Rat damage to vintage guitar

[donnyb]

Im working on an original un -modified 1967 Maton CW80 with bridge and other issues that also has what appears to be rodent damage to the back of the body. See photo. Probably occurred stored under a bed for 20 years in its original falling to bits cardboard case.

Im ok with doing cosmetic repairs, but this one is either for a specialist or in the"leave it alone" category. I expect the owner will want to do the latter and I agree.

However, the exposed gnawed wood surface is quite chalky , oxidised I assume and if left alone I think will continue to grow.

I was thinking to brush coat it with Wood Hardener or mask and air brush coat just the gnawed area with a clear seal coat. But I don't want to anything though that would make it hard down the track for a restoration job.

Any suggestions welcomed !

[Fathand]

Suggestion:

Spray the damaged area with shellac. Shellac can be used over or under most any finish that might be used in the future.

Zinnser Bullseye aerosol is what I use, available at Home Depot etc.

[donnyb]

Thanks for that info. I have some Zinser spray shellac . Cheers,

[phavriluk]

I don't know anything about Zinsse's product line. I have a spray can of their clear shellac, and it's clearly labeled 'wax free'. I'd be looking for something like that before I used it on an instrument.

[phavriluk]

I don't know anything much about Zinsse's product line. But I have a spray can of their clear shellac, and it's clearly labeled 'wax free'. I'd be looking for something like that before I used it on an instrument.

[srick]

The Zinnser spray shellac is a great idea as it will protect the wood and easily allow for future repairs.

The repair will require some really sharp artistry to match the color and grain.

[donnyb]

Thanks for your replies and information. Ill check for wax content .

Rat Gnaw syndrome will indeed test the repairer's expertise !

[Fathand]

Zinnser aerosol is wax free, you don't have to worry about that.

I have used it over and under nitro, shellac, Tru Oil and Varathane.

They even sell it at Stew Mac now for 2 or 3X what you'll pay at Home Depot.

[donnyb]

Thanks Fathand.

[tadol]

You sure that isn’t insect damage? I think the repair would be the same. But you may want to add a little fumigation -

[donnyb]

Could be. The guitar was stored under a bed for 20 years in a ratty cardboard case.

The owner thought the rat/vermin attack could have been responsible and there were no droppings inside so it wasn't living in there.

What sort of insect could do that damage ? I have a friend in pest control I can ask too.

[tadol]

Most common would be silverfish, but could be cockroaches, or beetles - more likely were mostly after the cardboard case, and the guitar was secondary - cellulose can be very attractive to bugs, and older protein based glues are also appealing -

[JonWint]

Originally Posted by donnyb

However, the exposed gnawed wood surface is quite chalky , oxidised I assume and if left alone I think will continue to grow.

I was thinking to brush coat it with Wood Hardener or mask and air brush coat just the gnawed area with a clear seal coat. But I don't want to anything though that would make it hard down the track for a restoration job.

Oxidation won't cause damage other than discoloration. I bleach out discoloration with oxalic acid. I'd wire brush lightly to remove loose wood and dust and coat with shellac sealer by brush to protect the wood from dirt.

The damage appears to be through the top veneer of plywood. "Restoration" can only involve patching the wood so anything you do locally won't affect future work. Restoration could be effected by routing the top veneer, leveling, and patching new wood. Wood grain painting would help blend a final finish.

[FrankHudson]

If it was insects that caused the damage, then using shellac would be apt revenge I'd think.

[Fathand]

Originally Posted by FrankHudson

If it was insects that caused the damage, then using shellac would be apt revenge I'd think.

:😊 Every time I hear reference to Shellac and bugs it brings to .mind my grade 7 Industrial Arts class and the Shells of the Lac Beetle lesson.