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Bridge Out!! Questions

PostPosted: Tue Nov 06, 2018 12:34 am
by Gordon Bellerose
One of my customers brought in an electric guitar that had some "bridge issues".
The posts have moved forward under string pressure, and one of them actually pulled out.
I have attached a couple of pics to help explain.

You can see that the wood in between the bridge and the bridge pickup has cracked all the way through, and moved forward slightly.
The holes are oblonged.
Bridge Out 1.jpg

The other side is not quite as bad, but still cracked all the way through.
Bridge Out 2.jpg

First a bit of background.
The guitar is a Parker Fly. It has a vibrato bridge very similar to a Strat.
The bridge is equipped with piezo saddles that seem to be run through the bridge plate, and then run through one thin wire to the control cavity. The wiring seems to be "glued" or "coated" onto the underside of the bridge plate. I'm not sure how that system works. I will post a couple pics of it in my next post, so you can have a look also.

I do not want to lose the piezo capacity, even though the owner doesn't really care. He says it's ok to put a different bridge on the guitar if necessary. He does not use the vibrato, so it's ok to lose that too.

My thoughts are to cut the broken piece out and replace it with new wood. I would even fill the spring cavity with new wood, and fill in behind the trem block also, to stabilize the bridge in one position. That way, I could drill new mounting holes and screw the bridge plate down, leaving room for the piezo wiring.

My questions are these: What in your opinion is the best way to proceed? Do you think my method will work, or is there an easier better way?

Re: Bridge Out!! Questions

PostPosted: Tue Nov 06, 2018 2:02 am
by Peter Wilcox
I assume there is a crack/split along the bottom of the pickup cavity, and one in the trem block cavity also. Can you knock that piece of wood back into position? If so, maybe wick some CA along all the cracks to keep it there. That would seem to be the simplest solution. However, I'm not familiar with this guitar, and probably don't understand the extent of the problem.

Re: Bridge Out!! Questions

PostPosted: Tue Nov 06, 2018 5:02 am
by Joshua Levin-Epstein ... trem-stud/

Gordon, I remembered a similar repair posted.

Re: Bridge Out!! Questions

PostPosted: Tue Nov 06, 2018 10:33 am
by Barry Daniels
I have seen this several times before. There is just not enough wood there to support the posts.

If you can put in new wood and maximize the contact with the body then you have a better chance of success. I would use hard maple for the patch to provide support for the posts. And I would taper the sides of the patch to minimize the chance of future slippage.

Re: Bridge Out!! Questions

PostPosted: Wed Nov 07, 2018 3:24 pm
by Gordon Bellerose
Thanks guys.
I think in light of the fact that the owner doesn't use or want the tremelo function, I will fill the spring cavity, and the trem block cavity with new wood, including cutting out the broken piece.
I can even remove the trem block and drill new holes in the bridge behind and under the saddles to attach to new wood farther back.
This only leaves the question of drilling new string through holes and inserting ferrulles.
The back of the guitar is pretty much covered by a large cavity cover, so this wouldn't even be seen.
I guess the next question is if the owner wants to pay for all that!

Re: Bridge Out!! Questions

PostPosted: Mon Nov 12, 2018 11:11 pm
by Gordon Bellerose
I'm still thinking about this repair.
I believe Barry has the simplest solution.i will cut out the broken piece on a taper, and replace with good hard maple.
After that I think I might drill 4 new holes and use 6 screws to re-attach the bridge.
That will spread the forces of the bridge across the whole width.

Re: Bridge Out!! Questions

PostPosted: Mon Nov 12, 2018 11:40 pm
by Gordon Bellerose
Here are the pics of the bridge wiring. What can anyone tell me about this type of wiring?

1. Wires under Saddles.
Under Saddle Wires.jpg

2. Wire Coating? on Bottom
Bridge Wiring Underneath.jpg

3. Wire Continues out rear of Trem Block
Bridge Wire in Rear Bottom.jpg

Re: Bridge Out!! Questions

PostPosted: Tue Nov 13, 2018 2:14 am
by Peter Wilcox
Apparently each saddle has an internal piezo crystal. These are connected via each wire to the strip under the bridge. There is a coaxial wire from this strip to the control cavity carrying the signal from the piezos on a central wire, covered by a grounded shield.

There's a schematic here which might help:

Re: Bridge Out!! Questions

PostPosted: Sun Nov 18, 2018 3:39 pm
by Gordon Bellerose
This is what the guitar looks like with the piece cut out.
Broken Piece Cut Out small.jpg

Here is the piece I am going to insert. Good hard maple.
You can see that I was able to cut on an angle on the treble side, but not the bass side. I had to cut straight there.
I am going to drill one or two holes and insert some dowel(s) to help stabilize that side. The force of the bridge will only pull the piece tighter once it is re-installed.
New Piece Fitted small.jpg

Re: Bridge Out!! Questions

PostPosted: Tue Nov 20, 2018 4:07 pm
by David King
You'll have more string tension on the treble side generally anyway. Lastly the glue will give you all kinds of strength if it's a tight joint which it looks like it is. I wouldn't bother with the dowels myself but if it's easy then go ahead.

Re: Bridge Out!! Questions

PostPosted: Tue Nov 20, 2018 4:49 pm
by Gordon Bellerose
Thanks for your input David, I appreciate it. I do have a very nice tight fit on this piece.

I've got a small 90 degree adapter for a drill, and a set of stubby drill bits.
I've checked it out, and it will fit in the given space to drill a straight hole.

My plan is to make a small drilling template so that the dowel will fit into both pieces exactly.
I am thinking I will use an epoxy glue for this.

Do you think the epoxy glue is better for this kind of repair?

Re: Bridge Out!! Questions

PostPosted: Mon Nov 26, 2018 9:52 pm
by Gordon Bellerose
I decided to insert a small dowel, just to make me feel better about the repair.
It's only 3/16 in diameter, but should hold quite a bit.
Dowel in small.jpg

Here it is glued in.
New Piece Glued small.jpg