latex rubber mold - hand made

[Anonymous]

Has anyone used fiberglass screen to replace gauze strip in making latex rubber rock molds?
"the helix"[:p]

[dgwinup]

No, I hadn't thought of that. I'm wondering, though, if the screening would be a little to stiff to get the casting out. Fiberglas screen is flexible and I think it would work on shallow molds less than 1" in depth. Beyond that, you might experience trouble bending the mold back enough to peel it off the casting without damaging the casting or the details on the casting. It would definitely make your mold stronger and longer lasting.

I have always used Handi-Wipes cloths cut into strips or patches the size of my mold. They are nearly indestructible themselves and really strengthen the mold. I have cast many rock faces from the same mold. I even made a long mold of a brick pattern so I could cut the casting into wall sections for 'scratch-bashing' (sort of a cross between kit-bashing and scratch building). Worked really well for that, too.

Handi-Wipes are cheap and available about everywhere and you also can use them to make your own cleaning pads for Aztec's (?) track cleaning car. What you don't use for model railroading you can use around the home or car.

If you try the screening, let us know how it turns out and if you liked it.

Darrell, casting about, but quiet...for now

[cacole]

I've used fiberglass screen material in the actual castings of tunnel portals and rock walls with good results, but not in the molds themselves. The screen material is very stiff compared to gauze, and you would probably have a hard time getting it to conform to the shape of the rock.

[dgwinup]

QUOTE: Originally posted by cacole

I've used fiberglass screen material in the actual castings of tunnel portals and rock walls with good results, but not in the molds themselves. The screen material is very stiff compared to gauze, and you would probably have a hard time getting it to conform to the shape of the rock.

WOW! What a great tip for adding strength to your castings! Why didn't I think of that?

Darrell, banging head against wall, but quiet...for now

[bp020897]

I used a different process described in the Molding & Casting Handbook, to cast 5" x 7" walls which did not require fabric reinforcements. The process goes like this:

I first coated the master rockface wall with liquid dish soap and let it dry. The soap acts as a mold release agent. I than brushed 4-5 layers of latex rubber on.

I built a temporary frame around it using some strips of lumber. The wood strips were about 1/4 th inch higher than the thickness of the master wall and also 3/8s inch wider all the way around.

I than filled the resulting cavity with plaster of paris and let it dry. After removing this casting it becomes the base for the latex rubber mold. Just pour the plaster in for your wall an your on your way. I always apply liquid dish soap to the latex rubber mold before each pour to help release the new one.

It can take some effort shaking the new castings out of the mold. My plaster base cracked in half after about six pours but that really helped as I now pull the base apart first and than peal the rubber mold off the new wall.