Polyester finish BLAST OFF!!! Need repair tips...

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matarroano
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Polyester finish BLAST OFF!!! Need repair tips...

Post by matarroano » Tue Apr 23, 2019 9:21 am

Seems I just added "character", "history" and "personality" to one of my guitars... BIG TIME!

Schaller locks are to blame! Yeah, yeah, yeah... I should have check the drill size first. Now I now... ;)

Image Image Image Image

So.... I plan on "DIY repair" this! I've read about nail polish, super glue, epoxy, layering and lot's of other "techniques".

Which one would you recommend? The one that gives best results "cosmetically". I've read about some "specialty luthier supplies" that are great for this job. Recommend any?

Also any links or "how to" videos I should use as reference?

Any and all ideas and advice are very much welcomed!

Thanks in advance!

Greetings,

Con-Tiki!
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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by Con-Tiki! » Tue Apr 23, 2019 9:31 am

looks like you have all the chips.
I would super glue them back on, and forget about it.
it takes forever to build up lacquer to fill a finish that thick
(Christopher, also)
I've been to one World's Fair, a picnic, and a rodeo, and that's the stupidest thing i ever heard come out a pair of headphones.

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by 601210 » Tue Apr 23, 2019 9:41 am

Agree with just supergluing them back. You'll probably never get a seamless fix short of just stripping it down and redoing everything, so you might as well do the easiest and least offensive way.

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by matarroano » Wed Apr 24, 2019 7:27 am

Thanks for your help and replies!!

Yep. I'm going to go the "easiest route" and glue the chips back. Later I'll try to fill the small cracks and sand and buff it somehow... It doesnt need to be perfect but, is there a way to bring it close to "as it was"? Glue, fill, buff and shine? Any tips?

Thanks in advance!

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by aRoseisaRoseis » Wed Apr 24, 2019 2:44 pm

Are you sure it's Polyester and not Polyurethane?
I've been reading up on the subject since I'm doing some repairs/touch-ups on a piano black polyester finished credenza.
Tenax Knifegrade Polyester Glue has been recommended by piano technicians on several occasions. It comes in black and takes a polish well, so it could be definitely used as a filler, you might be able to use it to just glue the chipped out paint and scrape the excess, but I'm not sure whether it's viscosity would allow the paint chips to sit flush with the surrounding finish.
Here's a link
Last edited by aRoseisaRoseis on Wed Apr 24, 2019 5:11 pm, edited 1 time in total.

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by MatthewK » Wed Apr 24, 2019 3:51 pm

If it were me, I would not try to glue the chips directly because any tiny misalignment (0.2mm or 5 degree rotation) of the first one would mean that the others wouldn't fit cleanly. Instead I would take some time and care to dry fit them perfectly, and then leave them in place while you wick some very thin superglue into the cracks to lock the chips in place. If it's polyurethane or polyester you could then use nail polish remover to wipe off any excess superglue. If it's nitro lacquer that wouldn't work of course. Acrylic lacquer, I would try it out on a hidden part of the surface e.g. under the pickguard. Then a polish with e.g. toothpaste and a soft cloth, or just a polishing cloth.

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by aRoseisaRoseis » Wed Apr 24, 2019 5:00 pm

MatthewK wrote:
Wed Apr 24, 2019 3:51 pm
If it were me, I would not try to glue the chips directly because any tiny misalignment (0.2mm or 5 degree rotation) of the first one would mean that the others wouldn't fit cleanly. Instead I would take some time and care to dry fit them perfectly, and then leave them in place while you wick some very thin superglue into the cracks to lock the chips in place.
(Not having seen it dry fitted) I'd be wary of the glue not penetrating well enough. A slow setting CA glue like Permabond C4, or that Tenax epoxy, would allow a 'wet assembly' and alignment still.

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by matarroano » Sun Apr 28, 2019 6:42 am

Thanks everyone for their input and suggestions!

So, like I told you I chose the "easiest and conservative route".

1.: First, since I had all the chips, gluing them back using basic "superglue":

Image

2. and 3.: The following steps will be a solution that is a "combination" of both these videos:

https://www.youtube.com/watch?v=Y8m1rKJjRqM

https://www.youtube.com/watch?v=rTVScFJoe24

I'm getting some sandpaper, micro-mesh pads, and something to buff it to perfection...

But, before I fill the "spaces" with the black Gluboost Fill n Finish Black Scratch Repair I would like to try to remove the big amounts of superglue leftovers that are now on the finish. It looks pretty sloppy but it really isn't...

My question is: should I first clean it with solvent ar go straight for the razor-blading?

I've been reading conflicting opinions regarding how acetone's response on polyester...

Any thoughts?

Thanks in advance!

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by aRoseisaRoseis » Wed May 01, 2019 3:26 pm

matarroano wrote:
Sun Apr 28, 2019 6:42 am
Thanks everyone for their input and suggestions!

So, like I told you I chose the "easiest and conservative route".

1.: First, since I had all the chips, gluing them back using basic "superglue":

Image

2. and 3.: The following steps will be a solution that is a "combination" of both these videos:

https://www.youtube.com/watch?v=Y8m1rKJjRqM

https://www.youtube.com/watch?v=rTVScFJoe24

I'm getting some sandpaper, micro-mesh pads, and something to buff it to perfection...

But, before I fill the "spaces" with the black Gluboost Fill n Finish Black Scratch Repair I would like to try to remove the big amounts of superglue leftovers that are now on the finish. It looks pretty sloppy but it really isn't...

My question is: should I first clean it with solvent ar go straight for the razor-blading?

I've been reading conflicting opinions regarding how acetone's response on polyester...

Any thoughts?

Thanks in advance!
As Matthew already suggested, trying out the acetone somewhere concealed would be the best way to find out.

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by matarroano » Sun May 12, 2019 7:21 am

So... I think "Stage 1" is close to complete.

Acetone proved "safe" (remember this is a polyester finish, not a polyuretane one) and I proceeded to clean the Super Glue residues with a combination of acetone rubbing and light scraping with a razor blade to achieve this result:

Image

The razor blade left some scratching and the surface isn't flawlessly seamless. Shine is totally gone in the area I'm working at.

NEXTt: GluBoost Glu Dry Acelerador and GluBoost Fill n' Finish to fill the cracks, using this video as reference:

https://www.youtube.com/watch?v=Y8m1rKJjRqM

What do you think? I "happy enough" on how I'm doing so far... What do tou think? Any input and advice?

Thanks in advance!

Cheers,

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by Amon 7.L » Sun May 12, 2019 9:43 am

Don't worry about how it looks now, it's a work in progress.
Just go ahead with the GluBoost Glu Dry Acelerador and GluBoost Fill n' Finish to fill the cracks as described in the tutorial and then TAKE YOUR TIME with all grades of wet & dry sandapaper starting from 800 grit upwards to 2000.
Don't use the razorblade, fold the sandpaper in a block of wood and keep a steady sanding motion.
Once your done with the highest grit, I found out that I get the best results by using some automotive abrasive paste such as this:
https://arexons.it/en/products/car-wash ... sive-paste
It really helps to get rid of the tiniest marks and it gets the surface to a point when it just mirrors.
The last touch with a polish compound and you're golden.
JUST BE PATIENCE, Black doesn't forgive ;)

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by matarroano » Sat Jun 01, 2019 9:21 am

So... STAGE 3!!!

I filled the cracks with GluBoost Fill n' Finish, also using GluBoost Glu Dry Acelerador.

Image
Image

It was a great product to work with. Seems like it does do the job.

BUT!

I wish I didn't use the "soldering build up technique". Too much material to sand-off... It will mean much more additional work. I would like to have gone "thinner". Well.. Nothing I can do about it now.

Nevertheless, I'm really happy about what I am achieving. And actually... This is giving me pleasure (!?). I can't wait to do some additional cracking and blasting off!! ;D :P

NEXT IS A MIX OF WET/DRY MIX OF SANDING AND MICRO-MESHING.

Keep your comments and input coming! It is really more than welcomed. Thanks in advance!

Greetings,

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by Amon 7.L » Sat Jun 01, 2019 3:00 pm

matarroano wrote:
Sat Jun 01, 2019 9:21 am
I wish I didn't use the "soldering build up technique". Too much material to sand-off... It will mean much more additional work. I would like to have gone "thinner". Well.. Nothing I can do about it now.
Don't worry about the build up, mate. :)

For what I'm seeing you're doing just fine, I'm pretty confident you'll even find yourself enjoying the last work of finess up to the polishing stage more than you're imaging now!!

Little disasters like this are a blessing in the long run... You not only learn how to fix things but you also -and most important- gain a "fuck it" attitude that is priceless when accidents happens. "Oh, well.. bummer. I CAN FIX THAT :D "
matarroano wrote:
Sat Jun 01, 2019 9:21 am
I can't wait to do some additional cracking and blasting off!! ;D :P
What can I say... I wish you a great crack'n'blast, man! :D

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by matarroano » Sun Jun 02, 2019 1:36 am

Amon 7.L wrote:
Sat Jun 01, 2019 3:00 pm
matarroano wrote:
Sat Jun 01, 2019 9:21 am
I wish I didn't use the "soldering build up technique". Too much material to sand-off... It will mean much more additional work. I would like to have gone "thinner". Well.. Nothing I can do about it now.
Don't worry about the build up, mate. :)

For what I'm seeing you're doing just fine, I'm pretty confident you'll even find yourself enjoying the last work of finess up to the polishing stage more than you're imaging now!!

Little disasters like this are a blessing in the long run... You not only learn how to fix things but you also -and most important- gain a "fuck it" attitude that is priceless when accidents happens. "Oh, well.. bummer. I CAN FIX THAT :D "
matarroano wrote:
Sat Jun 01, 2019 9:21 am
I can't wait to do some additional cracking and blasting off!! ;D :P
What can I say... I wish you a great crack'n'blast, man! :D
Oh... You are so right about this. I can "feel" that already. And it is really, really freeing... Now I feel more and more these are "just tools" (to enjoy and make music) and not holly totems. I've been hearing that for 20+ years and it's finally "clicking"...

I might actually have the confidence to do and learn a lot more. Read, learn and practice. I'm aiming at being totally self-sufficient as far as setup, maintenance and small repairs goes. I actually have some pickups I might try to solder myself... Let's see how that goes.

As for the last stages...

Any tips on the sanding? I guess no more razor blade scraping, right? A little? None?

And for the last stage of buffing and polishing is there a particular product you would recommend? Auto body polish? Something "guitar-specific"? "Something black", right? Let me know.

Thanks in advance. Thanks everyone for their input and support!

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Re: Polyester finish BLAST OFF!!! Need repair tips...

Post by Amon 7.L » Sun Jun 02, 2019 2:55 am

matarroano wrote:
Sun Jun 02, 2019 1:36 am

Any tips on the sanding? I guess no more razor blade scraping, right? A little? None?

And for the last stage of buffing and polishing is there a particular product you would recommend? Auto body polish? Something "guitar-specific"? "Something black", right? Let me know.
No more razorblade. What I can recommend you is what I've already suggested earlier in this very thread:
http://www.offsetguitars.com/forums/vie ... d#p1563189

Depending on the size (height) of the material you still have to remove, use a tiny file (a fingernail one is perfectly fine) to remove the bulk, then fold sand paper around said file starting from 400 upwards to level things up, then you can do some "massage" with your fingers when you have everything levelled.
Then, an automotive abrasive paste rubbed with some cotton to remove the very last swirls off the 2000 grit sandpaper and last but not least: rub some automotive polish compound with another piece of cotton.
BE PATIENCE :)

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