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jrgpots

Member Since 15 Mar 2013
Offline Last Active Today, 12:42 PM
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Posts I've Made

In Topic: Which Do You Prefer For Joining Process?

Today, 12:42 PM

If you have problems with joins then magic water alone or slip made with magic water or magic water slip made with paper pulp is worth a try. 
 
You are adding sodium (from the sodium silicate plus the soda ash) which is a strong flux which helps fuse the joins together. Also, the silica in the sodium silicate adds a titch more glass former to the join. Sodium silicate is also really sticky stuff which helps the joint bond plus slip made with it dries really hard. It also acts as a defloc and is water soluble so is able to work into the surrounding clay a bit. So in theory the bond is stronger while drying right through to the finished join having more melt and fusing better when fired.


Do you make your own magic water or buy it? If you make your own what recipe do you use?

Since each clay body has a different % shrinkage, do you make up paper clay slip for each clay body?.....how manyclay bodies does everyone use in their studios? I would undoubtedly get my paper clay slips mixed up if I had many clay bodies.

Jed

In Topic: Disasterous Firing, Work Looks Salt Fired

18 September 2014 - 10:10 AM

HOORAY!!!!!
 
i resprayed several of the pieces with a different glaze and THEY CAME OUT FINE! :D
 
this is where i REALLY wish i could post pictures.


Great save

In Topic: Stacking Help For Reduction Gas Firing

17 September 2014 - 07:36 PM

Like Marcia mentioned, if you're using normal size shelves for an electric that size, they're probably too big. If you've only got an inch or so around the shelves, they are probably trapping the air and heat at the bottom. Go to a smaller size or cut those down. Typical sprung arch gas kilns with 2 burners have fireboxes that are about 6" wide, then the bag wall, then a couple more inches before the shelf edge. That's a total of about 20" of open space in a kiln that usually has 24" wide shelves. Lots of breathing room. If I remember correctly my old gas kiln had 22 cubic feet of stacking space, and a total interior volume of 40+ cubic feet. So for your kiln to really fire properly, you're going to have a much smaller stacking area than you may have thought.

I will cut the shelves down to 12" allowing about 2" on the sides. If the shelves are smaller than that, I won't have much stacking room left....sigh...

 

The next firing will be Sat.  Hopefully the airflow will be better with the changes..

 

Thanks guys

 

jed


In Topic: Stacking Help For Reduction Gas Firing

17 September 2014 - 01:22 PM

Are the target bricks slanted at 45 degrees to bounce the flame up? I have built double cross drafts before and they fired well.They were much bigger 40 and 60 cubic feet. I don't question the concept.
You need space for the flame to travel and you need to bounce it up. Are you using smaller shelves than you would if this were electric?

Marcia

Yes, I have slanted target bricks to redirect the flame upward when the flame reaches the distal wall.  I have 5" flame trough below the first shelf.  The flame travels about 16 " laterally before being deflected upward,  I also have  2 smaller target bricks at about 7" to deflect some of the flames upward along the lateral walls.  I think I will make a better bagwall along the back of the kiln to help direct the flames to the top of the kiln.  I'm thinking of placing  1/2" x 1/2' holes in the bagwall about every 4 " apart so some of the flames can get into each of the shelves.  Again, I am flying by the seat of my pants here.....  I'm still mourning the loss of not getting the Alpine 24 cubicfoot kiln recently.

 

Jed


In Topic: Stacking Help For Reduction Gas Firing

15 September 2014 - 10:29 PM

Marcia, the kiln is a bit backwards. The burners are horizontal on either side of the exit flue. The flames hit the back of the kiln where they are deflected upwards. I stacked 2" posts with 1/4 airspace between posts acting as a bag wall for the first shelf.

The flame was forceful and not licking. I neeed to turn down the air I guess and let the kiln heat up more slowly.

The drawing is the same orientation as the kiln. I am sure it will cause lots of questions.

Jed