Official Luthiers Forum!

Okay, Amazon has Mirka 6" Solid PSA, peel and stick abrasives for $24.00 or thereabouts per 100. My question: What grits are most useful to you on a Random Orbital Sander or DA dual action sander? We are talking acoustic guitars here, bodies mainly, Necks where appropriate.

Here are the grits they list in the Mirka Gold by Bulldog.80,100,120,150,220,320.

Free shipping over $25 which means two boxes minimum. Most have 5" machines, anyone with 6" want to split an order and share the expense, I'll probably get at least three grits, thanks, Bruce

Bruce, I think I use all of the grits that you listed. I got a bunch of them (not Mirka) from Grizzly's catalog. It'll be a while befor I get those used up though.

Oh well, I use the 5" disks anyway.

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Dave Rector
Rector Guitars

The first time I turned my sander on, a six inch Porter Cable, it paid for itself. But I've only used up three discs so far and the one that came with it.

So it's now time to stock up and I'm looking at Mirka and one more that's more like a heavy belt sander type backing and color. Red not yellow.

I start with 20 grit and then move directly to 2000 grit.

no but really I do 150, 220, 320 and then make sure there are no swirl
marks by hand.

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John Mayes
http://www.mayesluthier.com

Bruce may I recamend that you give micro mesh pad a try on your orbital you can get them in psa or loop and a soft touch pad adapter. It makes final leveling a breeze on backs and topsMichaelP38587.7001851852

check out industrialabrasives.com
I have been using thier stuff for years. If you know a cheaper place let me know
john hall

Michael, do you use a lubricant of some sort with the micro-mesh pads on your ROS? I tried running over some nitro with it dry and it gummed up the disk almost immediately.

If so, what type of lube do you use? And how do you keep it from going into the soundhole or bridge pin holes? I can't quite make myself do it for fear of trashing the inside of a guitar.

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Dave Rector
Rector Guitars

Yes. Soapy water I am speaking of a pneumatic variable speed orbital sander

As far as keeping it out of the interior of the guitar I use a balloon and a plastic butter lid. I blow up a balloon insert it into the sound hole; fold a plastic lid enough to get it in the hole. The balloon holds the lid tight to the inside of the top. Actually the balloon is already there I use it to seal the sound hole while spraying finish. I don’t mount the bridge or drill bin holes till after I finish with the micro mesh the only hole that is drilled in advance of spraying finish or leveling is the end pin hole because I want the finish to seal at the end pin edges to eliminate any chance of the finish pealing there.

Hey Bruce. Just curious. Do you use that sander? I go thru 3 discs in an hour.

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Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Micro-mesh MX series for hard woods and soft metal are better for dry sanding that the regular micro-mesh, but for final finish wet sanding I use the regular

The grit grading is differnt so be aware.

Bob, Not like you do apparently. But after using in on one guitar, it convinced me of it's value in the luthiers workshop. When I get a pile of these Mirka discs, and at 25 cents each, I won't hesitate to change them. Actually the Mirka and the Porter Cable ones are different. Paper backed as opposed to cloth backed, which cost a buck a copy.

Bruce that is a great tool. I usually get the discs from Target Coatings. They carry Mirka too.

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Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

I looked at Industrial Abrasives, but couldn't quite find what I was looking for. Target, okay, been there before. Well I went with Amazon and Mirka. You pays your money, you takes your chances. Ships get this, Sept 6, I can expect delivery Sept 15, yippee free shipping, while I sit and wait for three weeks by my mail box. What a deal. Of course I could cancel.

I bought some yesterday at Lowes to tie me over. (tide me over? Heck something like that.)

Michael, thanks for the explanation!

Gonna have to try doing it your way. My arm is getting tired.

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Dave Rector
Rector Guitars

[QUOTE=Dave Rector] Michael, thanks for the explanation!

Gonna have to try doing it your way. My arm is getting tired. [/QUOTE]

be sure to get the soft back pad for you RO. the standard backing pad that comes with most ROs is to stif to conform to a contour surface therfore only part of the pad is in contact and gives uneven wear. I use 100-320 MX series (eq. to 320p-800p) to dry levelIt does not clog near as much, also I do this with my electric and holes for vacume dust removal. Then 1800-12000 regular micromesh to wet polish,polish with Meguires #7 then buff out with fine compound and your good to go.MichaelP38588.7150231482