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Sealing a Guitar Body and Neck Before Lacquer

Now that all of the body modifications have been completed, I’m ready to begin the finishing process.  The first step in finishing a bare wood guitar body and neck is to seal the wood.  This fills the grain, locks out moisture and provides a smooth surface to which the lacquer may adhere.  Here’s a great article about finishing schedules, and recommendations for various types of wood.

Now that I’ve decided to move away from “rattlecan finishing”, I decided to pick up a spray gun.  As I mentioned previously, I purchased this gun from Harbor Freight for about $25.  This type of gun is called an HVLP, or high volume low pressure, gun.  This gun allows you to spray a nice, controlled coat of lacquer and will actually save you money in the long run.  If you consider that spray cans of lacquer cost around $7 to $10 a piece, you can see how this might quickly add up.  Note, I also added a moisture separator and an adjustable pressure valve (both at the bottom of the gun).  The moisture separator removes any condensation from the air, before it enters the gun.  The pressure valve allows me to adjust the air pressure entering into the gun.
I found this air compressor on Craigslist for about $70.  There are a lot of great deals to be found on Craigslist for compressors!  If you were to purchase this new at Harbor Freight, it would cost you about $130.  In a previous post, I mentioned that I had purchased a smaller compressor for my HVLP spray gun.  I ended up returning it, because it was just a little too small.  It would work, if I really needed it, but ended up running all of the time. 

When spraying anything, USE A MASK!  Seriously, don’t come whining to me when you’ve got something nasty going on in your chest because you wanted to look cool, or save a couple of bucks.  I purchased this mask from Sherwin Williams for about $25.  Trust me, when you are spraying with a compressor and HVLP gun, you are releasing a lot of potentially harmful material into the air.  Also, a lot of what is sprayed, when finishing a guitar, is flammable.  Make sure you have a well ventilated work space, away from open flame (or BAD things can happen).  Again, if you have any doubt about how to safely operate any of this equipment, please refer to the disclaimer, aka the “I’m not liable if you do something stupid because I told you not to do it” clause.

 Any time I use the spray gun for the day, or when changing materials, I always flush some lacquer thinner through it.  This cleans the internal mechanism and ensures that you aren’t mixing anything that you hadn’t intended to mix.

Since I’m not spraying overly porous wood, I can get away with going straight to vinyl sealer, which I buy this from Stewart – MacDonald (along with just about everything else).  Again, this is used to level the surface, fill the wood grain and protect the guitar from moisture.  It also provides a strong surface to which the nitrocellulose lacquer may adhere.

To get the best results, you should hang your body and neck for spraying.  Here’s the neck after a second (wet) coat of sealer.  Note – The neck looks greenish in this picture but that’s only due to a combination of the lighting and the wet coat of sealer.  The Behlen Vinyl Sealer actually dries almost completely clear.  Another item of note is that I masked the fretboard to prevent overspray.

 Here’s the guitar body.  Again, you see the greenish tint, and while that’s mostly a product of the wet coat, and lighting, the wood itself does actually have a bit of green in it.  The body is made of poplar which has a natural green tint.  I wouldn’t use poplar if I were doing a semi-transparent finish, but since this will be 100% opaque white, it really didn’t matter.  Also, as a tonewood, many people swear by it (even though it is considered a less expensive wood).

Last but not least, here’s the back (more green).  After this drys (two coats / 24 hours), the next step will be to sand this using 320 grit paper, to prep for lacquer.