Basalt

[Mark Rosenbaum]

Has anyone used basalt fiber as a liner to their lehrs?
I currently use refrasil and it breaks down quickly and becomes dusty and airborne.
Basalt is made from volcanic rock and has a melting point of 2600 degrees F with an application temperature of 1800 degrees. It comes in lots of weave patterns and densities....
It can also be used to minimize thermal transfer in lehrs and furnaces, but that is for another day...

[Sky Campbell]

I ordered a bunch of basalt samples that came in 10” squares. All the weaves I used turned brittle when fired. Basalt is not a new material it’s been used for muffler packing for a long time. That said I found ceramic fiber that has served me very well for many years. I bought cheap welding blankets from harbor freight that held up far better then brand name refrasil. I think refrasil is made from silica not a ceramic. I’ll be honest I’m not sure what the difference is but I do know some of the ceramic fiber cloth I use lasts years longer then silica based cloth. I cut and hem pads with staples that get layered in between blown ware. You would be amazed at how much I can stack in a annealer.

[Mark Rosenbaum]

Originally Posted by Sky Campbell

I ordered a bunch of basalt samples that came in 10” squares. All the weaves I used turned brittle when fired. Basalt is not a new material it’s been used for muffler packing for a long time. That said I found ceramic fiber that has served me very well for many years. I bought cheap welding blankets from harbor freight that held up far better then brand name refrasil. I think refrasil is made from silica not a ceramic. I’ll be honest I’m not sure what the difference is but I do know some of the ceramic fiber cloth I use lasts years longer then silica based cloth. I cut and hem pads with staples that get layered in between blown ware. You would be amazed at how much I can stack in a annealer.

Thanks Sky.... are the Harbor Freight blankets ceramic?

[Eben Horton]

You can spend a lot of time going down a rabbit hole or you can fill a cookie sheet full of sand.

[bob gent]

I've always used plaster, without adding water, of course

[Sky Campbell]

Originally Posted by Eben Horton

You can spend a lot of time going down a rabbit hole or you can fill a cookie sheet full of sand.

I’d like to see how you use layers of sand to stack work in the annealer.

As far as the harbor fright welding blanket. I would guess they constantly change suppliers. They buy whatever they can get the best deal on. I wouldn’t count on anything from there being consistent. I bought one to try years ago when it held up I bought a bunch of them. I have plenty of pads to use for stacking wares and separating hot things in hot places. The ones that I’m using now are labeled ceramic welding blanket.

[Eben Horton]

Sky, I have a metal rack in my annealer that I welded up that is the same width as the cookie sheets.

[Mark Rosenbaum]

Originally Posted by Eben Horton

You can spend a lot of time going down a rabbit hole or you can fill a cookie sheet full of sand.

Yes, but with tall flattened work, I want some stability at the bottom. A layer of sand doesn't provide that. I need something solid so when I open and close the door, the piece doesn't fall over. i use sand trays for weights and marbles