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Post by pauls on Jan 18, 2014 21:22:34 GMT -5
Firebricks are made from fireclay. (duh). Fireclay is a type of clay with high Aluminium Oxides which allow it to be used in high temperature environments (Furnaces and Kilns) without melting. Firebricks are always a light color. For jewellery making you are better of with insulating bricks, same stuff just that when they are made a high concentration of sawdust or similar material is added, this burns out when they are fired creating lots of air pockets for insulation. Insulating bricks are softer and lighter than the solid bricks and nearly all the heat goes into your project rather than heating several pounds of bricks. Your bricks look like fire bricks. The insulating bricks work awesome for soldering. When the surface gets uneven or pitted from use, take it outside and scrub it on the sidewalk a few times to resurface it. I like them because I can use pins to hold delicate work in place. They also last a lot longer than charcoal, or at least they do for me One insulating firebrick can be cut with a hacksaw into all sorts of slabs and shapes that can be stacked around your work to make temporary kilns or soldering stations. They can be cut into weird shapes to hold difficult items or to reflect heat back onto the work area. As well as pinning my work I also scrape cavities or push pieces of work into the brick.
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Post by Pat on Jan 20, 2014 15:34:30 GMT -5
pauls Take a look at my first photo. I made that little oven by cutting one brick lengthwise and crosswise to give me four equal pieces. It is soft and full of holes. I can push pins etc into it easily. It was sold to me as a firebrick, but sounds like it is really an insulating brick. Opinion? Thanks.
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Post by pauls on Jan 20, 2014 21:49:14 GMT -5
Pat The firebricks in fireplaces and areas like that are hard heavy things so they don't get smashed about by logs moving, Kilns furnaces forges are often lined with hard bricks for durability but have a layer of soft insulating bricks as well to make them cheaper to run, the heat stays in the furnace to do work rather than leaking out through the sides. They are just two versions of the same thing, The soft spongy honeycomb firebrick you have is made at the same factory out of the same clay but has sawdust mixed in which burns out and leaves insulating air spaces. They are fantastically handy things to have around for any hot work.
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Post by bobby1 on Jan 26, 2014 10:41:55 GMT -5
I solder directly on the fire brick. If you use a tripod and the heavy screen it takes an awful lot of heat and a large torch to ever get the metal up to soldering temperature. To get the effect of heating from the under side just turn your torch up to a larger flame and heat a spot on the fire brick up to glowing red, use your solder pick to slide your piece to be soldered over the hot spot and continue heating the piece to its solder point. I use the light, soft fire bricks because they don't require so much heat to get to the solder point. Bob
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Post by 1dave on Jan 26, 2014 11:01:32 GMT -5
That is a tip I never heard before. Thanks!
Sprinkle a few borax crystals around and when they melt you will know you are getting to the right temperature.
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