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I have a stratocaster body that a friend of mine has painted, I know I need to lacquer it before I do anything else, like sorting out the electrics etc. I'm just unsure what lacquer to use so that I don't accidentally ruin the artwork on the body or something.

This is the first guitar I'm attempting to build so this is all pretty new to me.

bidby
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    What kind of paint? It probably doesn't matter, but I'm not well-versed in using lacquer. – grfrazee Apr 13 '16 at 21:30
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    ___Practice on scraps you can afford to destroy before you go anywhere near the instrument!___ – keshlam Apr 14 '16 at 00:02
  • I can't second keshlam's comment above strongly enough. The main issue with true lacquers (solvent based) is that they are very reactive and have been known to attack paints if applied over the top. This is enough of a problem that broadly speaking you could say you don't lacquer over paint. That's a slight exaggeration but not by much. So you MUST test for the specific paint type or you're potentially in for a world of hurt. [contd] – Graphus Apr 14 '16 at 07:21
  • [contd] I presume because of the nature of your query that you don't actually have any experience working with lacquer, so just in case you don't know, you have to spray-apply, they can't be applied by brush. So do you at least have a spraygun or airbrush and a compressor? If not you need those first before you can even start practising :-( – Graphus Apr 14 '16 at 07:25
  • I don't have any of that stuff, but I was aware I'd have to spray it. I need to ask the artist what paints they used, but let's say it is the worst case scenario and she's used a couple of types and I can't lacquer the body. Is there any other way of preserving the paintwork? I'd hate to be stuck with a guitar body that I can't turn into an actual guitar! – bidby Apr 14 '16 at 12:08
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    We like to provide answers whenever we can, but this time your best answer may be "ask the artist who painted it". She is likely to be far better versed in applying finishes than any of us are, especially when it comes to (potentially) expensive custom paint work, and when it's her own work. She may have a recommendation other than lacquer that will work well with the paint she used and provide the protection it needs. – FreeMan Apr 14 '16 at 12:24
  • I fear not, she's a friend of mine who is not a professional artist. Nonetheless I will contact her as to what she thinks is best. – bidby Apr 14 '16 at 14:58
  • She may also know of others who are more experienced and may be able to help out as well. – FreeMan Apr 14 '16 at 15:23
  • Traditional Japanese technique for applying lacquer is to brush on, and immediately wipe off, then polish. Repeat many times with complete drying between wiping and polishing. So, you don't need to spray lacquer on, though it probably goes a lot faster. Traditional lacquers are made from tree resins and might not dissolve paints as readily as some modern alternatives. But, of course, per keshlam's point: try on a scrap first! – MattD Apr 18 '16 at 21:54
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    As you're just starting out, perhaps you use the word "lacquer" loosely, as "shiny clear protective coating". For the folks here, lacquer is a very specific finish that has certain virtues along with a finicky nature that causes many folks to prefer modern alternatives. James answer is a good one I think, in that there are polyurethanes and other clear coatings that are much less likely to damage the existing paint than lacquer (and the aggressive lacquer thinner it contains). – scanny Dec 21 '16 at 22:50

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In this case the safest bet (you should still check with the artist about the kind of paint used) would be to utilize a waterborne sealer.

The technology has come a long way and is as durable if not more so than old fashioned sealers (poly, lacquer etc). As additional bonuses, the smell is far less offensive, it dries more quickly, and is not prone to yellowing.

As far as application goes I would suggest spraying it on if you have the facilities/tools. An HVLP sprayer is great for projects like this, it conserves material when you are working on small objects.

To avoid any damage to the artwork apply very light coats until you have a full seal, and do NOT sand until you have a solid base of coating built up. Sand light with large numbered grits (at least 200 probably, or 000+ steel wool).

Once you have a full seal you can apply thicker coats that take longer to dry.

James
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I agree with the comments above re: testing on scrap and asking what paint was used.

However, it's really difficult to get that classic high gloss finish out of a water based varnish. The pros use spray lacquer, building many coats and then wet sanding level, followed by polishing.

Best bet is to read Bob Flexner's book on wood finishing and choose your finish from there.

FreeMan
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Minnow
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  • There are a lot of products out there now that will allow for a high gloss finish. In fact most large companies use a poly finish instead of lacquer these days. There are downsides to water based finishes for guitars. They tend to be thicker, which can affect the tone (purely subjective). But they cure faster and are less finicky to apply. – guitarthrower Dec 23 '16 at 18:29
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Guitar finishing can be a bit different than traditional wood finishing. There are a lot of similarities though too.

Primary considerations are protection of the instrument, and look.

Lacquer has historically been used, because it can provide a glass like finish. The downsides to lacquer are the time to cure, the specific conditions needed (low humidity, and warm temperatures), cracking and yellowing over time.

Large manufacturers have long moved to a poly finish for a lot of reasons. Easier to apply, less finicky (overall), can be nearly as glossy as lacquer, if waterbased then less yellowing. Downsides are that it is a thicker finish and can affect the tone.

Everyone has mentioned this already, but test, test, test! Prepare a test piece of wood and have the artist put some of the same paint they used on the test piece (doesn't need to be the same design). What is important is how the clear coat will react with the paint. Use one side for lacquer and the other for poly and try it out.

There are a lot of great guitar specific resources for finishing. I will list a few here for reference:

guitarthrower
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