Sound Post Adhered, maybe sap?

BassAxe · #1 11-04-2009, 01:26 PM

I have a 2 year old bass, hand-carved top, laminate body. I bought her new. She recently developed a crack at one of the f-holes on the G side.

I took her to a local luthier who put in a diamond cleat at the crack and glued with hide glue, but each time he tightened the strings, the tension opened up the crack again. So he changed to white wood glue for the repair, but still had the same result.

He discovered that the sound post was glued in-place!

Now, here's my question: I just got off of the phone with him and we are considering the possibility that the bass builder did not deliberately glue the sound post in, but since this was a new bass, it might actually be the natural sap of the wood which caused it to stick in place. Has anyone else heard of such a thing happening, before?

The bass was made by what I would consider to be a reputable builder and I'd like to think that gluing the sound post in place was not done deliberately.

Cody Sisk · #2 11-04-2009, 01:44 PM

It's unfortunately not uncommon to see soundposts glued in place. Chances are, that post is too long and being glued in place only creates serious problems for the top.

I think your luthier was trying to be nice when mentioning the sap thing. I can tell you with 100% certainty that's not the case though. The process used to "dry" the wood involves removing the sap. If you had a bass constructed of wood that was not properly dried and sap was still present, it would self-destruct on you and your soundpost would be the least of your worries!

You'll want to have that soundpost removed, but unfortunately the top will probably have to be removed to fix the areas affected by the glue. Big globs of glue under where the post used to be will cause serious problems to the poor guy trying to fit a new soundpost.

This won't be a cheap fix. It might be time to consider a new axe..

Cody Sisk · #3 11-04-2009, 01:47 PM

BTW, if the bass you're refering to is the Upton bass listed in your profile, the post will definitely not be glued in place.

Though it might be in there pretty tight as the instrument is new and still settling in. Soundpost adjustments are needed pretty frequently for new instruments. Yours might be long overdue..

Eric Hochberg · #4 11-04-2009, 01:51 PM

Wait a minute, he tried to fix the crack with the soundpost in place? Does that make sense?

BassAxe · #5 11-04-2009, 02:26 PM

I haven't updated my profile in a long time. I'm deliberately leaving the name of the bass maker out of the discussion.

I'm the one who asked the luthier if it might could be sap. Maybe some other varnish or something from the building process? He might not have had time to think the idea through, but seemed to go along with the possibility. I haven't seen it, yet.

Yes. It was long past due for a proper set-up.

drurb · #6 11-04-2009, 02:45 PM

Why not consult the builder of the bass for more info?

**Matthew Tucker** · #7 11-04-2009, 03:33 PM

It could be rosin; sometimes, if the soundpost is hard to set in a bass with steep arching, some rosin on the post ends stops it slipping. I suppose if they used too much it could melt and get gluey.

I would definitely not try to glue a crack with the soundpost in place.

forester · #8 11-04-2009, 03:41 PM

Quote:

Originally Posted by ehochberg

Wait a minute, he tried to fix the crack with the soundpost in place? Does that make sense?

sometimes it helps to leave the post , using it to push against to open the crack to get the glue in,then drop the post and clamp.
this works well on f-hole splits.

(sap)hardwoods..(resin)conifers
seems unlikely that a green SP was used and that it lost enough resin out of both ends to glue itself in place.

and what mathew said.

Eric Rene Roy · #9 11-05-2009, 12:02 PM

Neal is being nice trying not to draw any negativity our way, and Neal and I have "talked" back and forth about what happened with his instrument. So, I'll confirm it's our bass...and the sound-post is glued in.

But before you shoot me, let me explain.

Basses that ship have sound posts that are spot glued in place. A drop of extremely watered down hot hide glue is put on both ends of the post. The post is not previously sized and a lot of the glue is wicked into the end-grain of the spruce post. This leaves an extremely starved glue surface. The intention of this spot of glue is to keep the sound-post in place during shipping. The glue is so weak that one hit with a sound-post setter will break the glue and let it be moved (I know, we have tried it dozens upon dozens of times). The bond is not tight enough that it cannot be hit free and will not pull up or damage wood in the process.

Instruments that are picked up from our showroom do not get this treatment as there is no need.

When we did not glue sound-posts in on instruments that ship, we found that maybe 25% of the time the sound-post would fall. Customers who just received an instrument would then have to find a luthier who could set the post in place...often times paying too much $ to do so...and frequently no luthiers were local enough to even get to. The tack gluing of sound-posts has eliminated this from happening and we are confident that the weak hide glue bond does not cause any damage or problems with our basses. We back this up with a 5 year warranty to...I believe that is the longest in the business for a new instrument.

Feel free to eMail me if you have questions. eroy@uptonbass.com

Thanks!

Cody Sisk · #10 11-05-2009, 12:56 PM

Eric,

Though this might just be asking the competition to reveal their business secrets, you might check with the guys at Lemur. I've not seen the contraption myself, but evidently they have a method of holding the post in place with some sort of duct tape assembly. It holds the post in place during shipping and all that the player has to do is pull a string and it yanks out the entire tape assembly. I thought it was a cool idea but have no idea how they pull it off..

draftsmann · #11 11-05-2009, 01:51 PM

Why use glue when a nice woodscrew through the front of the bass and into the soundpost's endgrain would be so much easier?

Adrian

forester · #12 11-05-2009, 02:22 PM

yup,its us...
beats the way yamaha ships, w/ a SP so tight you have to chase it back to the end block before it falls.
and that cotton string on the bridge melts into the finish at the treble side f-hole 8 out of 10 instruments.

Eric Rene Roy · #13 11-05-2009, 02:38 PM

I've been asked what glue sizing is. I thought since I brought it up here i would answer here.

End-grain can be thought of as the end of straws. If you put glue on end-grain...almost all of the glue is wicked or sucked into the the "straws" and very little is left on the surface. This makes for a compromised (weak) glue joint.

When you size end-grain, it means you saturate it with glue to the point it will no longer accept glue, and let it dry. You then resurface the wood and apply the working (final) glue. The wood will no longer wick the glue into the end-grain after sizing, and you have a strong glue joint.

As an example...when we make rib assemblies...all of the blocks are glued to the plates by end grain (the block surface) to face grain (the plate surface). We size the blocks first.

Hope this helps...