Problematic pickguard reglue- maybe I'm losing my mind!

[Mark A. Kane]

1965 J50 with the thick celluloid p/g. I used LMI instrument glue TWICE, clamping with custom cauls inside and out. The THIRD time I resorted to Weldwood contact cement (from my days installing Formica onto countertops etc.). All to no avail. The p/g starts to lift in the middle after a short time. I read that celluloid will soften slightly if heated in warm water to between 90-100F so I may try flattening it first, then gluing. 

 

I have a job ahead of me removing the contact cement, but I take the good with the bad in this job!

 

Any thoughts would be appreciated.

 

Adding insult to injury, I just (right now) knocked a 15 year old bottle of Old English from a shelf onto my workbench. The plastic is so brittle with age it literally exploded. I'm sorry I don't have a camera handy as it's one helluva mess!  This is gonna take awhile.

[Grahame Myers]

Bad luck with the Old English bottle, something similar happened to me with a full bottle of Lemon Oil where the cap wasn't screwed on properly, don't ask me how long that took to clean up :-)

'Bout your problem: Take a look at the "custom" pick guard I made (it was the customers idea, not mine :-)) for a Takamine: I stuck it on with Titebond generously applied, and clamped it up with everything I could lay my hands on at the time. It's still holding up over a year later, and the owner plays a lot of gigs. If I had to do it again I'd probably use a perspex caul the same shape as the pick guard, and perhaps HHG instead of Titebond, but Titebond seems to work.

Good luck with the cleanup :-)

 

Grahame

[Paul Hostetter]

Those thick pickguards were styrene, not celluloid. Try and get all traces of previous adhesives off before trying anything else. This will involve solvents perhaps, but mostly scraping and elbow grease. Or you could concentrate on getting the layers of crud off just the guitar, and use something else for a replacement guard.

[Mark A. Kane]

Quick follow-up on my dilemma: Shortly after my post, in walked the answer, so to speak. I've a customer who is, by coincidence, a Professor of Chemistry at Duke University with a research lab named after him. I won't out him, but here is a blurb from his lab's mission statement "..Our research interests are broadly based in chemical biology, mechanistic enzymology and molecular medicine. Towards this end our group is engaged in understanding the chemical and kinetic mechanisms, substrate specificity and therapeutic importance of enzymes that posttranslationally modify chromatin, such as histone deacetylases, histone demethylases, histone methyl transferases, and chromatin assembly and remodeling complexes. Building on a mechanistic foundation, our laboratory is also interested in the design, chemical synthesis and evaluation of small molecules to modulate the activity of chromatin modifying enzymes within living cells." The dude has a Ph.D. and knows his stuff (and he's a fine player).

 

He walked in as I was cleaning up the Old English, went straight to my bench, picked up the p/g and said something to the effect of "...check out the OLD celluloid. We use this stuff in blah, blah, blah etc. etc."

I told him of the problem I had keeping it secured to the guitar and he was immediately on the iPhone, accessing some crazy big chemistry database on the properties of celluloid, suggesting a water temperature of around 180F because of the thickness of the p/g in order to make it pliable enough to flatten it out. I boiled up some water, cooled it down a little and poured it into a plastic bin and dropped in the p/g. After about 30-40 seconds I pulled it out and sure enough, it was pliable enough to bend easily and mildly freak me out. I popped it between two heavy, flat pieces of Corian and clamped the daylights out of it. Ten minutes later, out came a flat p/g. It had blushed white over its entire surface like a nitro finish (as it turns out, celluloid is about 75% nitrocellulose) but it came right off and buffed out nicely. He, in the meantime, suggested several options for gluing, based on his cursory search. BTW, the old contact cement wiped off both surfaces with naphtha in about a minute, no drama necessary, thank God. I decided to try some double-sided adhesive tape I got at the Martin factory on my last visit. Since both surfaces were good and flat, it stuck better than gum on a tennis shoe. I rolled it with my thumbs, then clamped it which seemed unnecessary, as it was well and truly stuck upon initial application. I unclamped it before I left for the day and it looked great. 

I can now count upon the services of a Professor of Chemistry, a mechanical engineer whose field is the study of vibrations and resonances, a  medical doctor who knows everything in general, countless IT geeks, this forum, and a couple of clergy if all else fails!

 

Thanks to all for the suggestions!

[Mark A. Kane]

I think the thick black p/g's are possibly styrene, but the tortoise I was dealing with is celluloid for sure. I should have clarified that in my original post. Thanks!

[Paul Hostetter]

Perhaps we mean two different things when we say "thick." I can't think of a black guard on a Gibson, at all. Martin's black guards were ABS, and they were thin. Here's a '65 J-50 with a polystyrene guard:

It's what I call thick, but it's not celluloid, though acetone glues like Duco will stick to it much like celluloid. What you have on your guitar may be something different. Gibson used primarily celluloid for guards, before and after this era.

[Mark A. Kane]

That's the pickguard I had trouble with, but it fairly reeked of camphor when I wet it. Maybe my Ph.D isn't qualified, after all!

I seemed to recall LG0's with black, screwed-on p/g's but maybe they were just exceedingly dark. It wouldn't be the first time I've made a color mistake!

[Paul Hostetter]

Dark, almost opaque, brown, but I too remember some black ones:

These guards were problematic because they cracked easily where the screws went through (another aspect of styrene as opposed to celluloid), which explains why so many have been replaced. This entire era of Gibson was fraught with bad decisions which eventually sank the company.