How to have a smooth back after fusing?

Bea · Post by **Bea** » Sun Aug 10, 2003 10:32 am

I am fusing small pieces of glass on fibre paper in my kiln.

After fusing there are traces of the fibre paper on the back which I wash off and sand off but I can't seem to finish this bit off without the effect of an orange rind looking surface........... any clues?

thanks
Bea

Brock · Post by **Brock** » Sun Aug 10, 2003 10:50 am

If you go to full fuse temperatures, the back of your pieces will conform exactly to the substrate upon which they are placed. A properly prepared kiln shelf is still the smoothest surface available, although I haven't used or seen the newest Thin Fire paper.

Apply several coats of kiln wash, (it varies, but you should see NO tinge of colour from your shelf, through the kiln wash) in alternating directions per application. Then, apply a couple of coats of hot water also in alternating directions. Pre-fire. If it still isn't smooth enough, lightly brush the fired shelf with stockings, a flat piece of paper, anything to smooth it.

If you are firing solid opalescent glass, with it's propensity to pick up kiln wash and fibre paper, a paper may still be your best bet, although, you may be able to achieve the look you want in a soak at a lower temperature.

Lorelei · Post by **Lorelei** » Sun Aug 10, 2003 11:39 am

Thanks for that tidbit on using warm water, I'd never seen that before.

How would you compare your method to using a sprayer?

I've recently had some horrible failures with a kiln wash I bought down in Gardena. Up until then, I'd always used HotFire and found it to be great. This new stuff just "cracks" apart under my work. I've tried making it thinner, applying it with a brush, with a spray... thicker..thinner.. nothing works. It's just crap.

Brock · Post by **Brock** » Sun Aug 10, 2003 11:47 am

Dang, there goes another secret technique. I've tried various sprayers, and they seem to leave a "balled" or "pilled" effect. Kiln washes are made by many manufacturers, you can make your own if you wish, but Bullseye kiln wash is by far the best I've ever used. It seems to be a finer powder, and that smaller particle size means a smoother finish. Brock

Tom White · Post by **Tom White** » Sun Aug 10, 2003 1:07 pm

I like the back side of my jewelry items to be smooth and shiny so I borrowed Bert Weiss' recipe for kilnwash and purchased alumina hydrate and kaolin clay from a local ceramic supply house, mixed it 80% alumina/ 20% kaolin, by weight, made a thin mix in water and appled several coats to the kiln shelf with a wide brush. The release was good, the surface was shiny, but the texture was too rough to suit me. I determined that the texture was coming from the alumina hydrate. It felt grity between my finger and thumb while the kaolin felt silky smooth. Lacking a ball mill to grind the alumina hydrate finer, I put some of it into a Vibrasonic vibratory tumbler with porcelain cylinder media about 1/8" dia. X 3/8" long with diagonal cut ends (/===/). I had to run this dry because it froze up and quit rolling every time I added water to the mix so I covered the top of the tumbler hopper with multiple strips of clear 2" packing tape to contain the alumina hydrate dust I wanted. I ran this overnight and when I sifted the alumina hydrate from the porcelain media in the morning it too was silky smooth between my finger and thumb. I modified Bert's recipe to 90 grams fine alumina hydrate and 10 grams kaolin in a pint jar with water to fill the jar. I added a small amount of gum to give better green (unfired) strength to the mixture. Using system 96 cathredals and float glass in different firings I get very smooth, very shiny backs to my jewelry size items. I fuse by observation and flash the kiln very briefly when the two layers form a smooth rounded edge that I want then aneal for the glass used. I have not used this release for a large (10" to 12") fuse yet so I cannot say how it works for large items. I'll get brave and try it some day when I have time and glass to spare.

In the other hand, I like the "Free" powder from Unique Glass Colors http://uniqueglasscolors.com/ over regular ceramic kilnwash when I flatten wine or Coke bottles. The wine bottles are fired to 1550 F for a smooth top while the Coke bottles go to 1475 F to retain the texture and wording on the bottles. The Free powder produces a shiny finish on the bottom of both types of bottles with just a slight texture. The nicest thing about it is I have fired more bottles than I can count on these shelves without scraping and recoating! I rub the Free powder that adheres lightly to the bottom of the bottle back onto the shelf, smooth it out with my palm amd load the next set of bottles on the same shelf. If the powder coat looks a little thin I shake on some more but this is only every fifth firing or more.

I took a chance and used some 19 ga. stainless steel safety wire from the hardware store for hangers in my bottles. I cut it 2 1/2" long then bend it into a u shaped staple and insert it into the bottle leaving 1/2" hanging out. I have fired several bottles using this wire and can detect no more stress between crossed polarizing sheets with the SS wire than the nichrome wire I have been using. The stainless wire costs less plus it is available at the local (large) hardware store instead of ordering the nichrome through the mail and waiting for it to arrive. Be sure to test this in your application before switching to stainless.

Best wishes,
Tom in Texas

Bea · Post by **Bea** » Tue Aug 12, 2003 6:07 am

My kiln shelf is fibre board and I have been told NOT to use kiln wash..... and I have not tried the thinfire paper as that is not easy for me to obtain so I will have to use fibre paper.......

Would lowering the temperature or reducing the fuse time help? I have been fusing at 1470F for 3-4 minutes.......

Bea