After starting with epoxy work I realized how fun it is to turn epoxy projects on the lathe and a few other projects where a cylindrical blank would be the easiest to work with. Especially on a lathe a cylindrical blank cuts down the amount of chipping an cracking you can get while turning epoxy projects. Also when working with a blank already close to the desired finishing size of the project you are trying to complete it saves on the amount of waste. After trying a few different ideas I simplified the process of crating the cylindrical blank down to 10 easy steps.
In the video and the photos provided I am using a clear tube that were originally shipping tubes. This process should work with any tube with sufficient wall strength and thickness to allow for sealing and withstanding the weight of the epoxy and materials used in the mold pushing outwards. I prefer to use pvc as with the thick walls make for easier sealing of the sides and a strong bottom to attach to the base. Also when using pvc pipe for the mold you are able to use the mold multiple times without having to make new ones. Below is a list of tools and materials you will need.
-Plastic Tube or Pvc Pipe
-Packing Tape or mold release tape
-Zip ties or pipe clams
-Epoxy ( I use Total Boat epoxy and it works great)
-Pigments for coloring epoxy ( I use Kp Pigments as they work awesome and have great colors)
-Wood or any other materials you would like to embed into the mold.
- Small piece of Mdf, Melamine, or smooth plastic
-Tape measure or ruler
-Band saw or hacksaw
-Clamp (if cutting tube or pvc with hacksaw)
- Razor Blade
-Optional (pressure tank if available)
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Step 1: Cut Tube or Pvc Pipe to Length
When determining the length for your mold keep in mind that you will be filling the mold with material and then epoxy. With that in mind I always suggest making the mold a minimum of 1/2 of an inch longer that the desired finial length of the blank. This minimum of 1/2 inch of length will allow for the epoxy to fully reach from the bottom to above the desired blank length when poured. Especially when adding any materials such as wood you need room for the epoxy to reach over the desired length of your blank without spilling out of the mold.
Once your mold length is determined using a tape measure or ruler mark on the tube or pvc the length you would like the mold to be. Using a band saw or hack saw cut the tube to the desired length. If using a band saw set the fence to the desired length if you have one. If not you can clamp a stop block or guide at the desired length from the blade. Move the tube into the blade and while keeping the tube as straight as possible rotate the tube or pvc back toward you. This will make the cut much easier to keep straight from my experience. If using a hack saw clamp the tube or Pvc to a work bench or in a vice (making sure not to crush the tube or pvc) to make the cut getting the end as straight as possible.
Step 2: Step 2: Split the Tube in Half
After cutting the mold to length it is time to split the mold down the center. Doing this process now makes adding the release tape and removing the mold much easier. I suggest using a band saw and a fence if available. This will make cutting a straight line down the center of the tube or pvc much easier. Take the diameter of your mold set the cut for half the diameter of the tube or pvc and make your cut. If making the cut by hand use a piece of tape as a guide to make the cut as straight as you can. Clamp the tube or pvc from the inside to the edge of your workbench so the clamp is out of the way and also does not distort the mold as it is cut. Once the cut is made rotate the tube 180 degrees and again use tape as a guide to get a straight cut directly across from the cut you just made. The mold should now be in two identical halves.
Step 3: Step 3: Use Razor Blade to Clean Up All the Rough Edges
Now that you have to halves to the mold you need to clean up the edges. Using a razor blade with the sharp edge perpendicular to the edge, scrape off the rough edges and remove all of the remains from cutting the mold to length and splitting the mold. Make sure not to dig into the edges or deform them as this can cause problems when sealing the mold together.
Step 4: Step 4: Preparing the Mold Base
It now time to prepare the mold base. You can use anything flat and sturdy for the base but I would suggest using Melamine. If you cannot use melamine or lexan then something like mdf can be used but if there is any issues with the covering of mdf the epoxy will stick to it making clean up and mold removal much more difficult. The size of the base should be a minimum of 1/2 of an inch lager all the way around the mold when together. This will allow for plenty of space to attach and seal the mold to the base decreasing the risk of leaks. After you have a sufficient size base for the mold line the entire base with clear packing tape or mold release tape. This will make removing the mold much much easier. When laying down the packing tape make sure to slightly overlap the strips of tape to fully cover the base.
Step 5: Step 5: Apply Packing Tape to the Inside of the Mold
After applying the tape to the base the same should be done to the inside of the mold halves. Start in the center of the mold applying the tape from center outwards. Apply one strip to the center of one of the halves then to the outer edges. Making sure to overlap the strips of tape on each side. Making sure to not leave any of the inner faces of the mold exposed as this will make it more difficult to remove the mold. Repeat this process for the other half of the mold.
Step 6: Step 6: Seal the Mold Halves Together
Now that the interior of the mold is lined with packing tape to aid in releasing the mold it is time to seal the halves together. This is one of the most difficult parts of this process and it is one of the most important to get correct. With the proper seal the mold will have much less risk of leaking. Using a hot glue gun is the easiest and most efficient way to do this. With the hot glue gun up to temperature start by applying glue to all four interior edges of the mold. This must be done with some speed due to the fact that you do not want the glue to set up and harden before you attach the halves together. Once all four edges are lined with glue press the two halves of the mold back together with the ends lining up. Apply slight pressure but not to much so as to not squeeze out all of the glue from the edges. Hold this slight pressure for as long as it takes for the hot glue to harden. If the halves move when released pull them apart and remove all hot glue and start the sealing process again. If when released and the halves hold allow the glue to fully hardened. Apply a liberal amount of hot glue to the outer seam on both sides of the mold. Make sure the full length of both seams is fully covered. Allow for the outer seams of hot glue to fully harden. Then it is time to move on to the next step.
Step 7: Step 7: Secure the Mold Halves
With the glue is fully hardened it is time to secure the mold halves. I use zip ties as they hold just fine but you can also use pipe clamps of sufficient size to tighten around the outside of the mold. Secure the mold in a minimum of three different places with more added with a longer mold. Start with securing the ends and work you way to the center of the mold moving back and forth until you reach the center of the mold. Do not over tighten the zip ties or clamps. This will deform the mold and can also cause sealing issues in the center of the mold.
Step 8: Step 8: Seal the Mold to the Base
With the mold halves fully secured the next step is to attach the mold to the base. Start by applying hot glue to the bottom edge of the mold. While the glue is still hot place the mold glue end down onto the base holding the mold in place until the glue is firmly set. Once the mold is in place apply a liberal amount of glue to the seam where the base and mold meet. This seam will hold the most pressure so make multiple passes start with the center making sure to apply a full bead around the seam and repeat the process at least twice more on top and bottom of the center glue seam. Allow the glue to fully harden.
Step 9: Step 9: Add Material to Mold, Mix Epoxy and Fill
Once the glue is fully hardened. Add any material to the mold that you would like. Anything you would like to have encased in the epoxy. Once the mold is full, thoroughly mix your epoxy adding any pigments. Once the epoxy is fully mixed. Slowly fill the mold almost to the top of the mold but not spilling over. Once the mold is full (apply pressure if available in a pressure tank), let the epoxy fully harden.
Step 10: Step 10: Remove Mold and Enjoy
Wait to remove the mold until the epoxy is fully hardened. The length of time that will take will be different depending on what epoxy you use. Once the epoxy is fully hardened you can remove the mold by first cutting the hot glue on the base of the mold and applying pressure to the mold with the base clamped to the table. The mold should come loose from the from the base with a slight tap. Once the mold is free of the base cut the zip ties or remove the pipe clamps and then split the hot glue along the seams using a razor blade. Using a flat head screwdriver and slight pressure place the head of the screwdriver into one of the seams and twist moving up and down the seam until the mold is released. Repeat this process on the other seam and you will have your fully formed cylindrical blank.
For the best results let the epoxy fully cure before turning or using. If you have any question on this process make sure to leave a comment below.