Sanding EM6000

[Chris Lounsbury]

I've been browsing the forum looking for general tips on using EM6000, or to be specific, final sanding and buffing EM6000.

I did come across one post which suggested using "thinned mineral oil" as a wet sanding lubricant instead of water. Now, I assume mineral spirits would be the thing to thin mineral oil - is this correct, and what is the advantage over water?

Also, I polish by hand after wet sanding. Don't have a buffing station but if a particular handheld tool would help, I am open to it!

Just finished spraying a couple of solidbodies a few days ago and looking forward to continuing to improve my process of getting to the glossy finish line.

Chris

[Bob Gramann]

I don’t wet sand EM6000. I’ve been using 3M stickit 320 on a 2” rubber eraser to level after the first 6-8 coats. Then after 6 more coats, I level with 800 stickit in the eraser block, I then hand polish with the LMI FCP polish and then Mezerna 208 polish to final shine. When I really want a shine, I follow the 800 by working through the levels with Abralon to 4000, then the polishing compounds. Sometimes, I use a small automotive type polisher with the compounds. I clear the sandpaper when leveling by wiping it on a piece of carpet and vacuum the carpet and surface often.

The sandpaper will make seeds in the finish if the finish is not sufficiently cured or if vigorous sanding makes the surface too hot. When the finish is cured, sanding produces a fine white powder.

I’ve been afraid of a rotary buffer. I’m sure that I would occasionally launch a guitar. I have yet to produce as shiny a finish as I see sometimes on a nitro finished guitar, but I get to pretty good.

[Barry Daniels]

Here is a discussion where I show my process for buffing:

Buffing

[Marshall Dixon]

I use a rotary buffer and once launched a guitar. Fortunately it didn't take off across the room. Just hit the back against the bench. The crack in the back got repaired nicely but not a good selling point.

I used EM6000 (with the crosslinker) for 15 years or so. Sprayed 3 coats then level, 3 coats level, then 3 coats and let cure for 2 weeks. The can says cure for 5 days but I found it better to wait. Buffing it out too soon then having it cure more can dull it.

I tried water, soapy water, used it dry with 4F pumice, and used mineral oil (yes mineral spirits to thin it or wipe it off) in the final leveling. I would avoid oil in between coats fearing some residual contamination. Used 320 or 400 wet dry papers for the in between coats, going down to 1500 or 2000 at the end. A smallish sanding block with one edge angled to get onto tight corners. And another wrapped in cotton T shirt for polishing in tight corners. Then a buffing arbor with Menzerna medium and fine for the final shine.

As Bob says above, I eventually found dry sanding with 320/400 initially, then working to the finer grits, was the easiest. The important thing to remember is follow through over the edge pushing the dust off the surface and to clean the paper and the surface meticulously after one or two strokes. Either wet or dry, any little corn on the paper will scratch. Less time consuming to clean the paper frequently like this than to pry off those little clumps. Or repair the scratch.

I've used buffer pads on an orbital sander and an auto body buffer with a wool pad like Barry does. Use a 3M product and Macguire's similar to what he uses on some things. They work well but with arthritic hands I find it easier to hold the work against the machine than vice versa.

But, back to sanding; keep your paper and surface clean. I clamp a brush, bristles up on the bench for the pad and have a brush in the other hand for cleaning the surface.

[Chris Lounsbury]

Thank you for taking the time, Bob Barry and Marshall.

Dry levelling during the build process with 400P Mirka gold paper went very well. Was able to wet sand with water and Mirka W/D 1200P and 2000P without incident using a fresh white rubber eraser as a block. Again, this went fine.

Buffing out by hand with Novus (2) Fine Scratch Remover is not going to cut it (especially since one of the two instruments I'm working on is black!). Simply cannot find an available unit of the ShopFox buffing arbor I was considering so, I have ordered the handeld polisher referenced in the thread Barry linked to, with supplies. Will happily report back when I've received and used it.

[Barry Daniels]

Yep, buffing by hand is really difficult. On some repairs where I have small areas that need to be buffed out, I use the Meguiars 105 on a cotton cloth wrapped around my index finger and apply a bunch of pressure. It doesn't take long to wear out the finger.

[Chris Lounsbury]

Probably should have reported back earlier but, at least I have good news. The handheld polisher from Adam's Polishes was just the compromise I needed between too-laborious-and-unsatisfactory-anyway hand polishing and the unavailable-at-a-reasonable-price buffing arbor setup. Worked well and even the black instrument came out looking pretty good. Thanks to everyone!

[Barry Daniels]

Another happy customer for the Adams. I have recommended it to at least 6 builders that have tried it and liked it.