How do you straighten a nitro pickguard

[arnoldziffel]

i have an older 1/8x12x12 piece of 2 ply pickguard material that is badly cupped . tobacco tortoise / white ...maybe 30 years .old .

would you boil it , bake it , put it in the sun ?
i don't have experience working with nitrocellulose.



there is a sticker warning that it is extremely flammable
switchplate thermite.

[AllanAllen]

I think you fix it by buying a replica made out of plastic.

[arnoldziffel]

no. not for a vintage mandolin . pvc would look pretty silly .

i just need to make the thing flat.

[deacon Mark]

It is made of Nitro and now is going bad simply because it is starting to warp. I would not use and find ABS plastic that is safer and no rot going to happen.

[wintermoon]

post a pic, it may not be decomposing/offgassing but just warped.

[Hammertone]

I use a steam kettle, a couple of flat pieces of plywood, some parchment paper and a few clamps.

[Easy2grasp]

Warm it up slowly with a hair dryer until you start to smell it. I used to use an iron on low with a cloth, but I feel I have more control with the blow dryer. Then set a large pot of near boiling water on top of the material on a hard flat surface. I use a piece of thin cloth between the pot and the pick guard material sometimes. I have used this method successfully on a few different vintage ES-175 pick guards which are almost always cupped it seems. You may have to do it twice depending on the deformity. Let it cool to room temperature before removing pot.

[Cunamara]

OK, let's bear in mind that nitrocellulose was first used as a gunpowder replacement in firearms and explosives for mining. That's what "very flammable" means. It's highly reactive with heat and oxygen. I would not hit it with a blow dryer or heat gun. There is a reason that this material has been phased out of a lot of things, which is that it is not chemically stable. It shrinks, it burns, it rots, the outgassing damages the instrument's finish and the case.

Take the original and have it duplicated in a nice tortoise shell plastic material or wood with the right colorway (like cocobolo) and mount that to the mandolin. Put the original out of harms way to go with the instrument if you or your descendants ever sell it. A little light relic-ing to the new pickguard and it'll look like it belongs there. Being a good steward of a vintage instrument sometimes means changing something out for something that works better.

A few years back I replaced the pickguard on my Ibanez GB10 because it looked to be deteriorating and to be adversely affecting the gold plating. I had a luthier make me an identical pickguard out of a cocobolo head plate blank which perfectly matched the colors of the original, is much more stable and no one has ever noticed that the pickguard was replaced- even people who've held it in their hands.

[arnoldziffel]

ok, here it is

[arnoldziffel]

yes, the protective plastic shrank and cupped the material. no deterioration, vinegar etc.. shiny and good.

the mandolin was damaged by the original TS pickguard- the wood shrinks around the thing , cracks the top.

[Gilpy]

I would find the flattest part of the pickguard material and cut out the new pickguard. Easier than trying to flatten the whole sheet. Remove the protective plastic sheet.
Then, as Hammertone suggests, protect it with paper and clamp it between two pieces of flat wood. I haven’t tried steam to heat it, but have put the clamped pickguard in a hot place( like the inside of a car in Summer) for a few days. I suppose wrapping it in a heating pad would work too. Let it cool before removing the clamps.
I have flattened several vintage pickguards this way.

[Woody Sound]

Being a good steward of a vintage instrument sometimes means changing something out for something that works better.

[Mick-7]

Um, with nitroglycerine?

[GuyBoden]

Um, with nitroglycerine?

Yes, the same as nitrocellulose on guitars, it's potentially very dangerous stuff.

"nitrocellulose formed by nitrating cellulose through exposure to a mixture of nitric acid and sulfuric acid. One of its first major uses was as guncotton, a replacement for gunpowder as propellant in firearms. It was also used to replace gunpowder as a low-order explosive in mining"

[stevo58]

Five-ply celluloid; that’s interesting. To be honest, it looks just like the five-ply plastic (acrylic?) stuff you can buy all day long. If it were my mandolin, I would just buy a new sheet of non-celluloid five-ply acrylic and use that. No celluloid worries, and non-original is non-original, regardless what it’s made from.

On my own vintage instruments (1950 Epiphone Devon, 1910 Gibson A4, 1921 Gibson H2, monstrously butchered 1958 ES-125T) I used modern single-ply acrylic tortoise to make new pickguards. I use the 3mm StewMac sheet when I want a bound pickguard, and the 2mm Boston sheet (available everywhere under various names) for the unbound mandolin/mandola pickguards. My original (deteriorating) H2 pickguard looks just like the Boston sheet, except for the patent stamp.

Just my 2 euro-cents worth. It’s worth what you paid for it.