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PostPosted: Wed Jan 17, 2018 3:48 pm 
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Cocobolo
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Joined: Wed Feb 17, 2016 8:54 am
Posts: 288
State: Texas
Country: United States
Focus: Repair
In the middle of a Hofner neck reset, neck came off just fine. However the previous owner had a home gamer repair to the fingerboard extension in an effort to try to keep the neck from pitching forward. When he did this it caused the fingerboard extension to become horribly ski-ramped. It's really tough to photograph it but hopefully you can get an idea from these pics. I would like some input from you experienced guys (Hesh that means you ;) ) on the way to approach this.

This little piece of plywood was pushing the extension into an extreme ski ramp as the neck moved over time. He had just shoved it under there to try to stop the neck from moving. Sadly it did more damage than good.

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Fixing this is complicated by the fact that it is scarfjointed under the fingerboard. My thoughts are as follows

1. 50/50 approach. Remove frets, level extension down a bit, refret, and level frets on the extension to make up difference. The ramp is so drastic that if I leveled it all out solely on the fingerboard, there'd be barely a sliver left of the fingerboard at the end. Doing half of the level on the board would let me make up the difference in the fret height. This is the easiest option.

2. Remove fingerboard, steam out the extension support, reglue, install partial carbon fiber rod to straighten extension. This would hold the extension straight but would also push out the repair completion date by a good amount of time.

And just fyi, this is a "blank check" sort of repair, he's not concerned with price. Extreme sentimental value is the only reason I agreed to do it.

Any ideas are welcome, hopefully it's visible in the pictures what's going on.


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PostPosted: Wed Jan 17, 2018 4:17 pm 
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Old Growth Brazilian Rosewood
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Joined: Fri Nov 02, 2007 9:49 am
Posts: 10040
Location: Ann Arbor, Michigan
First name: Hesh
Last Name: Breakstone
Country: United States
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Hey Dan:

Man that looks ugly and you do indeed have an olympic sized ski ramp there.

Seems to me that this one may benefit from some of the following or maybe a combination of approaches below.

Refret and level the board inducing fall-way but simply shooting for level would be an improvement. You will need to remove a lot of material and deepen the fret slots toward the end of the ski ramped extension.

Dave Collins has developed a method that we have used with great success on inexpensive instruments when appropriate for the instrument. The idea is to remove forward bow or in this case a ski ramp.

Clamp the neck in a vice and induce back bow to the extension with clamps, weights, etc. Use a "supervised at ALL times" heat lamp to warm the extension while in back bow because of the clamps and/or weights.

After a hour or two, all supervised since heat lamps are dangerous and you only want the lamp close enough to warm not make hot put the lamp away. Then while the thing is still clamped or weighted in back bow on the extension frets wick in thin ca being careful not to drip any down the outside of the neck.

The CA fills the voids created by inducing back bow and when dry prevents the thing from returning to it's former ski ramp because the dried ca creates compression not unlike manipulating tang sizes as in a compression refret which is what's next.

Another idea is to do just that, use Martin sized compression fret wire and compress the hell out of the extension frets with over sized tangs to counter the ski ramp.

There's three ideas for you Buddy that something here hopefully will help. Maybe a combo of some of these too and not just one of them.

Good luck and let us know how it goes?



These users thanked the author Hesh for the post: DanKirkland (Thu Jan 18, 2018 10:10 am)
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PostPosted: Wed Jan 17, 2018 7:57 pm 
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I've fixed something similar to this before. In my estimation, putting that FB extension support back where it belongs is the only place to start. The heat and pressure method that Hesh described is what worked for me. Your just reversing the glue creep. Providing no one shoves a wedge under it again, it's not a joint that sees much if any stress.

Steve



These users thanked the author StevenWheeler for the post (total 2): DanKirkland (Thu Jan 18, 2018 10:10 am) • Hesh (Thu Jan 18, 2018 5:35 am)
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PostPosted: Thu Jan 18, 2018 10:12 am 
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Cocobolo
Cocobolo

Joined: Wed Feb 17, 2016 8:54 am
Posts: 288
State: Texas
Country: United States
Focus: Repair
Thanks for the tips Hesh and Steven.

I decided to give the heat/compression a try. I left it clamped overnight after the heat had been applied for a while. I'll let you guys know how it turned out.

It needs a refret anyway so once the compression is done and I see what the result is I'll likely just use some wider tang wire anyway to help hold the extension as flat as possible.


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PostPosted: Fri Jan 19, 2018 10:29 pm 
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Cocobolo
Cocobolo

Joined: Wed Feb 17, 2016 8:54 am
Posts: 288
State: Texas
Country: United States
Focus: Repair
Hesh, since you asked to see the results.

Success was had. I tried the heat lamp thing you guys suggested but it was only marginally successful, it moved but it sort of "sprang" back to where it was before. Perhaps I did something wrong (it's likely I missed something important).

After that, I decided to take a little more direct approach. there was a *tiny* gap at the base where the extension is glued in and scarfed to the neck. I ground down the tip of my steam needle in my little rig and used a 2mm bit to cut 3 small holes in the gap. Nobody will see these after the fact since they're underneath the extension. I ended up plugging them once all was said and done.

I didn't want to dissolve the glue at the seam just soften it. I bounced between the three holes quickly with soft blasts of steam to help build up heat and water but not blast the glue out of place. I put a small shim under the extension to help bend it back in place and kept it clamped to my sanding beam. As I added heat and steam I also added tension with the beefy C Clamp. With the shim underneath the edge of the fingerboard it created enough room to bend the extension back to where it needed to be. I left it overnight in this manner.

Image

Next morning it was flat, the steam seems to have done the trick. After a refret she's all good to go. Thanks again for the advice gentlemen, it is appreciated!

Image

Image



These users thanked the author DanKirkland for the post (total 2): Hesh (Sat Jan 20, 2018 8:03 am) • Johny (Fri Jan 19, 2018 11:14 pm)
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PostPosted: Sat Jan 20, 2018 8:03 am 
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Old Growth Brazilian Rosewood
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Joined: Fri Nov 02, 2007 9:49 am
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Location: Ann Arbor, Michigan
First name: Hesh
Last Name: Breakstone
Country: United States
Status: Professional
Good going Dan!


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PostPosted: Mon Jan 22, 2018 4:59 pm 
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City: Lenoir City
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Nice!

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Steve Smith
"Music is what feelings sound like"


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