Buffing alternatives

The Achilles' Heel of Luthiery
kredwards

Re: Buffing alternatives

Post by kredwards »

Tony,

I second Josh's comment. For us first timers, the devil is in the details.

Kent
DaveH

Re: Buffing alternatives

Post by DaveH »

I primarily work with Nitro-Lacquer, but the concepts should apply to all film type finishes. As others have commented, let the finish cure. Since I spray at a 50% reduction each coat is fairly thin. I will typically build my total finish over about a week period. Applying no more than 2-3 coats per day. Depending on drying conditions, I let my finish sit about 4-7 days before wet sanding and rubbing. If you apply your finish with a brush I would apply at the rate of one coat/day. A brushed coat will build 3-4 times faster than a sprayed coat. You will likewise need many fewer coats. You may want to let a brushed finish sit longer. In only sand up to 1000 grit and look for a pefectly flat (dull) surface. This will also be a perfectly level surface.

I hand rub. This is by far the safest approach and can provide excellent results. Use soft cotton rags - clean ones! You can use a variety of rubbing and polishing compounds. I use automotive compounds. I have some 3M Imperial Rubbing compound that I've had for years. A little goes a long way. Start with a rubbing compound, working in small circular motions. If the correct amount is used it will quickly breakdown and start to polish. You can then follow up with a polishing compound. There are many out there (3M, Mequirs, etc). These will vary in the amount of abrasive. Some can act more like a rubbing compound and some will act more like a swirl-remover and light wax. Read the labels carefully or get on the manufacturers website for a more detailed description.

While a power buffer may make for quick work, it can likewise make for a quick mistake! You've already got a 100+ hours in your guitar build. You can make a mess is a matter of seconds. It should only take an hour or two to rub and buff a guitar. Why try and do it in 15 minutes?
Ken C

Re: Buffing alternatives

Post by Ken C »

I know this thread is about alternatives to power buffing, but there seems to be a push to steer folks towards hand buffing rather than learn how to machine polish. While I certainly don't want to encourage someone to stretch too far beyond their comfort level, I can't whole heartedly support the recommendations to avoid power buffing. If the guitar you are working on is the only item that you will ever buff or if your funds or access to tools is very limited, okay, then by all means hand buff. But if you have ever wanted to learn, now could be the best time.

Would you rather learn to machine polish on your first guitar that may already reflect a few 'learning experiences' or would you rather learn on your 5th guitar when your craftsmanship has really improved? The biggest mistake you can make with machine buffing is burning the finish, which can result in refinishing, but contrasted to other building mistakes can generally be invisibly repaired. Hand buffing can bring out the gloss, but a good machine polish provides stunning clarity.

Like any aspect of building a guitar, finishing is just another step to learn. You need to decide how nice you want the finish and how far you are willing to go to get that finish. Some guys want the finish but send the guitar to a professional finisher to get it. If hand buffing is something you are comfortable with and will be content with, then the hand buffing recommendations in this thread will be great. But if you want that uber clear, high gloss finish that only a machine polish can provide, then by all means dive in and learn how. The difference is not simply a savings in time.

Ken
tippie53
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Re: Buffing alternatives

Post by tippie53 »

Fit and finish is the hard part of building. Nitro finish is my choice. I like the back door factor but when it comes down to it , you have to find the technique that works for you. My finish schedule is the same a Martins.
I use a thinned mix of about 80% nitro 10% Butyle acetate and thinner, The butyle acetate is a retarder and allows the material to flow. I do not use deft but will use Mohawk , Behlens , or Shirwinn Williams. I will not use shellac as a sealer , this may cause adhesion issues and I don't use Deft. I know some of you may and I am not saying not to but after 11 years I found this is the better products to use.
I stain then seal . I use the vinyl sealer after stain and again after the filler. My filler is pore o Paq . You have to find the technique that works best for you. Once I have the filler I hit the body with sealer and while that is tacky I hit it with a fogged coat of lacquer to get a good weld in on the finish. When I do hit the finish I spray 1 coat every hour for 8 hrs to get a .016 to ,020 build. Then I let it cure 3 weeks and start to level sand.
One the coats are level I hit 3 more finish coats thinned and retarded for flow. Cure 3 weeks and start the finish wet sand process and buff and polish. I tried hand, auto buffer , then the random orbital and finally got the arbor. I know not all of you have the space for the tooling .
Hand buffing is tedious but will work. I can't stress enough about the patience and prep. Finish is all about patience and technique. Once you get it dialed in and you find your techniques you can see the end results are what you want . don't change.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Tony_in_NYC
Posts: 827
Joined: Thu Aug 12, 2010 9:11 pm

Re: Buffing alternatives

Post by Tony_in_NYC »

jdb wrote:
Tony_in_NYC wrote: Doing it by hand takes a little elbow grease, but not too much. You dont need, and cant really apply much pressure when buffing anyway. I would give it a shot by hand first.
Tony - can you go into more detail on when you did it by hand? What compounds did you use? What material, etc.?

I am currently in the stage of wet sanding and have the exact same questions as Kent.

Thanks in advance!

Josh
OK. Assuming all of your prep was good, and you level sanded everything perfectly flat, and ran the grits up to 2000 or higher, here you go:
I used Wizards Finish Cut One Step to compound out the finish. Read the instructions for your compound and watch videos on youtube. It helps to use the product correctly. I followed with Wizards Shine Master. Again, follow the instructions on the bottle and work small areas at a time. Its not hard at all.
I agree with Ken Casper that a buffer will get a better shine if used properly. Your best bet is to finish some test panels before trying your technique on your guitar.
kencierp

Re: Buffing alternatives

Post by kencierp »

I would indeed steer builders away from power buffing. If proper grit progression followed by high quality rubbing compounds and polish (I recommend Wizards) a manually buffed surface will match one that is power buffed. As a matter of fact at the "Williams Paint School" (training compliments of GMC) here in Michigan we were instructed to work one half of our test panel each way just to prove that point. Note that even with a power buffer "swirl remover" and final polish are usually applied by hand anyway. Power buffing a flat panel is pretty simple --- a guitar has a zillion curves and edges --- a split second too long with a power buffer and all the finish can be removed from an edge -- I can assure you that the anticipated joy will also disipate instantly replaced with a very high level of anger. Not to mention the new work you made for yourself. --- $.02
tippie53
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Re: Buffing alternatives

Post by tippie53 »

Martin has a cnc power buffer and before that it was hand power buffed. this is where you need to decide what works best for you. A proper buff job will make or break the finish.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
kencierp

Re: Buffing alternatives

Post by kencierp »

Many of the you tube Martin videos have been removed --- since Martin now sells a factory tour DVD --- but I'll try and find the one where Dick Boak makes a comment stating most of the justification for the new CNC process was the prevention of burn through and the associated repair cost. He states that this was a problem even for his most skilled associates.
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
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Re: Buffing alternatives

Post by tippie53 »

the cnc also proved to help ergonomics but still the power buffing was used a long time. Burn through can happen if you are not careful. The end results are worth the effort in learning how. I was at Woodstock Ny at the guitar show and finishing is always a topic . All the pros that I know use them.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
kredwards

Re: Buffing alternatives

Post by kredwards »

Well folks, I have finished (?) my first build and I must say it sure sound good. Now all I have to do is learn how to play. I used aerosol cans of clear lacquer from Stew Mac (20 coats), let it cure for a month ( one of the longest months of my life), leveled with 800 micromesh and wet-sanded with 1000, 1200, 1500 and 2000 micromesh. I then completed the finish with micromesh pads from Stew Mac up to 12,000 and Meguiar's Swirl X swirl remover. The end result is amazing. I am sure it took a lot longer than a buffer would have, but I am very pleased with the results.
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