some more. as for the slumping schedule, i admit i don't know how to interpret the word SLOW. i dont know if that means 50dph, 100 dph, or what. it will be slumped into a shallow curve.

the plate is quite heavy, more than 1/4" thick, probably 5/16, and 16" in diameter.

200dph to 1250? i think it might be slumped by this temp.

same coming back to 960? 50 dph to RT?

some posts in the past referred to schedules as slow as 50dph. that's where i got this idea.

thank U for your help, as always.

Kitty wrote:okay, i am back from the stone yard, and had the rim of the plate polished some more. as for the slumping schedule, i admit i don't know how to interpret the word SLOW. i dont know if that means 50dph, 100 dph, or what. it will be slumped into a shallow curve.

the plate is quite heavy, more than 1/4" thick, probably 5/16, and 16" in diameter.

200dph to 1250? i think it might be slumped by this temp.

same coming back to 960? 50 dph to RT?

some posts in the past referred to schedules as slow as 50dph. that's where i got this idea.

thank U for your help, as always.

Yo Kitty

Heres some technology applicable 2 U

Baffle n Go

Fiber dizer n Wash

Zap n Blastem

On fire polishing my view is 2 use baffles ( on a side fire kiln )

Finishing just above the glass above the glass

Fire at max temp above aneal temps

U R metting the surface of the glass but not the body so fire polishing

Then fast cool 2 above aneal

All this technology is in the archives

As 4 the surface prior 2 kiln

I prefer a slight grit finish so I go 4 a 280 sanblast

Although the edges get about 400 or 600

Spoil those nice stone yard people U have a real good contact there

Kitty wrote:okay, i am back from the stone yard, and had the rim of the plate polished some more. as for the slumping schedule, i admit i don't know how to interpret the word SLOW. i dont know if that means 50dph, 100 dph, or what. it will be slumped into a shallow curve.

the plate is quite heavy, more than 1/4" thick, probably 5/16, and 16" in diameter.

200dph to 1250? i think it might be slumped by this temp.

same coming back to 960? 50 dph to RT?

some posts in the past referred to schedules as slow as 50dph. that's where i got this idea.

thank U for your help, as always.

Hi Kitty-

Now that your edge is more polished, you should get the shined edges you want in your slump. You didn't say what they brought the edges up to - 600? cork? do you have any idea? That would help me a little.

But, I'll go with what I do know so far. Other than your white, I only know that you have frit and . . . hmmm - something else. Don't know if you've mixed tons of colors together or if any of the other design elements have been fired numerous times, but I'll venture a guess that they haven't and go from there. (If I'm wrong, slow this down even a little more.)

Your 200 an hour to 1250 sounds fine. I generally add a soak of about 15 minutes at 1000 to give the temp a chance to even out, but given that you're going fairly slow, you may be fine in skipping it - although it wouldn't hurt.

Since you haven't done this slump with this sort of glass before, I'd recommend watching it so you can stop the slump where you want it. It sounds as though this mold wouldn't allow the glass to roll down on itself because you said it was quite shallow, but it will be good to watch so you know for next time. It may end up being done at 1175 or 1200, but not knowing your kiln, it's hard for me to guess. If it is done early, just skip to the next segment - most controlers have a way to do this.

When slumped, go afap to annealing, I'd soak for 90 minutes myself, but you can check out what BE recommends. (I think they say an hour soak for a half inch thick piece, but I am generally more conservative because my work usually has so many colors.) Then 100 degrees an hour to 600. If your kiln cools slowly just turn it off there and let it cool to room temp on its own.

There are certainly other schedules that would work as well, but this seems like a fairly uncomplicated piece. If you had a huge mixture of colors, high-fire elements thrown in, or used glass that had been fired multiple times already, I may change it a little, but if not, you should be good to go. Let us know how it turns out-

Good - luck,
Jackie

aloha jackie
tony at the stone yard used various polishing pads, ending with 8,000, which is as high as he could go. maybe the pads are diamond dust imbedded in the pad's rubbery material, for the finest polishing. i saw them, and the coarse ones were gritty, but the smoothest-polishing ones were flat dots all over the surface of the pad.

the edge is now very smooth to the touch, the clear glass is high shine, and the opals along the edge are somewhat less shiney.

your suggestions on firing fit what i was imagining. i will indeed watch it and see when it has sagged into the mold fully. i never crash-cool the kiln -- Paragon GL22, top elements only -- but in this case, maybe i'll do so to get down a few hundred degrees. i will hold at 960 for 90 minutes.

there are several colors of frit, some cut pieces of neo lavender about the size of a finger, some peas of clear BE, and some rejected dichroic cabochons. all of this is sitting on top of a 3mm piece of BE white. the white was fired previously (it had another life as another bowl, and got re-flattened) but all color was only fired once.

charlie thought i should be pretty conservative on the descent, as do you, so i'll go 100 dph until 200. i think this kiln falls a little faster, and charlie said i might break the piece if it cools too quickly.

thank you for your time, Jackie! i took pictures to post, but am too technologically challenged to post them, and the cyber gods hate me. i keep getting an FTP error window warning me about posting adult content or being an abusive Bulk Emailer. what the hell. better to just stick to the glass, i guess.

i shall report back results of slump tomorrow.

my annealing schedule for 3/8 is

9999 970 90

50 850 0

100 700 0

200 500 0

off

thank you, Charlie.
i will use that.
really appreciate your helping me out with this one.
aloha,
kitty