Frit-Happens !

Technical Forum => Search Tips and Techniques => Topic started by: Lorac on April 02, 2015, 11:17:47 AM



Title: frit and powder painting
Post by: Lorac on April 02, 2015, 11:17:47 AM
Am loving using powders and frit to create paintings but am experiencing some problems with bubbles. I tack fired black silhouette of bird on 3mm AND powder background on 3mm Bullseye. When I turned the silhouette over [to have smooth top surface] and fired to 780 degrees celcius to fuse the two layers together bubbles formed around the silhouette and spoilt the appearance. Will try to upload before and after pictures [follow link below to photobucket] and hope someone can suggest possible solutions!  I am also wondering how many times you can tack fuse [760 celcius] to build up the layers of powder and then frit without noticable devit? any ideas anyone??
Many thanks
Lorac
http://s1368.photobucket.com/user/lorac12/library/frit%20happens?sort=3&page=1


Title: Re: frit and powder painting
Post by: fionaess on April 02, 2015, 12:53:06 PM
Sorry to say that I have no answers for you.. but I have say what a beautiful piece.. lets hope you get the problem sorted because I want to see more.. ;D


Title: Re: frit and powder painting
Post by: Moira HFG on April 02, 2015, 01:45:40 PM
That's a lovely picture.
Two thoughts: firstly, make sure the thing is completely dry before firing. Secondly, try a slower rise up to your final temp to allow bubbles to escape.

And thirdly (sorry, an afterthought!) I would say that in my opinion a few bubbles don't spoil a handmade glass piece, just makes it look 'glassy'.

Don't know about devit, I don't think I've ever fired the same piece more than twice.


Title: Re: frit and powder painting
Post by: Pat from Canvey on April 02, 2015, 02:05:20 PM
You can purchase devitrification spray. Creative Glass Rochester call it Overglaze, see http://www.creativeglassshop.co.uk/product/31205/overglaze-250ml.html  In the past, I've put tiny pieces of glass in the corners between layers to be fused so that the centre falls slightly quicker than the outer margins. That allows air to be pushes out from between the layers.


Title: Re: frit and powder painting
Post by: flame n fuse on April 02, 2015, 03:32:05 PM
running transparent stringer out from troublesome areas (between the 2 layers of glass) sometimes helps dispel bubbles. devit depends a lot on the colours and type of glass. With Bullseye, I find the opaques (esp royal blue) are worst.


Title: Re: frit and powder painting
Post by: Nicknack on April 02, 2015, 04:04:59 PM
I find the stringer in the corners trick works well, too.  Lovely piece, don't think the bubbles detract!

Nick


Title: Re: frit and powder painting
Post by: MeadMoon on April 02, 2015, 04:43:50 PM
Brad Walker has a recipe for devit spray in "Contemporary Fused Glass":

"Mix 1 part Borax with 8 parts water.  Heat the water until the two mix together well; you should not have to bring the mixture to a boil.  Add a few drops of detergent (any dishwashing liquid) to the mixture; this will help keep the mixture from beading up when applying to glass.
To use the solution, clean the glass then spray or brush the liquid on the top surface of glass before firing.  Don't coat the kiln shelf or the bottom surface of the glass.  Allow the spray to dry before firing. Slumping temperatures may not be hot enough to mature this spray, so use it for fuse firings only."

Note that I haven't tried this yet since I haven't had severe devit problems except with bottle glass.


Title: Re: frit and powder painting
Post by: flame n fuse on April 02, 2015, 05:04:15 PM
note that borax isn't a very nice chemical and the MSDS says that it can harm the unborn child, so I'd avoid inhalation and skin contact. Also, I'm not sure whether it would fume off during firing.


Title: Re: frit and powder painting
Post by: Zeldazog on April 03, 2015, 12:28:06 AM
Any idea if "Borax Substitute" would work?

I've never been able to get Borax where I've looked, although it's something often mentioned, especially in traditional cleaning books (I've got a couple of the ilk "Grandmas Household Tips", which usually seem to be US based)

I saw this in Boyes a few weeks ago, so I picked up a box, seeing as it's supposed to be such a useful thing (along with my white vinegar, soda crystals, etc)

http://www.dri-pak.co.uk/borax-for-laundry.html#.VR3L3eFQBhU


Title: Re: frit and powder painting
Post by: Pat from Canvey on April 03, 2015, 07:39:19 AM
Cooksons do borax, http://www.cooksongold.com/Jewellery-Tools/Borax-Powder-1kg-Un-3288-Tnt-prcode-998-116 I've just added borax to hot water to get a saturated liquid and brushed it onto the surface of the glass with a haik brush. It's particularly good with bottle glass. It can also be sprayed on.


Title: Re: frit and powder painting
Post by: Zeldazog on April 03, 2015, 09:57:29 AM
Cooksons do borax

Must admit I've never checked specialist places, I guess I kind of expected it see it in shops as its recommended for a lot of things, but I guess it's not so readily available


Title: Re: frit and powder painting
Post by: Moira HFG on April 03, 2015, 10:43:12 AM
I'm surprised to hear borax is now 'specialist'. It used to be available from every chemist and hardware shop. We used to boil it up with water in a bucket in the Dramatic society, to fireproof the canvas and other textiles used on stage. And people used it for laundry. I've never heard of it being particularly hazardous. Gosh, I'm getting old!

 'Borax substitute' is apparently sodium sesquicarbinate - a double salt of sodium carbonate and sodium bicarbonate - so good for laundry but I doubt it would help with devit!


Title: Re: frit and powder painting
Post by: flame n fuse on April 03, 2015, 10:54:52 AM
Last time I tried to buy borax (to treat algae on garden seat), Boots had stopped selling it, but a local chemist still had it. I used gloves and painted it on. If I were to spray, I'd wear a mask and do it outside.
In the lab, we use it to fix chromosomes in plants, so maybe that function indicates the current health concerns with it.


Title: Re: frit and powder painting
Post by: Pat from Canvey on April 03, 2015, 03:57:33 PM
Gosh, I'm getting old!
My hair is whiter than yours, Moira.


Title: Re: frit and powder painting
Post by: Moira HFG on April 03, 2015, 06:24:53 PM
Only just, Pat!  :D


Title: Re: frit and powder painting
Post by: anditsinthefish on April 03, 2015, 08:49:19 PM
Cooksons do borax, http://www.cooksongold.com/Jewellery-Tools/Borax-Powder-1kg-Un-3288-Tnt-prcode-998-116 I've just added borax to hot water to get a saturated liquid and brushed it onto the surface of the glass with a haik brush. It's particularly good with bottle glass. It can also be sprayed on.

Pat you are a wealth of knowledge. This is a wonderful tip! Thank you.