I'm about to fit a new bridge to an archtop guitar. Dan Earlewine has a good StewMac trade secrets column on how to do it with a Stew Mac bridge fitting jig, but he uses sign painter's tape and 3M Stickit Gold paper. I'd like to find a source for small quantities of either, since I don't do that much guitar work and probably would never use whole rolls of either sandpaper grit or the tape. Does anyone know a source for small quantities? I haven't seen either the paper or the tape in the local hardware... . Otherwise, I'll use regular paper and figure out a way to hold it down.
I plan to buy a StewMac Bridge Fitting Jig and then sell it after. I've fitted a couple of bridges before "freehand" and this tool, while a little pricey, is what I think I need to do a good job. It does look like something I could make for a one-off, but finding the materials and building it up seems like more time and labor than it's worth for one job. I figure that buying and then passing on the tool is a good way to get its use for a reasonable price.
BTW, Dan E. warns about the possible damage to finish from regular masking tape and I concur: this guitar has a nitro finish and when it was shipped to me the shipper used stick-it notes to mark the approximate location of the bridge. The notes left a nice bit of crazed finish under the sticky parts.
I don't know of any places for small amounts of sign papers tape and would like a source as well. I would think a very small amount of naptha and a clean polish cloth would get the haze out pretty nicely.
Are you absolutely sure the post-it left the spot or is it the scuff left by the foot of the bridge when it was strung up? Anyway, if the finish has been setting for long enough to cure, using low-tack masking tape, ( I use the blue) shouldn't hurt the finish because you're not going to leave it on for very long.
Personally, I've never felt the need for a tool to fit a bridge to an archtop instrument. I've always padded the top with a layer of tape then just laid sand paper on that. Some of the bridge bases need to be trimmed up a bit by hand to get them close first but it's not really all that hard for me to get it close then get a good fit this way. It's not a vigorous process.
I think its a good idea to measure the position so you are fitting the bridge to the correct part of the top. It doesn't have to be prefect, just close. I NEVER depend on someone's notes or marks or tape or stick-its to locate the bridge. Check the position for yourself. I've seen a lot of bridges that were out of place.
The spots are clearly from the post-it: nice little outlines of the bridge foot ends. The bridge foot scuff was clearly inside the boundaries of the post it note and looked different--it was, well, scuffed. The post-it mark was crinkled like any reactive chemical would make on nitro lacquer.
I've fitted bridges to several mandolins. I did what you suggested by hand but I found it tedious and difficult to get it dialed in. Now, several years later, I have some arthritis in my hands and find it difficult to keep a tight grip on the bridge for long enough to get the job done.
I do measure the position. Fortunately, with a movable archtop bridge, it's easy to make minor adjustments to dial in good intonation.
I did a post last year (?) about the 3M blue painters' tape. I used it and it wrecked the nitro finish on a new Gibson. Sure enough, when I checked out 3M's documentation, they warn AGAINST using it on lacquer. It was my lack of knowledge that caused the issue.
The universal 3M "green tape' is formulated for use with lacquer, and I agree with your assessment to leave the tape in place for as little time as possible. I can tell you from personal experience (due to intermittent brain death) that the green tape will not hurt cured nitro after being on there for 2 months. MAN, was I ELATED to discover that. :)
Also, hat's off to Tom for using console tape (Scotch 256). It's the best stuff on the planet as it's thin paper backed with a natural rubber adhesive. A joy to work with and it's uses are limitless. The only downside: It's hard to find other than on-line and it IS expensive. :)
Paul - thank you for the heads up.
I've not seen an issue with the 3M Blue on Acrylic Lacquer or Polyurethane finishes (short duration, always). Thankfully, I've never used it on Nitrocellulose Lacquer simply due to habitually using a lower tack tape on that type of finish. . Looking at 3M's site, they warn about the Nitrocellulose specifically as you state:
ScotchBlue™ Painter’s Tape works well with most water-based paints and coatings, such as acrylic, urethane, vinyl latex and enamels. It also works well with many solvent-based coatings – alkalyds, varnishes, most enamels and some polyurethanes. In addition, ScotchBlue™ Painter’s Tape works well with plaster, glazes, textures and metallics used in faux and decorative painting.
However, be careful when working with lacquers – nitrocellulose-based lacquers react with the adhesive composition on many painter’s tapes, seemingly bonding the tape with the lacquer, making it impossible to remove. Before you start, make sure the tape you choose can be used with lacquers – higher adhesion levels such as tan masking tapes are a better choice for this particular use, because their adhesive does not react with the lacquer in this way.
I like the blue painters tape for fret leveling and dressing due to it's abrasion resistance but will likely stop it's use altogether and stick to the natural rubber adhesive tapes going forward.
I've seen surface reactions with Acyrlic adhesives before in my Engineering career. One of the first clues is that the best residue cleanup solvent is pure acetone - which is definitely not something to apply to a fine instrument finish. Isopropanol doesn't even phase most of the Acrylic film adhesives for cleanup. Like dissolves like so the damage is not unexpected.
I made a call to 3M this morning to ask them about Lacquer finish-tape product compatibility. They do not recommend use of any of the 3M Blue Tape products over lacquer or any type. The only products that they recommend are 2020 (High Tack) and 2050 (Med-Hi Tack). The recommendation applies to all Lacquer finishes. I requested clarification between Nitrocellulose and Acrylic finish types and the response was that they did not differentiate between these types in their application guide. Both of these products are tan masking tape.
I suppose I've been lucky. I haven't used it on a "new" finish that wasn't French Polish and haven't run into problems there. When I fit a bridge, I tape up, fit and remove so the tape isn't on for very long at all and I also don't apply much downward pressure on the bridge base, letting the paper do the work.
I recently bought a supply of the green tape but haven't used it much. I'll remember to avoid the blue in the future. Thanks for the correction.
Re the sign writers tape, have you tried a sign writer? Surely they would be able to advise.
I use standard paper with masking and simply tape it down with masking tape. Works great. If I the finish is delicate I put masking on the back of the paper too. I use the Stewmac tool. However, it could be easily made at home. Grizzly sells gold roll paper in smaller rolls with or without adhesive. ~ $23. or $17. respectively.
Also, speaking of 'Post-It'; for very low tack situations I have a roll of that white tape that is basically Post It. The same stuff some folks use on recording consoles to mark channels.
You should make sure the shipper knows about
that damage too. Thats a little piece of sadness...
I told the shipper, who took note. It could have been because the builder used an unknown lacquer that was more delicate than the usual stuff, but it's still worth considering if you don't know what you're working with.
Fortunately, the damage is not too noticeable. I may try buffing it out when I have the bridge and strings off for the bridge fitting.
BTW, the shipper marked the bridge because he removed it for shipping and padded everything else. Any comments on whether this is a good idea with an archtop instrument?