I have a piece that I'm working on
13 inch round ,Spectrum Clear with blue design elements..
I'm not real thrilled with the top and I want to put a clear cap on it. (The design is full fused flat)
which is better to do...use a solid round disc or cover with clear frit?
If useing frit, what size should I use...powder...large?
I'm on a time crunch for an upcoming wedding so i don't want to have to start over.
Any help or suggestions will be GREATLY appreciated.
Thanks in advance
Diane
If you use frit you should use the largest size, because it will be the clearest. The smaller the frit the more air bubbles you will trap and it will look cloudy.
I personally would use the sheet with Brock's chads because that's what I have experience with. But, I have seen great results with the large frit too. Hopfully someone with experience with both will chime in.
I have not had the success with the chad method that others report. This may just be me, or heightened expectations, or some variable in our firing schedules.
If you use frit, as it melts into the surface the individual pieces of frit will displace the underlying blue glass leaving a visual texture of pockmarks below the surface of the glass. The size of the pockmarks will be a little smaller than the size of the frit. This will be noticeable with large frit. It will be less so with medium frit, more a visual softening of the underlying glass, and there is little effect with fine frit. I have not used powdered clear as a cap layer.
After a full fuse, a careful look in the right light will reveal the faint traces of the outline of the frit pieces. This takes some intent studying to actually see it. The outline pattern will be most clearly a pattern with large frit.
I have not had a bubble problem with a cap layer of frit, but, as Amy has said, the larger the frit, the smaller the chance of bubbles.
I frit cap from edge to edge, so I must constrain the frit with an edge wrap of fiber paper (not Thin Fire) to keep it in place. I then have to cold work the edge to remove the fiber paper marks. If you are only wanting to affect the appearance of the blue glass and it is not at the edge of the piece, you can apply the frit to that area and avoid the edge treatment. I would brush off the random frit which landed on areas where you do not need it.
Now, let's go back to ask why do you want to cap? Is it to get additional depth to the piece or do you have a film on the surface similar to streaks on a window that didn't get completely cleaned? I have have success removing this from Bullseye glass by refiring to full fuse with a coating of Super Spray. I use Super Spray because that is what I have and other overcoating may work as well.
I would suggest you clear cap and use a schedule to reduce the potential to trap air. This is a schedule used for 90 coe glass, adapt according to the glass you are using.
On your ramp up, from 1150 F ramp at 60-100 dph to 1250 F and soak for 10 minutes. This helps the glass squeeze out the air before it begins to laminate. Then I ramp up at about 500 dph to full fuse. This should help get that cap as bubble free as possible. Clear shouldn't devit, but just as an insurance policy I would put an overglaze on that cap since you are hanging out for a long time from 1200 on up.
All the information you got about frit for capping is what I've experienced as well. You could use the chad approach too. It works by placing chads of glass right at the leading edge of your glass (acting as lifts), suspending the clear blank above the base. As the blank sags, the center touches the work first and squeezez out the air as it is laid down. You will get some distortion and ghosting of where the chads were once finished, and if you placed them poorly or they slip, you'll trap a big pocket of air where the chad sat.
None are failsafe, but I would use the slow ramp schedule over frit or chads.
Now you have to decide what to do with all of this input
Thanks everyone for your suggestions. I think I'm going to try to go with the frit method. The design I have already has a crackle effect so the outline of the frit will just blend in.
I'll post a picture when I'm done.
Thanks again
Diane
This is so timely for me, I hope you don't mind if I jump in here...
I just fused a smallish piece - about 9" round. It's three colors on the bottom with clear over the top. I ended up with a few bubbles and I'm wondering if this is salvageable.
The mention of using clear frit made me start wondering if I could crush the bubbles, fill the spots with additional clear frit and then re-fuse. Do you think this would work? Or am I likely to end up worse off than I am now.
If I do try this, should I use the same schedule I did last time?
Thanks!
Joanne
I will tell you that I did drill into the bubbles opened the top so I could put pieces of scrap, very small maybe the size of large frit, and refused. Worked great. Did this one time and haven't had to do it again. It seems the first time I try things they alsways seem to work out but then when I try again all h___ breaks lose.
