Twist in Plywood Doors

Troubleshooting tips for twisty plywood doors, and advice on choosing MDF core instead. April 16, 2009

Question
I have nearly completed a large free standing storage cabinet for my first paying customer. It is a very simple frameless unit; 93" high by 43" wide by 16" deep. It is built out of 3/4" birch plywood (1/2" back) and it has 6 doors on the front with 3/32" spaces all around. I have used Blum hinges for the full inset doors.

All the doors, except for one, look like they will be nice and flat. The sixth door has some twist in it (about 3/16") and I am wondering if there is anything I can do to take the twist out.

The customer wants to finish the cabinet herself with a water based finish after I deliver it. I am worried that the doors will twist even more when she applies the finish.

Forum Responses
(Cabinetmaking Forum)
From contributor M:
I try to use particle or MDF core for doors. Plywood will bow and curve like sleigh runners sometimes after it is cut. (Offshore stuff is notorious for this.) You can try screwing hardwood cleats on the back of the door to help straighten it. Other than that make a new one.


From contributor P:
I've never had luck getting a twist out of VC plywood. Depending on the amount of resistance, you might be able to improve it with a good magnetic catch or by very slightly adjusting the hinges front-to-back (kind of difficult to get away with on a full-inset job) to move the protruding corner in.

Whatever finish is being used, it's very important to use equal coats of the same finish on fronts and backs. Also be careful that all sides and faces of the door are quickly sealed. If the client puts a coat of sealer on the back and leaves the face raw for a day, the unfinished face will soak up moisture and cup.

Keep in mind that most of the door manufacturing companies use 3/16" as their tolerance for twist in their guarantees.

Welcome to the high-paying, fast-paced, and exciting world of professional cabinetmaking. I'm sure you'll have your share of these white-knuckle episodes. Whoever it was that described the trade as "days of tedium punctuated by moments of stark terror" sure had it right!


From contributor S:
If your doors will be painted rather than clear coated, I agree that the best solution is to make another. On the other hand, if you have some matching figure issues to consider, hinge adjustments and catches are your only real solution. These doors are probably in the 30" tall by 21" wide +/- range. A magnet catch will probably be too wimpy. If the sides of your compartments allow, I would use adjustable double ball catches from Outwater Hardware. Pricey little guys and kind of a nuisance to locate properly, but if you set them up right they do the job. If you've built some stops into your cabinets, these catches won't work. I prefer to mount catches on the side panels – top and bottom. I don't like the interference of a catch on the bottom panel. Have done that but don't like it. Good luck. Remake gets my first vote. Yeah, and welcome to the club. Good that you have this web site as a resource.

1/29 #6: Twist in Plywood ...

Gerry
garobson@shaw.ca

I think I will deliver the cabinet with the twisted door and an explanation that I will replace all 6 doors with MDF core doors if it doesn't settle in. (The finish will be clear, so grain matching will require all new doors.)

Yes, this is a good resource to have. I am very impressed with the content and the quality of information available on this site. Thanks to each responder for getting me a little further up the learning curve.


From Professor Gene Wengert, forum technical advisor:
In any case, make sure that the finish is applied to front and back equally and at the same time.

From contributor V:
Take a double look at Gene's response. If the customer is doing the finish, I would be careful. They may not understand the importance of sixth sided simultaneous finishing.
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