Casting Silicone or Faux Silicone Finish?

I’m doing a product design for school, and it consists of a solid color underneath what would be a frosted, translucent, silicone overmold over the whole product. However, I’m not quite sure how to show this finish on my model. I’m going for something that looks like this: I’m going for the look over the feel, but having both would be a major plus. I’m intending for the silicone to have a few millimeters of thickness on the product itself. The following are options I have considered and problems that may arise from them:

  1. Casting silicone over my painted model - I have never casted anything before and I’m not sure how I would pull off casting the silicone only around my model

  2. Styrene - Vacuu-form the two halves of my product with clear styrene, either sandblast or paint it, and then encase my model with the 2 styrene halves. The problem with this is that I’m worried adhering the two halves together with solvent might get a little messy and I’ll end up with a messed up looking part line down the middle. The benefit of this method though, is that the styrene will give the thickness of silicone I want to convey.

  3. Layering clearcoat - this is probably the easiest method. I’m thinking about getting some type of clear coat or clear resin that will go on thick, and spray with something to make it look frosted. However, I tried layering just regular clear coat, and it doesn’t build up enough.

So guys, I’m really stuck. What do you guys think? Any suggestions for these methods? And other ideas?

I’m no model marker pro, but I’d say that #2 is the best bet, with the most control. You can work out the seams with sanding and polishing before sandblasting and if you sandblast on the outside will hide most defects I think.


There are a number of polyurethane rubbers you can use but if you need to simulate a translucent rubber overmold for a model take a look a Plasti Dip® - PLASTI DIP®. There are dip and spray products – they will give you the look without having to create a mold and all of the other problems associated with overmolding a one off piece.

Awesome, I actually saw that Plasti-dip stuff just the other day at Tap Plastics. How does the spray kind go on though? Does it go on pretty thick? If not, does it build up well?

Thanks for the feedback though guys - it helps me out a lot. :smiley:

Hi guys… I’ve got a similar requirement for a project I’m working on - attempting to show a perforated, rubberised grip on a casing that will be rapid prototyped. This Plasti-dip stuff looks good, but does it produce a glossy finish? Is there an easy way to show perforations on the grip? How thick does it set?

Thanks to anyone who can help!