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What works on nitro to take off CA and tape residue?

I'm thinking not acetone...

tape residue comes off with naphtha but ca is a totally different problem. Perhaps light sanding?

Naphtha on nitro?

naphtha for tape CA nadda that burns into the lacquer the best you can do is wet sand and polish

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

We scrape CA level and if necessary drop fill with lacquer to repair - there is no solvent that will remove CA from lacquer. For tape residue, naphtha is a safe solvent and will remove adhesive residue. Solvents in most tapes - including all of the Blue 3M tapes - will swell nitro if left on fresh finish for more than an hour or so. If the finish swells, let it out-gas after cleaning up any stray adhesive and let it sit for a day or two before sanding and buffing.

_________________
For the times they are a changin'

- Bob Dylan

Naptha is a great cleaner for nitro but also will not phase CA ---- scrape and polish, like a drop fill repair, sand paper will most likely make a mess

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Ken Cierp

http://www.kennethmichaelguitars.com/

Sorry to be contrarian, but I'm not in agreement with several of these replies, to varying degrees. First of all, I've never had naphtha react negatively to lacquer, and I use it every day. Second, I've never seen blue or green tape swell lacquer. Actually the opposite, and that goes for all the blue and green 3M tapes. With every one, I've experienced them leaving a texture that is "burned-into" lacquer, in which it is slightly below the original surface. Maybe that's the result Woodie speaks of after out-gassing. Luckily, we can usually sand it out with minimal risk of sanding through...with the exception of Hendersons and Sobells. Those tend to be impossibly thin (And neither are nitro, btw). As far as scraping and polishing vs. sanding, we do both -- scrape down almost to the surface, hard block with 1000 wet, 1500, 2000, then buff. Guaranteed to shine like a diamond with no low or high spots.

Again, I'm not disputing what works for other people, I'm just sharing my experiences as an owner of a full-time repair shop.


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Mountain Song Guitars www.mountainsongguitars.com

Once CA hardens nothing will dissolve it, I'm confused. Naptha is perfect for tape residue like when you tape off the fretboard for a fret job or something and then peel it off and have to deal with the tape glue left over. If you use tape to hold the binding in place for example and wick in thin CA for a binding job and it runs down the tape onto a finished surface (usually shellac) then you have to sand and or scrape it flush.

Jfmckenna...

Pretty sure acetone will dissolve CA off of poly...

The only direct reference I can find in the thread to the safety of naphtha use on a nitrocellulose finish is from my post:



To further clarify: naphtha good...blue tape bad (if left for long periods on fresh lacquer).

Whether the tape is drawing volatiles out of the finish or vice versa, 3M is clear about the adhesive on all of their blue tapes and compatibility with lacquer...which is to say that it is not recommended. At 30-45 minutes on the surface, all of the blue tapes seem to be non-marking on even the freshest lacquer. 3M 2080 (formerly 'Delicate Surfaces' - now 'Walls + Wood Floors' tape) seems to be the lowest risk 3M ScotchBlue product, and on test panels, we've seen a non-marking mask on Mohawk lacquer for up to 12 hours...but we still pull any tape as soon as possible to minimize compatibility issues. When we've seen scoring or marking on the finish, we avoid any working of the surface for a day or so to allow any VOC differential to even out.

From 3M's web site (the Tape Comparison Chart):



3M recently rechristened their lacquer-safe 2060 (aka 3M Green) as 'Scotch Masking Tape for Hard-to-Stick Surfaces 2060' in recognition of the extremely high tack. 2060 is safe on lacquer for extended periods (2-3 days), but that very high tack makes it unusable on anything other than well adhered finishes in very good condition, so we find ourselves using lower tack drafting, masking, or ScotchBlue 2080 and 2090 and observing a time limit on masks.

We've been trialing Scotch Platinum for a few weeks, which has a poly versus paper backing, but early indications are that it is not an improvement over existing tapes and is nearly as difficult to tear cleanly as paper-backed tapes.

_________________
For the times they are a changin'

- Bob Dylan

Right, I misconstrued John Hall's comment to mean naphtha could melt lacquer.


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Mountain Song Guitars www.mountainsongguitars.com

And we avoid using the 2060 for the reason you stated -- the incredibly high-tack doesn't come anywhere near a checked finish.


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_________________
Mountain Song Guitars www.mountainsongguitars.com

Oh ok I see, now I get it.

I use goof off, (a solvent mixture) and 2 i.n u, haul brwn tape, vy sticky for veneers, and purf/binding, better than S/Mac.