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open seam

Discussion in 'Setup & Repair [DB]' started by kip, Nov 14, 2002.


  1. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    I have a 3/4 carved top, flat back DB built in 2000.
    It sat in the the store until a month ago when I became the proud first owner. No seam problems were evident. The luthier did some set-up that included shortening the sound post. After about two weeks in new environment ( my place) the seam between the lower bout, treble side and the back opened up, about the width (edge side) of a business card. I had it re-glued at the shop and when the clamps were removed it popped again. They applied a stronger mix of hide glue and it appeared to be fixed.
    Back home again and in a couple of weeks it opens again. I use dampits and monitor them daily. There is no buzz when played, and no flap when I thump the back.
    Questions:
    -The weather has cooled, should sound post tightness be re-examined, I assume yes.
    -Is this unusual to reoccur at the same spot?
    -What is the structural possibility that the bout was cut incorrectly and extreme tension results from trying to close the seam? How is this remedied? I don't wanta know, but go ahead, tell me. ( strange, though, this didn"t happen earlier, when in the store).
    -What if i just leave it like it is?
     
  2. erik II

    erik II

    Jul 11, 2000
    Oslo, Norway
    I have glued the back seam on my flatback several times, but it has never come open again in the same spot.
    In some places, especially on the lower bouts, the side plate has bulged out so much I had to rig a fixture (in addition to the clamps) to hold it in place while the glue dried. But it has held up in those places too.

    I must be a damn good seam gluer :eek:

    Maybe you should take it to a different luthier...? Or you could just drive a nail through it... :D
     
  3. tsolo

    tsolo

    Aug 24, 2002
    Ft. Worth
    My American Standard has small nails at the coner blocks, neck block and tail block. Is this normal?
     
  4. Assuming that your luthier did the job correctly, it is quite possible that your bass was not put together with hide glue. Unfortunately, most factory made instruments made today are assembled with aliphatic resin type (white or yellow) glue because it dries much faster than hide glue. If that is the case, hide glue will not stick to it. Ask your luthier to try cleaning the opening before reglueing with hide glue. If that doesn't work, you may not have any choice but to have it reglued with aliphatic glue.
     
  5. Non-hide glues, the bane of lutherie.
    It likely that there is some contaminant fouling the wood in this area, either old (non-hide) glue, or oil. Short of removing the plate completly, perhaps alternating injections of phenol and alcohol can be applied to the seam and a card inserted to absorb the contaminant.
     
  6. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    Kip says,
    This is a hand made Romanian bass "under direct control of Master Luthier Gliga Vasile". I was told this is a small operation, not production, and the bass in question was 1 of 4 ordered and built for the music store. No problems with the other 3. Original glue is hide. The area luthier is well respected. Chances are the re-glue was done by a staffer doing a what was considered ordinary repair. I am going to talk with the luthier soon, and I do appreciate this additional input.
     
  7. I doubt if you will find phenol in too many luthier's shops. From what I've read, phenol can be dangerous stuff. According to ATSDR "Exposure to high levels of phenol has resulted in liver damage, diarrhea, dark urine, and hemolytic anemia". I was taught to use white vinegar on aliphatic glue, but in a small area like a seam, I doubt if it would do much good. Luthiers like to stay "pure" and use hide glue when ever possible, but when an instrument is made with non-hide glues, I see nothing wrong with using aliphatic glues to fix them.
     
  8. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    Pete O'Leary says " Short of removing the plate completly...

    What does this mean? How do you do this, from the violin corners and remove the whole bout? I haven"t a glue errrr clue. Appreciate some more info. Sounds dangerous.
     
  9. What I meant was to slip a piece of cardstock into the open seam to the open area of the seam to sop up any dirt, oils, old glue dissolved by the solvent. This is done in lieu of removing the back completly and cleaning the entire mating surfaces.

    Also it is quite possible that this area needs to normalize a bit and that the localized popping is a result of some stresses built up from change in humidity. It would be a good idea for your luthier to open the seam a bit wider, a couple inches either side of the popped area, and let the bass sit a couple days. Then reglue.
     
  10. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    Pete says...."It would be a good idea for your luthier to open the seam a bit wider, a couple inches either side of the popped area, and let the bass sit a couple days. Then reglue."


    Thanks, Pete

    Will see luthier on Tuesday and this suggestion is logical, and worth trying before attempting any major surgery.
    Kip
     
  11. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    As it turned out, it appears that the back brace Where the sound post rests (this is a flat back) swelled on the treble side and caused the seam to pop at the lower bout. The ends of this brace are beveled and more surface area and grain are exposed at these junctures. I use those dampit things and really wring them out, but I guess I should get a reliable hygrometer and only use the dampits when humidity is clearly in the danger zone. Should have the bass back soon and appreciate everybodies help. Any further coments or similar experiences and cures is welcomed.
     
  12. 'Twas a good thing you got the bass in to your luthier as soon as you did. That could've got scary.
     
  13. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    Years ago I worked in a shop that had a large volume of basses come through the door. Instruments in for repairs would be brought into the showroom and the customer would usually take the accoutrements [case, bow, moisture adding device} home and just leave the bass. I never got to see whether the bass had "moisture adding devices". The bass would be brought into the back and I would dismantle it. Many times I would notice waterstains on the ribs where they are glued to the endblock. Many times there would be distortion of the rib and sometimes the rib would be swelled out past the back. I just figured the owner had kept it in a wet basement or something. I saw many dozens of this situation. One day a bass came in and the "moisture adding devices" were still in the effs. I removed them, took off the top plate and noticed the stains. I then mentally visualized how they would hang in the bass-looked at the stains and realized that it was the devices that were causing the stains. All along. In all the cases. I informed the propieter of the shop and he agreed as the evidence was well, quite evident. It then became policy to advise all users of these devices to wring them out thoroughly. It wouldn't be prudent to advise people to stop using these devices-after all many were sold in this shop. Everyone bought them.
    End of story, right? Well, not really. Now most players have got the word that these devises must be wrung out well. No more water damage. Yes, that true-but players are getting a false sense of security by using these devices. You havta understand humidity a little better. If you take a 10 by 10 by 20 room and the humidity is 60%-if you could extract all the water out of the air-how much would you have? A cup? A quart? No, you'd have many gallons. Now, let's bring it down to 30%. If you took a water spray bottle and sprayed a good spray on the table you could watch it dissapear in a matter of seconds-well, mebbe a minute. This is how much water is contained in a well wrung damn it. It's the proverbial fart in a windstorm. There is only one way to prevent damage to your bass concerning humidity. You must monitor and correct the humidity. You must posess a hygrometer and a humidifier. Below 40% is when danger is present. Maintaining 48% is better and is achievable thru the winter in most cases.

    ps- apologies to those that know I've talked about this before and am repeating myself. I just haven't ranted in a while and felt the need.
     
  14. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    I appreciate the rant. My luthier also disdains use of "moisture adding devices". He previously lived in Alaska and was quite active in repairing low humidiity damage. Says those water eels didn't seem to help, and , as you mentioned, may have been a false sense of security.
    The thing is, I do wring them out thoroughly and swelling occured. Because the bass is in the shop I can't be sure, but is this plausible? That being that I keep the bass on a stand and the angle may bring the dampit (placed in the upper eff} in close proximity or direct contact with the brace. Hmmm, this may be more of a caution than a query, as it appears very probable that this is the source of the problem. Beware!
    Also, if swelling occurs perhaps a combination of humidifier/de-humidifier is needed. Can do, and this is fine as long as all my gigs are at home.:)
     
  15. Jeff Bollbach

    Jeff Bollbach Jeff Bollbach Luthier, Inc.

    Dec 12, 2001
    freeport, ny
    I think that a wrung out damn it will still wick some water especially if the end is touching something. How much I'm not sure. Never really tested this. Should be easy enuf though-hang one so that it touches a paper towel and see what develops.
     
  16. kip

    kip

    Sep 11, 2002
    Sausalito, Ca
    I've been to the store three times now and I can tell you that the Brawny brand works the best. Hold on, what's that Peggy Sue? She says I'm supposed to wet the dampit, not the paper towel. Dang, back to the drawing board.

    Seriously, I appreciate your accumen and insight. This whole site is generally muy simpatico.

    Update: bought a digital hygrometer/thermometer, $22.00 at Ace Hardware. no more guessing.