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| Cocobolo rosette finish question http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=22956 |
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| Author: | SteveSmith [ Sat Jul 04, 2009 1:38 pm ] |
| Post subject: | Cocobolo rosette finish question |
I'm brushing not spraying. When I brushed on a coat of shellac to protect the top during construction the color from the coco bled out on the top, from the alcohol no doubt. No big deal then but now I've got everything sanded back and ready to start finishing. Any ideas on how I can get a coat of shellac on the top with out having the color bleed out all over? My only thought is to get a small brush and just coat the rosette first and then try to move fast enough when doing the rest of the top not to get through that first coat on the rosette. Surely someone has a better idea? |
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| Author: | peterm [ Sat Jul 04, 2009 1:51 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Apply shellac first to the rosette with a small brush or Cotton swab and let dry then seal the rest of the soundboard. |
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| Author: | WaddyThomson [ Sat Jul 04, 2009 2:00 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Another way is to seal the rosette with egg white. It will not cause the rosewoods to bleed, and will seal them and keep them from bleeding. Put it on you whole top, to raise the grain, then sand back lightly. |
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| Author: | SteveSmith [ Sat Jul 04, 2009 4:10 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Thanks for the suggestions guys. Ah yes, egg white. How could I forget that discussion. Was there ever a concensus on the best way to use it, i.e. raw egg white or whipped egg white or doesn't matter? |
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| Author: | jmpbuffalo [ Sat Jul 04, 2009 4:44 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
My understanding is that you apply the egg white without whipping, when sizing the top (and coincidentally sealing the rosette and binding.) FWIW, on my build I just dipped a paper towel in eggwhite and rubbed it on, then sanded lightly when it was dry. Joe |
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| Author: | SteveSmith [ Sat Jul 04, 2009 6:27 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Good, that's what I'll do too
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| Author: | SteveSmith [ Sun Jul 05, 2009 3:55 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Good advice Todd, I'll check on scrap first. This coco bleeds more than about anything else I've used before. I've done a lot of spraying, some commercial, and am trying to avoid this in my little shop. But if I can't do anything else reasonably then I'll spray it. |
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| Author: | SteveSmith [ Sun Jul 05, 2009 6:36 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
The egg white worked like a charm.  Thanks everyone! |
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| Author: | SteveSmith [ Mon Jul 06, 2009 7:20 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Well, the egg white didn't bleed so tonight I very lightly sanded with some 800 then tried to brush on a coat of shellac. Disaster! Orange coming out everywhere. Once again I declared victory too soon. I won't be able to get back to it till Wed. I'll sand the top back down and try again. I think I'll try the CA next. |
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| Author: | StevenWheeler [ Mon Jul 06, 2009 9:53 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Steve, Go back and read Peter's reply and proceed accordingly. Even when I use egg whites, I still seal as Peter prescribes. Works every time. Watch out with the CA if you're using a Spruce top. Steve |
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| Author: | SteveSmith [ Tue Jul 07, 2009 8:48 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
Todd, as you noted it appears that the egg white did not act as a satisfactory barrier coat. I don't think I sanded through since I used 800 and approached it like I was sanding a dragon fly wing. I think the time that it took for the finish to flash off was a definite issue as well. I used about a 1 1/2# cut. I think somewhere around 3/4# or 1# might work better. I won't be able to get back to this until later in the week but I will try brushing either CA or shellac on the rosette next. If one doesn't work then I'll try the other, there are plenty of variables here and I'm sure I'll find something that works and learn a lot in the process. It turns out that building this guitar is much like my projects at work (I'm an engineer in an R&D lab); failures sometimes outnumber the successes and it is pretty common to have to do things several times to get a satisfactory result. Guitar building is sure a lot more fun though and I don't have any schedule to fight  I sure appreciate the hints, pointers, and thoughts - keep em coming. |
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| Author: | Burton LeGeyt [ Tue Jul 07, 2009 9:04 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
I try to spray the first coats of shellac. My shop is miniscule also but home mixed shellac (with grain alcohol) isn't an airborne danger so I don't sweat it too much. I use the little preval sprayer for this. With burls or woods that will bleed I will brush on epoxy inside of the purfling line and then level with a razor blade. I don't fully trust it to not bleed a little though and I will still spray the first coats. I have been able to rub the shellac on in a circle and then change pads(same as with bindings). This takes a couple of coats and a good control but it does work also. I'm not sure there is anything I would trust to seal completely so I could brush across the top and over a rosewood rosette on the first couple of coats. If you do find something that works let us know! |
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| Author: | SteveSmith [ Tue Jul 07, 2009 10:03 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
Burton, about what cut of shellac are you spraying and do you thin the epoxy for brushing? I've been mixing up my shellac using denatured alcohol but grain alcohol is safer and, who knows, it could have other uses around the shop  As I ponder this task in my mind I'm not sure how I'm going to proceed. I may be trying too hard to avoid spraying so I may just decide to spray the first few coats of shellac. It's not hard to just mist on light coats of shellac, which I've done before for color, and I don't think there's any way to do the same thing with a brush. |
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| Author: | Burton LeGeyt [ Tue Jul 07, 2009 10:33 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
Hey Steve, I usually use around 1 1/2# cut when I spray. Sometimes a little thicker but rarely thinner. When I brush the epoxy I do not thin it, it will go on a little thick and then I scrape it away. I use the West Systems brand. If you are not sure of your brushing skills I would tape off around the purflings, I found that the epoxy would soak into the spruce and discolor it like CA. Taping off helped that. I do think that spraying it would solve all of your problems but I understand the resistance! I tried for a long time to avoid it also. Any method where something is dragged over the surface, especially shellac which is activating the layer beneath it, can drag oils. And with the alcohol in the shellac I feel it can bring the oil to the surface as the alcohol evaporates and your next coat drags it even when the first coat seemed fine. I have had this happen (or at least I assume this is what is happening). If you really don't want to spray though a rag loaded with shellac and rubbed over the rosette area following the circle, and in one motion, done many times will over time seal it(you will see less and less stain on the pad each time etc...). You do have to build up around it though after which while not super hard, is a bit of a pain. |
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| Author: | SteveSmith [ Tue Jul 07, 2009 1:58 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
I don't think brushing the epoxy would be too much of a problem as I have a fairly wide purfling line around the coco. The worst thing is that I won't be able to try anything till Thurs. I'll try to remember to take and post a few photos so those who haven't experienced this can see it. |
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| Author: | Alexandru Marian [ Tue Jul 07, 2009 5:54 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Try not to brush at all. Fold a cloth in 4 and damp the tip with a few drops of shellac, wipe the area, unfold the cloth and refold exposing a cleaner face, wipe, etc. and then again load and wipe etc. Very light applications is the key. A brush holds a lot more alcohol, even if you think you squeezed it enough. |
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| Author: | Chris Paulick [ Tue Jul 07, 2009 6:11 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Do you think whiping it with a damp acetone towel first would help suck up some of the oil and help with the bleeding? |
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| Author: | SteveSmith [ Tue Jul 07, 2009 8:03 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Chris Paulick wrote: Do you think whiping it with a damp acetone towel first would help suck up some of the oil and help with the bleeding? I don't think so, this stuff bleeds color even if you wipe it with a dry paper towel (after it's been cleaned with naptha). Alexandru, I agree that brushing with shellac is not the way to go. That did put down way too much shellac.But I don't think brushing with epoxy would be a problem. I should be able to sand of the top tomorrow morning but I won't know for sure what I'm going to try next until I get back to it Thurs afternoon. |
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| Author: | Ken Franklin [ Wed Jul 08, 2009 2:01 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
I do what Alexandru does. Follow the circle with your folded pad of cotton t-shirt material and just a little 1 1/2 lb cut shellac. Just go around once. Make sure you let it dry and then do it again with a clean surface on your pad. Eventually you have enough dry shellac so the rosewood won't bleed through. The problem with the epoxy can be the thickness. If you use epoxy, cover your finger with apiece of tape and spread it thin. Avoid getting epoxy on the spruce, |
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| Author: | Chris Paulick [ Wed Jul 08, 2009 6:12 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
Would it also help if you sealed the spruce first around the rosette and let it dry and then sealed the cocobola with the above method or CA. If shellac keeps CA from leaching into spruce when gluing inlay then wouldn't it do the same thing as to keeping the cocobola stained CA from leaching into the spruce? I've nevered worked with Cocobola so I'm just throwing some thoughts out here. Good discussion be cause I'm planning on working with coco soon and it's nice to have a heads up on this bleeding. Sounds like a bit of a hassel especially if one was unaware of it to begin with. |
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| Author: | Chris Paulick [ Wed Jul 08, 2009 7:58 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
Is that an answer to my question? I'm not sure. I'm thinking that I seal my channels before inlaying and appling binding because I use CA and I also usually will seal the whole top or at least about an inch past it so the CA doesn't leach and discolor. So if the shellac acts as a barrier in that case , well ? Or do I just have to do a test and see how this coco acts or am I missing something? Finishing isn't quite my forte. 
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| Author: | SteveSmith [ Wed Jul 08, 2009 8:55 am ] |
| Post subject: | Re: Cocobolo rosette finish question |
My top was also sealed with shellac before I CA'd the rosette in. The coco bleeds into the surrounding finish, not the wood(thankfully). I took some photos when I was in the shop earlier. I'll post one later but have to go right now. |
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| Author: | SteveSmith [ Wed Jul 08, 2009 4:07 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Here's what I was talking about. The orange from the coco has bled into the surrounding shellac, it is not in the wood. I used shellac to seal the spruce then CA'd the rosette followed by egg white sizing. Then brushed on shellac. Looks like the egg white did not adequately seal the cocobolo. I've already found, as some have said here, that wiping on the shellac works much better. You can get a thinner, more even coat. Tomorrow I will try to wipe on multiple coats of shellac until the pad is clean. If I can't get that to work then I'll probably try epoxy. Attachment: DSCF0281.JPG
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| Author: | Corky Long [ Wed Jul 08, 2009 6:36 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Nice looking rosette!! Once you solve the bleeding issue - you'll have a fine looking guitar there! |
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| Author: | Chris aka Sniggly [ Wed Jul 08, 2009 6:52 pm ] |
| Post subject: | Re: Cocobolo rosette finish question |
Steve I had that very same problem with a bloodwood rosette on my first guitar. Cotton pickin thing bled all over EVERTHING. I solved it by using a 2lb cut of shellac - dipped a Q-tip in it - and using a rolling motion (by that I mean that I rotated the head of the Q-tip so that a fresh clean surface was in contact with the rosette/top at all times) I applied the shellac making sure I didn't cross any of the maple purf lines. It worked perfectly. I let it dry over night before I applied anything else...which was more shellac to the whole top. Solved my problem. Chris |
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