I read something the other day about borax damaging the ceramic/insulating material in gas forges....Any truth to this or just rumor?

Thanks a bunch

Its true...........

It will also do damage to castable refractory but not near the degree as the ceramic wool.

You can use a high phosphate or phosphate bonded refractory and fluxes won't hurt it at all. Most common refractories though are very susceptible to hot flux, especially caustics like molten borax. It'll go through ceramic blankets like kaowool like hot water through cotton candy.

Frosty

Is there anything I can put down to help protect the floor of my gas forge before the damage gets bad?...Just finished up the forge, but find out about the flux eating away at the wool til everything was done.

I read somewhere online that ceramics used on the floor of the forge might help but I'm thinking it'll never hold up to the heat/abuse.

Any suggestions?

You can use 3,000f split fire brick for the floor by leaving out enough blanket for it. Flux will eat the brick too but it'll last a lot longer.

Or you can buy some high alumina kiln shelving, again in the 3,000f range. Flux will eat it too but it'll last pretty well.

And you can make a SS tray to lay on the floor when you weld to keep the flux off the refractory.

Frosty

Jymm Hoffman uses Plastech 85 for the shelf of his forges which he uses day in and day out for years. My friend Bruce Godlesky and I visited his shop yesterday and he graciously showed us around. Got educated. After we left his shop, I bought some of the stuff for my forge shelf. 55 pounds per box at about 100 dollars.

I found this description on the Infernalnet, is this the product you are referring to? PLASTECH 85P 55# (STD)

Jymm Hoffman uses Plastech 85 for the shelf of his forges which he uses day in and day out for years. My friend Bruce Godlesky and I visited his shop yesterday and he graciously showed us around. Got educated. After we left his shop, I bought some of the stuff for my forge shelf. 55 pounds per box at about 100 dollars.

Yes Unicorn, that is the stuff. I haven't opened mine up yet but I've seen it in action at Jymm's shop.

The floor of my vertical welding forge is mostly vermiculite, with enough kaolin to bind it together and keep it from blowing away. The mixture is very cheap, and is intended to be disposable.

Frosty, I think you meant high alumina refractories. Phosphates are often used as binders in refractories, but it's the alumina that makes them flux resistant.

I'm sure this is something that's come up quite a few times and I appreciate yall posting the info again :-)

Thanks a bunch

No, I meant high phosphate or phosphate bonded refractories. They aren't common but they're virtually immune to fluxes. High alumina is resistant, not proof against.

These specific plastech products are phosphate bonded high alumina. High alumina refractories without the phosphate are less flux resistant.

At least that's what the guy at EJ Bartells told me while we were discussing the subject some years ago. I ended up buying Pyramid Super air set, a 4,000f high phosphate refractory and it's lasted better than 13 years in my little gas forge. Every once in a while, when it becomes a problem, I scoop out the puddle of molten flux, slag and metal grit that accumulates in the bottom.

Frosty

My mistake then, sorry. Looked like a typo. That's very interesting about the phosphate binders. About a year ago I was looking into the possibility of some kind of phosphate binder to make insulating blocks of vermiculite or the like, but I never came across that tidbit. Thanks.