Split bridge & top

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vandenboom
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Split bridge & top

Post by vandenboom » Fri Jan 30, 2015 7:18 pm

Hi all
Today I got my first return with a more serious problem.
This is a steel string dreadnought I made/sold 4 years ago.
A year after delivery,it came back with serious action problems as client had put on 13-56 guage after I had delivered it with 12-52's. I had never dealt with this heavier guage and recall being concerned by a more pronounced lift in the top behind the bridge. Anyway, I set it up for the heavier guage and it was fine. It came back today and action had not really altered since then. i.e. playability had remained very good.

The customer returned it because "the pickup was not working properly". It has an artec under saddle piezo with pre-amp unit installed in side.

When I started to look at it, I discovered 2 more serious problems before I even started to explore the pickup.

1.) Cracked top in the lower bout on treble side, about 9cm long. See pic below. It has a serious ding at the start of the crack near the rim/binding. The guitar came in a very weak case and had clearly been on an overseas flight. So there are 2 possible explanation for the crack. i.e. Damaged during flight or damage when copping a heavy knock producing the ding.
Proposed solution : Glue a small patch on the underside of the crack and wick the crack with supa glue. Any other suggestions?
split top.jpg
2.) Bridge cracked between pin holes 2 to 5 with another finer crack in front of pin hole 6. I inspected the bridge plate and can't see any noticeable crack. Although I use a slotted bridge, I had a hell of a time getting some of the heavier strings out and wondered if the winding above the ball had jammed in some of the slots (because they are thicker than lighter guage) resulting in the bridge itself doing too much work instead of the bridge plate. What do you think?
More importantly, do I have any alternative remedies other than bridge removal and replacement? i.e. If I drown it in supa glue, will it do the job?
split bridge.jpg
I haven't explored the pickup problem yet but that should be straight forward though a part of me is wondering if it is related to the bridge crack. Pickup is working but very low and inconsistent volume.

Thanks. Frank.

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Bob Connor
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Re: Split bridge & top

Post by Bob Connor » Fri Jan 30, 2015 9:33 pm

G'day Frank

The split needs to be repaired with a splice, which will require a re-finish.

The bridge should be replaced. Superglue won't fix the problem.

None of the above problems looks like warranty work to me.

Regards
Bob, Geelong
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Mainwaring and Connor Guitars

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Mark McLean
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Re: Split bridge & top

Post by Mark McLean » Fri Jan 30, 2015 10:01 pm

Hi Frank
It seems that this guitar has lived a bit since you gave birth to it. That is a good thing, right. We don't want our creations to be kept under the bed. However, if it has copped a bit of a hiding that is not your responsibility to rectify. My thoughts are not those of an expert repairer, only those of a hack amateur builder.

For problem 1, I would make sure that the guitar is humidified before fixing the top crack - but agree with your plan to put a cleat under it (with Titebond?), and also wick in some CA glue from the outside. You can't get a clamp out that far from the sound hole to clamp the cleat. You probably know the tricks for that already - including the snazzy StewMac scissor clamp, or make your own small finger adjustable one like this. Alternatively, the Don Teeter method of using a guitar string and tuning machine to pull the patch up tight (sorry don't have a picture of that handy).

The bridge crack is more of a dilemma. There is a good chance it was caused by trauma as well. If the owner has not even noticed it he might be reluctant to do the whole replacement job, but that is what it needs. But flooding it with CA might cause trouble by sticking it down to the soundboard in a way that is harder to undo if you later decide to remove the bridge. Could run/ooze into the pickup or wiring also. Would make me a bit nervous. Maybe it is best to just watch it for a while.

Mark

Hard Road
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Re: Split bridge & top

Post by Hard Road » Fri Jan 30, 2015 10:03 pm

I haven't seen a bridge spit like that before, does he hit the pins in with a hammer?

Lex
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Re: Split bridge & top

Post by Lex » Fri Jan 30, 2015 11:37 pm

I agree with Bob, It's not a warranty Job, so make sure that whatever you do ,you charge well for it

Tod G

lauburu
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Re: Split bridge & top

Post by lauburu » Sat Jan 31, 2015 6:30 pm

does he hit the pins in with a hammer?
The crack does suggest the pins have been inserted too forcefully. If the bridge has cracked, is there further damage to the soundboard or the bridge patch?
Miguel

vandenboom
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Re: Split bridge & top

Post by vandenboom » Sat Jan 31, 2015 8:41 pm

Thanks everyone for your insights.
It hadn't occurred to me that the bridge split is likely to have occurred because the bridge pins were forced in. That makes sense.
When I cut the slots for a slotted bridge, I always do them quite precisely to handle 12-52's. It never occurred to me that someone might want something fatter in there. In future, I will be making them a bit wider to accommodate that possibility.
I can't see a visible split in the bridge plate with a mirror. A matching split in the top will only become apparent once the bridge comes off.
I will have the conversation with said customer on Monday.
I won't be doing anything about it for at least a month as I'm still recovering from carpel tunnel surgery on both hands. Not much joy there but hopefully long term benefit.

Thanks again everyone.
Frank

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needsmorecowbel
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Re: Split bridge & top

Post by needsmorecowbel » Sat Jan 31, 2015 9:24 pm

Wishing you a speedy recovery Frank!

Stu

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Kim
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Re: Split bridge & top

Post by Kim » Tue Feb 10, 2015 3:50 pm

Frank,

One school of thought suggests that in order to reduce the possibility of aligning the BP holes with a single grain line of the bridge wood thus inadvertently introducing a fault line prone to cracking as a result of the wedging effect of the pins, that the BP holes are best drilled to a mild radius. Doing so does mildly alter the break angle of strings 'D' and 'G' to the saddle somewhat, but not so much to be of any concern IMO.

Cheers

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Trevor Gore
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Re: Split bridge & top

Post by Trevor Gore » Tue Feb 10, 2015 8:00 pm

..also laminating in a layer of CF makes splitting the bridge almost impossible. Maybe something to think about if you end up replacing the bridge.
DSCF4341s.jpg
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simso
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Re: Split bridge & top

Post by simso » Thu Feb 12, 2015 10:10 am

Some cleats underneath and a new bridge and all done, easy enough repair.

Definitely not your fault

Steve
Steve
Master of nothing,

Do your own repairs - http://www.mirwa.com.au/How_to_Series.html

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