classical top touchup

[Mario Kessels]

morning guys,
has anyone found a way to match colour on classical cedar tops decently? This is the one finish after repair that i just dont get satisfied with.
I have gone through my whole collection of acrylic paintbrush colours, and tright a dark shellac, but nothing looks really good to me.

I would think maybe mixing some ink in my 2k clear lacquer but have not experienced with that yet. Its transparant finished of course, which is harder anyway but still there should be a satisfying formula.

Your advise is appreciated, grz mario

[Michael Lewis]

Mario, do you have a picture? Depending on your specific situation there are many possible solutions, so we need to know what you are dealing with. Is it a chip, or sanding through finish, or something else?

[Mario Kessels]

sorry, no pic at this moment. In a few days i can take one. The colouring is the typical orange that they pretty much all have.
Its indeed sanding through to equalize the repair area, revealing the bare wood colour, which is way lighter.

[Michael Lewis]

Since I can't see it now I will withhold suggestions and comments. I'll wait for pics.

[Mario Kessels]

http://s327.photobucket.com/albums/k472 ... %20repair/

[Michael Lewis]

Mario, that looks like a crack that was glued without getting the edges level with each other, then trying to level the surface. A rather common misstep. The damage is done and cannot be undone, though it can be somewhat camouflaged with skill and patience. I think it will be easier to remove the bridge and refinish the whole top if you are looking for a totally even color.

Amy Hopkins went through a repair similar to this in an old discussion. Basically you have to seal the wood with clear, then diluted color is brushed on the area, and little by little the coats build and dry until the color is what you want, then finish the job by applying as many clear coats as necessary to match the surrounding finish. This is much easier to do on a thick finish and much more difficult on a very thin finish.

This explanation is a very brief overview, the actual process can be a bit more involved.

[Mario Kessels]

That is exactly what happened. i repaired this guitar a year ago or so, but than a month ago someone decided to fall over on the guitar and managed to get that crack reappear but not so nice this time:-) so i could close it again but it wasnt flat anymore and i couldnt close it as neat anymore.

[Michael Lewis]

Yes, all too often we get only one chance to do a repair well, and after that it becomes less good. All things (guitars) are new only one time.

[Mario Kessels]

Well i took off the finish completely. so now its gonna be a complete refinish which i hate...one day i need to get a spraybooth.

[Michael Lewis]

Did you remove the bridge? It is much more difficult to get a professional appearance if you have to work around the bridge. The other area of difficulty is around the fingerboard, but it is a bit easier than working around the bridge.

[Mario Kessels]

well. This has been interesting. I have done the complete refinish with nitro satin and was really satisfied. I let the bridge be and had no problems really.

This morning I got a call and it appears the crack has now gone all the way to the soundhole and has reappeared! I am seriously surprised and feel very shitty about this one. Since when do my crackrepairs open up again??? I am not sure what to do with this one now. I dont think it makes any sense to glue it again. Probably back to the "one shot" story, reglueing a repair is just not working.
I am thinking about cleaning up the crack and put in a filler strip and then do the whole refinish again.......:_((((

[Mark Swanson]

Are you sure the crack has re-opened, or has the new lacquer just shrunk into the repaired crack?

[Mario Kessels]

yes it has opened up. Unbelievable. The first time I have repaired it with ormal Titebond. Like said that was good, till the guy fell on it. Still a bit strange that it cracked exactly at the same point then but there was no indication of a weak area before this fall.
The last time i decided to glue it with PU. Not my preferred type but I did this for a couple of reasons. The crack was not clean anymore because of the first repair but it was still 'tight' enough to not want to put anything in it to clean it and it was possible to get the PU in. I thought for this crack it was ok now to use this type of glue. And I wanted a STRONG bond. Well i tested it afterwards and it felt rocksolid to me. Its hard of course to pull exactly in the direction that the wood is going to do.
So now it has opened....
I have no explanation but that the repair I did was not good enough and I feel shit about it to say the least. First time this happens. Anyway, more important for me now is to find out how it is possible it opened again.
I dont have trust in reglueing it again. That would mean just doing the same thing again and expecting another result. This crack at least has to be cleaned properly and then I would think needs a fill.
The guy said its not possible it starts to shrink now after 40 years. I think it has dried over the whole lifespan and now it starts to display the results.

[Barry Daniels]

The guy fell on it?!!!! And you are surprised that it cracked again?!!! The fact that it cracked in the same place is a bit odd, but if the guy fell on it then it was going to break somewhere.

[Mario Kessels]

haha. . no: first time it was cracked and I repaired it and it was good. A year or two later he falls on it and it breaks again. This time I repaired it and finished the whole top. Now obviously the crack has reopened. .

[Michael Lewis]

This repair will probably show but can be solid and functional. First the crack must be cleared of all old glue. I would glue a couple cleats across the crack on the inside using a flat non stick surface on the outside (plexiglas and waxed paper) to make sure both sides of the crack are flush with each other, and once it is dry proceed to fill the crack. A sliver or shaving (depends on how wide the opening is) firmly fitted, and glued. Once dry it is leveled and finish touch up completes the repair.

Strong magnets can be very helpful in a case like this, as it can be very difficult to fit clamps to close the crack.

[Mario Kessels]

thx for the inputs guys. Yes thats probably it, i will just have to open up the crack to clean it up. I did a complete refinish the last time, which was nice. So I will just do that again. . this one is starting to give me a headache.

[Greg Robinson]

Mario, when you re-glued with polyurethane, how did you clamp it? I can't imagine being able to clamp a top split with anywhere near the pressure required for a good polyurethane bond. PU naturally forces joints apart when it foams on exposure to moisture, and the joint can seem perfectly strong, until it receives any sort of shock (an expanded joint is very brittle), or just peels apart, for seemingly no reason.
Unfortunately, there's no way to clean a PU contaminated joint except mechanically, so you're pretty much stuck with a splint.

[Mario Kessels]

thx Greg. That is not wat I can find in any documentation really. I just spent an hour checking to see if I am completely wrong but according to what I can find I would need less pressure than with e.g. PVA. I did try to glue with the maximum pressure possible but indeed its only limited since there's no way to really clamp it.
I first put a strip of mdf with baking paper on the crack to flatten the top, the strip was an inch wide. Then I used klemmsia clamps to push this piece sligthly down , and therefore by flattening the top, creating pressure on the joint. I fixed the sides with a big clamp, very carefully of course, just to fix the side so that the klemmsia will create lateral pressure.

The joint looked tight and good, and there was normal squeeze out. Then I tested it in a way I thought was more than necessarily.
Well obviously I am wrong, otherwise this post would not be here:)

[Tom Sommerville]

Clamping is absolutely necessary with poly glue. It expands as it cures. Many praise it for its "gap filling" qualities, but this is wrong. Unless the mating surfaces are in perfect contact your joint will be a web of foam. The cohesive strength of poly is very low.

Water based glues, on the other hand, shrink as H2O evaporates. To some extent we rely on on this characteristic to help draw the surfaces together.

The upshot: never use poly for a repair like that.

My advice: pop the bridge off and fill the joint with a splint of bass wood and apply cleats underneath. Use stainless steel to clean the joint if you can since iron residues can react with glue and turn grey. Hot hide glue is best.