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I put the seventh and final coat of finish (water-based polyurethane from target coatings) on my first electric guitar yesterday. I know I need to let it cure for a week or more before doing the final work, but I'm unclear as to what is the best method for getting a gloss finish. The book I have mentions going from 400 up to 2000 grit wet sandpaper but it also mentions polishing compounds and a buffing pad on a random orbit sander. Are these "either/or" options or both part of the process? Is 400 grit too low to start with? I'm afraid of sanding through the finish as I don't have the best touch when it comes to sanding.

Any help would be greatly appreciated.

Here's where I'm at now:

   If you want a high gloss there are no short cuts. You must sand through the grits from 400 to at least 1500 then you use buffing compound then polishing compound. 3M Finesse it and Imperial hand glaze are good products.
     The final buffing is with a swirl remover. Most of the products can be found at auto parts stores. I spend about 8 to 12 hrs buffing out a guitar

Very interesting!
400 should a good place to start if your surface is pretty level and work up through the grits. Then you can go a product like Fineese It from 3M, and the finish off with so McQuires No. 7. That should work pretty well.
Another option is to get a Micro-mesh kit and work up from 1500 - 12000. There grit don't match anything I know of. this works really well also.
Be sure to wet sand or the paper will glog really fast, with lacquer anyway.
You may find that 400 is too fine to start with depending on how level your coats are.

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Jim Watts
http://jameswattsguitars.com

Looks like John beat me to it.

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Jim Watts
http://jameswattsguitars.com

I can't picture not having to go though the sand down process. Even if you thing the coats are dead level you will be supprised when you put some level sanding scratches on it I start with 400p amd move through 800p then move to 3200 micro-mesh and work through 12000 micomesh. polish with Magurie's #9 then Miguires #7. For ultra sheen I then go to the buffer and extra fine compound.MichaelP38555.7183680556

   What I look for is the cutting down of the surface . As you sand you can see the surface start to level. The object is for the finer grit to take out the rougher grits marks.
    The surface will have an orange peel look and as you start to cut it down you want to be at the finer grits as you hit level and flat. Use a sanding block as this will help to keep the surface flat and even, Once this is accomplished you want to hit the buffer and work out the shine.
    Often I have to add a few "finishing" coats. I like to have a rough build of about .016 then when I am finished to have about .008 left.
   In elec bodies you don't have to worry as much about thickness killing tone so I build heavier on them to about .020
     Finishing is a process and maybe the hardest one to learn as you have to have a good process and patience. Finish will make or break the appearance. I have seen many great builders , but the finish came up short and made them just average. Eye appeal is buy appeal. If it looks good that is a big plus.
John Hall

Thanks for the detailed description, John. What I'm most concerned about is knowing when to move on to the next grade of sandpaper. Do you typically sand for a certain amount of time, just hit every area of the body once, or is there a distinct set of visual clues that tips you off that it's time to move up in grit? Can you go by feel, like you might when sanding wood? Also - do you try to sand the same direction each time as if you were dealing with wood grain or do you go perpendicular every time you switch sandpaper so that you can tell which scratches are from the new paper?

Finishing is definitely the make or break part of building the guitar. I was fairly pleased that I got to the finishing stage with only minimal (in my mind, anyway) mistakes. I kind of thought the finishing problem was the downslope leading to the finish line. Turns out I haven't even climbed the mountain yet! ( :

Andy

I would not start sanding with something as coarse as 400-grit. I usually sand my finish dead level before my last two-three coats. Let it cure for a while and start wet sanding with 800-grit or 1000-grit. You'll be able to see easily when you wipe the water of the surface when it is level. If your final cured surface is pretty rough, I recommend you start sanding with 600- grit.

wet sanding at 400 is fine. Not alot of pressure. You want to cut the high of the finish. Once you see that happening go to 600 and watch the finish. As the hollows start to disappear go to 800. I like to bottom off with 1000 then set the fishing off with 1500 then 2000 then go to the buffer. I like Mirco mesh with a little soapy water.
   You can get a very high gloss . This is with Nitro. The object is to work the surface iperfections off in stages so when you get to the leveling you are into the finer grits.
    Finishing is a process that is time consuming but when done right is worth the effort. I won't touch a finish for 2-3 weeks after spray to let the lacquer cure.

I always started with 600 as well.

I wrote an article on the finish process over at www.lint.org

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John Mayes
http://www.mayesluthier.com

    We all have our one techniques. There is more than one way to skin the cat but the important thing is to find the process that works for you. Finishing is not easy to do well. it is a process that takes time nad effort. there are no shortcuts
john hall

Forgive me if I'm missing the obvious and forcing you all to belabor the point. If my initial sanding - say I start at 600 grit - is simply to level the guitar...then I should end up with a level surface that is not uniformly scratched. As I continue to higher grits and the surface becomes more and more level the scratched areas will spread over the guitar. Therefore when I get to the buff stage I should have a totally level guitar with essentially equally spread out light scratch marks from the highest grit paper I go to?

If you haven't figured it out yet I'm totally new to woodworking. I built a couple lousy projects in junior high shop class and did a really basic shelf for my father as a present. This is my first major undertaking. My wife's grandfather has been sharing his insight, but his experience is pretty specialized: cherry and black walnut furniture are about all he's ever done.

I really appreciate you taking the time to help.

Andy

I don't know if I quite understand what your saying. Here's what you want to do. Use 400 or 600 grit paper to completely level the surface. Don't get it mostly level and let the finer grits level the rest, GET IT COMPLETELY LEVEL. Then your just using the finer grits to remove all the previous scratches from the 400 or 600. After 600 go to 800, 1000, 1500, 2000. You will see some scratches but it should be looking pretty good when your ready to start buffing.

you should have level and smooth sanded to at least 400-600 before
spraying your final coats. IT makes for a lot less work.

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John Mayes
http://www.mayesluthier.com

I did that, actually. My surface feels very smooth with the exception of one or two small areas that I had a hard time reaching. I'm getting ready to start with 600 grit, and we'll see how it goes.

Andy

HELP!!!!!

I started tonight - sanded lightly for quite awhile with wet/dry 600 grit till everything was level. I then moved up to 800 and did one light sanding of everything. When I wiped it off with my rag and let it dry out, several white spots appeared. I assume that means I sanded through the finish - what's odd is that I can't feel anything!

So now I have no idea what to do. If the areas are white, that would mean I've sanded off my dye. Do I attempt to reapply it somehow with a q tip or something, even though there are finish coats on the instrument? Do I just accept it and do one more coat of finish over it? Will one coat be enough?

I couldn't be more frustrated - I was being really careful and thorough...then these spots appear out of nowhere.

Here they are:






I'd like to do something about the problem tonight, so here's hoping that everybody has nothing better to do than watch the forum!

Thanks, as always,
Andy

Andy, I have almost no finishing experience. However, I'm wondering if you could tint your lacquer and spray a few more coats? Lots of guitar finishes are tinted lacquer as opposed to stained wood. Come on you experts, what is Andy's next step?

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Don Atwood
Arlington, VA

Often you will need to add to the finish. I do a 2 part finishing. First is the seal then fill and seal again. After that I will shoot about 6 - 8 coats of lacquer amd let set about 2 weeks.
   As you can see it is easy to go through that first layer. That is why I use the 400 and then after the 800 I am searching to that tell tale signs of popping through.
   If I see that happening I usually end up shooting another 2-3 coats. this is then left to cure 2 weeks . I then start at 800 since I have a good level base. Wet sanding is best as you get a better feel for the surface feel

I ended up touching up the spots with more trans tint dye in a slightly more potent solution than I'd originally used, since the original dye job was two coats. They pretty much blended in after that and the dye quickly took - you could definitely tell where there was still finish and where it had been worn off. I let it dry, then applied 3 coats of my polyurethane finish (I'm brushing since I don't have access to spray equipment) with 1.5-2 hours between each, sanding very, very lightly between coats. These coats are going on thicker and smoother than my earlier coats. I think sanding through was inevitable after my bad decision to water down the finish for my first set of coats. The instructions said you "could" add 1 part of water to 4 parts finish for brushing...I incorrectly took that to mean that you "should" do so. Turns out that the finish spreads nicely without any dilution. At any rate I think I'll have minimal level sanding to do after these coats cure. I'm going over early tomorrow morning before my last day of summer school teaching and I'll decide whether or not to apply one final coat. I may salvage this thing yet!

Andy