# Instruments and Equipment > Builders and Repair >  repairing nitrocellulose finish

## jazzjune18

As luck would have it, my 5 year old attacked me while i was playing, resulting in the nick in the finish in the image below (boy meets music stand meets mandolin).  At any rate, contrary to what it looks like, i am 98% sure that the nick is just in the finish, not the wood (it is the lighting of the photo that creates the illusion).  Is this something that can be easily repaired by a violin or music shop?  Im in Billings, so have one of each store... If so, any (ROUGH) estimates on what this would cost??



I know that this is the first of many nicks in the finish, but ......

THANKS for your help.

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## sunburst

It can be fixed, but it will take someone who knows how to repair lacquer. (Are we sure it's lacquer?)
I can't tell from the picture if color touch up will be needed or if there is any indentation in the wood. Repairing wood damage and color touch up are skills separate from repairing the lacquer, so I can't speculate on potential cost or on whether anyone at your local shops can do it.

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## Rodney Riley

http://www.stewmac.com/tsarchive.html

Check out Issue 174 on one way to repair a chip.

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## jazzjune18

It is definitely nitrocellulose. Also I don't think it needs color touch up.  Like I said, not the best photo.   

  I will try the method described in the video.  It doesn't look too difficult (famous last words).   No but seriously, I think it is doable.  (Watching the video it looked like too much cant Go wrong.  I emailed a local shop and he quoted me 125 assuming all goes well. That's a little steep for what goes into it (IMO).  

Btw, doing some research I see some using nitro, nail polish, and even super glue (stew Mac video).  Y'all have a preference??


Btw.  In unrelated news, as of tonight I've got the saga kit I'm building for my son built and sanded (I finished it minutes before he gave me my nice dent shown above).  Now just need to decide on the finish.

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## sunburst

Given plenty of time, I prefer to use lacquer for touch up. I leave the lid loose on a small bottle of lacquer so that it dries partially and thickens so it fills faster. It needs to cure for at least a couple of weeks before it can be scraped and sanded, or it will shrink and leave a low spot. That is the reason for using superglue to touch up lacquer, it's faster. Sometimes, it can look fine, other times lacquer looks better.
Color touch up is more like an art. Getting a good match is not always easy.
$125 does seem a little high for a simple touch up.

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Rodney Riley

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## Michael Lewis

It's real easy to make it look worse!  It is new only one time.  If it bothers you I would have an expert with lacquer do the repair.  It's not hard but it IS touchy and requires skill.  Send it to John Hamlett or check with Dan Roberts in Bozeman.  Dan is an expert repairman and has worked for the Santa Cruz Guitar Co. for many years and before that he worked for the Gibson factory there in Montana, and he lives in Bozeman.

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## multidon

The super glue drop fill technique does work but it will never look the same as the surrounding finish. It can't because it does not blend into lacquer. You can get it to the same level with the scraping and sanding but it will never be invisible. Lacquer drop fills on lacquer on the other hand have the potential to melt into the old finish because the solvent partially re-dissolves the surrounding finish. A professional could make this almost completely invisible. 75 dollars or so seems more reasonable for this. Its not as much of do it yourself project as you would think. The first time I tried this myself I messed it up so badly I ended up having to re-finish the entire back. It was an inexpensive instrument and a learning experience so no big deal. But that demonstrates how easily things can go south when working with solvent based finishes. You don't say what you have. If it were me I might try it as a do it yourself if its an inexpensive instrument and you don't have a lot to lose. If its of more considerable value a professional is definitely the way to go. The problem with do it yourself lacquer repairs is you don't want to buy a whole quart of the stuff just for one little chip. Weber advises its customers to use clear nail lacquer for small chips but only if bare wood is showing to protect it. As you yourself alluded to perhaps the very best solution is to leave it alone. I know the first chip is the most difficult. Your eye is drawn to it every time you open the case. But the only one who really notices is you. And there will be others. Will you try to repair every chip as they happen? In that case you will have accumulated hundreds if dollars in repairs. If you just let the chips fall where they may it becomes "mojo ". Some makers even sell "distressed" models and charge extra! You can distress your own instrument for free.

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## John Arnold

I have done many, many finish touchups with CA, but IMHO, lacquer is the preferred method to repair nitro. The only downside is the amount of time required for the lacquer to completely cure. Besides using thickened lacquer, you can also put a fan on the area to speed up the process. 
I suggest melting the existing lacquer with retarder as a first step. It will dissolve the white look that comes from micro fractures in the lacquer, and it will promote amalgamation with the added lacquer. If retarder is not available, lacquer thinner or acetone can be used, but it may require many more applications to completely clear it up.

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Rodney Riley

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## sunburst

> ...If retarder is not available, lacquer thinner or acetone can be used, but it may require many more applications to completely clear it up.


I dabbing butyl cellosolve on some lacquer damage as we speak...

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## George R. Lane

Contact Music Villa in Bozeman. They will tell you who can do the repair job.

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## George R. Lane

Try Mike Blohm. He is in Laurel. (406) 628-4261

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## Bernie Daniel

> I dabbing butyl cellosolve on some lacquer damage as we speak...


aka 2-Butoxyethanol.  I did some research on that compound along with a number of similar compounds back in the early 1980's when I spent a few years running a toxicology lab at the National Institute for Occupational Safety and Health (NIOSH) -- it does have some significant health effects but these are evident only in long term inhalations of high concentrations or extended skin contact.  It's really not particularly volatile and is a common paint solvent.  

I was just wondering where you purchased your supply?  The solvent used to be sold under some commercial product names such as Dowanol or BH-33 but when I asked at a local hardware store they just said huh?

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## Rodney Riley

If you would be OK with the wait. Think I would follow John or John's  :Laughing:  or Don's advice. Drop fill with lacquer.

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## sunburst

> I was just wondering where you purchased your supply?


I had some that I got from Stewmac, but they quit carrying it, so I did the normal thing for the contemporary human being... I goooogled it, and found it at The Chemistry Store.com.
I needed some to "heal" some lacquer cracks in an instrument that turned out to be polysomething rather than lacquer, so the quart that I have here should last a long time, considering how little I use. It doesn't evaporate very fast.

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## jazzjune18

Thanks for the advice guys.  This is an amazing website.   It looks easy enough via videos, etc. but I could see it easily turning south in a hurry.  I am currently finishing my sons Mando so I have some nitro sitting around.  I think I'll finish some spare wood, dent the finish and try my hand at repairing the spare.  If all goes well I (may) try it out myself on the actual Mando.  If i feel at all uncomfortable I will likely follow George's advice and contact Mike Blohm in Laurel.  Thanks!




> Try Mike Blohm. He is in Laurel. (406) 628-4261

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## John Arnold

I bought butyl cellosolve at a Sherwyn-Williams paint store. As I recall, they had to order it.
It works great (mainly due to the slow evaporation), but I disagree about its toxic effects...at least for me. IMHO, it is not worth the risk, especially when there are other alternatives.

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## crooksj

I could use some advice on how to fix this: Two days after my last NC lacquer build coats I decided to pull off the FB masking tape...I knew to scribe the lacquer/tape joint first ...but a senior moment left me with a peeled back section of finish.  Lost clear lacquer over vinyl sealer and dyed wood, measures about 0.007 in thick.  This is my first scratch build and I'm not sure how to fix. H ave drop-filled thick lacquer but I don't see that as a fix.  Watched a Behlen lacquer burn-in video using hot knife and that seems an appropriate fix... your thoughts please...I want to fix this soon before the finish cures to much to melt in with my final coats...thanks!  If the  photo doesn't upload, the defect is about 3 inches long and up to 3/16 in. wide.

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## fscotte

I've gotten very proficient with airbrushing lacquer.  The above looks like something an airbrush could fix.  Patience and time.

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## Dale Ludewig

Did you mask the side of the fingerboard?  It looks like it from how clean the fret ends are in the photo.  That's not normally done.  Normally it's just the top of the fingerboard.  Regardless, I wouldn't go near it with a burn-in stick and I've been doing this for 40 years with furniture and instruments.  Top coating over the burnin with nitro isn't going to stick to it well, even if you manage to not ruin the existing finish with the burn in.  I'm not trying to be discouraging, just factual.

Time for a deep breath and relax.  New nitro will melt in just fine with what's already there.  No hurry.  In fact, don't hurry.  It looks like you've got a second area next to the big one.  Is that lifting up?  Airbrush might work well if you have one.

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## sunburst

> I could use some advice on how to fix this:


I wouldn't airbrush it, nor would I use burn-in sticks. I'd drop fill it. Actually, I'd brush on some of the thickened lacquer I mentioned earlier in this thread, build until it will level, then proceed with the finish.
(If the lacquer is showing a strong tendency to separate from the vinyl sealer, you may have a recurring problem, and you may end up considering a re-finish in the future.)

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## crooksj

Thanks !  Yes, I masked the FB side...never gave it a thought since my last mando was a kit with unbound FB.  I was going to buy an airbrush for my next build to darken the perimeter of the dyed sunburst top.  With an airbrush, can I both finish the FB binding, and fix the lacquer peel?  I assume vinyl sealer on the binding is needed first.  How do I prep the damaged area?  Any feathering of the edges needed before spraying.  Mask off the defect from the rest of the neck and spray many fine coats? Thanks again...this forum is a great resource...

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## sunburst

> I assume vinyl sealer on the binding is needed first.


Nope, nitrocellulose lacquer bonds directly with cellulose (ivoroid) binding.

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## Greg Mirken

Crooksj, whether bound or not, the side of the fingerboard is finished. 
Pick at that edge with your fingernail a bit. If it flakes off easily, you have an adhesion problem and you need to refinish [Skip the vinyl sealer, use fresh shellac if anything]. If not, brush a few coats of lacquer where the finish lifted [and the binding]. Sand the high spots, and spray a few thinned coats to melt everything together.

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## Rick Lindstrom

Good candidate for a speed neck treatment.  :Smile:

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Timbofood

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## mirwa

> I could use some advice on how to fix this: Two days after my last NC lacquer build coats I decided to pull off the FB masking tape......


First you have an adhesion problem with your finish, its not the tapes fault, it simply highlighted a problem when you removed it.

The only time you tape your binding is if you are spraying a solid colour or tinted colour, and you only ever tape the neck not the body, we tape the neck, because its damn difficult to scrape a smooth line with a razor blade when frets keep getting in the way

First, for future painting sand the surface a bit coarser before spraying first coat, 220 grit is ideal to key into wood

What type of sealer did you use. I usually sand my sealer coats with 350 grit before doing any nitro work

As far as repairing, you need to clear over your binding anyway, so you do not have a hard paint edge from the binding down, so wet sand it smooth, flatten that area out, apply 3-4 coats just at that location and then clear the whole neck, hopefully the rest of the neck does not have the adhesion problem as well

Steve

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