I’m playing around with a Christmas ornament design and would appreciate a bit of feedback.
The current plan is to use a bowl bit to rough out the dished center in a piece of 1/2" thick X 3.75" X 3.75" walnut, then engrave the artwork with a 60d v-bit. Then I fill the engraving with epoxy (ideally with white pearl pigment, or at least white tint - not gold as the artwork shows). A day or two later, come back and do a finishing pass with the bowl bit to remove the excess epoxy and proceed with the remaining profile & chamfer passes. Then wrap the edge with a strip of brown leather.
Simple epoxy stuff, which I’ve seen plenty of others do on YouTube.
After a trip to my local Rockler, I came away with Alumilite Clear Casting (Slow) Resin. I mixed 5 grams each of A & B, and added a small scoop of Pearl Ex Powdered Pigment (just enough to cover the tip of a small popsicle stick). I mixed everything together for at least a minute, then poured it into the engraving. The initial pour did have a few bubbles, but with the 40+ minute working time, I figured that allowed plenty of time for them to rise to the surface (making them easy to simply carve away). The Rockler salesman said there was no need to pre-seal the wood…
The temperature in my shop was in the 50’s, and humidity around 35-40%.
24 hours later I ran the initial bowl pass again (it swelled up too much to go straight to the finishing pass). It was at this point that I realized the epoxy, while hard & brittle, resembled a loaf of bread - it was 100% saturated with air bubbles throughout the entire depth of the resin. Nearly all of the resin chiped and ripped out of the engraving. 10 grams of exoxy had swelled up so much it nearly filled the entire bowl cavity…
So, any thoughts as to what I did wrong? Should I go ahead and pre-seal the carving (spray shellac?) and maybe pour the epoxy inside the house where it’s warmer?
I should note my initial test piece was with a scrap piece of long leaf reclaimed pine.
After pouring the epoxy, hit it with a heat gun or torch. That will get most of the bubbles out.
I have quite a few epoxy projects under my belt, and can offer the following tips.
I do not think you want a casting epoxy unless you are pouring .75 to 1 inch deep. I have my best results using a low viscosity (LV) epoxy with either a slow or medium hardner. MAS makes the stuff I use. The LV is so viscous that most bubbles will take care of them selves, but I still hit it with a torch.
I always seal my wood with clear epoxy before I pour the tinted epoxy. I would do my carve, then mix up a small amount of clear epoxy, and mix 50/50 with denatured alcohol and brush it in like a varnish. This step will help prevent the pigmented epoxy from bleeding into the wood.
Give yourself permission to screw it up! It took me a long time and a few ruined projects to get it dialed in. Epoxy is expensive, and so is the learning curve. Consider switching from a ballnose to and endmill. I would think that the grooves from a ballnose may make for an impossible sanding situation.
Hope this helps!
Thanks Ken & Bern. I will pre-seal the next test piece and will use the torch. I think also warming up the epoxy in a warm water bath might help it flow better to help the bubbles evacuate.
Bern - the v-bit carving is about 0.1" deep. I’m assuming the MAS Table Top Pro resin is the best choice since it has a max pour depth of 1/8" to 1/4"?
Here’s a couple pics to show the air bubbles - I never imagined this many bubbles was possible. LOL
Try total boat high performance next time. It looks as though the epoxy was mixed and a lot of air was stuck in it from mixing. Was this stuff very thick? It should be closer to maple syrup than molasses. You cant leave bubbles/foam.
Thanks - it was fairly thick. However, It flowed pretty well (enough to self-level) and there was no indication of that many air bubbles while I was mixing it. I mixed it in the Rockler 3-piece Silicone Glue Applicator dish the Rockler salesman recommended, and it was mixed with a popsicle stick by swirling it around in circles. But it definitely did no look foamy, or even excessively bubbly when I poured it on the piece. Whatever the problem was, it caused it to nearly double in volume while curing. LOL
Depending on the clarity of what im pouring for I may seal the board with a thin layer of epoxy and then rough it up with sandpaper and blow it off prior to pouring. Without doing that the worst I ever got was a few bubbles along a river where it meets the wood. Im not familiar with the product you used, but you may want to save it for those exceptionally thin pours. Totalboat has worked Ok for me up to 1" even though it doesnt recommend that thick. The deep pour stuff has givin me trouble on not setting up for a long period of time and all my pigment settles.
also keep in mind that your test peices are pine, which is probably the least epoxy friendly wood there is! Sealing and a torch will help immensely, not to mention the fact that fire is awesome! Here are some of the pieces I did…
That’s a pretty small piece. Don’t tell the wife but I made a makeshift vacuum chamber with some PVC pipe and a food vacuum sealer that has a place to connect a hose. It was a 6" diameter pipe with caps on each end maybe 6" long. I think anything bigger would be beyond what the pump in the sealer could handle.
What pigments are you using for those?
I use these Mixol tints these days, and various brands of mica powder when I need to add some sparkle. Before I invested in the Mixol tints, I used craft acryllic paints which worked well also. The Panther one is acrylic paint, and a great option when getting started as long as you dont use too much (too much will prevent a proper cure). Another advantage to acryllic when getting started is that you can easily find a color you need to match using this kit: Acrylic Paint Kit
One more voice of experience: I create epoxy inlay in pine. I use Total Boat (same version as mentioned above). I preseal the vbit engraved areas with 2 coats of Bullseye Sanding Sealer. No torch. No bubbles. I spread the epoxy with the edge of an old credit card, like a squeegee. I skim off the cured epoxy with a surfacing bit.
I had picked up one epoxy tint kit and ended up using an entire jar for 1 project and it only ended up slightly pink. im not sure which one it was
Acrylic paint is an interesting idea. I’ll definitely be trying that. Thank you for sharing your work! I’ve tackled several projects lately, and each had multiple “first time” learning experiences. Those first-timers really add up when you’re experimenting with different products.
I always mix epoxy with a plastic knife in one direction only and very slowly like a snail for 5 mins or more.
I also heat the epoxy A in the warmest room of the house for a few hour before mix so its warm for the mix and poor so bubbles can escape the low visc
Thanks Michael - I may have to try that. I’m using thinned epoxy for the first sealer coat, but I’m finding it’s flowing and pooling up in the tiny engraved letters, which I expect will cause problems when it comes time to fill with my color coat (won’t be able to get enough color in the engraving). I suppose I could switch to a the penetrating epoxy instead of trying to thin what I already have. But a simple spray-on alternative might be nice to try and easier to apply in a production run.
Is A & B parts always the same, regardless of brand? I remembered seeing someone mention a warm water bath for one of the parts, but I couldn’t remember which part.
Bulls Eye Sanding Sealer is brush on, not spray. It is essentially shellac cut with den. alcohol. It holds detail well because it leaves just a thin film. 2 coats work best.
NO I have Epoxy at 1 to 1 , 2 to 1 and 5 to 1 ratio depending of the type and brand of Epoxy
I would assume A is usually the epoxy and B the hardener. I Put them both in the warm room even though my dealer says just A. But i don’t really think it matters