Shiny finish

The Achilles' Heel of Luthiery
ruby@magpage.com
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Shiny finish

Post by ruby@magpage.com »

I am almost applying finish on #9. I have always brushed a finish and then leveled and polished it out by hand with whatever paper or mesh I am using wrapped around a hard rubber block to give a little flexibility. What I came up with early on is a sequence from 400 wet/dry paper, through micro mesh 8000, then a couple grades of polishing compound - about 10 different sessions. I keep thinking I am doing too many different grits and compounds.

If you finish by hand, what is your sequence of abrasives?

thanks

Ed
Ed M
tippie53
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Re: Shiny finish

Post by tippie53 »

I know a few hand finishers
the pretty much do it your way then use buffing and polish compounds.
it is a time consuming process . He uses felt pads on the buffing. They are about 2 by 3 in.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
jread
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Re: Shiny finish

Post by jread »

I'm still learning and you've seen my threads but am getting close to a desired schedule so here's what I'm doing and a sample result.

My shellac hand polishing is going something like as follows but my main note is that each day the guitar tells me what it needs on the finish. If I dare think I'm on a schedule, it goes haywire. But in a dream situation here it is for me currently.

One more note. It is true that the longer I wait between sessions in the last phases, the better. Stuff takes a lot longer to harden than you imagine and is definitely is easier to work with 2 or more days apart vs trying to jump on it the next morning. The whole thing takes 2-3 times longer than you would expect if you add up the sessions. Just keep polishing and stop counting is my current goal.

I am not really starting w/ bare wood because I pretty liberally use shellac to seal everything throughout the build. By the time I get to finish, I feel I'm well into the build sessions.


shellac wash coats
wet sand to 320 or 400.
I use leather or felt or styrofoam

shellac build coats, w/ baby oil
lots of building sessions, sanding in between if really needed but that means you prob went back to step 1
sometimes 400 or 600 going up to 1000 at the end of the build coats
when 1000 seems good and you polished over that, we are at the end of build.


shellac polish coats
spirit, compact, harden, lightly build, smooth w/ sandpaper bits as needed. lots and lots of times. Build up low spots on the rim, etc.
i tear little bits of 1000g and address tiny scratches if it is just in the shellac
sometimes I wet sand the whole top w/ 1000g and that resets polish coats w/ a better surface prep. Just don't go through to wood.
Experience will have me doing this less.
I hand polish w/ the t-shirt ball but sometimes go up the micromesh stack if it seems to want it.
I've actually spot wet sanded w/ the 12000 pad w/ shellac on it to address bits after the 1000g is too rough.

Finish:
At this point, there should be no need to use the mesh pads. 12000 should seem too rough. Novus 2 scratch remover is my final session and I do
that at before string up. Then, a few weeks later one more time which hasn't happened on this example yet.
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jread
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Re: Shiny finish

Post by jread »

Sorry to fill your post but I feel I'm doing well w/ this hand polished shellac business.

I tend to hit my FP 1st thing in the morning and today's status is what I described in my 1st reply. The little 'bits" that stick up out of the finish and also the little scratches and divots that dip below your surface are what you are after in these final polishing stages. This stage, 1000g paper is too rough. I try to buff w/ the t-shirt rag but if a spot won't give in, I may take the 12000 mesh pad and just use that instead of the t-shirt. I does not ruin it and I haven't even had to clean it. This is basically doing what a buffing wheel would do. Getting those little tiny bits and maybe dust off, filling little tiny divots. If 12000 doesn't work, you need to go back a step.

I ensure I'm well lit and I always keep the glare of the lights in my eye on the spot I'm working. The audience will see faults in a guitar's finish when it hits the glare spot. Hard to see when there is no glare is what I'm saying. Seeing the surface is a learned skill for sure. Use different lighting and don't worry about magnifying glasses because no one is ever going to get that close to it.

The one on the bench is basically done. I'll let it sit for a week then Novus 2 scatch remover. that stuff is magic. You can rub it pretty hard to get any spots you missed, then when it dries it wipes off and buffs w/ an old t-shirt. Shiny like mad.

This finish feels just great. I get nothing but smiles and compliments about how it feels. The one being played will get one more novus 2 pass after it gets a final setup.

final caveat: I'm just starting out w/ less than a year of experience. Take all this with a grain of salt. FP is a huge topic.
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ruby@magpage.com
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Re: Shiny finish

Post by ruby@magpage.com »

j

I did my first 2 in shellac, one in 2012 and one in 2013. They don't get heavy use and I just noticed on the second one a spot about 1/4" in diameter that looks like I spilled some Jack Daniels on it - finish almost all gone. This is right on the top so I would have noticed it soon after it happened, and the finish had plenty of time to harden up. I don't use shellac anymore and have tried several varnishes, both water based and conventional. That is what I am looking for advice on polishing. I can get there, I just need to know if I am going through too many steps

Ed

1) KTM 9 on dyed mahogany - water based, not made anymore

2) Wipe-on Minwax on Alaskan Yellow Cedar

3) TruOil on Ash
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Last edited by ruby@magpage.com on Wed Jul 15, 2020 7:44 pm, edited 2 times in total.
Ed M
jread
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Re: Shiny finish

Post by jread »

I realized after i typed it all up but oh well. :D
jread
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Re: Shiny finish

Post by jread »

I realized after i typed it all up but oh well. :D
Kevin Sjostrand
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Re: Shiny finish

Post by Kevin Sjostrand »

Ed,
When I was finishing by hand, I was hand sanding after leveling 600, 800, 1000, 1500 then switched to rubbing compound (by hand and also using a RO with buff pad on it), polishing compound, and swirl remover. Worked for me until I got the buffing wheel setup. I don't remember what Micromesh 8000 is equivalent to.
Those steps resulted in a scratch free finish (to the naked eye of course).
ruby@magpage.com
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Re: Shiny finish

Post by ruby@magpage.com »

Naked eyes are all I got, Kevin. Your information is what I am looking for - anybody else?

Thanks

Ed
Ed M
Diane Kauffmds
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Re: Shiny finish

Post by Diane Kauffmds »

If I have to level to finish, I wet sand starting at either 600 or 1000g, depending on how much I think the finish needs leveling. I do this very lightly, and I add a couple of drops of dish detergent to the water for lubrication.

When the whole guitar is dull, I use micromesh, starting with the lowest grit, which I think is 1500g, and i go through the whole sequence, which i think is to 12,000g. I finish with Novus #2.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
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