How do I get a durable gloss wood laquer?

March 12, 2005 9:48 AM

I want to find out how to get a durable glossy lacquered(?) wood finish for pseudo wooden instrument cases. I know almost nothing about varnish/lacquer. My last attempt resulted in this, which is definitely the right look for the finish, but the problem is that it's far more prone to damage than it should be, such that I now feel I should try to keep the surface covered and protected, which makes me reluctant to actually ever take it out of the closet or use it.

I used a product from the local Michaels craft store called Minwax fast-drying Polyurethane clear gloss. I used about four or five coats to get it glossy. Its can also prominantly says Superior Durability, but as you can see from the arrow in the photo, when this stuff's surface is damaged, it doesn't chip so much as peel, that light coloured area around the chip is where the coat has lifted off the wood, allowing for further peeling which in turn lifts more of the surrounding surface.

What am I doing wrong? Am I using the wrong product? Should I expect months or years instead of weeks for full hardness to be attained? Might the (aerosol) woodstain I'm using be reducing the effectiveness (if so, how do I choose woodstain?).

What product do you use, and how do you use it?

What about those hard-laquered japanese jewelery boxes where the surface is so smooth and hard it looks like plastic - how is that done?

posted by -harlequin- to sports, hobbies, & recreation (11 comments total)

pseudo-VINTAGE wooden cases, sorry, not pseudo wooden. Old-looking cases made of real wood.
posted by -harlequin- at 9:51 AM on March 12, 2005

I have zero actual experience here but you might want to check out an epoxy based product like this stuff. I'd try a hobby store.
posted by Leonard at 11:05 AM on March 12, 2005

Laquered finishes are traditionally built up from dozens of very thin layers of resin. Very labour-intensive.

Polyurethane is probably the right way to go from a durability standpoint... maybe something else is wrong. Was the wood prepared correctly?

This seems like a good place to start for comparing finishes.
posted by Leon at 11:07 AM on March 12, 2005

Polyurethane is definitely the right material, in my limited experience. You might want to check out what folks have to say about PRS Guitars, which are wood with fabulously, famously beautiful finishes that are also quite tough.

They use GM automotive poly clearcoat finishes - or so goes the scuttlebutt. This has to be sprayed on in a booth with a spray rig - it's at least 1 step up from your basic DIY.

That's a pretty Geiger counter, by the way. Does it still work?
posted by ikkyu2 at 12:29 PM on March 12, 2005

Polyurethane is really not a very sophisticated finish for small boxes and fine furniture; it tends to rob the wood of depth and color. I would consider using something else: real laquer can be great but is chock full of hazardous vapors. Shellac or French polish might all be good choices. Some elbow grease required. I'm a low sheen guy myself (my second piece of furniture has an oil-beeswax finish which still smells great every time I open the drawer) so I don't have a lot to recommend specifically, but polyurethane really belongs on floors and hardy kitchen tables where the beauty of the wood is less a priority.
posted by Dick Paris at 3:04 PM on March 12, 2005

Both water and oil based polyurethanes are available these days. Water based ones probably don't deserve the name, I suppose they're really just a special acrylic mixture, and the -urethane bit gets it placed on the shelves next to the real deal. It's easier to use and clean up, but I've found it to be totally inferior, in terms of hardness and water protection. If you used a water based version, that's probably your culprit.

As well as the Genuine Lacquers (Wiki), some of those "hard as plastic" items are plastic. Nitrocelulose laquer can be had in jars and aerosol cans, but it's toxic stuff to work with, don't take it lightly. I have refinished a few things with products from Rudd. As far as using things, and not feeling nervous about the finish, it might be easier to use something like tongue oil, wich can be buffed, sanded, and touched up much more easily.
posted by Jack Karaoke at 3:55 PM on March 12, 2005

I've been experimenting with butcher's wax, shellac, and tung oil. I say go natural -- well, "natural" -- and you'll end up with a thicker and more luminous result. I find polyurethanes kind of thin and disappointing and too... perfect. Do some tests, you might like it.
posted by RJ Reynolds at 4:58 PM on March 12, 2005

Crap, my browser froze due to some disk-swapping, and next thing I know I've accidentally marked a random answer as "Best Answer" (Ikkyu2's post). Which isn't to say it's not a helpful answer, just that it's a bit early for me to be discouraging extra help by implying I already have sufficient answers.

Leon:
The wood was prepared correctly, however even using a dark stain, I have to use a lot of it to get the wood such a dark colour. I'm wondering if this saturation may be interfering with the penetrtion of the urethane. Perhaps using one of the tinted lacquers mentioned by others will reduce the amount of stain needed, which might help.

Ikkyu2:
Yes, the geiger counter works. I haven't done labels for the controls yet, and there are a few extra electrical features I want to finish/add (finish hooking up the inlaid solar panel, add a DC jack), but currently it runs on its batteries fine. Has a great analogue click too. (Most of my meters that have speakers produce modern beeps, rather than that cool eerie old analogue click :-)

Jack Karaoke:
I just checked, it's an oil based polyurethane. Damn, no easy fix there :)

Others - thanks for your suggestions and recommended alternatives, this is all very useful!
posted by -harlequin- at 11:03 PM on March 12, 2005

According to the PRS site, they use a polyester basecoat with an acrylic urethane topcoat.
posted by ikkyu2 at 4:26 AM on March 13, 2005

A woodworking forum would really be much more rewarding I think, but I'll take another stab. If that's an oil based finish, my first guess would be that there was residual finish of some type, or dirt/oil. 2nd would be a ridiculously heavy single coat, instead of layered application.

Besides that - It's hard to judge from your photo, but it looks like that finish would have benefited from either a good dusting, some sanding sealer, or more sanding/steel wool between layers.

Provided the stain has dried completely, it's not a likely culprit, but you could always test on some other scrap wood. If you wanted to take the time, I suppose you could mask off a portion with several strips of tape, stain, peel a strip, stain, peel a strip, etc.. You'd essentially have a test strip like in photo printing, but in stain. Finish and observe results.
posted by Jack Karaoke at 9:22 AM on March 13, 2005

If you can handle a more semi gloss look shellac is what you want. The problem with polys, as you've found out, is they are very hard leading to easy chipping and more importantly the chips are very hard to repair. They work good on floors and to a lesser extend furniture because a wood floor is a couple inches thick and so doesn't flex much. A few coats of shellac topped with wax will wear much better because it is softer and shellac can be repaired easily and flawlessly.

Plus shellac is used to coat food and the solvent is alcohol (grain alcohol is the best) so you can't get much more non toxic.

Shellac is also a good barrier finish. So if you have a finish incompatability like Jack says a coat of shellac between the two will stop them from reacting. Plus practically everything sticks to shellac and ivice versa.
posted by Mitheral at 7:28 AM on March 14, 2005