Polyurethane resin casting FAQ

The tutorials we posted are very basic. We wanted to show how easy it is to do and it IS easy so if you’ve never done it, give it a try! Here are some questions that have gotten asked…

Can you use dyes in resin?

There are resin dyes that you can mix in before you pour. We’ve seen some great results with using resin dyes but we, unfortunately, have not had much luck with Tap Plastic’s resin dyes. We haven’t tried any other products either (we just stick with painting), so we can’t recommend any other products. Sorry!

Can you make a mold of a resin cast?

Yes, you can cast molds off a resin cast. The reason we recommend you go from the original is because the original is usually the truest form of what you want and like vhs copies, things degrade as you copy.

Can you make round things like a ball or things with 2 sides?

Yes. What we have shown here currently is flat backed molds. Molds of round objects require a 2-part mold and are a little more complicated. Next time we have to do something that requires a 2-part mold, we’ll take pictures and post another tutorial.

How safe is this stuff?

Definitely read the labels and safety sheets on the product you’re using. Polyurethane resin and rtv are relatively safe compared to other products we’ve used. Unlike polyester resin and fiberglass (which have to be done outside or in the garage), we use these products inside… mostly in our kitchen. Ok, we’re not recommending you do the this on your kitchen counter but it’s not like any of us really know how to cook so it’s not really an issue. =D

An important safety factor, other than not ingesting this stuff which should be obvious, is that when you’re sanding polyurethane resin, wear a mask and do it outside. You don’t want to be inhaling the particles that get into the air as you’re sanding. If you’re doing a lot of sanding, goggles are a good idea too.

And keep you casting equipment separate from your eating equipment! Don’t use spoons you eat with to stir your resin; that’s what plastic disposable spoons are for. You’re probably going “Well DUH” but we got griped at for not stating that in a panel. We thought it was pretty obvious but just in case, now you know!

What is the shelf life of these products?

Shelf life is how long the product can sit around and still be good. While these products (rtv and polyurethane resin) keep decently well, the shelf life isn’t that of twinkies. If it’s going to sit around for more than 6 months in your garage, it will go bad. You’ll know because the product won’t work as well: it won’t pour as well or cure as quickly or even mix as well as it should.

We don’t have exact numbers but we’ve noticed differences when using products 6-10 months old and we have resin and rtv sitting around from over year ago that isn’t usable anymore. So the point here is: while this stuff is cheaper to buy in bigger quantities, don’t buy way more than you think you’ll need because it’ll just go to waste.

How attractive are pools of curing RTV or resin to cats?

LOL. Cats are born troublemakers and get into everything! We (in this case: Judy and AJ) usually store our curing molds in the oven and then tape a note on the oven door so someone doesn’t turn on the oven and set them on fire. It’d almost be funny except that we’ve both set ovens on fire before, not with rtv molds in them thankfully. Actually we did it cooking… not sure that makes it better but there it is. =D