Cracks in Finish

The Achilles' Heel of Luthiery
phavriluk
Posts: 554
Joined: Mon Jul 09, 2012 9:49 pm

keeping sandpaper clean

Post by phavriluk »

I found by accident that I could remove most of these lumps of melted finish that clog sandpaper by swiping my sanding block across the carpet on top of my work bench. One pass and most of them are gone. It was an epiphany.

Also found that all sandpaper is not created equal in regard to clogging. My last project I splurged on the expensive stuff at the hardware store. Clogging reduced by 3/4 as compared to wet/dry sandpaper. My local hardware store is a True Value affiliate, perhaps its selection of sandpaper is available nationally.

The rattle-cans of Zinsser shellac that I have are identified as wax-free, which lets me lay down an even seal coat. I need all the protection from myself that I can get.
peter havriluk
MaineGeezer
Posts: 1711
Joined: Wed Aug 13, 2014 12:14 pm

Re: Cracks in Finish

Post by MaineGeezer »

I've found, as somebody already said, shellac takes longer to completely harden up that one might think. It may he "dry" in a few hours, but it may take a week or more to get really hard. I suspect the same may be true of lacquer, and if one builds up too much thickness too fast it may do weird things.
Don't believe everything you know.
Anything is possible if you don't know what you are talking about.
When things are bad, try not to make them any worse, because it is quite likely they are bad enough already. - French Foreign Legion
TEETERFAN
Posts: 342
Joined: Fri Sep 07, 2018 12:43 pm
Location: Kansas City, MO

Re: Cracks in Finish

Post by TEETERFAN »

In the “old days” custom car builders would let their cars with lacquer based primer dry for months before sanding to account for the shrinkage. (modern epoxy type primers hardly shrink)
Kevin Doty
Kansas City
tippie53
Posts: 7011
Joined: Fri Mar 03, 2006 7:09 pm
Location: Hegins, Pa
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Re: Cracks in Finish

Post by tippie53 »

yeah not all shellacs are the same. I think 12 hrs should be fine but I only use
flake shellac and everclear I make my own
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
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