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Advice on finishing a body
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10123&t=48300		 Page 1 of 1
Author:  isherwoodc [ Tue Sep 20, 2016 8:50 am ]
Post subject:  Advice on finishing a body
Hello all,

I wonder if I could get your input into my latest 'project'. It's a tele kit build with the pickups replaced to something a lot better. I've marked out the holes and it's now ready for its paint/finish.

I've recently finished a re-paint for my nephew, where I applied a primer, many coats of paint, many coats of gloss finish, then I sanded it back with 1200 grit paper and polished. I wasn't too happy with the finish - it was a little uneven (where I hadn't sanded enough and I know for next time) and it didn't come up shiny and 'new guitar' looking - not sure if it was the sanding or the polish I applied, but it's more of a satin/dull gloss finish. This has kind of put me off doing the same for my latest guitar, so I'm asking if anyone has any other avenues I could try, which may be a little easier for me being a beginner (maybe wood stain? or a colour with the wood grain showing through?).

Here's the guitar just before I dismantled it.

Image

Look forward to hearing your suggestions!

Chris
Author:  Chris Pile [ Tue Sep 20, 2016 10:36 am ]
Post subject:  Re: Advice on finishing a body
Easy finish.... TruOil, Watco Danish Oil, MinWax Wipe-on Poly..... all apply with a rag or brush.
Author:  Rodger Knox [ Tue Sep 20, 2016 11:22 am ]
Post subject:  Re: Advice on finishing a body
What king of sealer, what kind of paint, and what kind of gloss finish? Was it sprayed, wiped on, or brushed, and if brushed, what kind of brush.
I'll agree with Chris on his recommendations, but it would be nice to know why what you did before did not give the results you expected, and we need more information for that.
Author:  Freeman [ Tue Sep 20, 2016 11:44 am ]
Post subject:  Re: Advice on finishing a body
There are as many ways to finish a guitar as there are those of us who build them. Your post implies to me that you "painted" your first guitar - an opaque finish that hides the wood and provides color. Most of the time when we do that (think of all the Fender colors) we use automotive products and frankly I'm not an expert on those. If you want to follow that route I would suggest finding someone who finishes cars or better yet, a custom motorcycle painter and get them to help.

Next choice of finishes are the all the variations of oils - usually these are some sort of furniture finish and the results tend to be what you would expect on a coffee table. One very popular candidate here is TruOil - its a gun stock finish that you can get at any sporting good store. There are good instructions on line, it does buff to at least a semi gloss. I tried it once on a tele clone made from reclaimed wood - I wasn't happy with it, stripped it off and shot lacquer. Here was my Barncaster with the TruOil

Image

There are a couple of other traditional finishes - French Polish is hand applied shellac and was used on a lot of classical instruments. I've never done a FP, if I was ever to build another classical guitar I would tho. Instructions on line.

I've built about 20 guitars to date and my finish on all of them has been either nitrocellulose lacquer or a waterborn lacquer. I have finished guitar with rattle cans but now have a compressor and small gun. I highly recommend lacquer - it does have safety and environmental issues but its just darn hard to beat. Here is the Barncaster with rattle can nitro

Image

I highly recommend Dan Erlewine's book on guitar finish and StewMac has a whole lot of information about their products on line. As with anything else, practice on scrap.
Author:  isherwoodc [ Tue Sep 20, 2016 3:13 pm ]
Post subject:  Re: Advice on finishing a body
Rodger Knox wrote:
What king of sealer, what kind of paint, and what kind of gloss finish? Was it sprayed, wiped on, or brushed, and if brushed, what kind of brush.
I'll agree with Chris on his recommendations, but it would be nice to know why what you did before did not give the results you expected, and we need more information for that.


I used a matt black spray paint (acrylic - made for any surface) it went on really well and stuck nicely, I also used a blue spray paint (which is for automobiles - gloss finish, also spray) I then used a clear 'sealer' spray with a gloss finish, which I used about 5 - 6 coats. I then wet sanded it with 1200 grit, cleaned it, then used car polish to finish it off. I would love to know what I should have done differently (can provide photos if you need them!)
Author:  isherwoodc [ Tue Sep 20, 2016 3:20 pm ]
Post subject:  Re: Advice on finishing a body
Thanks again Freeman - you gave me some help with my bridge in the other forum post!

I've decided on the Tru oil for the maple neck, and I've found some pretty good stains/oil finishes from Crimson guitars, who also have a lot of youtube video's on how to apply it etc.
Author:  Rodger Knox [ Tue Sep 20, 2016 3:35 pm ]
Post subject:  Re: Advice on finishing a body
I don't see anything wrong with your schedule, except maybe the wet sanding. I think it's typical to work from ~800 grit to ~2000 grit with a backing block, but I've never sprayed nitro so I don't know. Also the products you're using are all acrylic, which is fine for solid body electrics but not so good for acoustic guitars. If you're going to use TruOil, I do have experience with that. Here's my schedule:
TruOil Finish
The pores need to be sealed, but not necessarily completely filled before you start the TruOil, I typically brush on a couple of coats of 2# cut shellac, and sand back to wood. This does not fill the pores, but it does seal them. You don't have to sand, but I prefer the appearance of the oil directly on the wood. If you do sand, you need to get all the shellac off or it will show. With the pores sealed, the first 6 coats of TruOil will fill them. The first couple of coats will take a bit more oil to seal the wood, unless you left the shellac. Once it starts to shine a little after it dries (usually 3 or 4 coats), you can use less oil. I put the TruOil on very thin, at least 4 hours between coats. Every three or four coats I'll let it dry 24 hours and level sand, starting with 400 or 600 grit, and working my way up. When I get 16 to 20 coats, and have level sanded with 1000 grit, it's almost done.

The last coat has to go on perfectly, and then I'm done. I don't sand back after building the finish as is typically done with a nitro finish. This method produces a "soft gloss" which I prefer over the appearance of nitro.

I've found it works better if you stretch it out, there's less shrinkage if you allow more drying time. I'll frequently wait 3 or 4 days to sand back, 24 hours is a minimum. I usually take at least a month, sometimes six weeks, to do a finish. It's probably only 4 hours of actual time spent, and can be done in a week, but there will be some shrinkage, similar to nitro. Nitro is sanded back, and you can also do that with TruOil, but I wouldn't advise it. It's thinner than nitro, and getting it thick enough to sand back would take 40 or 50 coats.

Do NOT wetsand at any point after you start the oil, use dry paper on a block. Wetsanding will usually guarantee witness lines.
Author:  isherwoodc [ Tue Sep 20, 2016 3:41 pm ]
Post subject:  Re: Advice on finishing a body
Thanks Rodger, is the shellac really required? I'm just a bit worried as I have no experience in it and don't want to add more steps in that could trip me up from being a beginner. Would your process differ at all for the fret board? as I'm assuming I won't be sanding that down. At the moment, and what I've read on the Crimson guitar product pages, is that the finishing oil they sell (is similar to tru oil) and the more coats you apply the more gloss it looks - and I assume you don't need to finish it once you have it at a point you like the look of
Author:  Rodger Knox [ Tue Sep 20, 2016 3:56 pm ]
Post subject:  Re: Advice on finishing a body
You don't need the shellac for maple, it does not have pores that need to be filled. If the fingerboard is maple, you can do that the same as the back of the neck, but TruOil is not as hard as lacquer and will wear quickly on the fingerboard. Rosewood or ebony fretboards are usually unfinished.

I don't do any sanding or polishing, but you can polish TruOil to a pretty high gloss with an automotive type buffer. You do need to wait at least a couple of weeks before buffing, TruOil does shrink as it cures similar to lacquer.
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Here's a TruOil finish on paduk.
Author:  Freeman [ Tue Sep 20, 2016 7:17 pm ]
Post subject:  Re: Advice on finishing a body
isherwoodc wrote:
Rodger Knox wrote:
What king of sealer, what kind of paint, and what kind of gloss finish? Was it sprayed, wiped on, or brushed, and if brushed, what kind of brush.
I'll agree with Chris on his recommendations, but it would be nice to know why what you did before did not give the results you expected, and we need more information for that.


I used a matt black spray paint (acrylic - made for any surface) it went on really well and stuck nicely, I also used a blue spray paint (which is for automobiles - gloss finish, also spray) I then used a clear 'sealer' spray with a gloss finish, which I used about 5 - 6 coats. I then wet sanded it with 1200 grit, cleaned it, then used car polish to finish it off. I would love to know what I should have done differently (can provide photos if you need them!)


I'm not familiar with those materials but the schedule looks basically OK. With nitro I prep the wood in a variety of ways (depending on the type of wood), spray enough coats to get the build and color that I want. With nitro you can spray three coats a day and I sand to 320 or 400 each day (sometimes between coats). After the last coat I let it set at least 2 weeks - I would wait longer for acrylic unless it was catalyzed. Then, assuming there are no scratches and minimal orange peel I start wet sanding with 800, 1000, 1200 and 1500 - each grit takes out scratches from the previous one. Then I buff with medium and fine compound - I like Meguiars #2 and 3 but there are other choices - avoid wax and silicon.

I have a friend who is a custom motorcycle painter (he has traded paint jobs for a vintage Les Paul if that gives you an idea of what he charges). He uses basically your schedule on metal - primer, color, clear, sand from 800 to 1500 and buff. The only big difference is that he uses catalyzed finish.

I don't know if it will help, but here is a translucent color lacquer finish being applied to my current build. The finishing starts at the bottom of page 4 of the thread. It gives you some idea of the care I take with sanding at intermediate stages.

http://www.harmonycentral.com/forum/for ... -335/page4

Other than my one try at TruOil, I have no experience with any oil finish so I'll leave that to the people who work with it
Author:  dzsmith [ Tue Sep 20, 2016 7:55 pm ]
Post subject:  Re: Advice on finishing a body
I tried Tru-oil once and I may use it again.
The key process that worked for me was to apply it, then wipe it back off leaving thin coats.
Don't soak the wood, it will take forever to dry. I made this mistake based on a video I saw.
I did not end up with a mirror finish, but the grain and figure enhancement using Tru-oil is outstanding.
It's a joy to apply, especially compared to lacquer.
Dan
Author:  isherwoodc [ Wed Sep 21, 2016 3:53 am ]
Post subject:  Re: Advice on finishing a body
dzsmith wrote:
I tried Tru-oil once and I may use it again.
The key process that worked for me was to apply it, then wipe it back off leaving thin coats.
Don't soak the wood, it will take forever to dry. I made this mistake based on a video I saw.
I did not end up with a mirror finish, but the grain and figure enhancement using Tru-oil is outstanding.
It's a joy to apply, especially compared to lacquer.
Dan


That looks beautiful, what finish did you apply to that if any? (other than tru oil)
Author:  Rodger Knox [ Wed Sep 21, 2016 11:11 am ]
Post subject:  Re: Advice on finishing a body
That's the lovely soft gloss of TruOil, and there's nothing better to pop the grain, especially on nice figured wood.
Nice Tele, Dan.
Author:  dzsmith [ Wed Sep 21, 2016 11:28 am ]
Post subject:  Re: Advice on finishing a body
isherwoodc wrote:
dzsmith wrote:
I tried Tru-oil once and I may use it again.
The key process that worked for me was to apply it, then wipe it back off leaving thin coats.
Don't soak the wood, it will take forever to dry. I made this mistake based on a video I saw.
I did not end up with a mirror finish, but the grain and figure enhancement using Tru-oil is outstanding.
It's a joy to apply, especially compared to lacquer.
Dan


That looks beautiful, what finish did you apply to that if any? (other than tru oil)

Only Tru-Oil was used on this one.
Dan
Author:  Don Williams [ Wed Sep 21, 2016 6:37 pm ]
Post subject:  Re: Advice on finishing a body
I'm really surprised how few on this forum have any experience with actual "painting" of instruments using automotive type paints...!
I have to believe it's a real specialized thing. It can't be hard...and seems it's a matter of finding the right information regarding fillers, sealers, primer coats, base coats, and clear coats. Darned if I can find much, even on youtube. Lots of info on "refinishing" so perhaps that's the stuff to look at.
Author:  Freeman [ Wed Sep 21, 2016 7:29 pm ]
Post subject:  Re: Advice on finishing a body
Don Williams wrote:
I'm really surprised how few on this forum have any experience with actual "painting" of instruments using automotive type paints...!
I have to believe it's a real specialized thing. It can't be hard...and seems it's a matter of finding the right information regarding fillers, sealers, primer coats, base coats, and clear coats. Darned if I can find much, even on youtube. Lots of info on "refinishing" so perhaps that's the stuff to look at.


I have a friend who is one of the best custom motor cycle painters in the world (he has traded a paint job for a vintage Gold Top if that gives you some idea of what he gets for his work). Anyway, on this page there are a few of his guitar paint jobs (click on the image to blow it up)

http://www.trickpaint.com/galleries/helmets.shtml

I asked him about the products he uses, here is a quote from that e-mail "When I refer to automotive finish I am really referring to polyurethane products, which are generally 2 part systems, the primer/ paint/ clear coats are mixed with a catalyst and harden through chemical reaction"
Author:  fumblefinger [ Wed Sep 21, 2016 9:39 pm ]
Post subject:  Re: Advice on finishing a body
At the risk of being banished for quoting another forum, this conversation has some of the best advice from a couple of the best. Brian Howard does finish work for other luthiers. Worth a read if you're thinking of 2K acrylic.

http://www.mylespaul.com/forums/showthread.php?t=365754
Author:  Chris Pile [ Wed Sep 21, 2016 11:52 pm ]
Post subject:  Re: Advice on finishing a body
Quote:
I'm really surprised how few on this forum have any experience with actual "painting" of instruments using automotive type paints...!


I used to shoot a bunch of nitro back in the 80's and 90's. I can still do it, but no one is asking.
And while I wouldn't call it hard, you DO have to have your crap together.
Author:  Freeman [ Thu Sep 22, 2016 8:45 pm ]
Post subject:  Re: Advice on finishing a body
For the OP, there is a pretty good thread about TruOil running at the main forum right now.
Author:  Rodger Knox [ Thu Sep 22, 2016 11:00 pm ]
Post subject:  Re: Advice on finishing a body
Don Williams wrote:
I'm really surprised how few on this forum have any experience with actual "painting" of instruments using automotive type paints...!


Just because I use TruOil doesn't mean I don't know how to use lacquer, I did custom paint on motorcycles in the '70s. Here's a couple of teles I did for my grandkids.
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