Damming a curved line

This is the main board for discussing general techniques, tools, and processes for fusing, slumping, and related kiln-forming activities.

Moderators: Brad Walker, Tony Smith

Post Reply
Havi
Posts: 619
Joined: Wed Jul 02, 2003 6:01 am
Location: Israel
Contact:

Damming a curved line

Post by Havi »

Hello friends,
Happy Holidays, Happy New Year

I want to make a piece , whose contours on one edge are completely curved. I want to do it strip-fusing.
It must be dammed, but I am not sure I know how.
I was thinking of making a dam from 1/2" fiber board. But I know that this thickness of fiber board is insulating, and probably will cause a thermal shock at the edges of the piece. It happened to me once...

Is there another suggestion???

I'd be more than grateful to consider.

Many thanks in advance,


Havi
A1.png
A1.png (69.64 KiB) Viewed 9285 times
Haviva Z
- - - - with a smile :)

"Speed comes from the Devil" - (an Arabic proverb)
Image
http://www.havivaz.com
Brad Walker
Site Admin
Posts: 1489
Joined: Fri Mar 07, 2003 9:33 pm
Location: North Carolina, USA
Contact:

Re: Damming a curved line

Post by Brad Walker »

I would cut it out of Ceramaguard, but I'm not sure that's available in Israel.

Second choice would be to use long strips of 3mm fiber paper, which can be wrapped around the dammed area several times, then secured with lots of small kiln posts and strips of cut up kiln shelf.
Havi
Posts: 619
Joined: Wed Jul 02, 2003 6:01 am
Location: Israel
Contact:

Re: Damming a curved line

Post by Havi »

Thanks, Brad
We get cermaguard in Israel, this was my original idea, but my experience is that cermaguard works as an insulator, therefore may cause a thermal shock.
So was thinking to put between the c.guard and the glass 3 m'm fiber paper. [like what you say above]

Do you think that this would be the better way?

Thanks,
And happy new year to you and family.

H.
Haviva Z
- - - - with a smile :)

"Speed comes from the Devil" - (an Arabic proverb)
Image
http://www.havivaz.com
DonMcClennen
Posts: 381
Joined: Sun Mar 09, 2003 9:09 pm
Location: Ontario

Re: Damming a curved line

Post by DonMcClennen »

If your concern is thermal shock then my approach would be to really slow down your firing ramps below 1000F so the glass has time to heat and cool evenly regardless of the dams.
"The Glassman"
Havi
Posts: 619
Joined: Wed Jul 02, 2003 6:01 am
Location: Israel
Contact:

Re: Damming a curved line

Post by Havi »

Thanks Don,
I never thought about what you say.... Sounds good idea.
Still
Do you think that slow firing will be enough to avoid [or go beyond] the difference in temperature between the edges and the middle of the piece, considering that the cermaguard is insulating the edges..

Brad?

Thanks again
and happy holidays again.

Havi
Haviva Z
- - - - with a smile :)

"Speed comes from the Devil" - (an Arabic proverb)
Image
http://www.havivaz.com
DonMcClennen
Posts: 381
Joined: Sun Mar 09, 2003 9:09 pm
Location: Ontario

Re: Damming a curved line

Post by DonMcClennen »

I fuse up to 12 layers (1 1/2") fully dammed ... I ramp at 200F up to bubble sqeeze... never had thermal shock.
"The Glassman"
DonMcClennen
Posts: 381
Joined: Sun Mar 09, 2003 9:09 pm
Location: Ontario

Re: Damming a curved line

Post by DonMcClennen »

In order to get a nice rounded edge on top layer edge corners your glass, contact with dam must be about 1/16" above dam. This is easily accomplished using 1/8" thick fibre around inside of dam. If your dam is higher than glass you will get needlepoints at top edge corners) If you are just doing 2 or 3 layers you could eliminate the thicker dam and just plot out your shape with the 1/8" fibre pinned to shape (shelf must be fibre or vermiculite to accept pins) Done carefully this should turn out 100%. Good luck
"The Glassman"
Havi
Posts: 619
Joined: Wed Jul 02, 2003 6:01 am
Location: Israel
Contact:

Re: Damming a curved line

Post by Havi »

Thanks again Don,
It's too late here, but I do not want to leave you without Any response. So thanks again.
2. I see that you are Canadian [?] which means that you use the metric system - correct? Then how much is 1/8" - 3 millimeter?
Hopefully i'll have more time tomorrow and be able to understand better what you say.
However, I am going to try first strip fusing, so the piece will be thick to begin with....

good night,
h,
Haviva Z
- - - - with a smile :)

"Speed comes from the Devil" - (an Arabic proverb)
Image
http://www.havivaz.com
Post Reply