Knocked Over Bridge! Yikes.

[Dr_Atomic]

So I just got out of playing a concert and, in an effort to get out before the chorus, went through a door a bit too quickly and knocked my bridge over. I think I fixed it correctly, but I don't really know and I'm regarding it as precarious right now.

The only thing that appears to be wrong is that there's some space under the foot of the bridge on the G side. I also don't know if I've put it too far from the fingerboard or too close or if I've put it really in the right spot in relation to the f-holes, etc.

Is there any way of knowing whether I've fixed it properly?

Thanks x

[fdeck]

It seems to me that it might be prudent to take most of the tension off the strings, with enough left over to keep the sound post standing. The luthiers are all on their way home from their Friday night gigs, so I assume you will get a proper answer soon. Best of luck!

With that said, I am sure you already checked to make sure the sound post is in fact still standing... Mine would probably have fallen.

[Jsn]

Originally Posted by fdeck

With that said, I am sure you already checked to make sure the sound post is in fact still standing... Mine would probably have fallen.

You know, that raises an interesting question.

I know it's verboten to glue a sound post in place. But what if you put a little daub of rubber cement on it? Nothing to bond it to the wood--just a little something to lightly hold it in place if/when the bridge pressure is removed. It wouldn't impede re-positioning the post when you want to; just a twist and it's loose.

Just curious, folks.

[fdeck]

Originally Posted by Jsn

You know, that raises an interesting question.

I know it's verboten to glue a sound post in place. But what if you put a little daub of rubber cement on it? Nothing to bond it to the wood--just a little something to lightly hold it in place if/when the bridge pressure is removed. It wouldn't impede re-positioning the post when you want to; just a twist and it's loose.

Just curious, folks.

I am not a luthier myself, but in my day job working with "instruments" of another sort, I deal with glue processes that have to stay put over many years on a submicron distance scale. In fact I have considered hide glue on more than one occasion.

My concerns would be twofold: A soft glue, on a long time scale, is a lubricant. Also, anything that gets into the toneplywoods could cause localized swelling that actually drives the post away from where it belongs.

[Jsn]

My concerns would be twofold: A soft glue, on a long time scale, is a lubricant.

Well, I imagine that the rubber cement wouldn't stay soft for long, anyway. It would dry to a hard thin film that could impede vibration, and also crackle and break. Buzzes galore! Never mind. Enough hijacking this thread.


Dr. Atomic, the approximate correct position for your bridge is centered between those little slots on the f holes (the ones that make it look like an "f" instead of an "s"). You also want (again, as a general principle) to center it down the midline of the fingerboard--the strings will pull it into that position if you don't.

The fact that you're reporting some space below one bridge foot is probably a sign you haven't found the right spot yet. Unless it wasn't set up right in the first place, a bridge should be expected to have full, solid contact with the top.

You can loosen the strings and experiment with a new placement, using the above criteria. But you'll probably want to get yourself to a luthier, if only to confirm that other damage wasn't done to the bass. And once you get the bridge right back where it's supposed to be, you might want to consider placing a few pencil marks at the feet of the bridge, for a positioning guide if the bridge falls again.

[1st Bass]

And, not to assume too much, make sure the flat side of the bridge is toward the tailpiece-- so that side looks like a right-angle relationship to the face of the bass.

[Martin Sheridan]

Do not put glue on a bass bridge, period!

If you'd had glue on it you'd have taken part of top with it when it went down or cracked hell out of it. Also, every time you tune your bass the bridge goes forward a little bit and it has to be continually pushed back into position. Didn't your teacher show you this? If not, the bridge is probably badly warped and might explain why the foot no longer fits right...or see next paragraph.

You may have put it on backwards? The strings would be too high on the G side and too low of the E if you did that. Why else wouldn't the feet fit right? Too far left or right, too far forward or back? Wasn't fit right the first time?
Gluing a bass bridge or soundpost is inviting problems with $$$$$$ signs attached that you don't even want to think about.

Incidently, arch top guitars also do not have the bridge glued on. The real reason they probably glue them on flat top guitars is that the players wouldn't know where they went otherwise. Sometimes the glue comes loose on those and they bring up part of the top.

[Dr_Atomic]

Cool. Thank you. I spoke with Barrie Kolstein today and he gave me some pointers. I will bring it to him or Gage when I get back to NY to be sure that things are in order... I also would like someone to double-check that the sound post didn't move. The bass still sounds lovely, so I'm not terribly worried, but I think you are correct that I still have to find the right spot for the bridge because there is that space under the G foot...

The bridge is not warped. It is brand new (very nearly). It just needs to be in the right spot and I, not being a luthier or experienced in these matters, don't know precisely where that spot is. Not to worry though -- When I bring it to the shop back home I'm sure Sprocket or David G will fix it for me.

[Dr_Atomic]

Actually, funnily enough, the bass is sounding nicer and more resonant since I put the bridge back up. Maybe the sound post moved in a favorable way? It probably didn't move a lot since I didn't notice any audible or visible shift.

[Jsn]

Do not put glue on a bass bridge, period!

Martin, your years of insight are, as always, very much appreciated. I always smile when I see your byline pop up in a thread. Perhaps I should apologize further for muddying up this discussion.

Dr. Atomic never said anything about gluing a bridge. Nor did I, for that matter. I briefly contemplated the possibility of using a small amount of rubber cement--not a glue so much as a flowable sticky gum, a substance you can rub off with your hand--to encourage a soundpost to refrain from falling if/when the bridge slips. And I was talking about a little bead of RC around the post's perimeter, not directly on the spot where it compresses against the top.

At any rate, I promptly concluded this wasn't such a good idea, and certainly not germane to the topic at hand. What I should have done was caution Dr. A to check that his soundpost hadn't fallen as well, and left it at that.

[Martin Sheridan]

The bridge should be positioned, centered, on the inside nicks of the f-hole.

Why put a rubbery gummy substance between the bridge and the top? It isn't needed. The strings will hold the bridge in place. I do know of luthiers who put a little powdered rosin on the feet of the bridge to keep the bridge from sliding around on shiny new lacqured basses, but I think it is better to scuff up the lacquer under the feet. Some also do the same on the ends of the soundpost, but that also should not be needed if the post if properly fitted.

[Jsn]

Originally Posted by Martin Sheridan

Why put a rubbery gummy substance between the bridge and the top? It isn't needed.

I couldn't agree more. Fortunately, no one in this thread has proposed doing such a thing.