Official Luthiers Forum!

Just wondering if there are some types of high grit sandpapers that work better with different finishes than others? In other words if you a chooose specific type/brand for nitro and a different one for poly etc.

Specifically, if there is a type particularly suitable for shellac?

More generally, what are your favourite papers for wet sanding, and where do you get them?

We have tried a few other brands such as Norton and Mercer, including a Japanese finishing paper that was quite good, but 3M Imperial P400-P800-1200 is our default wet sanding progression. Paper for wet use is always soaked at least overnight before use. The advantage of the 3M Imperial is that the backing holds up over months of use versus a few weeks, so we can cut and load the 400/800/1200 containers every few months and count on a well-soaked piece of paper for either new instrument finishing or touch-ups. We buy ours from Amazon directly through 3M, and accept that the usual delivery time frame is usually a few days versus the month + usually given on the site.

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For the times they are a changin'

- Bob Dylan

Thanks!

And do you use just water, or soap as well?

And also, what grit do you take it to before hitting the buffer?

For lacquer and two-component polyurethane, water and a bit of detergent to help float the sanding dust. For EnduroVar, we use the paper dry, although we're finding that sterated papers do a better job dry sanding. EnduroVar can be wet sanded with water, but only after fully cure (21 days) and at the risk of showing witness lines if the finish was applied in more than one session.

1200 for lacquer and 800 for urethanes - mostly because we can lean into the wheel a lot more without cutting through what is usually a very thin finish.

_________________
For the times they are a changin'

- Bob Dylan

Assilex , LOL and Buflex japanese sandpaper both from amazon, excellent papers can be reused and cleaned with water soap and a plastic toothbrush, I/ve used them on FP , shellac, and enduro var . I use 400 grit and 3k , they should be used with a velcroor foam backer. They also become softer with use ,so that a 400 becomes 500 and a 320 becomes 400. My 2 cents

I like using micron and trizact "papers" (mylar) for the finer "grits". They have more uniformly sized abrasive surfaces and can be used wet without soaking. They last a long time.

Assilex here also. I've tried lots of different types/brands of paper but find assilex far better.

I use it on Cardinal Luthierlac mostly now, but I have used it with success on 2 part royal lac also.

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Joe Beaver
Maker of Sawdust

MicroMesh for shellac works great ... when it clogs up, just swipe it across a piece of carpet.

For French Polishing, I'm getting the best results sanding to 4000 and then doing one (sometimes 2) final (fairly dry) session to achieve gloss

Also consider what you use for final polishing. We buff (using two of the Stewmac 14" buffers) starting with medium Menzerna compound...this cleans up urethanes sanded to P400, but P800 requires less time on the buffer and reduces the risk of cutting through thin finishes. Lacquer needs to go to at least P800 if not 1200 prior to buffing to avoid. For those without stationary buffing systems, the films and other finer grit foam-backed abrasives sound like an excellent idea.

I'll also investigate the recommendations made, as we end up dry sanding EnduroVar...which drove the replacement of the old compressor with a new Quincy this month. With the new compressor in the shop able to easily support air sanders, we've been doing more Abranet dry sanding of both lacquer and EnduroVar finishes, with the ability to quickly flatten the top and back a real timesaver. The 400 and 800 Abranet disks do a pretty good job on the Dynabrade air sanders as long as the shop vacuum is clearing the dust. I'm working on developing my technique for machine-sanding the sides, but I may need a smaller diameter, softer pad for that work.

_________________
For the times they are a changin'

- Bob Dylan