Grain Tearout - Ouch

The Achilles' Heel of Luthiery
twenty2late
Posts: 81
Joined: Sat May 28, 2016 8:48 am
Location: Savannah, GA

Re: Grain Tearout - Ouch

Post by twenty2late »

Diane,

Absolutely beautiful! I'm up to 7 coats on all surfaces now, and it's looking good. Not quite there yet though. Slight orange peel on the back, and the top has a few areas mainly on the upper bout that need to be thicker. It feels like I'm not making progress with each coat though :-/

I did notice, that on the last one I did FP on, that the top looks so blah now though. I don't play gigs or anything, and treat it with kid gloves, but it seems like the FP doesn't last...or at least it doesn't stay shiny.
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: Grain Tearout - Ouch

Post by Diane Kauffmds »

twenty2late wrote:Diane,

Absolutely beautiful! I'm up to 7 coats on all surfaces now, and it's looking good. Not quite there yet though. Slight orange peel on the back, and the top has a few areas mainly on the upper bout that need to be thicker. It feels like I'm not making progress with each coat though :-/

I did notice, that on the last one I did FP on, that the top looks so blah now though. I don't play gigs or anything, and treat it with kid gloves, but it seems like the FP doesn't last...or at least it doesn't stay shiny.
Shellac reacts with skin oils, deodorants, alcohol. It gets harder with age, but it will scratch. I personally, prefer my sides and backs highly polished, but i like my top to have a nice sheen, not hard polish. So, if I'm building for myself or someone who likes it the same way, I polish her up, then take a used white 3m scrungee ( scrubber sponge) and I lightly go over the top until it's the way I like. Then I spirit off with alcohol just enough to give me the look I'm after.

You're making progress. You will get to the point that you'll want to use 50% shellac and 50% alcohol. I count drops and use 3 drops of shellac and 3 drops of alcohol once the build up really starts.

The Orange peel is from being overworked. You can take it out with alcohol. Use only alcohol that has a little shellac in it, never fresh pure alcohol. I wet the pad pretty good, then go very lightly over the polish. As the alcohol evaporates, I increase pressure until I'm applying real muscle strength. That Orange peel and other imperfections will come out. It may take a couple of days of perseverance. This is also how I achieve a real shine.

A quicker way is to use fine wet sandpaper. I use 600g. Mix a drop or 2 of dish detergent to the water; it acts as a lubricant. Lightly sand it level. But, I prefer the alcohol method more.

When you see a polish that isn't as smooth as it should be, just stop. Don't try to correct it until it's harder. It'll just worsen if you continue to polish. I allow it to sit 2-3 days before dealing with it.

French polishing takes practice. The first time I tried, I wasted 2 cups of 2# cut of shellac. I just couldn't do it and the result was awful, so I kept removing it. That was my first guitar. I finally succeeded on my second guitar. It's an art. The BRW build in the photos, has conservatively, 50 coats at that time. It has a lot more now. When you think of how little shellac is in the alcohol, and how little you use at one time, 50 coats isn't nearly as much as it sounds.

Just do as many as you need to achieve what you want.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
Danl8
Posts: 733
Joined: Mon Jul 28, 2014 7:50 am
Location: Chadds Ford, PA

Re: Grain Tearout - Ouch

Post by Danl8 »

twenty2late wrote:I did notice, that on the last one I did FP on, that the top looks so blah now though. I don't play gigs or anything, and treat it with kid gloves, but it seems like the FP doesn't last...or at least it doesn't stay shiny.
FP can be reasonably durable (don't use the guitar as a cocktail coaster). It is nowhere near as strong as nitro. However FP is widely used for classical guitars and with a little care lasts for a long time and can be easily (?) touched up. If you are seeing a lack of shininess, it probably is a touch too much lubricant or not having spirited off. If you let the film harden for awhile, you can go back with a padding session as Diane says with mostly EtOH and a touch of shellac which clear things up. FP is noted for being extraordinarily clear and showing the figure and grain to its best advantage.
Diane Kauffmds
Posts: 3246
Joined: Sun Mar 09, 2014 8:13 pm

Re: Grain Tearout - Ouch

Post by Diane Kauffmds »

When you use the alcohol, it's called spiriting off. Shellac is repairable, because it'll melt into itself. So will nitro. I've had to take off a small section of shellac on a couple of guitars because of damage. I've been able to repair it.

A neck is the only place on a guitar, where I've used polyurethane, because it takes a beating. Now that I'm using nitro, I've switched to nitro.

I keep a cloth with every guitar, so I can wipe it down when I'm done. You can clean a shellac surface with naphtha.
Diane Kauffmann
Country Roads Guitars
countryroadsguitars@gmail.com
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