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| Preventing color-bleeding http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=39099 |
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| Author: | Beth Mayer [ Sat Jan 26, 2013 10:57 am ] |
| Post subject: | Preventing color-bleeding |
The OM I'm working on is EIR back and sides with curly maple end wedge and binding. Though I coated with shellac at certain times in the process, I notice now that everything is fully sanded and pore-filled, the maple has a light purple cast to it. It's my first solo built guitar and not going to be sold, but I want to be able to prevent this from ever happening again. I love contrast, so I'm going to have to deal with this successfully in the future. Next build will be Curly Maple B/S with Cocobolo appointments. How do you keep your light woods pristine during building with contrasting woods. On the same subject (and probably handled the same way but I wanted to mention it) I'm really struggling with whether to laminate the neck (a look I love) because that too is Curly Maple, and I'd be laminating with a Coco side cutoff. |
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| Author: | Alain Moisan [ Sat Jan 26, 2013 3:55 pm ] |
| Post subject: | Re: Preventing color-bleeding |
Hi Beth, To my knowledge, there is no miracle solution to this problem. I too get some purple in my maple bindings when using rosewood B/S. The best way I've found to reduce it is to scrape the bindings prior to applying the finish. I use the tip of a utility knife blade, using my thumb as depth controler, and scrape around the guitar. it doesn't get rid of all the rosewood dust, but most of it. Hope this helps! |
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| Author: | gozierdt [ Sun Jan 27, 2013 9:48 pm ] |
| Post subject: | Re: Preventing color-bleeding |
I also don't have a magic solution, but I did use cocobolo bindings and bridge on my last guitar, and it's a major PITA as regards bleeding, both from sanding dust, and even more from solvents in finish dissolving the dyes in the wood, coloring an area 1-2mm around the coco. I think what Alain said about minimizing sanding by scraping as much as possible will help. A good vacuuming and air blasting regimen will help get rid of any dust generated by final sanding or inadvertent sandthroughs. It might also be worth thinking about trying one of the waterbased finishes for both porefilling and final finish. I don't think water would dissolve the dyes in the wood. I'm going to try the PolyWhey waterbased finish that Mike Collins initially wrote about for my next guitar. There are several threads about it ongoing right now. |
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| Author: | WaddyThomson [ Sun Jan 27, 2013 11:04 pm ] |
| Post subject: | Re: Preventing color-bleeding |
Wipe with shellac on a cloth or paper towel. Do maybe a foot at a time, always using a clean piece of rag or paper. Work in one direction and never go from Rosewood to maple. Keep a straight stroke. I haven't had this be a big problem. Another thing that helps is to seal with egg white before finishing. Egg white usually does not cause bleeding of Rosewoods. You'll have to lightly sand it back after applying and letting it dry, but don't put it on too heavily. You can apply it with a brush or a rag. Brush works better. I have found lots of uses for children's water color brushes with soft bristles. They are great for glue and for brushing shellac or egg white. |
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| Author: | Beth Mayer [ Mon Jan 28, 2013 12:39 am ] |
| Post subject: | Re: Preventing color-bleeding |
Thanks all, for the helpful details! |
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| Author: | Eric Reid [ Mon Jan 28, 2013 3:26 am ] |
| Post subject: | Re: Preventing color-bleeding |
Again, no magic fixes. Some things that help: #1 Don't sand finer than 220 (finer dust gets trapped in the pores--especially spruce pores.) #2 Clean up by vacuuming the guitar, followed by a wipe with blue "shop towels". (These pick up a lot more dust than regular paper towels.) #3 If bleeding is an issue, seal difficult woods by wiping with very thin shellac on a barely damp pad. Make one pass, indexing your pad on the corner, if there is one. Wait a few minutes, then repeat with a new surface of the pad. Change pads when you run out of new surfaces. When the pad stops picking up color, you can be more bold. #4 Pick woods that don't bleed. Wenge is a great wood for contrasting color schemes. It doesn't bleed in alcohol or water, and it's very dark. #5 When all else fails, seal pale woods with CA glue before finishing. Thin CA will penetrate pores. Medium CA will fill small (Maple) pores. End grain blonde wood, next to dark, staining wood is the hardest. I have a couple of these in the shop for finishing: Attachment: andamento1.jpg
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| Author: | gozierdt [ Mon Jan 28, 2013 2:24 pm ] |
| Post subject: | Re: Preventing color-bleeding |
Todd Stock wrote: Scratches are what trap the dust, so sand to at least 220, then blow out the grain with a compressor. If you still have staining, sand the lighter wood to 320 and clean again. I have not had to resort to scraping to clean on a number of coco-bound or coco back/side instruments. Once things are ready to finish, I seal the bindings with epoxy if I'll be filling the grain, or shellac. On a coco-bound anigre jumbo, I sealed the coco with epoxy, while on a coco/flame maple bound SJ, I sealed the maple before filling the coco...no bleeds. Coco is a little unique - it has water-soluble, naphtha-soluble, and alcohol soluble extractives, so pretty much anything you wipe it down with will end up staining adjacent wood. Avoid solvent wipe-downs until the areas that may see staining are sealed. Once the first coat of z-poxy is on coco binding or B/S wood, there's not much danger of bleeds, and for coco radial purfling, I seal with epoxy and shoot with a mist coat of vinyl sealer and find that eliminates any bleeds. Oh well, so much for my plan to only use water-based finishes with coco. Guess I'll have to use Todd's method of sealing with epoxy.... |
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| Author: | Beth Mayer [ Tue Jan 29, 2013 12:45 am ] |
| Post subject: | Re: Preventing color-bleeding |
Todd Stock wrote: Might plan on spraying a mist coat of shellac to seal, then the WB...you may not see much bleed anyway if the first coats are fairly light. Just to clarify, Todd, Would shellac be better to seal the coco than vinyl sealer, or are you just referring to doing the shellac mist coat before the sanding steps? |
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| Author: | gozierdt [ Wed Jan 30, 2013 8:00 pm ] |
| Post subject: | Re: Preventing color-bleeding |
Beth, Since Todd was replying to my comment about using waterbased finish over Coco, I think he was referring to applying a light coat of shellac just before starting the waterbased finish coats. |
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