Reglue plastic bindings. What glue?

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Manel Liria
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Reglue plastic bindings. What glue?

Post by Manel Liria »

Hi there,

I have a Martin guitar with loose plastic bindings for repair. I know there is some cement for that use, but I'm afraid to damage the finish.
Any other options?

And the bindings are short now, so what is the solution, heat, new bindings?

Thanks.
Paul Breen
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Re: Reglue plastic bindings. What glue?

Post by Paul Breen »

I suspect that the loose bindings are at the waist of this Martin? That is where they usually come loose from the plastic shrinking over time.

I heat and stretch the binding before re-gluing. Just applying heat with a hot gun will make the binding expand some. It may even expand nicely back into place and be possible to glue like that. Chances are though that it won't stay. The cooled binding shrinks again and leaves it in tension. It is best to make a small, curved wooden shape that nests on the binding shelf. The shape of the block should be an outward bulge with a smooth curve to it. Heat the binding with a hot gun or a good hair dryer and push the binding onto and over the curved block as it sits captive, nested on the binding shelf. The idea is to physically stretch the binding slightly, giving it more length. Just heating it and pushing it into place won't stretch it enough, the small block gives you just a bit extra. You will need enough length to easily tape the binding back in place after it is cold. Go easy and repeat a few times and or a few places along the binding if necessary to get the length you need. It is also possible to just cut the binding and patch in a small piece but I prefer to not do that.

I use original Titbond for the glue. This works just fine if you don't scrape or clean the residue that is on the binding or binding shelf. Glue and use masking tape to hold it. After is is all taped, remove one piece of tape at a time, clean up any glue you find and re-tape it
Manel Liria
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Location: York, ME
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Re: Reglue plastic bindings. What glue?

Post by Manel Liria »

Thanks Paul for you detailed explanation. I will use that information in the future for sure, this one I decided to send it to a accredited repair shop. I am busy making classical guitars, so no need to get in trouble :)

And yes, it is on waist area were came loose.

Manuel
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Barry Daniels
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Re: Reglue plastic bindings. What glue?

Post by Barry Daniels »

Paul, do you have a photo of the wooden block you use. I am having a hard time visualizing it.
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Brian Evans
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Re: Reglue plastic bindings. What glue?

Post by Brian Evans »

I am a little surprised to see Titebond Original recommended for this, since Titebond doesn't stick to plastic at all. Are you depending on whatever residue of the original glue remains to create a surface for the bond? Anyway, I use very fine drops of slightly gel-ish CA glue, do the heat and stretch thing, and press firmly in place and hold - I often use the butt end or handle of an acid brush. As soon as I see any squeeze out I wipe with a acetone damp cloth (if the finish is acetone proof) or just with a dry paper towel. The gel CA glue sets up really slowly when not confined in the joint, so you have some time to work with.

Brian
Paul Breen
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Re: Reglue plastic bindings. What glue?

Post by Paul Breen »

You're welcome Manuel.

Barry, I don't have any images but attached a PDF sketch, see if that helps.

You're right Brian, Titbond does not stick to the plastic binding but it does stick to the residue. That is why I mentioned not cleaning or scraping the binding in my first post. I like the Titebond for the friendliness to finishes and ease of cleanup, as I have described in my previous post.

I also use CA on occasion or FCA adhesive from LMI. http://www.lmii.com/products/finishing/ ... -adhesives Often when the binding shrinks and releases, it cracks and crumbles the finish over it. If you are planning finish repair work anyway, then I would be more likely to use CA to re-stick the binding. The FCA adhesive I like for binding replacement and have had good luck with that over Duco cement. On vintage binding projects with existing celluloid binding, I will use Acetone to melt and re-stick binding layers. I have also used Acetone to help stabilize crumbling celluloid, I wick it into the crumbled are with a pipette. Doesn't make the crackled appearance go away but it melts the bits into each other and helps keep the bits from going missing.
Paul Breen
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Re: Reglue plastic bindings. What glue?

Post by Paul Breen »

OK...PDF is unaccepted file type. I had to start over and take a digital image of the sketch, couldn't legibly convert the scanned PDF to 150k or less. Hope this helps Barry, it took some unexpected effort to post this.
Attachments
binding stretching block.jpg
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Barry Daniels
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Re: Reglue plastic bindings. What glue?

Post by Barry Daniels »

Thanks for going to the effort, Paul. I get it now.
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Todd Stock
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Re: Reglue plastic bindings. What glue?

Post by Todd Stock »

The problem is that the ABS/PVC alloys such as Bolteron do not glue well to begin with...they really need a primer and a hot solvent like a methylene chloride...and whatever Martin used for the job from the early 1990's to today does not hold well for those plastics or for cellulose nitrate. For pure shrinkage, the worst are the Bolteron-bound instruments from the 1970's, where it looks like Duco (just gelled acetone) was used, and the binding material was even less stable than today's version.

Titebond holds...for a while. It gets the guitar out the door. I don't view it as a permanent fix, as any further shrinkage will break what is a low strength bond with plastics that it is not designed to glue. Titebond's great virtue is that it can be cleaned up with water, and that it does develop a bond of reduced strength with the residue on the binding. I have not had any repairs back in where I used Titebond, but I've had a few that had obviously been repaired and that repair had not held. I don't use Titebond anymore where the joint will be under any sort of load - I see it as a question of when - not if - the joint will fail again.

A step up from that is using CA Super Gold, which is a cooler CA with much less bite into lacquer than the regular stuff. Made by BSI and stocked in many hobby shops that carry the Bob Smith Industries line of CAs...BSI makes glues specifically for tires on R/C cars. Much more tenacious hold than anything else I've used on Bolteron, but the touch-up work on the lacquer will bump up the cost and time to repair, whereas a Titebond repair can be pushed out the door with much less work. As a bonus, CA Super Gold and Super Gold+ are lower fume glues...the Super Gold+ is odor/fume free.

LMMI FCA looks to be similar to the stuff that guitar factories are using for an all-in-one glue for ABS, cellulose acetate, and wood bindings, which concerns me, as I don't really know whether it's the best glue for any of those materials, and I see binding failures on relatively new guitars which appear to use the stuff. Close to the same amount of work as CA, so I cannot see using FCA unless there is some compelling reason (CA fume sensitivity).

Duco works ONLY on wood and cellulose nitrate - not a viable Bolteron glue, as those alloys need a hotter solvent to get a bite on that plastic. Even on wood, it releases pretty easily...Martin used the stuff for far too long on Bolteron and vinyl purflings, even after other adhesives were available.

Best practice in my view is to address the shrinkage directly, which might mean releasing the entire length of binding from the heel cap or under the extension back to the place where it release, then reglue and deal with filling the gap left on the centerline by the heel cap due to shrinkage. The issue with this approach is that the touchup work is much more of a job than torturing things in at the waist and regluing...if it's both sides of the guitar, that is essentially a refinish on close to two feet of binding...a few hours of work just on touch-up if the job is going to look good. Better repair, but way more work, and outside the budget for someone that just wants the binding on the back of their low-end Martin back on.
Paul Breen
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Joined: Mon Jan 09, 2012 11:39 am

Re: Reglue plastic bindings. What glue?

Post by Paul Breen »

Titebond holds...for a while. It gets the guitar out the door. I don't view it as a permanent fix, as any further shrinkage will break what is a low strength bond with plastics that it is not designed to glue. Titebond's great virtue is that it can be cleaned up with water, and that it does develop a bond of reduced strength with the residue on the binding. I have not had any repairs back in where I used Titebond, but I've had a few that had obviously been repaired and that repair had not held. I don't use Titebond anymore where the joint will be under any sort of load - I see it as a question of when - not if - the joint will fail again.

A step up from that is using CA Super Gold, which is a cooler CA with much less bite into lacquer than the regular stuff. Made by BSI and stocked in many hobby shops that carry the Bob Smith Industries line of CAs...BSI makes glues specifically for tires on R/C cars. Much more tenacious hold than anything else I've used on Bolteron, but the touch-up work on the lacquer will bump up the cost and time to repair, whereas a Titebond repair can be pushed out the door with much less work. As a bonus, CA Super Gold and Super Gold+ are lower fume glues...the Super Gold+ is odor/fume free.

LMMI FCA looks to be similar to the stuff that guitar factories are using for an all-in-one glue for ABS, cellulose acetate, and wood bindings, which concerns me, as I don't really know whether it's the best glue for any of those materials, and I see binding failures on relatively new guitars which appear to use the stuff. Close to the same amount of work as CA, so I cannot see using FCA unless there is some compelling reason (CA fume sensitivity).

Duco works ONLY on wood and cellulose nitrate - not a viable Bolteron glue, as those alloys need a hotter solvent to get a bite on that plastic. Even on wood, it releases pretty easily...Martin used the stuff for far too long on Bolteron and vinyl purflings, even after other adhesives were available.

Best practice in my view is to address the shrinkage directly, which might mean releasing the entire length of binding from the heel cap or under the extension back to the place where it release, then reglue and deal with filling the gap left on the centerline by the heel cap due to shrinkage. The issue with this approach is that the touchup work is much more of a job than torturing things in at the waist and regluing...if it's both sides of the guitar, that is essentially a refinish on close to two feet of binding...a few hours of work just on touch-up if the job is going to look good. Better repair, but way more work, and outside the budget for someone that just wants the binding on the back of their low-end Martin back on.[/quote]


Well, you said your self that none of your Titebond repairs have come back, neither have any of mine. As I had already stated previously, one must get rid of the tension in the binding for it to be lasting. If this is done, it should hold better than whatever Martin was using. I suspect the previously done Titebond binding work that you had to re-do did not have the shrinkage mitigated before glue up.

The CA comes out for more complicated binding repairs and or when I am already planning on finish work. I just use thin CA, wicked in with a small pipette. While I am careful not to let the CA run every where, I don't worry about some of it getting on the immediate surrounding finish. CA melts pretty seamlessly into lacquer and also sands and buffs well. I use it on occasion for drop filling dents too.

The FCA glue works like a contact adhesive. I use it when installing new binding and have had positive experiences using it. I apply it with a small, short bristled brush and just do a small section at a time. The solvent used in it is Acetone, I dip and wipe off the brush with it every few minutes. This adhesive can melt and bond plastics that dissolve in Acetone and or hold plastic to wood with the contact adhesion. My new glue of choice for new or replaced binding.

I don't use Duco but if you do, it helps to thin it with Acetone.

I agree completely that the tension in the binding must be relieved. Also, as you point out in so many words, where does one draw the line? A small finish repair, or, unzip the binding to the neck heel with small bits of lacquer flying off the whole way? I bought a pencil soldering iron from Micro Mark a few years ago that is configured with an Exacto knife blade fitting on the business end. The hot knife cuts the lacquer with reduced chipping and bindings cab be removed with less chip out.
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