Sealing Coasters and other Laser Cut Items

[impatience]

Not sure where is the right place to post this, so I figured “Everything Else” sounded good.

I’m currently working on some coaster designs, because, well, who doesn’t want to make some coasters right? I’m making them currently out of Proofgrade plywood materials. I’m thinking that they probably need to be coated in something in order to seal them and protect from moisture, at least on the tops. I’ve got cork for the bottoms.

So my question: I’ve been searching and reading online and seen various people use spray spar eurethane, others use brush on marine spar, others use a brush on clear lacquer. I’m not really familiar with these materials / methods and was looking on some advice for the easiest and best results in coating coasters. I’ve tried using spar eurethane spray but I’m getting mixed results for evenness of coat and it takes a lot of time to spray it, wait for it to set, sand, spray another coat, rinse and repeat.

So, best way to protect coasters?

Thanks!

[timtsuga]

I use spray shellac, dries fast and gives a nice finish. I have been happy with all the Zinsser products I have used.

Got photos of your coasters?

[markevans36301]

Against conventional wisdom, I say just leave it alone. I have a coster sitting next to me that is over a year old and has not started to deteriorate. Obviously, YMMV depending on how deep your engraves are and how much your glasses sweat.

[impatience]

Two different coaster types right now. One is engraved, and one is just multiple material cuts. These aren’t necessarily what MY designs will be, but they were easy to pick up vector files of the net and get playing around with it and the process.

Engraved (Some just engraved, some just painted as I mess with different styles of finishing):

Multi-Material Cuts (Again, playing with styles to see what I like):

I just happen to have that exact can of Shellac, though I was using that to try and seal to make the paints get absorbed less, didn’t even think about using it for the whole piece.

[impatience]

I had thought about just letting them be as well, just haven’t had time to test wet glasses on them for extended periods of time, so wasn’t sure how bad they would absorb the moisture and distort/stain. Good to know you’ve had good luck with them without any coating.

[cynd11]

Oooo, some nice designs there. I would think you definitely would want to seal the inlay ones to prevent edges from peeling off. Have you considered a pour-on epoxy resin?

[john.m.gaffney]

I used a water-based polycrylic and my coaster warped almost immediately. I tried it on the Medium Maple Plywood Proofgrade with a pretty deep engrave. The spray shellac looks promising! Right now I’m trying a brush-on shellac with a one-hour dry time.

[impatience]

I have not. Totally new to all this. That sounds…scary

[timtsuga]

Did you put finish on both sides? Finishing one side can cause warping.

[cynd11]

Here’s the kind of thing I’m talking about:

http://a.co/bQgFh56

[impatience]

Okay, I can give it a try If for nothing else just to learn more processes for finishing work. Definitely adds some time onto the creation of the items, and a bit of cost. Hoping to eventually have a coaster design I can sell.

[brokendrum]

Just to chime in.
Various Poly seals for normal use stuff and interior signage.

If it is going outside or another style harsh environment like a steamy kitchen, then Shellac or Lacquer is the answer (and even that will not stop deterioration, just slow it down)

Cutting boards are oiled. Not sure if would help a coaster made with plywood, but if it is a solid wood it probably would do fine.

[scott_trahey]

I love shellac for lots of things but keep in mind that it is alcohol soluble so if the coasters are for adult beverages the finish may be damaged by spills or drips.

[alan_ferrell]

I noticed you have some nice colors on some of those. Be mindful to use a varnish or shellac that is compatible with the paint you’re using on a given piece. The Bullyseye shellac above is good stuff, and will seal enamel wonderfully, but will fog badly over water-based acrylic paint. There are water based laquers, but of course they have their pitfalls as others have mentioned in this thread. The main thing to keep in mind is coasters are born to die, but the cut files last forever. You’ll never create an indestructible one, but they’re easy to re-do. One final tip - lacquer is for people with time on their hands. Spray it, let it dry pretty thoroughly, then give it a good scrub with some fine steel wool, then re-apply. Three or four light coats may take a few days, but the extra time spent with steel wool between coats really pays off IMHO. I particularly like that inlay idea btw. Nicely done.

[jbv]

alternatively, slate coasters will last for a very long time, and don’t require any finishing
(although oiling them can create more contrast)