Lepages PL Premium adhesive

fraublugher · #1 04-03-2013, 01:01 PM

Gluing my neck back on again and I'm using this 100%polyurethane adhesive.
Claims to be 3 times stronger than "normal".

Last time it glued fine with carpenters glue but roomates cat knocked it from leaning on a stool upright position and it fell
right on the back of the scroll .
Wish me luck .
cheers,
John

arnoldschnitzer · #2 04-03-2013, 04:38 PM

April Fool's day was two days back.

fraublugher · #3 04-05-2013, 10:25 AM

Hah , that's funny but , I am waiting for the glue to dry

**Lowactnsatsfctn** · #4 04-05-2013, 10:52 AM

If it was cleaned, clamped and fully cured, I'd trust it. I use that stuff all the time and have never had a failure with it, but Iv'e never used it on an instrument.

JoeyNaeger · #5 04-05-2013, 11:27 AM

That kind of crack isn't going to hold for long unless it's reinforced somehow.

**Lowactnsatsfctn** · #6 04-05-2013, 11:50 AM

Quote:

Originally Posted by JoeyNaeger

That kind of crack isn't going to hold for long unless it's reinforced somehow.

What would you suggest, Doweling, screws or??

fraublugher · #7 04-05-2013, 11:53 AM

Yes , this time i didn't use clamps , i pulled the neck into place with a screw.

It's strung up and in tune , now to see if it'll last the day.

arnoldschnitzer · #8 04-05-2013, 05:48 PM

Frau, I thought you meant that the neck had pulled out of its mortise (pocket). The only generally-accepted glue for putting a neck back in place is hot hide glue. Now that I see your problem, I guess anything strong will do.

eh_train · #9 04-05-2013, 08:29 PM

Quote:

Originally Posted by fraublugher

i pulled the neck into place with a screw.

Frau, where exactly is the screw? Please don't tell us through the fingerboard!

FWIW, I think you'd have an adequate repair if you pulled off the fingerboard, glued the two pieces of neck together, countersunk a 5" fastener like this to keep them together - http://www.grkfasteners.com/index.ph...oducts/cabinet - and put the fingerboard back on.

Cheers,

Paul (eh_train)

KUNGfuSHERIFF · #10 04-05-2013, 09:20 PM

I've seen that repair fail. Remember the old King I stuck back together?

James Condino tells me that strong hide glue is capable of repairing ye olde Kay-style lateral neck heel break like the OP's bass suffered. Masochist that I am, I'm sure I'll be putting that claim to the test soon enough.

uprightben · #11 04-06-2013, 07:43 AM

Fine wood working had a strength test where they glued different kinds of joints and tested how much force it took to make the joint fail. if my memory serves me polyurethane glue came in weaker than white glue, pretty much at the bottom, with good old tight bond coming out on top (hide glue was not included in the test). No glue for wood works well without a tight fit, and I'm afraid the fit does not look great in your photo. Polyurethane glue is completely water proof and can glue many different materials, so it has its place, but that place is rarely on an instrument.

**Damon Rondeau** · #12 04-06-2013, 09:40 AM

Also, some glues are actually a bit elastic even when set or cured. A lot of epoxies are in that category and that tends to surprise folks. Not sure about the Mike Holmes construction poly we're looking at here but I'd wager that it's elastic, too. Hide glue isn't.

misterbadger · #13 04-06-2013, 11:36 AM

PU glues are great for gap-filling, as they expand and foam a bit on contact with air, but don't set hard, sand poorly, and retain some elasticity. I'm a cabinetmaker by trade and have worked with most of the glue and epoxy formulations that are available. Polyurethanes are at the bottom of my list, as there are cleaner, stronger alternatives.

Jazzdogg · #14 04-06-2013, 12:14 PM

Quote:

Originally Posted by misterbadger

PU glues are great for gap-filling, as they expand and foam a bit on contact with air, but don't set hard, sand poorly, and retain some elasticity. I'm a cabinetmaker by trade and have worked with most of the glue and epoxy formulations that are available. Polyurethanes are at the bottom of my list, as there are cleaner, stronger alternatives.

Same here. I only use polyurethane glues when it's the most appropriate adhesive for the task at hand, which means darned seldom. How often do you have a need to glue wet lumber?

**Lowactnsatsfctn** · #15 04-06-2013, 12:37 PM

Quote:

Originally Posted by Jazzdogg

Same here. I only use polyurethane glues when it's the most appropriate adhesive for the task at hand, which means darned seldom. How often do you have a need to glue wet lumber?

It seems to be favored by a lot of speaker cabinet builders. Its stronger than liquid nails, and seals gaps better than titebond.

Jazzdogg · #16 04-06-2013, 01:21 PM

Polyurethane glues may very well be the most appropriate adhesive for rough work, like assembling speaker cabinets that'll be painted or covered; never said it wasn't.

For fine woodworking, like the instrument repair under discussion, there's almost always an adhesive that's better/more appropriate.

Mark Carlsen · #17 04-06-2013, 02:12 PM

Quote:

Originally Posted by uprightben

Fine wood working had a strength test where they glued different kinds of joints and tested how much force it took to make the joint fail. if my memory serves me polyurethane glue came in weaker than white glue, pretty much at the bottom, with good old tight bond coming out on top (hide glue was not included in the test). No glue for wood works well without a tight fit, and I'm afraid the fit does not look great in your photo. Polyurethane glue is completely water proof and can glue many different materials, so it has its place, but that place is rarely on an instrument.

I'll agree the fit doesn't look to good, so it may not last.... I have done many of these heel breaks and if you can extract the butt end of the heel from the mortise, clean the crack carefully and dry fit the two pieces to check the joint and fit, then epoxy them w. a good epoxy like West systems and then re-set the neck w. fresh hide glue and touch up varnish after words the job will be done correctly and last.

misterbadger · #18 04-06-2013, 05:17 PM

+1 for West Systems epoxy. Absolutely amazing stuff.

**Lowactnsatsfctn** · #19 04-06-2013, 11:31 PM

Quote:

Originally Posted by Jazzdogg

For fine woodworking, like the instrument repair under discussion, there's almost always an adhesive that's better/more appropriate.

If it will make projects easier, Im all ears. I've got an old newspaper rack that needs to be glued back together in a few spots. Its built out of red oak, about 3/8" boards. What other types of glues would be good for this?

**Damon Rondeau** · #20 04-07-2013, 07:16 AM

Hide glue is favoured in instrument making because you can usually reverse a glue joint -- take it apart for repair, etc. In the furniture world you're usually more interested in something that ain't never coming apart, so general woodworkers have mostly moved to more convenient adhesives. Why not use something simple like Tite Bond or the equivalent? Here in Manitoba Tite Bond isn't so widely available -- I like Lee Valley's 202GF, a polyvinyl acetate adhesive because it's easy to get and it has really nice squeeze-out properties... A well-fitted, clean and well-clamped joint shouldn't need very much glue and it should be good for the duration.

Don't use it on your bass, though!