Making Your Own Concrete Molds
Learning to make your own concrete molds is cheaper than buying them. Which makes it a great idea. It’s really not that difficult of a task, once you get the hang of it and used to the smells. In this guide, I will tell you how I do it. Plus I’ll add a video of the guy who I learned from myself. Like with any new adventure, practice is key. Your first few attempts might not turn out great, but that’s how you learn! Remember, if it was easy, everybody would do it! I’m going to tell you how to make latex rubber molds with a fiberglass shell for support. So, enough with the intro lets get down to business!
Stuff you’ll need
Here I’m going to list the products you need with a link to Amazon. Each one I list I personally use. So, at the very least, you’ll know you’re starting off with the right products.
- Liquid Latex Rubber: The rubber is for making the actual mold form of your model. The brand I recommend is Holdens. You can find it here, Holdens Latex Rubber.
- Fiberglass resin: The resin is what will add support to your rubber mold when it’s poured with concrete. I recommend this one. Fiberglass Resin.
- Fiberglass Matte: This stuff here is what you “paint” the resin on and is the other part of the support for the rubber mold. This one here is what you want. Fiberglass Matte.
- Chip Brush: This type brush is your best friend no matter if your making molds or painting the concrete statues. They’re cheap and very durable, Huge plus in this business. You can get them here. Chip Brushes.
- Acetone: This you use to clean your brushes after using the resin. It’s strong smelling, definitely use it outdoors or in a ventilated area (same goes for the resin itself) You can pick that up here. Klean Strip Acetone, 1.0 GAL
- Murphys Oil Soap: Use this to clean your brushes after your done coating the model with latex rubber. It makes it easier but it’s not perfect, nothing is that I know of. Murphys Oil Soap.
Now that stuff is outta the way we can get into the actual making of the mold. The first thing you should do is make sure your model your making a mold of is sealed. That way the latex rubber won’t absorb into it making it tougher to peel off after your mother mold (fiberglass shell) is done. Then you want to put your model on a piece of wood with at least 5 inches or so of room around the bottom of your model. Then your set for the next step.
This is when you start making your rubber mold. Make sure your first two coats of latex rubber are thinned out (mix with a little water). This is because it will better “grab” all the detail from your model. After your first two coats are done, you can use the latex rubber right out of the pail, no thinning. Now I do a minimum of 30 coats per model, more depending on the size ( the bigger the model, the more coats I use). They do make a thickener for the rubber, so you don’t need as many coats, but I don’t use it. Just personal preference, nothing against it.
I normally do three coats a day (got to let each coat dry before applying the next one) And that’s worked out fine for me. You could probably do some more, but I rather be safe than sorry later on.
Ok, so you got rubber mold ready and now you need to make your mother mold. Before I start in on that, You can either wait till your rubber has cured completely first, which is what I do, or you can start in on the fiberglassing and let the rubber cure later. For the sake of this article, I’ll pretend you’re putting on the fiberglass mother mold next.
Before you start doing that, you need to first apply a mold release so the fiberglass “shell” doesn’t stick to the rubber. I personally use castor oil mixed with denatured alcohol. It’s the same as you put inside the rubber before you pour it. For more detailed info on just that, check out my guide on how it’s done, Pouring & Making Concrete Statues. This is where I’m going to add the video on how it’s done for one reason. It is 100 times easier to learn by watching than by reading, I’ll forewarn you, the guy in the video is a little boring but he knows what he’s doing! Make note that it’s an older video, the phone number shown in it probably isn’t good anymore. It’s over an hour long, so yourself a cup of coffee!
That’s basically it. If you learn how to make these molds, you’ll save some money and possibly make a good buck selling them online. If that is something you want to do, try eBay. They seem to fetch a good price there. Hope this helps you out. Once you get this down pat your going to realize how simple it is and be surprised by how enjoyable and rewarding it is also. If you’re new to the ornamental concrete world and want to learn how to paint statues the right way, check out this guide here, Painting Concrete Statues. Good Luck!