Casting idea

[Avery Boyer]

Anyone ever tried using dental molding materials for casting resin models? Yes, like the kind used for making molds of your teeth.....someone tell me why this would not work. It's much cheaper than RTV. TIA

[Admhawk]

It would probably work for simple things, but for production:

It sets up too fast, wouldn't get into every corner. It sets in what, 5 mins? it can take 15-20min to poor a large mold, waiting for the rubber to seep into every crack.

It's designed to be used once, won't take the repeated flexing of production casting.

It's designed to be used with plaster, won't take the heat of large amounts of resin curing.

Just my thoughts, as I have thought of trying this as well.

Darren
The Resin Shipyard

[Sean Hert]

Alginate doesn't hold to the same level of detail as RTV either. You could do basic shapes, but details like doors and such would be beyond it.

Is it really that much cheaper? I'd always heard the opposite.

[Frank Spahr]

Hi all,

alginate (the stuff for ordinary dental impressions, not for crown and bridgework) is water-based. Hence it will dry out and shrink after curing if stored in a dry place. We store it wrapped in moist paper plus in plastic containers until plaster is cast into the impression.

Moreover, as Sean very rightly said, the stuff does not reproduce as well as silicone (and what it does it does only under pressure!), and it�s not mechanically stable enough for a resin casting process, let alone multiple castings.

I�ve used dental silicone for lab technicians for reproductions, and it works fine, but I assume that Germany is no the only country with overpriced dental supplies. You might get the stuff cheaper elsewhere!

My 2 cents as a dentist

Frank