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Re-topping a (nrealy)new guitar
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Author:  grumpy [ Fri Mar 15, 2013 11:36 am ]
Post subject:  Re-topping a (nrealy)new guitar
In the "destroying imperfect builds" thread, I mentioned how I've never had to scrap an entire instrument(yet...), but that I've had to re-top/re-back/re-neck a good many, and here's one I did just this morning! Fred Tellier 'met' this guitar last fall, when I took it to the Elora Guitar Summit. I literally shot the finish, including the sunburst, on the Wednesday, and in order to have the guitar strung-up on Friday, I had to have the bridge in place on Thursday. Long story short, even a good polyester finish can't always be leveled and buffed after only 24 hrs., with the result being that it needed to be refinished. I finally got around to doing it, and when I pulled the bridge, there must have been a sliver that pulled-up, and somehow, my sander grabbed it and tore a chunk out of the top! The damage can be seen in one of the photos... So..., yesterday I prepared a new top, and this morning removed the old and replaced it. I didn't exactly time myself, but it appears to have taken about 45 minutes from setting-up the router, to having the new top glued in place. Definitely worth the bother VS tossing the entire sound box!

To remove the old top, I set my router to cut just past the linings, and not quite deep enough to cut completely through the top. After routing the entire perimeter, I go around, carefully, with a utility knife and cut the rest of the way through. Then it's a simple matter of lifting the top, which will still be partially glued to the neck block, such that it will "peel-off" from the neck block. from there, I used a small plane to remove most of the spruce from the linings and blocks, followed by a quick pass in the motorized dish, checked and adjusted the brace inlets, and the new top went right back on! I always get the new top(or back) completely ready to go-on before removing the old one, so that the body won't have time to 'relax' and change shape.

Hope this helps someone "save" a future build; it's simple, painless, and definitely better than scrapping an otherwise perfectly fine soundbox(or accepting a big blunder and trying to cover it up)!

Attachment:
topoff1.jpg


Attachment:
topoff3.jpg
Author:  grumpy [ Fri Mar 15, 2013 11:39 am ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Whoa! Lance(or some other moderator..), can you please correct my spelling(it should be 'nearly', not nrealy... <lol>).
Author:  WudWerkr [ Fri Mar 15, 2013 11:39 am ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Nice work . Beats the way I did it last time laughing6-hehe These are exactly the kinds of threads I am hoping will end up in the repair and restoration subforum ... Looking good [:Y:]
Author:  Tai Fu [ Fri Mar 15, 2013 12:09 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
I was able to remove a guitar top and replace it, without damage to either part by wedging a knife between the seams (if hide glue) after the binding is removed (if plastic binding), or if titebond is used and wooden binding is present, some heat and steam can be used to release both parts. It is good practice to learn how to remove parts without damaging either part if possible (not counting finish damage - this is unfortunately necessary to get some parts off and a real repair job like this will require a refinish). You will never know when someone asks you to repair a badly damaged guitar but wants to keep the parts original. You can't always save a wooden binding but its easy enough to replace.

Actually one time I did remove a back that was improperly glued with PVA without damage to the finish. I basically heated the knife itself on a propane torch and carefully inserted the knife between the joint.
Author:  grumpy [ Fri Mar 15, 2013 12:23 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Yes, it is possible to remove a top or back without damaging it, but this is about a total replacement... This method is fast, and safe; very little chance of damaging the ribs.

One important detail I forgot:

I route the binding off as well, but in order to ensure that the binding doesn't come loose ahead of the cut and tear-off a chunk of the ribs(sides), all routing is done as a --climb-- cut! In other words, go backwards against the router bit. This holds very true if you're doing a simple re-bind, also.
Author:  Alain Moisan [ Fri Mar 15, 2013 1:22 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
grumpy wrote:
To remove the old top, I set my router to cut just past the linings, and not quite deep enough to cut completely through the top. After routing the entire perimeter, I go around, carefully, with a utility knife and cut the rest of the way through.


I do it slightly more simply. I drill a 1/2" hole in the top, near the lining, ang then use a bearing guided bit (3/8"), where the bearing sits on the lining. Then no need to go back with the utility knife. Of course, to do so you need to have linings that ar vertical, but it seems to be your case.
Author:  Kent Chasson [ Fri Mar 15, 2013 1:52 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Anyone ever tried saving the binding using Greven's method? http://www.grevenguitars.com/retopping-demo.html
Author:  grumpy [ Fri Mar 15, 2013 4:07 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Alain, doesn't that leave you with the spruce and bindings still at full height? That would require a lot more time and work before you had it ready to re-top...

Kent, that's a great method for a vintage restoration, but completely unnecessary for a new, or build-in-progress.
Author:  Alain Moisan [ Fri Mar 15, 2013 4:32 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
grumpy wrote:
Alain, doesn't that leave you with the spruce and bindings still at full height? That would require a lot more time and work before you had it ready to re-top...


Well not exactly, but I didn't understand your procedure right. I thought you routed the bindings off (which I do also, but just the bindings) and then route a chanel almost through the top. In your first picture, it sort of look like you used a 1/8" bit for that. But after a seconf look, I understand better what you do. You do one pass with the router and then chop off the top with the utility knife. I do one pass for the bindings, change bit and then another pass to remove the top. And I am left with the full top thickness on top of the bindings, which I guess takes a little longer to plane.
Author:  grumpy [ Fri Mar 15, 2013 5:14 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Yup, my photos aren't that clear....

I set the router to cut a bit past the linings, so, roughly 3/8", and -almost- the full depth of the top. What's left for the knife is a sliver, really, and if we look close, we can see that the thinner areas are darker, and these areas only have a few thou of spruce left. Just enough so that the router doesn't fall-through the top, which would then allow it to take a big bite out of the ribs and linings, ruining everything. Basically, it only takes 2 or 3 light passes with the knife to cut completely through.

I think I saw a photo from the Martin(or maybe it was one of the other big guys') repair department where they just take a jig saw and (roughly) cut out the top. I guess they then take a plane and remove the rest. Lots of ways to do it, but I can't think of a quicker, overall, way of accomplishing the task, since the router leaves the rim just about ready to accept the new top.
Author:  Kent Chasson [ Fri Mar 15, 2013 5:33 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
grumpy wrote:
Kent, that's a great method for a vintage restoration, but completely unnecessary for a new, or build-in-progress.


I've yet to do it but it sure seems like the extra time would be worth it to save the binding alone. But the real savings is to keep from having to refinish the sides. Will find out soon enough.
Author:  Dennis Duross [ Fri Mar 15, 2013 5:56 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Those linings are amazing.
Author:  FishtownMike [ Sat Mar 16, 2013 12:59 am ]
Post subject:  Re: Re-topping a (nrealy)new guitar
I recall seeing someone who has the ability to route off a top leaving the bindings totally intact. Anyone remember who this is?
Author:  Greg B [ Sat Mar 16, 2013 2:44 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
That's the Greven method. See link a couple posts above.
Author:  Ken Franklin [ Sun Mar 17, 2013 2:14 am ]
Post subject:  Re: Re-topping a (nrealy)new guitar
grumpy wrote:
I think I saw a photo from the Martin(or maybe it was one of the other big guys') repair department where they just take a jig saw and (roughly) cut out the top. I guess they then take a plane and remove the rest. Lots of ways to do it, but I can't think of a quicker, overall, way of accomplishing the task, since the router leaves the rim just about ready to accept the new top.


I guess I do it like Martin.
Author:  Pmaj7 [ Sun Mar 17, 2013 9:05 am ]
Post subject:  Re: Re-topping a (nrealy)new guitar
grumpy wrote:
I set my router to cut just past the linings, and not quite deep enough to cut completely through the top.
Do you do it in one pass?


Sent from my GT-I9300 using Tapatalk 2
Author:  hugh.evans [ Sun Mar 17, 2013 12:16 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Martin only used heat, steam, and thin spatulas in my experience. I have a souvenir in the form of an intact D-45 top that I has Chris sign for me.
Author:  grumpy [ Sun Mar 17, 2013 4:09 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Yes, one pass.

regarding the "Greven method", guys, that's an advanced repair/restoration technique that requires some pretty serious repair chops. All of that is unnecessary when re-topping a new and nearly new build. Don't try to save $10 worth of bindings; just cut 'em off. The finish on the sides? You'll be finishing the top, and it's a new instrument, so you -want- the finish to be seamless on the entire body, so you'll -want- to re-finish the sides, too. Consider them as pore-filled... <g> The key word here is 'time'. If it takes more time to execute the re-top, than it takes to make a whole new soundbox, it's not worth it. And you also want the entire thing to be seamless, such that no signs of the re-top are left behind. Don't over-think it! As it was, the one pictured here was re-topped in about 45 minutes, total. Given time for the glue(HHG) to cure enough to work on the body, I could have had it trimmed and bound a few hours later. Seeing as I began work on it at about 6:30am, I could have, if not for all the other work that took up my time, had this body re-topped and re-finished by 4pm, and could be leveling and buffing out the finish by tomorrow morning. As it is, it is now bound and ready for finish, which may take place tonight. Total hands-on time(and this includes the "thinking" time, so if you have to sit there and think about how to best approach the task for a couple of hours, count those, too) is roughly 2 hours., total.

K.I.S.S.
Author:  FishtownMike [ Sun Mar 17, 2013 5:11 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Greg B wrote:
That's the Greven method. See link a couple posts above.

Yeah I guess it was him. I seen a video demonstration that I believe was from a Guitarmaker synopsis or a G.A.L event. Not sure which one it was.
Author:  FishtownMike [ Sun Mar 17, 2013 5:13 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Ken Franklin wrote:
grumpy wrote:
I think I saw a photo from the Martin(or maybe it was one of the other big guys') repair department where they just take a jig saw and (roughly) cut out the top. I guess they then take a plane and remove the rest. Lots of ways to do it, but I can't think of a quicker, overall, way of accomplishing the task, since the router leaves the rim just about ready to accept the new top.


I guess I do it like Martin.

Yeah in one of the Teeter or maybe even the Sloane repair books they show Martin repairmen doing this.
Author:  Alain Moisan [ Sun Mar 17, 2013 7:45 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
grumpy wrote:
Seeing as I began work on it at about 6:30am, ...


6h30 am in the shop!

Your in a league of your own, man.... [uncle]
Author:  grumpy [ Sun Mar 17, 2013 11:53 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
I was in the shop at 5:30am that morning.... I've fought a lifelong battle with insomnia, and many years ago just decided to work the hours my body decided needed to be worked. Some days I start really early, some days, I end really late.. <sigh>

I --do-- try to avoid the table saw and bandsaw before noon, no matter what!
Author:  Alain Moisan [ Mon Mar 18, 2013 2:24 pm ]
Post subject:  Re: Re-topping a (nrealy)new guitar
Just hope you can find some family time in there...
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