I’m making a table lamp for one of my projects and need some help. I have created a foam model for it and plan on making a mold out of it to make a the final product in concrete. I’m going for a natural/stone finish and that’s the reason I chose concrete for the material. My only concern is that it might be too heavy and so I’m considering fiberglass resin for it. My question is that how can I finish the fiberglass so that it looks like stone? I’m going for something like this: http://www.simplyfountains.com/tabletop-fountains/lighted/miradatabletopfountain.cfm
Also, what material would be best for the mold? Thanks in advance!
If you’re only interested in making just one copy then instead of making a negative mold you could simply create that form in pink foam and wrap it in fiberglass. After that you’'ll have to sand a bit to fair it down but you’ll end up with a solid single piece body. You can then do something similar for the sphere and box and attach them all together at the end.
This guide shows a bit of the process.
Be sure to use an epoxy compatible with foam otherwise you’ll end up melting your model. In my experiences epoxy resin works and the polyester resins don’t.
As for the finish this guide is the closest I can find to something like that:
(check earlier on in the thread for more how-to info)
The above idea is what I would do if you are only making one, or even two for that matter. But if you are going to make a mold you can use plaster. Make it by covering your positive original with Murphy’s oil soap or Vaseline, then use plaster with something to reinforce it and paper machie to lay down on the positive.