castable refractory

[ThisOldGarageNJ]

once you have your first one cast,, can you fill it with expandable foam,, take it out then use that as a solid base form ? It could work on the outer surface as well, maybe ?

Mark

[mr g]

I like the way you're thinking. How much foam do you think I'll need? I've never worked with it before.

[david s]

Fibreglass is way more durable and more widely used for casting moulds. But I hate working with the stuff.

[ThisOldGarageNJ]

mr g,

you could probably do the inside mold with 4 or 5 cans,, you could use baloons to fill up some blank space and not waste too much foam,, In the states we have a product called Great Stuff,, They make a high expansion foam for sealing large spaces,, once dry it can be cut shaped etc,,,, Hope this helps,, as for the outside, I guess you could spray it on, maybe smear it down with a spackle knife or it may just take the shape well

Mark

[david s]

The foam is not particularly strong. I would be concerned about it breaking up after the second or third casting. Then you're back to square one.

[ThisOldGarageNJ]

If you have the HILTI brand foam (down under) it is much stronger... and very dense,, you could always foam to get the shape right then fiberglass the foam and you would definitely have a permanent form....

[david s]

Now you're talkin' but run some tests with the foam. Depending on the resin you use, some foam will dissolve on contact.

[david s]

Hey, I used to work for HILTI back in 1970 Their products are the best.

[ThisOldGarageNJ]

Davif S

Hey, I used to work for HILTI back in 1970 Their products are the best.

A Hilti is a tool you buy once and leave to your kids,,Because You will die before your HILTI

Now you're talkin' but run some tests with the foam. Depending on the resin you use, some foam will dissolve on contact.

Maybe the foam could be covered with a cheap painters tarp, plastic, etc.. Stop by an autobody shop that works in fiberglass they may have some ideas, I believe guys that build surfboards also use a foam core, so if theres a surf shop around they may have a few ideas as well..

Im even thinking, for the outside a plaster of paris cast, like a dr. would do on a broken arm, could be applied easily to the shape in strips and if you ever felt a cas it is pretty hard..

Mark

[asiapizza]

looking forward to your pics, awesome job!