spruce top

Hi Badeye,

  If it is in fact a lacquer, you have a few choices as about the only thing that will cut the original finish and possibly give you grief would be another lacquer.  Something that I have used with good results is a water borne lacquer available from stewmac.com.  It comes tinted and in aerosol in case you aren't too familiar with a spray gun.  It does require that you rough up the existing finish a bit with something like 400 grit (by their instructions), but I like to go even finer and use 800 wet sanding for that.  There is less chance of going though the original finish and does the job nicely.  Most important is to completely remove any contaminants like waxes or oils to get good adhesion.

  Several light coats will be needed to get the color even and as dark as you like, and then several coats of clear will put the finish on it. Allow 2 hours dry time between coats. You will not be able to sand imperfections out of the color coats, but can on the top clears, which then can be buffed and polished to desired gloss.  I usually finish sand with 2000 grit wet with a block to perfection and it does take a bit of time.

The finish should be allowed to cure about 150 hours before attempting any sanding on the new surface, or polishing.

Have fun with it and it should come out great!

Take Care;
Doug

If your wanting that aged golden hue. the best thing (IMO) to do is just be sure it stays out of it's case. UV light darkens it over time. You can even expose it to direct sunlight to reall speed up the process.. Just be sure it doesn't get too hot. Indirect light (like having it in a room with a lot of windows) will also speed up the process.

Here's a pic of a newer top (Seagull Artis Studio Rosewood)

And here is the same finish after a couple years. (S&P Pro Rosewood)

Both of those have the same woods and finish, The only diffrence is the age... I'd let time do the work for you No worries about mistakes or decreased value that way. Also unless your experienced with finishing a guitar, you can easily hinder top vibration and have detrimental effects on it's tone. -Pix

Hi Segosha,

You should email Marcalan here on the site, he knows all about restoring all timbers. He specializes in this field.
Im sure he can give some good tips.

Old Doll.

Just curious Doug... How well would a water based lacquer adhere to an oil based lacquer even with lite sanding? I know usually with any oil based finish that you're going to cover with a latex (water borne) finish a bonding coat of some kind is crucial for the transition from oil to latex for it to adhere properly and not flake/crack eventually. I would think that fish eyeing would also be a problem. I've never tried the product and am curious how it addresses these issues. I've never seen a Finish product that could.. Is there an extra step in there or do you spray water directly to oil?? Always open to gain some education -Pix

Hi Pix,

  Actually that is a very good question.  I've been using traditional finishes for something like 30+ years, both in the Antique Restoration and even Automotive fields.  Surprisingly, the new CFC Free waterborne products are very comfortable over the top of most finishes and if adhesion is questionable, a sanding sealer (clear) which also acts as an adhesion promoter is available to precoat.  We are talking about VERRRY thin coats of product.... to give you an idea, 10-12 coats when dry/cured is like 1 mil in film thickness.  The Stewmac product I used recently is a nitrocellulose base specifically formulated for wood musical instruments.... not like casting resin poured over a burl tabletop somewhere.  I've had good results with similar stuff over acrylics, alkyds, polyesters, polyurethanes, and epoxies.  Surface prep is paramount, as you want your spray to flow without "fisheyes" and you have to get the feel of shooting it as you cannot shoot for gloss, it needs a "half wet" coating which will level out over the first half of the drying time.  If I was shooting a bike or a car, I'd think I was going too dry and would expect to see an "orangepeel" result. Water borne coatings tend to respond to gravity, and threaten to slide off onto the floor at slightest provocation. So light coats are best.

  Personally I use a gravity feed HVLP with 3-5 lbs pressure at the gun through a .014 tip.  The really nice thing is the long open time which lets you get in there with a sharp probe and extract any foreign objects without losing the coverage locally, and not having to wear a full blown respirator to filter out the solvents.  No fire hazard, and better for the environment.  Mind you a line air drier is still a good idea, and dedicated air hose that has never ever seen the dumb end of any shop air tool which might contribute a bit of oil into the mix is a good thing. My paint hoses have a strange fitting that only fit the line drier/regulator on the one end, and the only things that will plug in the other is one of my paint guns.....  Tru-flate is for impacts, ratchets, grinders, and brute force tools....  Johnston fittings are for paint!

  Thanks for asking and sorry for the lengthy answer.  I really enjoy this stuff and tend to get carried away.

Take Care;
Doug