Epoxy Resin in wood turning.

[Martin Cramer]

I recently watched a short documentary on the work of the Moulthrop family. I was fascinated by Philip Moulthrop's use of coloured resin which he uses to embed multiple pieces of wood before turning. I've also seen examples of the use of coloured resin to fill voids. I have used epoxy in boat building and wondered if the epoxy I used would be suitable for such work. Does anyone have any suggestions as to a resin product suitable for use in wood turning?

Martin Cramer
Alberta, Canada

 

[JeffSmith]

Does anyone have any suggestions as to a resin product suitable for use in wood turning?

Martin:
I've used both the West System resins and the System Three resins (I too did some boat restoration at one time). Both have worked well for what I've done. Filling cracks I use hot glue to seal up any through cracks before filling - also for creating dams to hold the resin in place until it has cured. Both work well with just about anything I've used to color it - commercial colorings, wood dust, coffee grounds...even dry pigments.

 

[john lucas]

I have uses System 3 and West Systems in my turnings for years. Marilyn Campbell uses it in almost all of her pieces. http://www.marilyncampbell.ca/ I mix thickeners with it that West Systems sells. I mix all sorts of colors, inks, paints, powdered paints, and dyes. Mix a test before you use any of these because some won't mix and some change the chemical structure so it won't cure or loses strength. Most alcohol based dyes and inks will mix. I've used some water based paints and some oil based. Powdered paints work well and thicken it as well so it can be pretty handy for filling. for filling Knots with holes I often use sawdust of approximately the color I want. For smaller holes in knots I mix Ink but leave the epoxy kind of transparent. That way it picks up the color of the wood as well as the color the I put in it.
I just picked up what I need to do an article on mixing Gold Leaf with epoxy for some cool affects. Keep your eyes on the magazine.

 

[Martin Cramer]

Thanks for the advice, I'll have to do some experimenting. I tried coloring some West Systems with some water based aniline dye power and used it to fill some flaws. It worked but the resulting color wasn't very vibrant and I think the dried epoxy was a little softer than normal. I was wondering what gave those bright saturated colours I've seen in photos. Now I have an idea where to start.

Martin

 

[john lucas]

they make special colorants just for epoxy. I haven't used any yet but have achieved some pretty bright colors using paints. The problem I've run into using paints is if you use too much it changes the epoxy and it may not cure properly. Too little and you may not get the brightness that you want. If you get the West Systems epoxies get yourself a digital scale. For a lot of what I do I don't need a full pump using their pump system. So I squirt about what I need of the epoxy into a dixie cup. Weigh it. Then divide by either 3 or 5 depending on the hardener your using. This gives you the amount of hardener you need. That way I can mix up just exactly what I need. It's also really handy to weigh when your mixing paint into it so you know exactly how much you used. You can make this a percentage or ratio so that you can mix the proper amount of paint next time.

 

[Martin Cramer]

Weight sounds like a great way to accurately mix small quantities. I had pumps for a boat building project but they seemed impossible to clean in order to reuse some time down the road. Time to do some experimenting.

Martin

 

[Steve Worcester]

Weight sounds like a great way to accurately mix small quantities. I had pumps for a boat building project but they seemed impossible to clean in order to reuse some time down the road. Time to do some experimenting.

Martin

get a small scale that is accurate to 10ths of a gram

 

[John King]

West System Guidance

From West System Epoxy. - John

John,

WEST SYSTEM® Epoxy can be tinted with a variety of pigments. Most commonly used are powders such as tempera paint or chalk line dust, but there are many other options available. Bruce Niederer wrote an article for our bi-yearly magazine, EPOXYWORKS on this very subject; here is a link to the article:

http://www.westsystem.com/ss/assets/Uploads/Ew21pigments.pdf

Usually up to 2% of any pigment can be added without ill-effecting the cure. Dry powder pigments are best for coloring epoxy because you can add as much as you want. Tempura dry powder paints are excellent to pigment the epoxy. Another option is our 423 Graphite Powder will turn the epoxy black, add 1.5 tablespoons per 8 fl oz.

If you have any other questions feel free to let us know.

Best regards,

Don Gutzmer
Technical Advisor
Gougeon Brothers, Inc.
866-937-8797 ext. 1237

 

[john lucas]

Thanks John Your website has been very useful over the years. I dye my epoxy black with just a few drops of Alcohol shoe dye. It works great and I can make it anywhere from jet black to translucent smokey depending on how much I use.

 

[Richard Coers]

Anyone ever seen old pieces of these works using epoxy? I thought I read where it breaks down with ultraviolet light exposure. I also wonder about wood movement over the years, and with it imbedded in a brittle material, is there minor cracking? I was surprised to see the final polish, or lack of it, in some Moulthrop epoxy pieces at SOFA. I expected a perfect polish, but you could see some abrasive marks or maybe you could call it course rubbing compound marks. I expected it to look like glass, but maybe too tough to do in the black tinted epoxy..

 

[Owen Lowe]

Anyone ever seen old pieces of these works using epoxy? I thought I read where it breaks down with ultraviolet light exposure. I also wonder about wood movement over the years, and with it imbedded in a brittle material, is there minor cracking? I was surprised to see the final polish, or lack of it, in some Moulthrop epoxy pieces at SOFA. I expected a perfect polish, but you could see some abrasive marks or maybe you could call it course rubbing compound marks. I expected it to look like glass, but maybe too tough to do in the black tinted epoxy..

Epoxy needs to be over-coated with a UV inhibitor like varnish or some such. Unless your piece is outside, I’d think the materials you use to finish your non-epoxy containing pieces is adequate. Keep in mind that epoxies like the West System were developed for extremely harsh condiditons on boats with full sun exposure, constant water contact, high humidity, temperature swings, etc. When we use it for turnings it’s child’s play.

As to wood movement, the epoxy remains flexible and moves with the wood. I made a hand mirror years ago with an epoxy-filled design on the back. At different times of the year, you can feel that the epoxy has raised above the wood surface. It has not failed in the least from this cycling.

Lastly, because it remains flexible it is “soft” and does not keep a high polish with handling. To retain that gloss it has to be polished and contact needs to be kept to a minimum. (If the Moulthrop piece was ever polished to that degree is unknown to me, but it also may not have had the maintinence done to it.)

The manufacturers have a LOT of information on their websites about UV and adding pigments and just about anything you can think of. Take a look there to see if your concerns are addressed.

{One more thing, you could contact someone like Marilyn Campbell to inquire about epoxy behavior over the long haul.}

 

[john lucas]

I looked, I don't have any of my older epoxy pieces around. I did have some that were quite old and don't remember the epoxy yellowing but they may have been in the 8 to 10 year range and not really old. Epoxy will polish quite nicely but I think it depends a lot on the brand and what hardener you use with it. Most are fairly soft. I have been using some clear acrylic casting resins and they polish very well but they are also soft and show marks after handling. I did have a platter with a black epoxy rim that was a test piece. I knew the wood would move and epoxy wouldn't move as much so I kept it. I had cut a groove in the rim so the epoxy had a sort of tenon on it to help it adhere to the rim. After about 2 years one side came loose. After about 5 years the whole ring fell off. It still looked glossy and nice but just didn't stay attached to the wood.
I have done many mirrors like Owen suggested using epoxy, casting resings, or Inace. They all have the same characteristics of leaving a little lump at certain times of the year due to wood movement. Never had any fall out that I know of however.

 

[Bill Boehme]

I have used clear epoxy that has a long cure time and I like it for some of the inlay work that I have done. I don't like the regular epoxy or the fast cure epoxy for that sort of inlay work because they are yellow from the beginning and cure with a lot of trapped air bubbles. It is a good idea to undercut the wood when applying epoxy or any other decorative filler.

I have used a lot of Inlace which is a two part plastic resin and hardener. It sets up to a rubbery consistency in about ten to fifteen minutes so it requires fast work and a lot of planning ahead. It is crystal clear and can be turned after about twelve hours although it is still slightly tacky. Once fully cured, it is quite hard and can be polished to a high gloss. I use it on wood that is stable, but even then I make sure that I undercut the wood because Inlace doesn't have the same bonding strength to wood as epoxy does. Generally, wood does not move much once it is dry and has been finished with varnish or shellac or lacquer.

 

[Steve Worcester]

If the epoxy is dyed, you won't likely notice the yellowing. Unless it is red, then since red and yellow make green, but if it is opaque, you still wouldn't notice. Transparent , maybe.

as far as coating it with a UV inhibiting finish, there isn't as many choices as you would think. Check the manufacturer to see if the product really has UV inhibitors. Most wood finishes don't because yellowing is the direction you want the wood to go, sort of.

 

[JeffSmith]

As I recall from the days spent restoring a classic ChrisCraft, UV degradation of the epoxy didn't cause it to yellow, but to form a powdery white surface in places. For wood that was exposed to the weather, epoxy was mixed with a special catalyst for top coating (nearly perfectly clear) - all surfaces were coated. Thinned down Epifanes marine varnish as a top coat for the high proportion of UV inhibitors. Worked very well. With continuous weather exposure on a boat in the water in the Pacific northwest, the varnish needed a refresh every spring, but it was a quick scrub, sand to rough only and recoat.

 

[John Tisdale]

Epoxy for finishing???

To my thinking there are two uses for epoxy: to fill voids and to coat the inside of a hollow-form. The thought of using it as an exterior finish is, again to my thinking, bizarre. From all I've read, spraying it is next to impossible - that leaves wiping and brushing. Sanding a fill spot is one thing - sanding epoxy brush-marks quite another. While there are a few that can "torch it flat", not me.

Here's another something to think about: after the first coat of "whatever", you're no longer in the wood finishing business - you're in the finish finishing business. The surface of the finish is the issue. If the finish is low-solids and penetrates, then the surface of the wood becomes the surface of the finish, with all its grain patterns and anomolies. As most "low-solids finish" never really set, the next coat blends in. However, with epoxy, after one coat, you're in the epoxy finishing business. All subsequent coatings will have to bond mechanically. If that coat of epoxy is less than perfect, each following coat will be no better and probably worse.

I have used WEST and System-3. Dave Schweitzer of D-Way Tools turned me on to Aero-Marine, specifically the 300-series low viscosity. It actually penetrates and, when mixed with colloidal silica or other thickeners, does whatever fill-job you might come across. As our Grand Pooh-Bah stated, a jewelers scale with graduation of .1-gram is a most valued tool in any shop. The Aero-Marine, just like the System-3, is 100/44. If you want maybe 1/4" in a mouthwash cup, that's 5-part resin and 2.2-hardner. I'll stir any colorant into the resin, stir, and then add the hardner - after that comes the thickener. I've found that you can actually shoot the 300-series in a #22 hypodermic (buy from a feedstore - it's much cheaper). Cracks that most would fill with CA are filled with epoxy - while I haven't done proper testing, I believe epoxy to be a superior long-term fix.

Epoxy is an integral element to all my "secondary" turning (after the vessel is around 6%MC). I inject it under the bark inclusions, fill little cracks, thicken and fill large cracks, and coat the inside. But you gotta have a scale - I bought a Sartorius AY511 M-prove scale from Itin Scales for $136 - it measures each drop.

The above is just my opinion - I could be wrong. And to those guys that do great finishes with epoxy, hats off.
John

 

[john lucas]

I have a friend who finishes all of his work with epoxy. They are beautiful and impervious to the elements. I need to ask him about longevity of the finish.
I also have another friend who sprays epoxy. His only complaint is cleaning the equipment and of course hazardous fumes. I have made quite a few darkroom sinks over the years they hold up really well but obviously don't get a lot of sunlight
A few years ago I needed to duplicate peeling paint. I dyed the epoxy thickened it and the. Wrapped it over several forms I made. I cut these sheets up and glued them to the wood. The customer was really happy.

 

[pat miller]

I have had moderate success using Aero-Marine's 21-300 epoxy as a final finish. Apply to raw wood, keep applying until it no longer soaks in leaving dull spots, until then wipe if off completely and let it cure. Maybe a second coat. It may or may not require sanding and buffing. I have also had good luck using the same as a finish for vessels that I want completely impervious to liquids- a different process using a home-made rotator that turns the vessel at several rpm. With the long axis parallel to the floor I coat the piece with 21-300 and let it rotate overnight. It takes some experimenting to deal with mounting the piece and how the epoxy runs out (or not) of the openings. This produces a completely smooth, very plastic'y and shiny finish not suitable for all work but excellent for others. Just another finishing option.