Tangled up in Glue

Thumpie · #1 02-13-2010, 07:45 PM

My '47 Kay has a tiny place on the back where the outer layer of the plywood has slightly separated. It's not a seam, so I can make a permanent repair. I'm temped to use super glue, but I read somewhere that the chemical composition of anything other than hide glue could contaminate the existing glues and cause problems. Is this hooey;? Should I go ahead and use super-glue?

And if I really need to use hide glue, will this stuff work:

http://www.buy.com/retail/product.as...ingid=34171150

jefkritz · #2 02-13-2010, 07:49 PM

i can't offer any help on this question, but i wanted to let you know that the mental image i got when i saw this thread title made my day

fdeck · #3 02-13-2010, 08:56 PM

Hey, another Madisonian.

I've got a Kay too, and have done these repairs with traditional hide glue. I figure that if I am ever going to attempt a more ambitious repair (and I have done so), then I might as well learn to work with hide glue on some less critical repairs.

My luthier also suggested using a bit of hide glue to coat the ragged edges of the plywood for protection against chipping.

Exploiter8 · #4 02-13-2010, 09:04 PM

I like the Bob Dylan reference.

X8

Thumpie · #5 02-14-2010, 08:08 AM

Early one morning the sun came up, I was glued in bed...

Thanks fdeck, but I've got enough on my plate with trying to become a double bass player without trying to become a luthier as well. If it's simple and easy, I'll do it myself, but I think I'll leave the hard stuff to the professionals. Something like coating the edges, I think I could handle.

I'm hoping someone can give me the lowdown on super-glue and the "store-made" hide glue that I'm thinking about...

drurb · #6 02-14-2010, 10:01 AM

Hide glue is not the glue originally used to bond the laminations, although fdeck seems to have used it with success. So, it would seem that it would be okay (preferable?) to use other kinds of glue. Perhaps a luthier or "wood expert" will chime in.

Jake deVilliers · #7 02-14-2010, 10:55 AM

Quote:

Originally Posted by drurb

Hide glue is not the glue originally used to bond the laminations

Au contraire DRUBB! (That's French for "on the contrary"

) The OP's '47 Kay is most certainly glued together with hide glue, all of it - the laminates, the linings, the blocks, the neck, the finger board. I think its one of the reasons that older Kays sound better; hide glue stays out of the way of the sound, whereas other glues are too stiff and strong and get in the way.

CA would be a bad idea for re-gluing delaminations (too stiff) as would bottled Liquid Hide Glue (not strong enough).

I'm not sure when Kay went to white glue but I know that Martin went to white glue in the summer of 1964. That seems about right to me for Kay as well - the later sixties Kays have a more 'compact' sound than the earlier ones.

THUMPER, please use hot fresh hide or get that family heirloom to somebody who will!

Thumpie · #8 02-14-2010, 12:30 PM

Thanks, Jake.

james condino · #9 02-14-2010, 03:02 PM

Bottled, premixed liquid hide glue is not the same as granular hide glue that is heated and dissolved in water. The bottled variety has a fair amount of urea in it that helps to keep it liquid at room temperature, but also has some issues with completely drying. I've done shop tests and it fails every time. I'm sure there are some resdent chemstry nerds that will correct me, chastise me, and fill in the specific details of the chemical makeup of both. Mine comes from a lifetime of experience as a luthier and 100s of additional years from all of my crusty old mentors.

An $8 bag of granular hide glue, and old peanut butter jar and a pot of boiling water (removed from the heat source), or a nice double boiler system will get the job done in the traditional method. If you really need an easy liquid fix, I'd use a watered down bottled fish glue as my first choice, but I never really have any reason not to use hide glue. By the mid 60s I've notced the switch to a white glue on many aspects of old Kays.

As far as a luthier vs. bass player, the reality is that life will be much easier in the long run if you learn a few basic skills like gluing loose rib seams and such. Basses break down all of the time. Most of us luthiers got started in some manner because our own instruments needed work and we were brave enough to go at it. Not being able to work on your old bass in some manner is like owning an old volkswagon and not being able to do basic work on it...I've owned both and spent a fair amount working each, always at the worst times...

j.

relacey · #10 02-14-2010, 04:09 PM

I can't give you any glue advice but fortunately you've had some real luthier's weigh in on this. I just want to compliment you on one of the best and funniest thread titles in a while. Wish I'd thought of it!

drurb · #11 02-14-2010, 05:30 PM

Quote:

Originally Posted by Jake deVilliers

Au contraire DRUBB! (That's French for "on the contrary"

) The OP's '47 Kay is most certainly glued together with hide glue, all of it - the laminates, the linings, the blocks, the neck, the finger board. I think its one of the reasons that older Kays sound better; hide glue stays out of the way of the sound, whereas other glues are too stiff and strong and get in the way.

Thanks for setting me straight. I was assuming, incorrectly, that the plywood used to make a Kay was manufactured like other forms of plywood. Was this also true of the later Kays? I figured that the blocks, linings, neck, and fingerboard were glued with hide glue but I didn't realize that the individual laminates of the plywood were bonded with hide glue.

Thumpie · #12 02-14-2010, 06:03 PM

I appreciate everything everyone has written here, but I'm still a little curious about the possibility of super-glue upsetting the existing chemistry of the laminate. If this is the case, then I can see why it should be avoided. But, if not, and I just use a dab to close up the laminate on the very edge, I don't see how the stiffness could really dampen the sound of the bass.

Anybody know about this chemistry concern?

(I'm leaning towards getting some REAL hide glue anyway, but I just wanted to follow through on my original thought process...)

gbaker · #13 02-16-2010, 12:39 AM

Quote:

Originally Posted by Thumpie

I appreciate everything everyone has written here, but I'm still a little curious about the possibility of super-glue upsetting the existing chemistry of the laminate. If this is the case, then I can see why it should be avoided. But, if not, and I just use a dab to close up the laminate on the very edge, I don't see how the stiffness could really dampen the sound of the bass.

Anybody know about this chemistry concern?

(I'm leaning towards getting some REAL hide glue anyway, but I just wanted to follow through on my original thought process...)

I have been putting a shipping-damaged Kay back together one ply at a time mostly with hot glue. It is a 1950 and I didn't want to replace the top or bottom with new parts because the old Kays sound better. So that left me gluing - a lot. Sometimes hot just doesn't work because it sets too fast. There I have been using Tightbond III which is both heat and water proof and therefore is not reversible but I never want those plys to come apart anyway. There may be a bit of an acoustical impact, if so I will live with it. I can do this because it is my bass, luthiers do not have this option.

It is my opinion that plate repairs outside the ribs have little impact on sound and hot glue is not imperative but never the less a good idea.

I don't think superglue is well suited to plywood repair as the wood absorbs it too quickly. Maybe on a small splinter or such.

Glue resources (ready to be tangled?):

Hide glue and cheap pot (Target sells the adjustable temp pot):
http://www.spurlocktools.com/id57.htm

Glue tests:
http://www.titebond.com/Download/pdf...urGlue_FWW.pdf

Overall there is a problem with these tests, as heat and moisture were not factored in. Tightbond III type I glue is the best performing (but not reversible) as it withstands repeated boiling/cooling cycles (212 F and 100% humidity).

In the study below, under high heat (150 F) and high humidity (84%) conditions bottle hide glue lost 2/3 its holding power while hot hide glue only lost 1/3.

http://cool.conservation-us.org/cool...AG_90_buck.pdf

A few tips:

You will need several small clamps, a sharp knife, and chisel and touch-up color(s).

One advantage of hot glue is that you can just hold the replacement ply until the glue sets.

If your edges are mostly light yellow/amber you may find a close color match with Minwax Scratch Repair (the metal shake tube) in golden oak. It seems to be lacquer based.

For ply face patching use a wood with some apparent grain not hobby balsa. I use a thickness sander to match the thickness of the piece removed. Apply it slightly over sized and orient the grain to match then work it to thickness and do the edge after the glue dries.

Sandable fine texture wood filler works on the really small nicks. Oversize and then sand it so stain/finish will stick to it.

Hope this helps.