questions on resin casting

[Westfalia Chris]

One more thing, I strongly suggest you make the masters from a not-soaking material, ie plasticard or wood sealed afterwards using superglue. If you use a porous-surface material, you´re asking for a lot of trouble, especially since it is pretty hard to seal styrofoam (you can use PVA glue, but that´s even more work).

[WitchfinderGeneral]

And please, use some kind of release agent. When I made my first mould I didn't used it . The result was that I couldn't remove the masters from the mould without damaging it.

[Fortescue-Smythe]

As to sealing surfeaces with superglue: how do you apply the glue? I was thinking of using white glue as a surface seal, which should be quite easy to brush on. I don't see that with superglue. Does it 'creep' enough so that it doesn't form blobs?

[Zafarelli]

In my experience, CA glue dissolves styrofoam, I think PVA might be better.

[Hammers]

Superglue has as you've probably noticed almost no surface tension (right word?) so spreads by itself extremely well. If it doesn't quite do the work for you there are stainless steel and nylon applicators you can use.

[Westfalia Chris]

Of course, you cannot use superglue on styrofoam, you´ll have to use PVA or varnish for that.

Superglue is to be used on paper and wood. I use a very thin variety for that, which immediately runs into every nook and cranny - take great care when applying it. I´d suggest carving the basic hull shape from balsa wood, then seal using superglue, let dry; then, sand down any irregularities, clean the piece, re-seal, and you´re done.

I would not use unsealed wood with RTV (again). The silicone easily rips off the topmost layers unless sealed.

[Skrapwelder]

I've found that sealing the whole master with a 50/50 PVA glue water mix give a good seal for casting. One thing I've really run into trouble with is when I've used styrene cement to bond two pieces of styrene together. If it isn't sealed up very well the rubber doesn't cure correctly around the area where the cement was used.

[Fortescue-Smythe]

Thanks again. I might try the balsa idea.