Repairing warped wooden 7x17 film holders?

[John Schneider]

I picked up a lot of 3 modern but warped 7x17 sheet film holders. The lot was less than 1/3 the price of a single new (but unwarped one) so I thought "what the heck?" In the dryness of the desert the least-warped one returned to flatness, but the other two didn't. The better one is off by 5mm at the opposite corner and the other by 9mm.

I was thinking of clamping them to a metal plate and using moist heat to see what effect that had (putting them in an oven with some pots of water, at maybe 80C or so). After that I planned to rout a 0.375 x 0.375 recess down the sides on the holders (while still clamped to the plate), stopping at the light trap and flap areas. Then I was going to epoxy an aluminum channel into the recess.

I don't know if the channel will have sufficient stiffness to keep the holder flat, or maybe I need to slightly bend and preload the channel to keep the holder flat. Or is there a better way entirely?

[Archphoto]

Steam should do the trick together with clamping.
The only place you will run into problems is with the light-traps and any glued fabric.

The warping is in the (uncured) wood though, but it could be worth the efford.
If you want to put in a channel, I would use steel in stead of aluminium that easily bends.

My 2 cents,
Peter

[John Powers]

Good luck on your project John. Do you know how the prior owner warpped these holders, so as to learn what to avoid on my own 7x17 holders? What brand or builder are they?

John

[John Schneider]

John,

I don't know what happened to the holders. They could have been subjected to adverse conditions, or the wood could have been improperly dried or it could have been compression wood that slowly sprang back into a warped state as it was planed down.

They were an eBay auction from the View Camera Store, and they were fully described as warped and sold as-is. They were sold as AWB holders, but I don't know if they hold any blame. In any event I wouldn't eliminate AWB just because these isolated holders are warped.

[Michael Jones]

John,

I don't know what happened to the holders. They could have been subjected to adverse conditions, or the wood could have been improperly dried or it could have been compression wood that slowly sprang back into a warped state as it was planed down.

They were an eBay auction from the View Camera Store, and they were fully described as warped and sold as-is. They were sold as AWB holders, but I don't know if they hold any blame. In any event I wouldn't eliminate AWB just because these isolated holders are warped.

John:

I've owned Alan's holders for almost 20 years and purchased them both new and used. I have never had one warp or fail and I've taken them into the Everglades and the desert. You might consider sending them back to Alan to see what he suggests. After all, he made them... He may be able to rehab them for a reasonable price.

Mike

[EdWorkman]

Doew warped denote twist or bow or both? You mention "opposite corner"
I assume the deformation is not pressed out by the spring back.
I'd try removing 1/16 thick x16 or so across the side rails on the convex side, glue back a strip of cherry wood and clamp with a very slight camber the opposite direction.- Camber about as much as the back can queeze out, and a little bit less