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| Does lacquer go after binding scraping? http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=54652 |
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| Author: | qualendi [ Fri Dec 24, 2021 11:18 am ] |
| Post subject: | Does lacquer go after binding scraping? |
Hi, I managed to get this far with my build. I'm left with binding, electronics and paint job. So my question is, do you scrape the bindings before or after lacquering? |
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| Author: | johnparchem [ Fri Dec 24, 2021 12:10 pm ] |
| Post subject: | Re: Does lacquer go after binding scraping? |
For plastic bindings I scrape after using a modified scraper (a notched filed in a scraper) that allows me to scrape a clean line. I see a lot of builders who scrape before and tape off the bindings. I am just horrible at taping; I do better with a scraper. |
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| Author: | Chris Pile [ Fri Dec 24, 2021 2:11 pm ] |
| Post subject: | Re: Does lacquer go after binding scraping? |
Scraping after is much less hassle, and doesn't leave a ridge in the finish like masking tape does. |
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| Author: | Woodie G [ Sat Dec 25, 2021 8:05 am ] |
| Post subject: | Re: Does lacquer go after binding scraping? |
I'm assuming that you plan on binding the instrument in plastic, and that you have some way to remove the neck (set neck electric instruments generally have neck and body bound separately, then are finished after the neck and body are joined and neck joint perfected). With that in mind, install your binding, level, assemble, and then prepare for finishing. Once the filler (if any is needed) and sealer coats go on, choose whether to partially mask off the binding or shoot color and fully scraper. For narrow binding such as on a bound Telecaster getting a solid color, it does not make much sense to mask, while for something like a 335 getting a top burst and a solid color or translucent finish on sides, back, and neck, you'll have to mask anyway. If you mask, consider keeping the tape to within 3/32" of the final trim line. That offset places the ridge in the finish due to the tape mask far enough away from the desired trim line to avoid the scraping issues mentioned by Mr. Pile, but reduces the overall amount of scraping on guitars with wider binding. It also avoids risking overlap and overspray on what should be a solid color on the top and something like a typical Gibson-style burgundy sides, back and neck (actually a medium brown toner with a near-cherry red tint coat). Also note that Gibson seldom scraped back to the inner edge of the binding on some guitars (e.g., carved top, bound LPs), choosing uniformity of visible binding width over risking an uneven reveal with a full-width scraper in the cutaway area. Things get interesting once the color coats are on, as lacquer needs to be scraped after it sets up enough to avoid pulls and stringing (if not dry enough/still plastic) - the damp lacquer can also adhere to other parts of the finish, creating a challenging clean-up task), but before it becomes so brittle that the scraper risks fracturing the finish at the scraped line. The window for this work will vary according to the lacquer used, number of prior coats (try to keep things thin...the more coats prior to scraping, the deeper the 'step' in the lacquer after scraping), the amount of thinner, whether it accelerates or slows flash-off, and shop or spray booth temperature and air movement. I usually ended up scraping after no less than 90 minutes and sometimes as much as 4-5 hours after the color coats went on due to top and back/side getting a different finish. Also keep in mind that the tape and paper masking must also be pulled after the lacquer sets for a bit, but before it hardens to the point of causing separations or pulls in the trim... I usually pulled masking after 20-30 minutes, and used the usual method of pulling away from the finish line parallel to the film, but at 90 degrees to the paint line. If you find that you've waited too long, it is usually an option to shoot a 50/50 or even 40/60 coat of thinned lacquer to reset the clock on the scrape...for a complicated top burst and finished sides/back, this burn-in coat can uniformly reset the scrape window on what can be a time-consuming job on something like a Country Gentleman rebind or an L-5. After looking at the Gibsons (many bursts) that came through the shop, a good scrape job was normal and a perfect scrape job rare... so don't get too wrapped up if things are not up to a Collings level of anal retentiveness... if you have to get close-up to see the minor issues with your first scraped finish, no one else will ever notice it. Sounds like the grand-babies are getting ready to get us adults up, but good luck with the finish work. |
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| Author: | dzsmith [ Sat Dec 25, 2021 11:34 am ] |
| Post subject: | Re: Does lacquer go after binding scraping? |
Should I scrape clear lacquer off the plastic binding or leave it on? |
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| Author: | Woodie G [ Sat Dec 25, 2021 1:51 pm ] |
| Post subject: | Re: Does lacquer go after binding scraping? |
We generally got all the scraping done before shooting any of the clear top coats, but as long as the lacquer is water-white, there are no real issues with building clear on the bindings. Order of finish steps can be important when handling different treatments on the back/sides and top. The Telecaster body shown was received from a hobby builder that got in over his head and desired some assistance with binding and finishing. The photo shows the body after the opaque black coats were applied and scraped for a clean edge. After this, the back and sides were masked to the edge of the shell in prep for a 'black burst' treatment of the top (translucent black center with nearly opaque black at the edges). The top got scraped back to the innermost black fiber purfling line, and the entire guitar got another 50/50 burn-in coat prior to five coats of 75/25 gloss clear and another two coats of gloss over the bindings. |
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