First time at the "Finish" line

[Patty Hann]

Hello all

Ok, first off, I'm a total novice at this.


I am making a computer keyboard frame from maple (the outside frame) and 1/16" (3-ply) aircraft grade birch ply (for the actual keyboard overlay, the part with all the holes for the keys.)


I'm using alcohol based dye and I did some practice pieces for both the maple and birch .
Sanded both to 220, pre sealed them with a thinned (50-50) oil based varnish, let it dry for 24 hours and then applied the dye.

Both practice pieces came out well, very little blotching and the different woods actually came pretty close in color similarity.

I want to use an aerosol lacquer (Watco) as a finish. ( I don't have anHVLP sprayer)

So my questions:
Does lacquer "give" at all or will it crack? The birch ply will experience some flexing (maybe 1/16" vertical displacement) when in use. Note: the keys are not attached to the birch at all, and don't come in contact with it in any way, but fingers do occasionallys lip off keys and may land on the birch overlay .


Should I spray on a first coat of Shellac (like Zinnser), andlet it dry , before spraying on the lacquer? I've watched a few you tube videos and that is how those demo folks did it.

Or, would it be better to use a [oil-based] poly-urethane varnish? If varnish is the way to go, for a small piece like this would wipe on application be preferable to brush or spray?

Thanks much for any help or advice.

[Jim Becker]

You'll be fine with the spray bomb lacquer for your application. (Just spray it outdoors for safety) Build up your finish with many light coats rather than spraying it on heavy. There's no need for the shellac here.

[Patty Hann]

OK....but what about the flexibility of the lacquer, the birch will be flexed a bit during use. Will the lacquer crack?

[Jim Becker]

I do not believe you will have any issue with the slight flexing...'sorry I didn't make that clear in my original response.

[Patty Hann]

OK. Thanks much.

[Patty Hann]

Sorry to revisit this after you answered my question but I have a related concern:

I've been reading about lacquer application and quite a few posts on other woodworking forums say you shouldn't apply lacquer over polyurethane varnish.
Or if you are intent on doing it you should let the poly totally dry out for at least a month.

The sealer I used is General Finishes wipe-on Seal-a-Cell, which I understand to be thinned polyurethane varnish.
I waited about a day, until there was no sealer odor from the wood at all, then applied the dye.
So I should wait...how long before using the aerosol spray lacquer? Thanks again

[Jim Becker]

The solvent based lacquer will generally dissolve other finishes and not in a kind way. Never put lacquer over anything like varnish or paint. I apologize for not catching that in your initial post. My bad. You'll need to stick with a non-lacquer aerosol for your top coats.

[Patrick Chase]

The solvent based lacquer will generally dissolve other finishes and not in a kind way. Never put lacquer over anything like varnish or paint. I apologize for not catching that in your initial post. My bad. You'll need to stick with a non-lacquer aerosol for your top coats.

If you're using spray lacquer then there is an option, but it's fairly advanced: After waiting ~2-4 weeks for the varnish to full cure (that's how long it generally takes), "dust" on several very light coats of lacquer.

Cured varnish can withstand very brief exposure to the solvents in lacquer thinner, so the goal is to apply such light coats that those solvents flash off before they can blister or otherwise attack the varnish. The finish won't look good after those coats due to dry spray etc, but after a number of such coats you can build up a thick enough layer of dried lacquer such that one or more subsequent coats can go on at normal wet-film thickness and flatten out the whole mess without disturbing the varnish. The catch is that this takes some experience and experimentation. It's not what I would call a "first-timer technique".

[Prashun Patel]

I've used cans and cans of Deft spray lacquer which I suspect is very similar to Watco. (I recommend the spray cans, not the brushable cans which will be more product/hassle than you need).

This style of lacquer is reasonable durable. They are not solvent resistant. So I would not use it for a table top (again ). They are reasonably scratch resistant.

It would be a good choice for me for your particular application.

[Bennett Ostroff]

Welcome, Patty. It doesn't seem like you're getting that answers you want about what product to use given the incompatibility of lacquer over polyurethane. It would be safe to use either polyurethane or shellac for your topcoats, both available in aerosol if you prefer. Poly will come in gloss, semi, and satin, while shellac is only gloss, so that may be a factor. A wipe-on formula will give you a nicer looking finish, imo. If it were me I'd get a can of satin wipe-on poly (unless you want gloss) and you'll have plenty leftover for another project.

[Patty Hann]

Thank you, Bennett.

What I ended up doing was using Man o' War spar varnish, both the Satin and the gloss, mixed and thinned to make it all wipe-on.
I thinned the satin 50/50 and put on 2 coats of that, then put on 2 coats satin thinned only 2:1.

At the moment I'm on the 2nd of three coats thinned 3:1. However the "3 parts varnish" was mixed 2:1 gloss to satin.
I wanted some gloss, but not a high gloss.

I've "sanded" between coats --a 24 hour wait ...ho-hum...twiddle thumbs--- using brown kraft paper (aka a grocery bag :-D), and it makes each coat silky smooth.

Anyway, so far so good. The gloss/satin mix has just the level of gloss I want, and the 3 coats of it will end it.
Any advice for a final polish after the last coat cures?

I've read some people use a paste wax or automotive [detail] wax.
Or just buff out the last coat?
Thanks

[Dave Cav]

Thank you, Bennett.

I've read some people use a paste wax or automotive [detail] wax.
Or just buff out the last coat?
Thanks

Regular old Johnson's Wax, in the yellow can from the hardware store will work fine.

[Bennett Ostroff]

You can also wipe off the final coat for a silky smooth finish, if you'd rather not deal with regularly re-applying the paste wax. Let the second to last coat dry for a couple days and lightly sand with 600/1000 to get it very smooth. Apply the final coat of poly as you normally would, wait 5 minutes or so, and wipe off. No wet coat for dust to fall onto = super smooth final coat. This isn't recommended for very large surfaces but should work great for your project.

[Patty Hann]

Thanks everyone for the replies and advice.... (still open to any more comments as I am still learning).
Found two drips, one not so obvious (back panel) and one pretty obvious.
Anyway, I have read about 4-5 articles on dealing with non poly varnish drips (dust nibs by comparison are easy!) and I think I'll be able to minimize them if not get rid of them entirely...more time on the learning curve!

[Prashun Patel]

If the sheen is as you like and it’s smooth, then there is nothing gained by buffing with wax.