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Help with Finish
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=3617		 Page 1 of 1
Author:  Ron Priest [ Tue Oct 25, 2005 6:57 am ]
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Hey Guys :

I am trying to finish two nitro lacquer guitars. Everytime I try to buff with Poly-Buff, my finish has millions of scratchs. I am trying to rub it out by hand as I do not have a power buffer. I am using medium then extra fine. These scratchs are driving me crazy. Anyone got any suggestions on how to finish without the scratches? I read somewhere that you can use Mirror Glaze 4 then 7. But my supplier doesn't stock #4. Another place said use MG #4 then #2 then #9. This is confusing me! I tried Micro-mesh then Poly-Buff still scratches so I presume it is the Poly-Buff compounds that I am scratching with?? As I must get these finished as I have people waiting for them. (I knew I should have used the KTM-9 raather then nitro.) Any and all suggestions will be greatly apppreciated. Thanks.
Author:  Don Williams [ Tue Oct 25, 2005 7:20 am ]
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Ron,
You have to power buff nitro. I've never heard of anyone doing otherwise. Part of what makes buffing nitro work so well is that it will sort-of flow into itself when buffing. I'm not sure "technically" what is happening there, but it works. I've used the term burnish before but Mario corrected me, it's not quite that and he's right. Find someone with at least an automotive buffer and borrow it, or pay them to buff it.
Author:  Laurent Brondel [ Tue Oct 25, 2005 7:24 am ]
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When I use nitro I wet sand up to 2000, which is probably overkill, then buff
with Meguiar's Deep Crystal System step 2. If I stop sanding at 1000 or 1200
I start buffing with Meguiar step 1, then step 2. 3M machine polish Finesse It
II works very well too (#39003), but I prefer Meguiar. All of those are wax &
silicone free and can be bought in auto shops. I buff by hand too but it's
killer on the shoulders. Make sure you use 100% cotton pads (old t-shirts a
must) and that there are no particles in the fabric but I'm sure you know
that. I also always make sure that my bench is super-clean.
Author:  Michael Dale Payne [ Tue Oct 25, 2005 7:37 am ]
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Go to you local High end hardware store and get 8" canton cotton loose stich buffing pads for hand drill these are 1/2" thin but this will work if you are carful with the drill. You will need several probably 6 to complete the guitar. one set of three for med menzerna and one set for fine. These are designed to use on a hand drill. They are small versions of the same buffers we use. Load with the compound, med first and buff till scatches are gone. then with a new set load fine compound and buff. You will need agood drill with some hp. but this can get the job done. Do not try to use these pads with liquid compound. keep your pressure light and let the compound do the work
Author:  Robbie O'Brien [ Tue Oct 25, 2005 9:19 am ]
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This guitar has a nitro finish and was done by hand. I show how to do this finish in my soon to be released finishing DVD.
After appropriate cure time, wet sand up to 1500 or even 2000 grit. The use Mcquires to rub to a high gloss.
Good luck





Author:  tl507362 [ Tue Oct 25, 2005 9:36 am ]
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I don't know how Robbie can get that shine by hand. I guess his muscles are bigger than mine. I gave up using Meguiar's and used Plastic Polish #2. Using a cotton ball, press as hard as you can and rub in a circular motion in a 4" area until you see a mirror glaze. I'm constantly amazed at this stuff! I've used it on Shellac(French Polish), Lacquer, and Poly and it shined so much I had to get my sunglasses on! Good luck!
Tracy
Author:  stan thomison [ Tue Oct 25, 2005 9:45 am ]
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Robbie that doesn't look very good. Send it to me and I will make sure you don't have to look at it any more. Well since that isn't an option the video sounds great, when are you expecting it out?
Author:  Jim Watts [ Tue Oct 25, 2005 10:10 am ]
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It is possible to get a very good finish with just micro mesh. The trick as near as I can tell is sand 90 degrees from the previous pass making sure that all the scratches are completely removed from the privious grit. This is really pretty tough to do as it requires lots-o-patients. I did a few guitars this way a long time ago but now power buff like most others. You should come out with a finish like Robbie is showing.
Author:  Robbie O'Brien [ Tue Oct 25, 2005 10:13 am ]
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Stan,
The DVD should be out the first week in December if all goes well. It covers everything form oil varnishes, urethanes, lacquers, shellac, waterbournes and of course French Polish. I think people will find it useful when it comes to finishing their guitars.
Author:  Ron Priest [ Tue Oct 25, 2005 2:56 pm ]
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Thanks

I've done some testing and have eliminated 2/3rds of my problem. I still have some very deep scratches though. Probably from the 600 paper I used first. Think from now on I will start with 800 and work up to 2000.

Should I keep trying to eliminate the deep scratches through various grades of sandpaper or maybe reshoot and start with 800?? Thanks again for all the input!!

DVD might make a good Christmas present for my wife.      I also have to put a shop fox arbor and buffing wheels c/w menzerna compounds on wish list. "Heavy sigh" this building can get expensive can't it. Seems like I am always buying something to help fix up or save time. But I love building guitars. Have a good night.
Author:  Jim Watts [ Tue Oct 25, 2005 3:51 pm ]
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Ron, you probably need to sand it out if its really a deep scratch, if you shoot nitro it'll just shrink into the scratch and you'll end up sanding it out anyway. If it's from the 600 paper the 800 should remove it pretty easily. If you always sand in the same direction it can be really hard to tell when to move to the next grit.
Ahh yes, there is always something to buy. it never ends!
Author:  csullivan [ Tue Oct 25, 2005 11:27 pm ]
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Ron,
if you are looking to buy an arbor you might want to look at the 1" arbor/
pillow block set sold by Klingspor for something like $89. If you have an
old motor and some scrap lumber you can put together something quite
serviceable for not a lot of money.
Author:  Dave-SKG [ Wed Oct 26, 2005 12:26 am ]
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[QUOTE=Jim_W] it requires lots-o-patients. [/QUOTE]

Sorry Jim, Lance has them all... already.
Author:  Jim Watts [ Wed Oct 26, 2005 3:17 am ]
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Perhaps Lance can spare a few
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