Fuseworks so called dichroic glass not quite compatible?

[noora]

I bought some Fuseworks "dichroic" glass to try it out since I can get it quite cheap. The first problem I noticed was that after fusing (tack fuse) the "dichroic" layer on some of the dichroic glasses came off. It was like dusty powder and came right off where it wasn't covered by glass Only some of the colours did this, for example the black glass with blue/green dichro and the clear glass with pink dichro. Has anyone else experienced this or did I get a bad batch?

My main question is however about compatibility. One of the tack fused pieces came apart and cracked. I used purple bullseye for the bottom layer and clear fuseworks with pink dichro as top layer, dichro side down. I don't know exactly what happened when it broke. I sold the piece at a fair and a few minutes later the customer came back. The piece had cracked in her bag, she noticed it was broken when she took it out to show it to a friend. The layers had separated, so it was clear she hadn't just dropped it on the ground. It was as if it never stuck properly. I quickly checked other pieces I knew were fused in the same batch and they were properly fused, so it couldn't be a temperature/time issue. The pink dichro layer was one of those that turns all dusty, so I suspect it prevented the fusing. However, I also suspect there was stress involved since the piece had cracked too. I anneal very carefully and nothing else has ever broken like that, so I wonder if there could be some compatibility issue.

Can I test/verify the compatibility in any way? If the compatibility is okay I may be able to figure out ways to work around the issues with the dusty dichro, but if it isn't compatible I'm tempted to just bin the glass.

At least I know now that I shouldn't waste more of my money on fuseworks dichro glass.

[Zeldazog]

I had to look up Fuseworks as I wasn't familiar with the name.  It says this on [ur=http://www.microwave-kiln.com/servlet/the-27/Fuseworks,-microwave-kiln,-Microkiln,/Detaill]this website[/url]

"Note: While Fuseworks glass is a 90 COE glass, it is NOT compatible with other 90 COE glasses due to differences in melting point (full fuse at 1350 F) and viscosity (thickness)."

Which I guess explains the compatibility problems.  I am fairly sure that Bullseye actually state that COE is not a guarantee of compatibility, its only a guide - I know it explains it in quite some detail, if I can find it I will post back.   Sorry this doesn't help how to fix it.

[Redhotsal]

You can basically "see" if there are compatibility issues by observing the stress in a fused piece. Under polarised filters (see other threads on here for details) if there is incompatibility you will see lots of black shadows in the glass. Stress as observed in polarised light can show up in both unannealed glass and also in incompatibility issues.

If you have any 3D glasses left over from a recent cinema trip you can use them (in addition to your flat screen PC monitor) to observe this stress as they are basically polarising filters. Hold them against the PC screen with the arms facing towards the monitor (you can take these off beforehand), sandwich the glass between the glasses and the screen and rotate until you see the stress lines.

[squirsygirl]

You can basically "see" if there are compatibility issues by observing the stress in a fused piece. Under polarised filters (see other threads on here for details) if there is incompatibility you will see lots of black shadows in the glass. Stress as observed in polarised light can show up in both unannealed glass and also in incompatibility issues.

If you have any 3D glasses left over from a recent cinema trip you can use them (in addition to your flat screen PC monitor) to observe this stress as they are basically polarising filters. Hold them against the PC screen with the arms facing towards the monitor (you can take these off beforehand), sandwich the glass between the glasses and the screen and rotate until you see the stress lines.

That's really interesting Sal - will this work for all glass? 

Kirsty

[Redhotsal]

Won't work for opaque glass as you can't see through it, but will work for all see-through glass, whether it is soda, boro or whisky shot glass.

[noora]

Thank you for the replies

I hadn't realized that my flat PC screen is polarized, but checking with my polarized sunglasses I can see you're right. I'll have to fuse some of the clear fuseworks with clear bullseye and try it.

Different melting points shouldn't cause stress though, should it? I mean, we combine COE 104 glasses with slightly different melting points all the time in lampwork and as long as the bead is annealed properly it doesn't cause problems. I guess different melting points and viscosity can however give less predictable results when fusing and you may have to adjust the schedules a bit.

Fuseworks is a beginner's line of glass fusing products. They also sell a microwave kiln for fusing. It's the same people who make the Fireworks lampwork starter kits.

[Redhotsal]

Well, really you have to look at glass as having a range of COEs really - it's not quite accurate to say that Effetre is completely 104, for example - It's not also correct to say that glass has a melting point per se - like chocolate it appears to have a huge range over which it will melt.

So, there are undoubtably differences in compatibilities  for all manner of reasons - for example - I 've never been able to encase some Effetre pinks (the paler ones) with clear - even though they are all meant to be the same COE.
It's also apparent to me that some colours just don't mix well, so it's not a precise science.

I've also found that while I love to use Lauscha clear for encasing it just doesn't anneal at 520C like Effetre does - it needs more heat - so there can be a huge number of reasons why "stress" can appear. Stress will show up if glass is unannealed but will also show up if there are incompatibilities in the glass too. You'll see little shadowy puckers at the junction between two colours of glass. But you can also see stress where you have inclusions, such as silver wire and so on. The real question is how much stress do you need before it affects the structural integrity of the glass?

[Zeldazog]

As Sal says, glass doesn't have a set melting point.  That's what makes glass such a wonderful and flexible medium to work in - it does different things at different temperatures. 

Different melting points WILL make a difference, even with the same coefficient of expansion - because if a glass "melts" sooner (or becomes soft and viscous) than another it is attached to, the first glass will move before the second one... causing stress.

Not being a lampie I am not sure, but I presume that the reason you CAN combine different glass in lamp-working with more success is that you're taking everything to much higher temperatures - it's ALL becoming viscous.  In addition, you normally melt one glass on, add another whilst that is still very hot and still has movement....  I guess its why annealing for beads seems much longer than for fusing (when you consider a normal size bead vs a normal size fused glass pendant)

At the risk of sounding like I work for Bullseye, this is one of the reasons their glass is successful for fusing.  It's not necessarily actually all the same COE, but it HAS been testing for fusing compatibility. 

I do wonder what's different about the Fuseworks glass though that they stress so much that its not compatible with other COE 90 glasses, as there is similar text on the instructions that come with the Microwave kiln as well as on that website I linked to.

[noora]

Maybe Fuseworks have to be extra careful about what they tell their customers since a lot of people who use Fuseworks glass run it in the microwave kiln. From what I understand you don't get as much control over the temperatures and ramps when you fuse in the microwave kiln, which would increase the risk.

Or maybe they just say so because they don't want people to buy other glass than theirs 

I'll see if I can do some tests this weekend, like tack fuse bits of the different Fusework glasses I have onto clear Bullseye. Then I should be able to see if there's stress in the clear, right?

Thanks again for the tip about using your PC screen. I tried it yesterday with my polarised sunglasses and a selection of my beads. They looked all good to me, which is a relief. I've always been a bit worried that I might be doing something wrong (not for any particular reason, just basic paranoia)

[Zeldazog]

I've never used one of those microwave kilns but I do have doubts about their ability to anneal glass properly when the whole thing is supposed to be quite quick (the technical side of using a microwave to ramp up, fair enough, to get the top temp, okay but to cool down properly, inside an igloo made of some strange material - hmmm, I'll reserve judgement)

So you're probably right Noora, if, for their own kilns, they recommend only using Fuseworks glass, then I suppose they can be more confident of compatibility, and therefore annealing.

I'd be interested to know the results of a firing in a microwave kiln, using only their glass and tested for stress....

Await the results of your tests!   

(or maybe you're right, they're just trying to stop you shopping elsewhere...)

[Redhotsal]

My friend has a microwave kiln and we managed very easily to fuse a couple of small pieces in very little time. However, I cannot see how a microwave kiln can possibly anneal the glass as the cooling time is just too quick. At least - with the "kiln" (really, it's a canister of "strange material"  ) - that we were using there seemed to be no way that you could anneal.

Anyway-  I put the pieces into my normal bead kiln and annealed them that way. I was quite taken with the microwave kiln - although I've heard that for some reason they kill microwave ovens. Never found out if this is true or urban myth.

[Zeldazog]

However, I cannot see how a microwave kiln can possibly anneal the glass as the cooling time is just too quick.

My thoughts exactly Sal, I knew it was a quick firing schedule, half an hour or something silly?

[Redhotsal]

I think it was actually quicker than that - I reckon it takes longer to scramble eggs in the microwave than to fuse some glass! Still, from a child's point of view, as Emily was with us when we were experimenting, it was fascinating to watch something which normally takes several hours in a matter of minutes!

[noora]

Now I've tack fused small pieces of the different fuseworks glasses onto larger pieces of bullseye clear. I can't see any stress in them with my polarised glasses and PC screen (I've looked at ends of used glass rods and at cheap non-annealed lampwork beads for reference and could see stress marks, so I think I know what I'm supposed to look for).

There was however one difference in how I fused the pieces today compared to when I fused the pendant that broke. The temperatures and ramps were the same, but I used a new kiln shelf that I got today. It's some sort of tile rather than the light fiber shelf I got with the kiln. I seems to affect the heating and cooling, so it may have affected the results as well.

[Zeldazog]

Refactory kiln shelves hold heat a lot better than fibre does, in the same way that a fire brick kiln holds heat better than one lined with ceramic fibre.

So, cooling down will be slower, a normal firebrick kiln, if left to cool naturally will still take hours and hours... a fibre kiln will only do a slow ramp down if you tell it.  That's why quite often, even though a ceramics kiln programmer will only perhaps have two ramps and a top soak, and no control over cool down through the annealing zone, they still cool down so slowly that they anneal stuff anyway.  Of course, they have nice thick walls.

Likewise, the thicker the refactory shelf, the more it will hold the heat. 

Interesting that no stresses though, so in theory ARE compatible - but I would say probably only compatible when done with a proper firing - and explaining why they specify using their own glass only in a microwave kiln, due to them not going through a "standard" anneal