Tack fusing schedule

[EliseT]

I'd like to tack fuse a finished frit mold element (bird) to a larger frit molded flower. Does this look like a good schedule to do this?

1. 200 1300 15
2. AFAP 960 90
3. 50 800 0
4. 100 600 off

I'm using BE frit and firing in a large, newer Skutt ceramic kiln. (No top element)

Thanks for any feedback!

[The Hobbyist]

I would eliminate the 15 min hold.

Jim

[EliseT]

Thanks for your reply, Jim!

Just to be sure I understand - you are saying that simply reaching the temp of 1300 is enough to achieve the tack fuse without holding the piece at that temp?

Elise

[The Hobbyist]

The 200 ramp all the way to 1300 should be more than adequate heatwork to get the glass sticky enough to attach the pieces. Too much heatwork runs the risk of losing the shape of the parts and the textures from the frit casting.

I am assuming that you have had success with tack fusing at 1300. All kilns are different and what works for me may not work for you.

There is also the meaning of "tack fuse". Some like a tack fuse to produce a solid looking joint between the parts without losing too much definition. Other, like me, think of tack fuse as a means of sticking two parts together just enough so that they don't come apart when handled.

Jim "The Hobbyist"

[Morganica]

Hold it, folks. Not enough information here to give a schedule that includes the anneal. How thick is the glass?

A tack-fuse schedule (well, any schedule) depends on the thickness of the glass, the number of different thicknesses of glass you have, the types/colors of glass that are being used, and the symmetry of the piece.

So...let's start with the thickness.

[EliseT]

I did go ahead with the firing last weekend, with no hold at the 1300 temp. Luckily, it worked perfectly Good point on the annealing, I guess I have no idea if the 90 min hold was long enough. Is there a good resource for looking up annealing times for thicknesses?

The flower is 6mm thick, the bird 8mm. Both created with a mix of fine & med BE frits. Thanks!

[Morganica]

I did go ahead with the firing last weekend, with no hold at the 1300 temp. Luckily, it worked perfectly Good point on the annealing, I guess I have no idea if the 90 min hold was long enough. Is there a good resource for looking up annealing times for thicknesses?

The flower is 6mm thick, the bird 8mm. Both created with a mix of fine & med BE frits. Thanks!

Yes. The Bullseye website has a full set of annealing tables. http://www.bullseyeglass.com/methods-id ... slabs.html

If the bird is 8mm and the flower is 6mm, and you've tacked one to the other, that's 14mm. You should be annealing for at least 28mm, or about an inch of thickness. That would be 4 hours at 900F, then 27 dph to 800, 49dph to 700, 162dph to room temperature.

So 90 minutes wasn't enough. If it really is that thick and the schedule appears to have worked perfectly, I'd be careful of residual stress and cracking later on. You may want to invest in a book, (or buy the Bullseye video tutorial series, which is an excellent value if you're not near a kilnforming center that teachings stuff like tack-fuses).

[EliseT]

Great info, thanks for the help