Warped pickguard

[Seppo]

How would you straighten a plastic mandolin pickguard that is bending upwards and nearly touches the strings?
Warm water and pressure?

When I took it off the supporting part also fell off.
There were signs of glue. What glue should I use for it?

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Thanks

Seppo

[David Houchens]

Warm water and flattening will probably work but it may warp again. Replacing the strip that runs up the long edge with a piece of ebony or other hardwood may help it hold its shape.
For the extra support, clean off old glue and reglue with CA.

[Pribar]

If you have patience, a steam iron and some thin wood you can straighten it the way I do, go to home depot or any nearby woodworking supply house and buy a piece of thin wood (they usually have these near the back of the wood section, ask if they have some precut drawer sides) I use oak, sandwich the pickguard between some wax paper and 2 of these, use the steam iron to heat the wood, being careful not to get it hot enough to actually melt the pickguard, when the pickguard relaxes clamp the wood and leave overnight, check the next day and see if its straight if so good, if you need to repeat until you get the desired result.

[Bernie Daniel]

Here is how I straightened a warped pick guard on a 1963 Gibson EM-150. It was made of the typical black heavy-duty plastic use in that era. Maybe yours is celluloid?

I removed the guard and then the hardware and placed it between 2 pieces of flat hardwood --making a sandwich. I think the wood I used was about 1/2" maple boards. I placed the sandwich on the middle shelf of the over and then placed a 16 pound lead weight on it. I heated the oven to slowly and at around 200 degrees F I noticed that the weight had flattened the plastic. So I turned off the heat and left it for 4 hours to cool. When I took the weigh off the guard remained flat and looked perfect.

BTW I did this on a fall day when I could open all five outside doors and the all of the great room skylights -- I set up a couple of large fans and had a good cross breeze. It served to dissipate the slight organic smell was omitted as it most likely is not something you want to inhale.

[Seppo]

Thank you all - these are great tips. It looks like I do not have to use my oven at all.
I finally received an answer from the maker of my mandolin. He was so kind and helpful that he promised to make me a new pickguard of the new material he uses that does not warp. Free of charge.
That's what I'd call great service.

[Dan Gellert]

Another question on this subject:
My 30's Orpheum/Strad-O-Lin has a light-colored quite translucent celluloid pickguard which is warped. It's a good bit thinner than a Gibson guard, so I figured if I can get it flat, it would need some kind of reinforcing to stay that way. Any kind of wood or plastic strut I'd stick to the back of it would spoil its looks, though.

What I'd kind of like to do is back the whole thing with a thin sheet of plexiglass or some such clear stiff plastic.

The problem, I think, is finding the right adhesive: It has to bond well to both materials (and damage neither!), stay permanently clear, and given celluloid's tendency to shrink, it probably needs to retain some flexibility.

Any chemical engineers out there?

[Seppo]

Hi Dan,

the maker of my mandolin uses this:

http://www.eclecticproducts.com/all_purpose.htm

[Dan Gellert]

DUH!

Of course! I've used that stuff myself on celluloid thumbpicks before!

[Paul Hostetter]

I've posted this response numerous other times this topic reappears. My usual technique is to put the guard face down in a flat-bottomed pyrex baking dish with water, put a slab of tile or heavy plate glass or similar on top of it, and heat it in the microwave. No chance of the extremely flammable and altogether unstable celluloid catching fire. When the water boils, the plastic goes limp, the piece on top, thanks to gravity, presses it flat. After it's all completely cooled down, it's time to take the weight off and take the guard out of the water.

Just remember: no metal in a microwave!

I've found that a dip in boiling water is seldom enough—it cools too quickly after removing it to get a decent result.

Guards often cup because the main sheet is contracting and a glued-on brace in back isn't going along with it. The tendency to cup and potatochip is always there.

I have used clear acrylic, ebony, and carbon fiber for the edge brace, glued with CA, but not an acetone-based glue, which tends to hasten the degradation of old celluloid. Carbon fiber seems to work the best in the long run. The main straight edge is the one to work on most.