New Project: Refinishing a Guitar

[midnightlaundry]

Sry.. Not an Electric.

Back story..

Got this thing more than 15 years ago. Pricey for me at the time, but I didn't play it a lot as I always concentrated mostly on Electric wankery.. Annnnd I fucked it up.. I kept it in the Case to long while putting Humidifiers in the Case without knowing what the hell I was doing. What happened is the Finish got cloudy. Moisture gets trapped under the Finish and it's over. I don't think it altered the Tone, but it kills me that it looks like pure shit from when I first got it.. This only affected the Back and Sides. The Top is fine.

This Guitar is twice the price now, and the new productions aren't as good. I gotta fix it. I'm up for the challenge. I'll just do the Body and leave the Neck alone. The Top has Nitro and the Back and Sides are Polyurethane, and that shit is HARD.. I started sanding by hand with 220 Grit Thin Sanding Sponges which are awesome, but it was taking Forever to get thru.. I had some Paper 100 grit and hit it with that and started to get it down.. I ordered some 120 Grit Sponges, so I'm on hold until latter today delivery..

I plan to wet sand the Nitro off the Top with 400 grit down to the Sealer and I'll do the whole thing with 2K Poly going thinner on the Top.. I think it will be fine.. Nitro is a fuckin pain and it keeps shrinking.. I want a Catalyzed Finish the cures right now and not in a month before I know I need to do touch ups or whatever, turning this Project into a 3 month Anchor..

These pics are in focus, which really shows how bad it looks..

 

[CDawg]

I think you should have tried Xylene before sanding and it would have taken that out in seconds. It'll re-emulsify most finishes that aren't water based.

Have to work fast and light or it'll melt the bindings/plastic but I've used that chemical to fix a lot of different finishes. It's primarily used for concrete/masonry but it's a powerful solvent that will work on almost any finish that is not water based. If it beads off immediately you know it's water based and won't work at all. Won't hurt wood or most materials but it'll melt plastics fast if you play around with it.

White rag ONLY or sprayer with 0.1 or 0.2 gpm tip. It needs to be dusted with Xylene.

I wish I would have heard something before starting. Xylene is magic. If Xylene is banned in your area Xylol is another option that's very similar. Takes blushing out fast.

 

[midnightlaundry]

I hear you mang.. But I deserve to take a beating on this one for fuckin it up.. LOL

I already taped out and went to the 60 Grit.. I'm getting good at judging when to back off and goto the 120 Grit. Dust EVERYWHERE already..
Makin' progress tho.. I'm half way done with the sides. The Back shouldn't take to long because it's flat..

I hit it with Mineral Spirits to show my progress. Really nice. I'll do Pore Filling and a little Sanding Sealer before the Clear..

Chunky ass pore on that Rosewood..

 

[CDawg]

If it was a water based product 0 % chance that would have been fixed with Xylene. Just beads off and does nothing. You'll know in 3 seconds.

If it was solvent based 95% chance that would have been fixed with a swipe of a white rag or spraying with a wand. 30 second job.

The reason for the white rag only is so dyes from the rag aren't broken down by the solvent and transfered to the guitar or whatever you're working on. No pooling or dripping. Can't do it in direct sunlight either.

A little hard to work with if you've never used it before but if you're dealing with blushing/moisture in a finish it can be an incrediblely easy repair compared.to anything else.

Take your time and I hope to see the final results.

 

[midnightlaundry]

Finished the Sides. Took me a solid 8 hours of brutality.. The low valleys in the middle on each side were extra heavy and hard as hell to remove..
The Back should be way quicker because I can Block it.. But it'll have to wait. I'm worn out, and Easter is tomorrow..,

 

[midnightlaundry]

Just finished sanding the Back.. Worked on it on and off all week.
Maybe a total of 14 hours sanding this ting down.. LOL Not recommended, but I didn't want to do an Solvent type remover because Classical Guitar..
Here are some more pic after I gave it a whack with Mineral Spirits..
CRAZY Pores with Rosewood. You can see it especially on the Back..
Hopefully today or tomorrow I'll start Pore Filling..

 

[midnightlaundry]

This week I've been working with this Sanding Sealer. It's water Based, so I've found it's really thin and leaves cured droplets and unevenness that need extra sanding. The Sides are coming out mint, but the back has rough Pores that are light in color that look like shit in the light.
Since I'm a noob and nobody told me, there's Ebony colored Pore Filler. Looking at original pictures I took of this Guitar, they definitely used that!
So I just sanded all the Sealer off' the Back and am waiting for the Ebony Filler to arrive sometime today..

 

[Omnipotent1]

You’re doing gods work. I admire your efforts.

 

[midnightlaundry]

You’re doing gods work. I admire your efforts.

My thoughts before going into this was that it's a delicate instrument, and I'll take my time and be careful with the sanding using finer Grits..
That shit goes out the window when you realize Polyurethane is hard as rocks..
You end up rag dolling it on some level.. Best intentions go out the window..
But I'm making progress and haven't wrecked anything, yet..

Now that I'm up and running, there's a hand me down Cabinet and a cool small Table that I picked out of the trash that I wanted to refinish. Those will be way easier to do I think. I have some Burgundy Stain left from when I did the Trainwreck years ago. I will try to blend that onto the Cabinet with the dark stain for Burgundy accents. It would be cool if I can pull it off. I'll try it..

 

[midnightlaundry]

Ooooo....