Introduction: How to Make a Resin Cast Colored Pencil Bowl -
I've seen some flat out amazing resin cast colored pencil projects made on the lathe, and I wanted to give it a shot but add a slightly different twist to it. My goal was to create a turning blank where the pencils remain intact and are embedded around the edge of the bowl. Well, I figured out a super easy way to get the pencils to stay in place and the project was a success! I hope you enjoy seeing how it was made, and I hope that you try it out or get some inspiration for another project from it.
Step 1: Step 1: Gather Your Casting Supplies!
First thing you'll need to do is grab some casting resin, some colored pencils and a plastic bowl to use as a mold. I found some pretty cheap colored pencils on Amazon, and they worked perfect for the project.
I used Alumilite Clear - Slow Set resin for my bowl, and that also requires the use of a pressure pot. Other items you'll need to have is a mixing cup, something to mix it up with, and some gloves to keep the resin off your hands.
Oh, and I almost forgot the secret ingredient: tape! I used tape to keep the pencils in place which worked great, but I'd recommend cutting the pencils down and only leaving about an inch or so above the rim of the bowl if you're using a pressure pot.
I also recommend drying out the pencils before you cast them to ensure there is no moisture in them. Most resins do not like moisture, so I pop the pencils in the oven at around 185 degrees for at least a few hours.
Step 2: Step 2: Get Your Casting On!!
Ok, so you have the pencils dried out and you've gathered your casting supplies, now it's time to set up your mold. To keep the pencils in place, the easiest way I found was to just put packing tape around the edge of the bowl leaving about an inch of tape hanging above the rim so you can stick the pencils to it. I tried to leave equal space between my pencils and just let the bottoms of the pencil barely rest on the bottom of the bowl, and I decided to just randomly place colors around the bowl.
With everything prepped, it's time to start mixing your resin. Make sure to read the directions for your resin to know what ratio of resin to hardener you need to use as well as whether it is measured by volume or weight. In my case, Alumilite Clear is measured by weight, and the ratio is 1:1. This casting took about 600 grams of resin, so 300 grams of Part A and 300 grams of Part B. The amount of resin will be dependent upon the size of the plastic bowl you will be using for the mold. Mine was approximately 6 inches in diameter and about 3 inches tall, give or take.
It's best to pour both parts of the resin into the same cup to ensure you don't throw off the ratio when pouring one into the other. It's impossible to get every gram of resin out of the one cup when you pour it, so it will always be slightly off if you pour one cup into the other. Once you've measured out your resin and hardener into a cup, you'll want to mix it thoroughly, and make sure you scrape the sides and bottom of the cup well to get all the Part A's and Part B's mixed up well. It's best to use a cup without any indentations or ridges, those will tend to trap resin in them and the resin won't get properly mixed up. I used a paint mixing cup, they are really great for mixing large amounts of resin and totally smooth.
When the resin has been fully mixed up, you just pour it into the bowl mold trying not to make the pencils move around much. If any pencils do move slightly, you can adjust them once you've poured all the resin in. If you are using a slow setting resin, then you'll just want to let it sit and cure. You could use vibration to help free any air bubbles in the mixture. If you will be using a pressure pot, then pop it in and clamp it down. Make sure to keep the pressure below the maximum PSI rating for the pressure pot you are using.
Step 3: Demold and Prep for Turning
After the casting has cured, it's time to pop it out of the mold. I used a plastic bowl made out of HDPE, and the casting just fell right out... demold done!
The next thing to think about is how you will mount the bowl to the lathe initially. I decided to use a bottle stopper mandrel to mount the bowl to the lathe initially while I trued up the outside of the bowl and cut a mortise into the base so I could flip the bowl around and grab it with the 4 jaw chuck. The stopper mandrel worked perfect for this size bowl.
In order to mount the bowl to the stopper mandrel, I first used a 1.5" forstner bit to drill out a flat spot in the center of the bowl that was coplanar to the base of the bowl. To keep the bowl safely positioned on the drill press table, I used double stick tape to hold it to a piece of plywood. I used a center finder to mark the center of the bowl, then knocked out the flat spot only drilling until the bit flattened the whole 1.5" area.
Next, I used a 5/16" drill bit to drill a hole in the center and used a 3/8-16 tap to cut the threads in the hole so the bowl would screw onto the stopper mandrel.
Step 4: Turn the Bottom
With the bowl ready to be mounted to the mandrel, it's time to screw it on and spin it up. I used a negative rake scraper to true up the outside and bottom of the bowl. Scrapers work really well on large resin/acrylic turning blanks, they are more comfortable and less aggressive than bowl gouges. Carbide tools, which are scraping tools, also work great.
There really isn't much shaping to do because the mold is in the general shape of a bowl already. That's not to say that you can't put your own spin on the shaping of the bowl, but I was happy with the shape of the bowl, and my intention with this piece is to keep the colored outside of the pencils intact. So, I wanted to follow the shape of the bowl mold. I also cut off about 1/4" of the bottom because there were a few air bubbles around the bottom of the pencils. This was due to the fact that I didn't dry the pencils out before I cast the pencils... lesson learned!
Once the bottom was flattened, I used my parting tool to hollow out a mortise about 1/8 - 3/16" deep and 2" wide. You want to make the diameter of the mortise close to the diameter of the jaws of your chuck when fully closed. For this bowl, the 2" jaws worked great and left enough resin material outside of the mortise to have enough strength for the jaws to grab it. A tenon would work just as well, if not possibly better; however, I prefer not having to cut off the tenon. I finished working on the mortise using a skew chisel to get match the dovetail shape of my jaws for maximum contact and grip when chucking the bowl up in the jaws.
Once everything was trued up and the mortise was ready to go, it was time to sand the bottom of the bowl. I started out with 150 grit sandpaper and went up to 400 grit. Because the ends of the pencils are exposed, you'll want to put a finish on top to seal off the pencils. I used spray lacquer for my bowl, but any top coat finish will work. When sanding, you will want to make sure that you get all the previous grit scratches out before moving on to the next step. I won't lie, sanding resin blanks does take a little more effort than wood because the surface is dense compared to wood that has grain. Plastics require diligent sanding and a flawless surface to ensure no scratches are visible in the end. Just take your time and crank up some tunes, and you'll be done before you know it!
Step 5: Turn the Inside of the Bowl
Once you've flipped the bowl and mounted it on the 4 jaw chuck, it's time to hollow out the core of the bowl. To make things a little easier, I used a 2" forstner bit to drill out the center first. Take your time drilling, you don't want to heat up the resin with friction, so clear the chips frequently.
After I drilled out a 2" hole, I switched back to the negative rake scraper to finish coring out and shaping the inside of the bowl. Again, my intention was to steer clear of the actual pencils, so I left the bowl a bit on the chunky side. I might try cutting into the pencils on the inside but leave the outsides intact next time to see how that looks.
Once you've cored and shaped the inside of the bowl, then it's time to pull out the sandpaper again and crank up those tunes! I went from 150 to 400 again on the inside.
Step 6: Apply Finish
Now that you're all finished shaping and sanding the bowl, it's time to apply the finish. I wiped down the bowl with some denatured alcohol to get all the sanding dust off the surface. I recommend just barely getting a paper towel damp with alcohol and wiping off the ends of the pencils. If you doused the pencil ends where the lead is, you could smear pencil lead all over, so just lightly dab them off.
I chose to use a gloss spray lacquer to seal and finish my bowl. It should only take about 4-5 coats, and the bowl will be nice and sealed up. I gave mine a couple base coats, then sanded with 400 grit in between coats from there on.
After letting the finish cure for a couple days, I "finished the finish". To give the bowl that crystal clear look, you'll want to sand and polish the finish. To take out any bumps or dust nibs that ended up in the finish, I used 400 grit paper. You don't need to sand aggressively at this point, you're just trying to flatten everything out. After it was nice and smooth, I moved up to 600 grit, then 1000, 2000, and 4000. Just like the resin, you're goal is to remove all the previous grit scratches before moving on.
For the finishing touch, I took the bowl to the buffing wheels first using the Tripoly buffing compound, then White Diamond. I use regular buffing wheels to do the outside of the bowl, then switch to the Beall bowl buffs to get the inside of the bowl.
Step 7: Impress Your Friends!
With it all done, now it's time to show off a bit =D I've gotten a really good response from my friends and family on social media, and I guarantee you will too!! It makes a great gift, and it's also a great product to sell!!
If you do make one, tag me if you post it on social media or shoot me an email with a pic attached through my contact form on my website. Most of all though, have just have fun with it!!
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Please be positive and constructive.