We've wanted to make a clock for some time now. We've also wanted to try molding and casting an object that was a bit bigger and more detailed so we could really test the limits of using Famowood Glaze Coat as a casting resin. The tape measure clock is the result. I know it will find a home on my desk and tick away while I enjoy the success of the process we used.
What you'll need
- Corn Starch
- 100% Silicone Caulking
- Baby Oil
- Mask (suggested - this stuff stinks)
- Epoxy Resin (brand doesn't matter, but we used Famowood Glaze Coat)
- Color Additive (optional)
- Means to make cavity for clock insert (forstner bit works best for this)
- Clock insert (determined by the size and shape of object you'll be casting)
- Patience (some resins take a while to cure)
Make sure you check out the video, it shows a bit more of each step than the images do. Please enjoy and if you make it or something like it, we'd love to see it.
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Step 1: Making the Molding Putty
The mixture for making the molding putty consists of corn starch, 100% silicone caulking and bit of baby oil. This isn't an exact science, but a good starting point is a 2:1 ratio of corn starch to caulk. As far as the baby oil, you'll only need a few drops.
Figuring out how much you need for your mold requires a good old guess. However, you are better off making more than what you might need, which isn't a big issue since this stuff is relatively cheap to make.
Once you have all of the ingredients in a pile, just start kneading it like it's dough. Fold, roll, wad it up; however you see fit. Just make sure you getting it all mixed together well.
You'll want to add cornstarch from time to time as you mix it. This will help reduce the stickiness of the mixture.
You'll know it's ready for molding once the dough stops sticking to your hands or gloves.
Once it's ready flatten it out and get ready for molding.
NOTE - add in corn starch and baby oil as needed, once you start working with it you'll begin to get a feel for what needs added
Step 2: Molding the Object (tape Measure)
To begin molding, simply press the object to be molded firmly into the putty. Hard enough that it leaves a good imprint, but not so hard that you push it through the other side of the putty.
Once you've pushed it in, you can begin to bring the putty up around the sides of the object while continually applying pressure wherever the putty meets the item.
Once you have the putty fit firmly around the object let it sit for about 30 minutes or so. You'll know it's ready to be released when the putty has become firm and rubbery.
Releasing the object from the mold might take a bit of force, but should come out fairly easy. If not, don't be afraid to pull a little harder. This putty is pretty strong.
Once the object is out, inspect the cavity of the mold for imperfections. If you're not pleased, mold it again. If it's up to par, move on to the next step - casting the object.
Step 3: Mixing and Pouring the Resin
We used a 2-part clear resin for this casting. The brand we use is Famowood Glaze Coat, which isn't necessarily designed for this type of thing, but works well anyway and is a bit cheaper than some other casting resins.
Like many two-part epoxy resins, this gets mixed in a 1:1 ratio. We kind of guessed on the amount we would need, but you could get a better idea by filling the mold with water and then pouring the water into a measuring cup. You would then split that amount in half and add equal amounts of parts A and B of the resin into the mixing cup.
Mixing times and steps differ from brand to brand, so follow the instructions that come with your resin. Famowood takes about 6 minutes to mix.
To give the object some color we added a metallic-like powder to the resin. You could also add a small amount of acrylic paint or other dyes that are available.
Pour the resin slowly and once the mold is filled to your liking pop any air bubbles that rise to the surface with a lighter. Just hover the lighter over the resin and the bubbles will pop.
NOTE - to get some of the bubbles from the bottom of the mold to the top, lightly tap the mold on the table to help them move to the surface
Let the resin cure for the recommended time. Famowood takes about 12-24 hours to cure.
Step 4: Releasing From the Mold & Inspecting
The object should release from the mold fairly easy since the mold is made of silicone. If not, get rough with it. The mold will hold up to some abuse.
Inspect the object. Everything should look pretty good. One common problem you may have is some pitting from the bottom of the mold where some bubbles never made it to the surface. If you can live with those move on to the next step. If not, you could fill in the pits with a mixture of clear resin, super glue or you could cast the object again.
Step 5: Inserting the Clock
Different clock inserts call for different size cavities. The back of the package should tell you what dimensions you'll need for the insert to fit properly. For our insert we needed a 1 3/8" diameter cavity that was 1/4" deep. We picked this up at Hobby Lobby for about $7. You can find them online, but they are roughly the same price when you include shipping.
The best method for making the cavity is using a forstner bit that is the same size as the dimensions that are called for. I'm not really sure how else you could make the cavity, aside from a chisel or dremel. I would love some suggestions on this though if you know another way.
If the depth isn't correct adjust in small increments. We actually had to make ours about a 1/16" deeper than what it called for.
You may also need to trim up some of the edges using a craft knife.
If the diameter was correct and you have everything set properly the clock insert should just snap right in.
Step 6: All Done!
You could really cast just about any object using this method, granted the object isn't enormous. You could make a clock out of just about anything. Using the homemade silicone putty method is by far the cheapest way to make molds; at least that we know of. So making trinkets and other stuff like this won't break the bank.
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