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How to finish this...
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=40887		 Page 1 of 1
Author:  dpm99 [ Mon Jul 15, 2013 4:21 pm ]
Post subject:  How to finish this...
I'm having some real trouble getting a shiny, level finish here. The shiny part is easy, but the level part isn't. I started with a nearly trash-worthy WRC top. I got it for free after it was left unwanted by a roomful of other builders, but I thought I could make it work. Structurally, it seems to be fine. And before I put the finish on, it looked level. I know that good surface preparation is the key to a good finish. If it was level before I started finishing (and I'm doubtful it was), it certainly isn't level now.

I'm using Tru-Oil, and I have done some wet sanding.

So the question is where do I go next? Should I lay on 7-8 more coats and sand back with a big leveling block? Should I try for a satin finish instead? I'm looking for some advice, as I'm clearly in over my head here. Thanks.

Image
Author:  runamuck [ Mon Jul 15, 2013 7:11 pm ]
Post subject:  Re: How to finish this...
It looks as if bracing or something else is telegraphing through the top - below the bridge down the middle.
It also appears that there's other issues but that's the most glaring.

You're not going to get that out by adding a few more layers of finish and then leveling it.
I really think you need to probably sand back to bear wood, flatten the surface and start again.
Author:  B. Howard [ Mon Jul 15, 2013 8:01 pm ]
Post subject:  Re: How to finish this...
Yea, that's more than a finish issue. That looks like a construction issue to me as well. If it's an opaque finish as it appears to be fill it in with some epoxy to level the surface and finish over that.
Author:  dpm99 [ Mon Jul 15, 2013 8:09 pm ]
Post subject:  Re: How to finish this...
Thanks for the input.

That's not the bracing. There are no braces there. The curvature isn't as bad as it looks. I angled the camera to illustrate it, and that black brings out every flaw. The spot where the bridge goes doesn't look as bad, though it has the same issue. It's not enough that I'm worried about the bridge getting good adhesion. In fact, if you look at the top from another angle, even now, it looks flat.

The epoxy idea is interesting. Would there be an advantage of doing that over trying to do the same thing with Tru-Oil?
Author:  dpm99 [ Mon Jul 15, 2013 8:14 pm ]
Post subject:  Re: How to finish this...
This might help. Here's another close-up from a different angle. This one's more representative of what it looks like, but I didn't think it illustrated the problem as well.

Image
Author:  runamuck [ Mon Jul 15, 2013 11:01 pm ]
Post subject:  Re: How to finish this...
To build up enough Tru-Oil to level it would require - I don't know how many coats but I would
guess somewhere between 30 and 100. And then I'd be concerned that that stuff probably wouldn't be
all too great at that thickness.

If you were careful you could get it done with 1 or 2 coats of epoxy.
Author:  Trevor Gore [ Tue Jul 16, 2013 4:37 am ]
Post subject:  Re: How to finish this...
David, what's that light stripe through the bridge area? It's not sap wood is it?
Author:  Barry Daniels [ Tue Jul 16, 2013 8:26 am ]
Post subject:  Re: How to finish this...
You may have thought that the surface was flat before applying finish, but it obviously was not. You can either strip and resand to flat, or just keep going and be happy with what you got.

Also, you should have cleaned up and rounded the edge the binding before you apply finish.
Author:  Rodger Knox [ Tue Jul 16, 2013 10:47 am ]
Post subject:  Re: How to finish this...
Once you've wetsanded TruOil, you_will_get witness lines if you put on more oil.
I see two choices, live with it as it is, or sand back to more or less bare wood. If the color is directly on the wood, you don't need to get it all off, just get it flat.
Author:  dpm99 [ Tue Jul 16, 2013 2:33 pm ]
Post subject:  Re: How to finish this...
To answer a couple of questions, that's not sap wood. It's just some coloring glue/pore-filling/finish that I haven't done anything about. As for the binding, I did clean it up before finishing, but had to do it again after the color coat, and have done it a third time because the Tru-Oil tints it.

I appreciate all the advice. I'll weigh my options for a couple of days and make a decision.
Author:  dpm99 [ Wed Jul 17, 2013 10:25 pm ]
Post subject:  Re: How to finish this...
Once again, thanks for all the advice. I'm learning from my mistakes as I go, and I'm tempted to try a layer of epoxy. How would I go about it? Obviously, I'd start by reworking the binding and laying down a coat of dewaxed shellac.

I'm wondering how I'd go about leveling the epoxy. Would I use a squeegee, like Todd uses here, or something like a firm block of maple? I have some West Systems epoxy with the slow setting 206 hardener, so I'd be inclined to use that.

[youtube]https://www.youtube.com/watch?v=YYHxMg7n9cI[/youtube]

Thanks again.

EDIT: Stupid YouTube links. I never can get them to work.
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