FIRE POLISHING

[Havi]

dear friends,

I hope you are all well and safe, enjoying the extra time because of social distancing!
I would like to know if it is possible to eliminate scratches on a spectrum 96 piece, thru fire polishing.

And if so, at what temprature.

many thanks in advance,

BE SAFE
Havi

[Michael Stevens]

Depends on how deep. but yes firepolish helps. is the piece flat?

[Havi]

Thanks for responding!
I guess it is a sculpture, I am asking this question fr a colleague, perhaps he could send me a photo

I asked my friend, who says that this is kind of a glass block, appx. the size of a fist... I hope this helps,

I would really love to help this colleague/friend, he always helps me when I need him --- [and he can't speak English]

thanks
Havi

[Brad Walker]

Havi, if it's a flat piece it can easily be fire polished, assuming the scratches aren't that deep. Just fire to 1400F/760C and hold about 10 minutes, then anneal as usual. If the scratch is deeper, you need to go high, to as much as 1460F/790C or so.

If it's not a flat piece, it's a lot harder because once you get that high the shape will distort. We've had some luck with Bullseye firing to 1350 and holding 5 minutes to shine up work, but I'm not sure that's hot enough to get out scratches.

And remember, anything more than two layers thick will either have to be dammed or risk some distortion and spreading.

[Havi]

Thanks, Brad
Then I think it's a lost case for my friend. It is a 3D piece. He told me that he did some coldworking on the piece, but got scratches, of which he wanted to get rid - thru firepolishing.
I assume he would not like to distort what he made.
Will ask him again

Keep safe!

Havi

[DonMcClennen]

If the piece is the size of a fist then the firing schedule would have to be quite long and controlled to avoid breakage/thermal shock. Such a schedule would cause much all over surface distortion and loss of detail.. It sounds like the best solution is more coldwork polishing.

[Havi]

Thanks, dear Don,
I feel as if I know you, for so many years....
Tomorrow morning I shall let my friend know all the resonses. [midnight here]
I must point out that he is IMHO , a very good conceptual artist. Sometimes I can not follow his ideas... But he explains them to me.

So, will let him know,
Happy I was able to help him, after all the help he helped me...

And thank YOU , for enabling this,
Be safe,

Havi

[Barry Kaiser]

This is just an academic question as I don't do any pieces larger than 2x2.
But: why could you not heat the piece to about 900 to 1000 (F) and stabilize there. Then, raise the temp AFAP to tack fuse temp, hold for a short time, then crash to 900.
The curing of the scratch problem is a surface problem. Can you treat it by only heating the surface quickly, then cool and anneal.

[Brad Walker]

Really hard to do that, Barry. We've had pretty good luck reheating cast life-size turtles to shine them, using a firing schedule not unlike your suggestion (only to around 1350), but the problem is having to remove scratches. That takes a higher temperature or a much longer hold and is much more likely to distort the piece. The problem is that thicker pieces hold so much heat that no matter how quickly you cool they still distort. I'd be reluctant to try fire polishing to remove scratches with a thick cast piece I cared for.

[Havi]

Thanks guys,
I already told my colleague, that the "cannons"
i.e. more experiences and knwlodgeable glassies, doubt the possibility of fire polishing his piece.

I shall repeat this after Saturday to him.

We are very grateful for that.
Warm Glass remains the best place for good professional advices. So grateful for that.

Havi

[Michael Stevens]

if scratches were from sanding down. I think he could cold work it more, wet sand up to 600 grit. then low temp fire polish would work. but keep an eye on it. if starts to mishape the stop it.

I've made coasters out of sculptures from over heating

[jim simmons]

Myself, I would go to an 800 grit before fire polish.
If you have the means, then go all of the way through cerium oxide.
This will give you a surface that is equal to float glass.
The other Jim