Lasering through a coat of west systems epoxy..

[Keith Downing]

I'm wondering if I can laser (cleanly) through a cured layer of west systems epoxy? I'm using the 2 part 105 and 205 epoxy if that makes a difference.

I'm going to be rastering some designs into some drink rails that have been masked, and painting the designs after lasering. So, I need some type of sealer on the rails to start, to keep the paint from running in the wood grains.

Since I plan to finish the railings with the epoxy afterwards, I was wondering if I could just put a thin coat on first? I've done this before with polyurethane or polycrylic applied before lasering; but wasn't sure if the epoxy would be too thick or potentially melt instead of burning off cleanly.

The alternative I guess would be to put down a layer of polycrylic before the lasering instead. But I wasn't sure if that would potentially cause problems with the west systems epoxy bonding afterwards.

Anyone tried lasering through epoxy or have input on why it might not be a good idea in general?

[Martin James]

Hi keith,
the epoxy will soak in and penetrate the wood getting deeper into the wood for about 15-20 minutes depending on the temprature and the wood. If you put it on thin it will "starve" meaning that it cant penatrate because there is not enough. It will usually penetrate un evenly when you dont use enough possibly making the finnish look blotchy. Normally they put on too much, wait then squeegee off the excess just before it starts to setup.

When the are putting fiberglass over wood the wood can soak up epoxy out of the cloth leaving the cloth "starved of epoxy" and much weaker than if they had flooded and waited before squeegeeing off the excess.

You can sand or use a scraper to get the surface thinner. The scraper works well after about 3/4 cure while the epoxy is still a bit soft.

epoxy should be topped with a uv coat to protect it from the sun.

i dont have experience lasering the epoxy, but i have heard that it might be a mess, so test and try multi passes so the heat doesnt melt the edges of the engraved area

Cheers. Marty

[Keith Downing]

I didn't have time to test before this project, so I had to go with another solution.

For those that are curious, I masked the project (stained but unfinished), lasered and then used a light spray paint to fill in the part that needed to be colored. Now I'm finishing with the epoxy, 3 layers. So far it's working well, very little run in the grain from the spray paint. Just 2 spots where the masking pulled up.

I do plan to test lasering wood with one coat of epoxy at some point though. My only concern is the potential hazardous offput melting it; trying to confirm that the epoxy is essentially inert once fully cured. I think it is, but I think you have to wait a full week or more for it to be considered fully cured. I know they warn about dangers sanding in the first couple days (even after it is hard to the touch).

I'll post my results if I do end up lasering some samples.

[John Blazy]

Hi Keith! Good question about whether its safe to cut or not from a fume point of view. I have a laminate that is mostly epoxy - two different kinds, but likely 1000 X thicker than you might be cutting/engraving. It smokes quite a bit when cutting, and cuts pretty clean as you can see below, but the smoke may mostly be from the phenolic backing (common brown formica core) that the epoxy is on.

When I cut the .050" phenolic alone, it requires a speed / power setting normally needed for 3/8" acrylic, and huge flame shoots up off the kerf. Which makes sense because phenolic resin was the resin used to make the Apollo re-entry heat shields, as it does not melt, it ablates away. The laminates that are all epoxy cut really fast with crisp edges. I used over five gallons of West System on my boat, but never lased it, although all the different epoxies I use now lase pretty well (non blushing epoxy, better than West System)

FireBurlEpoxy-clsp.jpg