Warped f5 pickguard

[MarkELynch]

I received a 1990 Gibson F5L into the fold recently and it is in pristine condition except for a mildly warped pickguard. I'm tempted to heat it evenly and gently in an oven like a shellac phonograph record to try and flatten it but would appreciate some guidance.

Any thoughts here?

Best Regards,
Markelynch@earthlink.net

[Paul Hostetter]

Not in an oven! They usually warp because of a differential between the basic sheet of celluloid and the reinforcing bar in the back. And it's often hopeless. One component wants to do one thing, the other wants to do something else.

But if you want to try to relax it, take a Pyrex baking dish with a nice flat bottom, lay the guard face down in that dish, and put a flat sheet of thick glass or a generous ceramic tile on top of that, and then a Pyrex measuring cup full of water on top of all that for additional ballast. Put water in the baking dish, and put the whole assembly in a microwave and nuke it for a few minutes. Once the water's really heated everything through, it'll relax to the bottom of the dish. Let it all cool in place completely before you touch anything. At least an hour. If it doesn't work well enough, do it all over again and nuke it for longer. Underwater there's no fire hazard. This'll turn the clock back for awhile, anyway.

[MarkELynch]

Paul, Thanks for your detailed reply. After examination I see exactly what you are talking about concerning the warping being caused by different expansion or contraction of the top guard and the underlying plastic stiffener. After marking the location I was able to separate the stiffener from the main guard without damage and things immediately became flatter. I will try your trick with the hot water and flatten the two plastic parts before joining them again.

Does anyone have a spare Gibson F5-L guard if I am not successful.

It is curious that the guards on my '23 A4 Snakehead, the '23 F4 and the '21 H2 are still in fine condition and I have owned these about 20 years. Why would a relatively new '90 F5 guard warp so soon?

[Paul Hostetter]

You might find that making that bar out of ebony or graphite might be better than reusing the plastic one.

I don't know why some guards last and others don't. It's not just recent ones. A good many of the old celluloid guards on Gibsons gassed off and rotted away, and had flatness issues as well. On balance though, you're right, they have generally done well over the decades.

[jim simpson]

Paul,
Would your technique work for a warped LP?

[Paul Hostetter]

Maybe. I never tried it. Might wreak havoc with the label. I know my microwave isn't big enough for a glass pan that would hold a 12" LP. But I have a few I wouldn't mind having play again (yeah, I have a lot of vinyl and still listen to it). Hmm.

I recently had a funky old A-1 come through recently. I did some cosmetic work on the headstock and refretted it for the first time in its life. It wasn't until I was stringing it up and putting it back together that I realized I'd made the pickguard from scratch, it must have been around 1971 or 72. All celluloid, reinforcing bar and all, it had had an earlier incarnation as a Harmony guitar guard. Its second life on the Gibson was faring quite well. It looked so old it was looking original, except for the side clamp, which I'd made from a violin chinrest part. And even that looked convincing. Nice when this happens.

[Darryl Wolfe]

The warping is almost always due to using Duco cement or acetone to join the pieces. #My early guards had a tendency to warp (well after I sold them to clients). The old original guards have an inlayed metal rod. #I have switched from Duco to cyano for the long reinforcement piece joint. No problems now other than the occassional bad cyano. #I still use Duco for all binding

Refer to this thread for more info
link

[Rick Turner]

The proper chemical balance for nitro celluloid is a very tricky thing, and the stuff ranges from totally unstable to merely temporarily stable. The stuff John D'Angelico used was horrible, and many of his guitars (and mandos) have already been rebound and re-pickguarded, and the ones that haven't been will need to be sooner than later. I'd be surprised if any celluloid makes it past 125 years unless it's been well sealed under finish, and even then, if the finish is nitro it's a down-hill slide. There are going to be a lot of vintage intstruments in the future with replaced pickguards and binding.

[Darryl Wolfe]

# #I'd be surprised if any celluloid makes it past 125 years ..There are going to be a lot of vintage intstruments in the future with replaced pickguards and binding.

Fully agree. I have stock that I can watch go downhill. Looks fine, then a year later it has bullet holes

[Paul Hostetter]

The warping is almost always due to using Duco cement or acetone to join the pieces...I have switched from Duco to cyano...

Way back when, there was no cyano, and a great many (though, as we well know, not all) of those guards are hanging in jes' fine. Gibson just used acetone straight in their assembly, though Duco is just acetone in gel form. Martin also glued their pickguards directly to raw wood using acetone. Almost none of them have done more than shrink. I think it has to do with the actual makeup of the celluloid in question, the suppliers and their formulas at different times. Late '30s Gibsons had trouble, but earlier ones didn't. D'Angelico's guards, as Darryl and I both very well know, were a real mess, as were some attempts to replace them.

I too use CA for making guards, no issues (so far). But I see some of my supposedly fab celluloid samples turning into stinky little potato chips right in my shop. Grrr. I ever even got to use them.

[Darryl Wolfe]

Another issue that comes into play is dimensioning celluloid. Let's say you work a piece of 0.150 down to 0.130 to make the reinforcing strip. If you take the material off just one side, it's guaranteed to warp. The stuff acts just like wood that is not dry enough

[Rroyd]

In response to the question about flattening LPs, I've rescued several that were too warped to play by placing them between two flat plates of glass and putting the sandwich in the sun. Depending on the label, flattening time would range from just a few minutes to a half hour or so.
(RCA used some sort of material from the late sixties on that was about as flexible as a chunk of innertube) It worked every time. A couple that were very warped seemed a little more "noisy" than they might have been before, but none of those big black CDs were totally quiet between cuts.

[Bob Denton]

I just used Pauls method on a badly warped '93 guard and it worked perfectly. Almost 100% straight.

I also removed and reglued the stiffner using Cy and clamped the guard to a piece of glass while setting.

Thanks for the tip!

[GTison]

I guess yall removed the pins before putting the guard in the microwave oven??

[Bob Denton]

Yes, I removed the stiffner and heated the water to scalding, then left it to cool with a large pyrex measurng cup on top.

I replaced the steel brads with brass and reglued with CY.

The guard is now rule straight, for the time being...