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Koa top crack
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=49865		 Page 2 of 2
Author:  bobgramann [ Wed Nov 15, 2017 5:28 pm ]
Post subject:  Re: Koa top crack
If at all possible, I would use hot hide glue on the cracks. That involves figuring out a quick and accurate way to clamp the pieces and warming all of the area before gluing. My second choice would be fish glue. I wouldn’t use Titebond. If anything went wring and I had to redo any part of the repair, Titebond would be very difficult to clean out before the reglue. The ohter two would not require cleanout.

If it were brought to me, and if I agreed to repair it, I would do so only under the terms that it would remain forever visible. If on examination, I determined that it did need retopping, I would tell them to go buy another guitar.

I have heard the fifth fret quote attributed to String Bean.
Author:  kwerry [ Thu Nov 16, 2017 1:20 pm ]
Post subject:  Re: Koa top crack
And Please don't think I was saying there was anything wrong with what you were/are doing, this is the kind of thing i think it great for people like us to take on it is not financially viable for the pros (I think Hesh said that) so those of us with more time and less $$ invested in this can take it on.. I also include family in the exempt category :-) and just so i come clean i also include my best friend who i have done work for at material costs.. Now someone off the street gets charged a rate based on the type of work and my skill which is below most reputable full time repair guys.. you do get what you pay for in many things..

Kerry

nathanpeirson wrote:
Time to come clean. I am not making money on this or offering my services for monetary gain at this point. The guitar belongs to a family member. The other instruments I've been working on belong to my employer (I work in Theatre). I have the time, energy and desire to do the work hone my chops and have additional skills at my disposal. I am 64 (cue Beatles). I have done cabinetry, fine woodwork and prop building for 34yrs. I currently have a Sinker Redwood top/Black Walnut sides and back guitar in the wings (still building tools.), 2 carved top mandolins, one Adi top/Maple B& S, the other Douglas Fir Top/Padauk B&S and an Octave Mandolin, Sitka top, Mahogany B&S. I believe you should never stop learning, honing skills and producing something that makes music. The Lord knows this world needs it. I appreciate this forum and various others I inhabit. The community is warm, intelligent and willing, all leading to good teaching/sharing. Thanks to all and keep the ideas coming.
Author:  kwerry [ Thu Nov 16, 2017 1:29 pm ]
Post subject:  Re: Koa top crack
I'll add my 2cents (Canadian) to this and say I would use fish glue, I say this because I have no experience using hide glue and if you do have experience with hide glue then that might be a good choice but for this which looks complex the extra open time of fish glue would be helpful I think.

Kerry
Author:  SteveSmith [ Thu Nov 16, 2017 3:42 pm ]
Post subject:  Re: Koa top crack
I have used fish glue a lot in the past. Recently I have been using liquid hide glue when I want the open time. Obviously not for high-stress components like bridges and such. I had shied away from liquid hide glue for years but in general I find it seems to be doing a good job.
Author:  nathanpeirson [ Fri Nov 17, 2017 2:19 pm ]
Post subject:  Re: Koa top crack
Here is where things stand; caul placed inside to push up the break, UHMW plastic clamping caul with light pressure- enough to hold things in place without distortion.ImageImageImage



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Author:  nathanpeirson [ Fri Nov 17, 2017 2:23 pm ]
Post subject:  Re: Koa top crack
nathanpeirson wrote:
Here is where things stand; caul placed inside to push up the break, UHMW plastic clamping caul with light pressure- enough to hold things in place without distortion.ImageImageImage



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I love UMHW for glue projects. I get mine from the cut off bins at a plastic supply company in town. They sell cut offs by the pound ($5). I’d recommend it to anyone that has a similar type supply near them.


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Author:  nathanpeirson [ Sun Nov 19, 2017 5:36 pm ]
Post subject:  Re: Koa top crack
Any one know what causes these white areas? I’ve dropped filled CA and I’m working it down with a razor scrapper, wet dry paper and micro mesh. These appeared after some wet sanding. Is it moisture under the finish? Is there a fix?Image


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Author:  bobgramann [ Mon Nov 20, 2017 11:53 am ]
Post subject:  Re: Koa top crack
Did you use accelerator?
Author:  nathanpeirson [ Tue Nov 21, 2017 12:14 am ]
Post subject:  Re: Koa top crack
I used it in an earlier application, but I though I sanded back down through that layer...after that I let it dry itself.
Author:  profchris [ Tue Nov 21, 2017 5:13 am ]
Post subject:  Re: Koa top crack
I've had the white residue when drop filling with CA, and just scraped back until it was gone and then refilled as necessary. But this was to correct defects on my cack-handed builds, no real experience of proper finish repairs.

I think in my case it was caused by adding too much CA in one go. A little, allowed to dry, and then a little more, and so on, seemed to prevent it.
Author:  nathanpeirson [ Wed Feb 28, 2018 12:01 pm ]
Post subject:  Re: Koa top crack
So, I have had some time to get back to working on the Koa T5. I was able to glue it up pretty well with little wedges from the inside. The finish is that UV cured poly, which has a tendency to want to lift off the edges of the break. I CA glued the offenders. I was trying to drop fill the larger areas of missing finish with think CA glue and all was going well until I tried to wet sand it. I let it dry overnight, more from my own time constraints than what the glue needs. I did not use accelerator. Anyway, the dry sanding with micro mesh went well, but the trouble came when I decided to wet sand in the finer grits. Portions of the drop fill blushed. This happened once before and I had to remove the CA and start over. Long story short, and advice requested, what finish can I use to go over the top of the repair? I need something that I can blend into the Taylor poly and will adhere to it and not crack off later. It looks very similar to the previous photo I posted regarding the same issue.
Author:  nathanpeirson [ Sun Apr 29, 2018 10:11 am ]
Post subject:  Re: Koa top crack
Well, I realized I didn’t post the finished project. It took a while since I only worked on it when I could. Learned a lot about the various aspects of repair, so it was a win for me. The finish took the most time. I ended up using CA glue wiped on in thin layers. Tried the spot filling but there were too many spots to fill. Thanks for all the help. It will further my appreciation for the craft. My son was more than pleased to get his guitar back.Image


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Author:  Clay S. [ Sun Apr 29, 2018 11:03 am ]
Post subject:  Re: Koa top crack
Looks good!
Author:  fingerstyle1978 [ Sun Apr 29, 2018 6:05 pm ]
Post subject:  Re: Koa top crack
Bravo! Job well done. If only the world had a few more folks like you around.
Author:  John Arnold [ Mon Apr 30, 2018 11:33 am ]
Post subject:  Re: Koa top crack
Looks better than I would have expected. I have done many similar repairs over the last 33 years, and IMHO the most important aspect is making the customer understand what the reasonable expectation should be.
FYI, you can overspray polyester finishes with nitro. Prep by sanding with 400 first.
Author:  nathanpeirson [ Mon Apr 30, 2018 2:07 pm ]
Post subject:  Re: Koa top crack
John Arnold wrote:
Looks better than I would have expected. I have done many similar repairs over the last 33 years, and IMHO the most important aspect is making the customer understand what the reasonable expectation should be.
FYI, you can overspray polyester finishes with nitro. Prep by sanding with 400 first.

Great to know about the Nitro, although it would have to be rattle can for me at this point. I don’t have the spray set up. I have used the nitro pens from SM for a couple spit repairs on my old Martin and it works great.



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Author:  kjaffrey [ Mon Apr 30, 2018 6:14 pm ]
Post subject:  Re: Koa top crack
Hat repair looks great!!!
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