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 Post subject: Nitro Finish repair(s)
PostPosted: Mon Oct 25, 2021 1:29 pm 
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Cocobolo
Cocobolo

Joined: Thu Feb 15, 2018 11:06 am
Posts: 271
First name: Roy L
Last Name: Smith
City: Apache Junction
State: Az
Zip/Postal Code: 85119
Country: USA
Focus: Repair
Status: Amateur
First guitar, this one had problems with bloom or blush around the end wedge which I posted before. Since my second is now my daily player, I thought numero uno should go for some repair work. I was worried about whether the edge of the lacquer removal would be obvious. After sanding the repair edges to a bit of a long bevel, sprayed with some shellac, 320 sand, unless I'm missing something, I feel pretty good about respraying that end...but
Image
I had originally done a crap job of wet sanding and polishing, so thought I'd try again, at least on the top. And my bridge install was a mess, have a thru hole fixture to use now, but the lacquer was disturbed around the bridge when I took it off. Peeled it back til adhesion felt solid, did some 320 hand sanding and a little more shellac. And now I'm thinking since I don't really know I'm doing this correctly, is there something else I should do before re-spraying with nitro? If it matters, I'm using Cardinal Gloss, about 20% thinner and mebbe 5% retarder. Thanks, Roy


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PostPosted: Mon Oct 25, 2021 2:28 pm 
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Contributing Member
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Joined: Sun Mar 06, 2011 12:04 am
Posts: 5743
First name: Chris
Last Name: Pile
City: Wichita
State: Kansas
Country: Good old US of A
Focus: Repair
Status: Professional
I never used shellac between coats of lacquer. It inhibited the "melting in" of layers.

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



These users thanked the author Chris Pile for the post: flemsmith (Mon Oct 25, 2021 2:50 pm)
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PostPosted: Mon Oct 25, 2021 2:50 pm 
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Cocobolo
Cocobolo

Joined: Thu Feb 15, 2018 11:06 am
Posts: 271
First name: Roy L
Last Name: Smith
City: Apache Junction
State: Az
Zip/Postal Code: 85119
Country: USA
Focus: Repair
Status: Amateur
Well dang, why didn't I ask earlier? Will denatured remove the shellac without hurting the cured lacquer?
Thanks for input Roy


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PostPosted: Mon Oct 25, 2021 4:02 pm 
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Joined: Sun Mar 06, 2011 12:04 am
Posts: 5743
First name: Chris
Last Name: Pile
City: Wichita
State: Kansas
Country: Good old US of A
Focus: Repair
Status: Professional
Can't say. I don't use denatured alcohol.

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


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PostPosted: Mon Oct 25, 2021 4:06 pm 
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Brazilian Rosewood
Brazilian Rosewood

Joined: Fri Aug 19, 2005 4:02 am
Posts: 3227
Location: The Woodlands, Texas
First name: Barry
Last Name: Daniels
Yep, alcohol will remove lacquer. It might be better to try and sand the shellac.



These users thanked the author Barry Daniels for the post: flemsmith (Mon Oct 25, 2021 8:00 pm)
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PostPosted: Tue Jan 18, 2022 4:16 pm 
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Cocobolo
Cocobolo

Joined: Thu Feb 15, 2018 11:06 am
Posts: 271
First name: Roy L
Last Name: Smith
City: Apache Junction
State: Az
Zip/Postal Code: 85119
Country: USA
Focus: Repair
Status: Amateur
Just for ff up, I did resand and spray the top, focused mostly on the areas which delammed around the bridge. Not perfect, and after I reattached the bridge I got another small area of lifitng nitro, so I need to rethink the prep sanding process before I start nitro. Plus, my finish sanding and polishing still needs work....I did send in an application to Azwoodworkers hoping to get some in person experienced eyes for finishing advice. I'm having trouble telling I still have scratches left over from an earlier grit til after I get to the polish stage.
Image
I also took the end wedge back to bare wood to get rid of the blush (or bloom!?) caused by incomplete sanding of the titebond prior to lacquer. I think next build I'll try the LMI glue with a blacklight before I start nitro.
Image
Looks like I may be using this guitar (my first) as a process experiment vehicle, but for now I want to hear it again and compare the sound to number 2. Roy



These users thanked the author flemsmith for the post: Chris Pile (Tue Jan 18, 2022 8:53 pm)
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PostPosted: Tue Jan 18, 2022 4:19 pm 
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Brazilian Rosewood
Brazilian Rosewood

Joined: Fri Aug 19, 2005 4:02 am
Posts: 3227
Location: The Woodlands, Texas
First name: Barry
Last Name: Daniels
That last photo looks a lot better.


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