Repairing Checked Lacquer with Dust/Mold Discoloration

I've been asked to recondition a very good sounding 60's vintage Saturn, hollow body guitar. It has no cracks, however the nitrocellulose lacquer is riddled with them (see pictures below). In the "Items for Luthiers" under the title Amalgamating Checked and Damaged Lacquer Frank, over 12 years ago, demonstrated repair of checked nitrocellulose lacquer using Ethylene Glycol Butyl Ether with the Dow trade name CELLOSOLVE®, which I have used many times successfully on clean finishes.

However the Saturn also has dust, and most likely even mold discoloration in those cracks. 

Is there a non-corrosive way to clear up the check lines before amalgamating them?

Stripping it is not an option. Any other "solution" will be highly appreciated.




Tags: Checked Lacquer, Dust/Mold Discoloration, Vintage Finish Repair

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This instrument looks exactly like it should after 40 years, and has a great patina. I also looked at Frank's link and don't quite understand the connection. I'm not trying to be obtuse...Are you wanting a 40 year old guitar  to look like brand new?,

Not entirely. - That's why stripping is out of the question.

But I do want to repair the existing lacquer damage, without locking in the decaying matter, which got into those check lines together with water absorbed through capillary action, thus inevitably accelerating the "aging".

BTW: Frank's Martin was 50 years old when he undertook the repair, and he hasn't transferred that page to The Way We Were"obsolete" repair styles - or will he now?-)

Any other constructive suggestions?

Sorry Zack, no. Other better minds than mine will post...

Without getting into a discussion on what is best for the instrument regards it's look and originality etc - it's the customers right as the owner to dictate what he wants done (after a wize luthier has apprised him of the options and outcomes regarding what can or should be done) and it's our place to either do the job or turn it down.   Ones mans "cool" is another man's "worn out"  and that's that really.

If the finish cleans up with naptha/de-ionised water etc go ahead with with refinishing as per the schedule.  If the dirt remains fixed in place, talk to the customer again.  R.

Hi Zack.

I'm encouraging you to give it a good cleaning with naptha and use deionized water to clean as much gunk out of the cracks as possible.  Then rub it out & polish using your established schedule.

Any other "fixing" of the finish will destroy the "character marks" of the guitar and will serve no purpose.  It's those types of things that make these vintage axes so very cool.

If your customer has a desire to spend some $$$ on this instrument, I'd start with a fingerboard leveling, a refret & upgrade the tuners & nut.  That's where he'll get his (her's?) best bang for the buck.

Best of luck (: 

Thanks, Paul:

I might resort to this method if there is nothing else out there, because I am aware that lighter fluid (naptha) has always been a polish cleaner of choice.

However Gibson, for example does not recommend it for nitrocellulose, because it apparently tends to plasticize it, modifying the rigidity (of the hollow body guitar in particular) for a prolonged period of time.

So, I'm still looking for some cleaner that does not react with nitro.

FYI: In my search I've come across some reports where people have used the new steam cleaners, which seams to be more effective than just distilled water. Anyone with experience of how safe that is?

Hello again Zack.

Your quote: "No more experimentation until I get input from someone who's had more experience"

Thanks for slapping us all in the face with that one.  Here's my 'experience':  I've been using naptha for over 30 years to clean (NOT polish) nitro.  I've used it liberally to clean everything from pre-war Martins to a '59 burst & a '58 'V'.  IT DOES NOT HARM NITRO.  I don't know where this bit of misinformation originated (probably the Internet?). BTW :

Gibson should be the last ones to take advice from regarding finishing.  They're using naptha as an excuse for their awful plasticized finishes that remain soft and become sticky under playing conditions, therefore rendering the instrument unusable for the working musician.  The problem (well documented since 2001) is with Gibson's formulations, NOT NAPTHA.

Whichever path you choose, best of luck (:

Wow, I missed this comment!

Sorry Paul, this Forum has become a labyrinth, because Franks "Reply" buttons are everywhere.

Just to clarify: By "No more experimentation (for me!)", I meant using degreasers like Goo Gone Extreme (which does contain Varnish Makers & Painters Naphtha & other mineral spirits) instead of just working with the industry standard, pure Naphtha. No Slap-in-the-face intended!-)

Of course there are uncountable degreaser in use, including my present point of interest: Lemonene (see my response to Russell on next page) with which I was not going to experiment, "until I get input from someone who's had more experience".

As Russell (and you) tells me that I've had "all the necessary advice ... I'm going to get", the ball is now in my court: I'll have to do my own experimentation after all:-)

But first, I'll wait a few more days to maybe get some more input from someone who's "boldly gone where no one has gone before".

Thanks for your input. Z.

Did you ever try a little degreaser on one of the marks to see if it would do anything ? just a thought Bill..............

In a way I did:

I used Goo Gone Extreme (a proprietary mixture of VM&P Naptha, Xylene, and Ethyl Alcohol) in an inconspicuous spot under the pick guard and it got me nowhere.

Except that the specific check line became considerably more visible.

No more experimentation until I get input from someone who's had more experience!-)



Zack, if you have not tried the deionized H2O, you really should give it a try. I think ( someone correct me) that it has a positive charge and draws dirt to it.  The stuff only works when the bottle is fresh though.

Hello Kerry:

Thanks for staying involved:-)

This much I know:

Both distilled and deionized water are free of both, positive and negative ions. The difference is in the purification process (distillation vs. reverse osmosis), making deionized water a cheaper option. However, both have the same effect in the cleaning process: Minerals dissolve in them readily.

Since household dust is mostly human skin flakes as well as hair and pet dander (the smaller percentage includes pollen, decomposing insects, bacteria, molds, dust mites, their excrement, etc...yuck!-), it's made up of mostly non-mineral, long-chain, carbohydrate molecules, not easily dissolved in water.

That's why I need an "organic" solvents of the "stronger kind" (e.g.: like the orange shop cleaner), but I don't know if it is available, has been tried by anyone, and what the "side effects" might be...


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