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Thickness of final finish. "nitro"
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=27060		 Page 1 of 1
Author:  Lars Stahl [ Mon Apr 19, 2010 2:32 pm ]
Post subject:  Thickness of final finish. "nitro"
Hi all. ok, for those who know I have been doing my fist "spraygun finish" I am finally done and I polished her today bliss . looks awesome. and I could not be happier. For those who read my previous post about the Varnish I was using. I finally sanded it all of as it was to time consuming and I wanted to get it to the customer sooner than waiting for the varnish to cure etc. So I got some Nitro and sprayed on for a few days.
My question is, what is a good nitro thickness on a finished top ? as I was warming up and then chiseling of the nitro where the bridge goes my thickness came out as 0.0075" or .20 mm. Is this a good thickness ? to heavy to thin ? Looks great though. [:Y:] . thanks you all for the help you gave me.
will post some shots later on
Lars
Author:  woody b [ Mon Apr 19, 2010 2:45 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
.005" is a good thickness for a Nitro finish. Nitro shrinks alot though. I let mine cure for 4 weeks before buffing.
Author:  Rod True [ Mon Apr 19, 2010 2:58 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
I was going to say the same thing as Woody. your 0.0075" is fine, but it's going to shrink alot and don't be surprised either if it crazes (cracks) too.

I have a funny feeling Lars that you are not a patient man :D . I too would leave nitro at minimum 3 weeks before leveling and buffing, 4 weeks is better and 5 is better still. It will still be shrinking even after several months of off gassing.

Hope this one doesn't come back to bite you in the butt too idunno
Author:  Lars Stahl [ Mon Apr 19, 2010 3:58 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
Quote:
but it's going to shrink alot and don't be surprised either if it crazes (cracks) too.
Why would it crack more if level sand after 3-5 weeks compared to now 1 week. ?
because it is that thin then ? .

I am not a patient man HAHAHA. true. allthough the gue I was fixing it for was not either. !! and I sold it to him really cheap and told him that this guitar is a training period for me. so if anything happends let me know and Ill fix it. and take all that happends on it as a learning period. :D . The time I had with the Varnish gave me LOTS of learning so I am thankfull for it even though it did not turn out as I woulod have wish.

Lars
Author:  Rod True [ Mon Apr 19, 2010 4:12 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
Only because it's leaving your shop (which i think is environmentally controlled) early in the shrinking stage?? Mind you with spring and summer on it's way, you shouldn't have to worry about the cold snapping the finish.

I'm just cautious about finishes as I've had way to many problems with mine.....maybe I'm worrying for nothing :)
Author:  Lars Stahl [ Mon Apr 19, 2010 4:31 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
Thanks Rod for your concern. The shop is "semi" controlled. This time around I am having the humidity set to lower than usual. around 35-40 as to the weather here Lars Rasmussen told me that he uses that humidity as the weather is here. Better that the wood swells a bit than srinks and cracks i guess.

Lars
Author:  BruceHerrmann [ Mon Apr 19, 2010 5:32 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
Lars, please excuse the small hijack here, I thought this might be of interest. I had to refinish the top of a damaged
guitar built by a well-known and respected luthier. He often uses Urethane finishes. I realized that, with care, I could
remove the Urethane layer in large pieces. The area underneath was obviously another material and well adhered
to the spruce. Here's an average thickness of the Urethane. Not being well versed in these finishes, I have no idea
if this is average or not. See what you think.
Image
Author:  Lars Stahl [ Mon Apr 19, 2010 7:21 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
wow thats thick ! like 0.5 mm right !

Lars
Author:  Laurent Brondel [ Mon Apr 19, 2010 7:41 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
BruceHerrmann wrote:
The area underneath was obviously another material and well adhered to the spruce.
I think it must be polyester, and Bruce, I think I know the builder. Pre-conceived notions are a hoot as the guitars usually sound great, and a fair number sound exceptional.

Lars, I will refrain from commenting on the nitro, others have. I would only add that the finish must be really soft now, and prone to be scratched and marked easily.
All I can say is I started selling my guitars only when I felt I had everything together and felt confident nothing would come back to give the buyer (and me) grief because of lack of knowledge or experience. But that's just me.
Haste does not pay off in lutherie, quite the opposite.
Author:  Lars Stahl [ Mon Apr 19, 2010 8:38 pm ]
Post subject:  Re: Thickness of final finish. "nitro"
Quote:
All I can say is I started selling my guitars only when I felt I had everything together and felt confident nothing would come back to give the buyer (and me) grief because of lack of knowledge or experience. But that's just me.


True, but this is a good friend of mine. So we are in full agreement. allthough he needed it fast as he has a gig and wanted to use it and get it shown.
Also, I see lots sending out their guitars to get it finished for them even though they have experience and knowledge. Are you referring to me as building guitars or as a finisher? I feel I got the chops for building guitars, just the spray technique and patience that needs some further thoughts on :D
Also, Laurent, I dont know if you read the post on the guitar that the buyer had posted where the glue was showing and lots of us was ranting on how poorly this luthiers work had been. until we all got to know the luthier was a well known guy with 40 years experience !! . I say it like my dad said to me as was younger. - you never get fully trained at anything, but you can do you best on your way there.
I took what you wrote quite hard as I think this is a personal assult to tell me I lack knowledge and experience. Even if I do or not It is not a good thing to say !. for your knowledge I sold this guitar for like nothing. He had put it in 0 humidity room in front of a speaker for 2 days the day after he bought it. thats the reason I got it back as the string height has sunk So I finally ended up doijng a neckreset on it. also he had benn using a plectrum and had scratched the top outside of the pickguard So out of kindness and also I felt I could use this opertunity to test my spraying I told him I would fix the top aswell for for absolutely no money at all. Allthough in the same time I was moving my gears into a different place so time ran out on me. therefor I had to move faster and therefor where I am now. !


Lars.
Author:  Lars Stahl [ Tue Apr 20, 2010 10:00 am ]
Post subject:  Re: Thickness of final finish. "nitro"
here are 2 shots of the finish.

Attachment:
IMG_0350.jpg
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