Duraboard repair

[Marilyn Kaminski]

I was really lovin' life with my new Duraboard (2", HD) until I tried a hi-fire on it ... long story short, I've now got massive gouges in it. Per a suggestion in the old archive, I made a paste out of kiln wash and rigidizer and applied it with a putty knife. A week later I tried sanding it smooth but the "spackle" didn't really stick to the board. Most of it flaked off with the sanding.

Any thoughts? Should I have sanded off the kiln wash before applying the paste? (had I thought of that one earlier, I probably would have tried it initially) Fired the board before sanding off the paste? What the heck do I do now?

At least I didn't cut up my old mullite boards in the meantime!

All help appreciated -- Marilyn

[Brock]

I was really lovin' life with my new Duraboard (2", HD) until I tried a hi-fire on it ... long story short, I've now got massive gouges in it. Per a suggestion in the old archive, I made a paste out of kiln wash and rigidizer and applied it with a putty knife. A week later I tried sanding it smooth but the "spackle" didn't really stick to the board. Most of it flaked off with the sanding.

Any thoughts? Should I have sanded off the kiln wash before applying the paste? (had I thought of that one earlier, I probably would have tried it initially) Fired the board before sanding off the paste? What the heck do I do now?

At least I didn't cut up my old mullite boards in the meantime!

All help appreciated -- Marilyn

A lot of materials won't take feathering, which means a gradual tapered amount of material coming back UP to the substrate. For wxample, asphalt. If you want to repair asphalt, you have to dig a vertical sided hole and fill it, you can't just spread the asphalt out thin on a depression. So . . . can you flip the board and start over? Brock

[Marilyn Kaminski]

Ah, hell, I was hoping for a Plan B before I get to this point!

I could flip it over, but the backside has a funky unpleasant texture that I don't like. I do have a second board still in the box, so Plan Z will be to start over with that one. Pretty expensive muck-up, though! Maybe I'll just keep fooling around with this one and see if I can discover a solution.

- M

[charlie]

since it's so thick, can you somehow shave it down somehow? it'd be a bit thinner, but so what?

a surface planer or wide belt sander would work well i would think, because it's so soft and they also use a good dust collection system. they make 36" wide ones. try a woodworking place or furniture quality lumber yard for one. if they don't have one, they'll know if there are any locally.

[Bert Weiss]

Flip it over. First rigidize with colloidal alumina or silica. Fire the shelf. Then grind it flat. I believe that John Groth ground his flat by using a very flat mullite kiln shelf like a sanding block. Continually check with a straight edge.

[Stuart Clayman]

I saw a product last night that was made to repair boards. It comes in a tube for a caulking gun. It was purchased from a supplier of items for boiler rooms and it said on it to repair the boards. I can get more info next week if needed.

Stuart

[Marilyn Kaminski]

I'd be interested in seeing what you find out. I'm experimenting on mine -- I figure I have nothing to lose at this point!

- Marilyn

[Bert Weiss]

I'd be interested in seeing what you find out. I'm experimenting on mine -- I figure I have nothing to lose at this point!

- Marilyn

Unifrax LDS moldable

[Stuart Clayman]

Thanks Bert,
that is it.