Official Luthiers Forum!

Hi everyone!

I'm finishing a 7 stringer with a maple drop top (flat). The finish will be a kind of tung oil based varnish, similar to tru-oil. I made some tests on body cut-offs, I find the curl to pop out more if I use the oil on bare wood, instead of sealing with shellac first. I like the color more too, and like the idea that the oil penetrates the wood a bit and ''cristalize'' it.

My interrogations are about the sanding. I heard and read different thing about how to sand curly maple to make it pop.
Some say to stop at 120-180.. some say go up to 320-400... some say hard block, some say cork block. What do you think?

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Francis Richer, Montréal
Les Guitares F&M Guitars

I've heard that going up the grits and doing a quick wipe down with alcohol between each one helps.

You can also stain it totally black and sand it all off till there's just a tiny bit left which will collect in the pattern of the figure.

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http://www.tinyhouseandland.com

I've heard the absolute best way to enhance the chatoyance is to scrape as the final step (I think from my violin days). I've never been able to get my scraper edges sufficiently blemish-free to try it myself.

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Dave
Milton, ON

I've had good results with the stain and sand (or scrape) back method. If you are going with a natural finish black might look a bit unnatural, may be better off with more of a brown or dark amber color. And +1 on the scraping. On a a box I made one face was sanded to 220 grit and another was straight off the plane, and the cut surface seemed to build a gloss faster than the abraded one when I was finishing it.
Oh, and here's a video on popping grain that has a popped vs. unpopped comparison at the end:
http://thewoodwhisperer.com/episode-32-pop-goes-the-maple/

This is a ultra light weight stock made of 5 pieces of hard blistered eastern maple. Sanded to 320 on a air DA with a 12k rpm and and a 3/16" orbit. Dyed with a diluted metal based dye, let dry then sanded back by hand using a leveling block to reveal any sand scratches. The leveling was done with 600 grit until all scratches were removed and that is under a magnifier lens. Then the stock was dyed black again with the diluted dye, let dry and sanded just enought to bring the white color back on the hard portions of the wood.

A teal dye was then used and all excess dye was washed off using lacquer thinner. This was done to make sure there were no wipe marks in the dyeing process. After this was dry, a thin diluted dye in lacquer thinner was sprayed evenly on the surface but no much color build was done.
Then the clear coat (automotive base/clear system) was sprayed light and dry for the first few coats. This is to seal in the dry sprayed dye. After allowing these first few coats to dry, then a wet/wet coat was applied and allowed to dry 4 hrs between subsequent dual coats. A total of six were applied and then allowed to dry overnight. The finish was then wet sanded using a leveling block, I use hard rubber on the clear coat process. All imperfections, orange peel etc were sanded out then ( I typically use 800grit)the stock was coated again with a tinted clear using the teal metal based dye. Spray light coats until the level of color depth is achieved. There is a very important reason to spray light coats! After the color coats are tacked, apply3 more wet/wet coats and let dry overnight. Make sure the finish has hardened, and if so start the wet sanding. If not, wait another 24 hrs. Wet sanding starts with 1000, 1500 then 2000. Go slow and watch any sharp corner.....again, there is a reason to go slow! I then polish with a high speed air polisher, again being real careful and slow! You can see the results!

Mike

Nice! What is that, a gun stock?

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Old growth, shmold growth!

A very nice gun stock.

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http://www.tinyhouseandland.com

HA!!! I was just saying to myself "what an unusual headstock design"!

I am trying to remember the last time I saw a blue gunstock..... ummmm, never!
VERY NICE!

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"Act your age, not your shoe size" - Prince

Oil, shellac and lacquer all have their own refractive properties and will 'pop' the grain in different ways. Direct staining with colors tends to accentuate the grain lines and yield a very 'dramatic' look that photographs well, but looks less 3D than a tinted lacquer coat over a clear sealer in real life. More imposing, less subtle.

Test each (full) finish schedule on scraps to see what result you like best - I occasionally use oil, usually use shellac, sometimes lacquer, sometimes only tinted clears on top, sometimes stain and sand back, all depends what look I'm going for.