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Andyjr1515

Martin celluloid binding - what glue?

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Hi

This isn't about fixing new binding (where I understand that acetone is generally the preferred glue) - it's a rather surprising problem on a pretty new and lightly used Martin GPC-18E.

A guy I've done some stuff for in the past has asked if I can do something with this:

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It's about 18 months old and the shop he bought it from have given him the standard 'Out of warranty, not our problem' line.  For a $3500 guitar that has spent 90% of its time in its Martin fitted case that's quite a...um...selling pitch.

I've been through the 'If I don't think I can do this, then I won't even start.' stuff with him.

My concerns are this:

  • The binding is thin celluloid tortoiseshell
  • It is clear that it has shrunk - it is VERY difficult to fully close the gap even with full thumb pressure
  • This is an otherwise immaculate guitar.  Any impact on the finish would be very, very bad news

My current thoughts are:

  • Enough force could be created by shaping two MDF formers working in both of the waist curves and squeezed together with a sash clamp
  • Titebond or acetone would not have the strength to hold the taught binding in place
  • CA glue probably would; thin epoxy syringed in probably would.  In both cases decent and accurate masking would protect the existing finish.
  • I know celluloid softens and stretches when it gets warm - but presumably this is all too temperature sensitive to risk anything that involves heat?

I think my first step is to make the clamping formers and do a dry run, to confirm that the binding will, in fact, close and that I can buffer the sash clamp well enough to eliminate any risk of damage.

I have also suggested that the owner contact Martin directly - I would have thought they would be as interested as anyone for a Martin-approved repair outfit did the job...

Have I missed anything?

 

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I can't tell if you've missed anything, the list looks comprehensive.

For what I've learned the current common binding material doesn't solve to acetone like the old one did. Then again it shouldn't shrink either. If it's the old skool type, acetone should soften it so it would stretch a bit while gluing. How to test, that's the problem.

Heating is another thing that can make plastics more elastic, but as you said heat might ruin the pristine finish. Nothing hotter than a hair dryer and even with that not too close is the hottest I would dare even try.

Contacting Martin before doing anything else sounds like the best option. Telling them that the issue is under discussion on this forum might add their interest as well.

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23 minutes ago, Bizman62 said:

Contacting Martin before doing anything else sounds like the best option. Telling them that the issue is under discussion on this forum might add their interest as well.

Yes - good point.  Thanks - I'll do that :)

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Note from the field: I used a heat gun on an old Kay mandolin fretboard and the binding VAPORIZED.  

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Just a warning...

If the binding is celluloid, CA glue will cause it to melt and swell quite badly. I found that out the hard way when gluing some celluloid inlays - it turned them into mush and took hours to set. I ended up going down the epoxy route.

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38 minutes ago, Stu. said:

Just a warning...

If the binding is celluloid, CA glue will cause it to melt and swell quite badly. I found that out the hard way when gluing some celluloid inlays - it turned them into mush and took hours to set. I ended up going down the epoxy route.

I'm leaning towards epoxy, I must say...

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Thanks for the feedback, folks.  Epoxy, I reckon.

I'll rig a sash clamp up later today and do a few dry runs.  Many thanks for the advice and suggestions  :)

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I was thinking epoxy as well, and perhaps a few careful strokes of touch paint if called for.

SR

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15 minutes ago, ScottR said:

I was thinking epoxy as well, and perhaps a few careful strokes of touch paint if called for.

Does that mean adding colour to the epoxy? Sounds clever, and being such it is something I always forget!

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7 minutes ago, Bizman62 said:

Does that mean adding colour to the epoxy? Sounds clever, and being such it is something I always forget!

That's a good choice, maybe better than what I was thinking, which was just to touch up any visible epoxy if it happened to end up filling the gap instead of completely closing it.

SR

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1 hour ago, ScottR said:

That's a good choice, maybe better than what I was thinking, which was just to touch up any visible epoxy if it happened to end up filling the gap instead of completely closing it.

SR

Yes - normally I would mix it with some very fine ebony dust I keep for the purpose.  I haven't on this simply to ensure that there is no possibility of the strength of the epoxy being affected by anything!

Update and background coming up ;)

 

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Instead of ebony dust, how about soot for colouring the epoxy? It's most likely finer than you could ever get by sanding and it's effective in much smaller quantities. Since it's burned it's also more stabile than wood dust. For what I know, most blacks are made out of coal or soot so that can't be a poor choice. All you'd need is a burning stick to create some pitch black nano particles and a piece of glass to gather them, plus a razor blade to scrape the soot off the glass.

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OK.  It's been an interesting day.

First, I cut a couple of close-fitting MDF formers and wrapped my sash clamp in copious amounts of protective foam:

_MG_8958.thumb.JPG.22037b07a3226d3f84a6a14e1cdd53a3.JPG

 

Then started masking either side of the gap, below it and along the binding itself, ensuring that the masking didn't inhibit the closure of the gap:

_MG_8962.thumb.JPG.15813238f3ce02ff82354e50b81f49ea.JPG

 

Then covered the whole of the back in foam sheet and did MULTIPLE dry runs to see if I could consistently close the gap:

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Then worried MrsAndyjr1515 by pulling out one of my syringes from my toolbox:

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Then  mixed up a decent amount of my second-strongest epoxy (Z-poxy) so I could guarantee that the mix proportions were  good.

Then syringed it into the gap, clamped it, wiped the excess off and checked for full gap closure.

_MG_8965.thumb.JPG.302269d5c9a1a43a91ea27b799cda679.JPG

 

Then way, way, after the cure time released the clamp and - pop - the binding sprang free of the epoxy.

 

Damn.  

So now, I am using THE STRONGEST epoxy I have ever used - it takes a full 24hrs to cure but is significantly stronger than anything else I can get hold of on the market.

And it's clamped again:

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We'll see if it's held this time tomorrow! :)

 

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It's now 13 hours since your post so we're halfways of this thrilling curing process now. Fortunately I spend most of that time sleeping and equally luckily I have some work to do so I can't check the progress hourly. And I already filed my fingernails unchewable.

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And...…...we can all breathe again :D

 

Clamps came off this afternoon and the first area of concern was OK - it had held!  I took off the masking tape and there was surprisingly little squeeze out and glue creep.

The tool you see here is a tool they use for prising the backs and tops of mobile phones.  Superb for gentle but effective scraping!  It scrapes off the glue without scratching the finish at all:

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An hour of gentle scraping, judicious use of single edge razor blade to get rid of any sharp edges, then progressive micromesh grades and finally a bit of polish, and I reckon this is as good as I could have hoped:

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There's one teeny light line at the side - ironically this isn't glue...it's where the crack had got to and is a slight crazing of the original finish which was evident in the original issue.  I'm going to leave that!

The repair is from this line to the left for about 2.5"  In fact, you can see the other side crazing just a touch too.  And I'm going to leave that as well ;) 

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Woohoo! What a relief! Very well done!

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Nice work, I wonder did he ever contact Martin directly? I'd have thought for a £3,000 guitar to fail like that within 18 months, you'd expect them to step in and do some work on it. Dealer obviously behaved appallingly too - If a car goes wrong just out of warranty, they normally at least try and put in a goodwill repair with the makers.

I watched a recent video on youtube with a 5 year old PRS that the chap had bought second hand, the ebony board and shrunk significantly and the frets sprouted through the lacquer. He sent it off to them for a quote and 4 months later, they sent it back, refinished the whole guitar and didn't charge him a penny. I know not all companies are the same, but when you spend that money on an instrument, you expect it to be a heirloom, not a two year replacement 👎

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