Sealing panels before assembly

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161
Location
Stockport, England
It's been a long time since I've built any cabinets from solid wood - I normally use veneered MDF for all my carcasses.

But this week we're on a job making solid oak bedroom furniture. I'd cut the side pieces for two large chests of drawers, machined the dadoes to hold the drawer rails, and was explaining to my guys how we would have to take into account wood movement when fixing the rails in place - something they've never had to consider before.

My finishing guy came up with some thoughts. Shouldn't the panels be sealed with lacquer before assembly to match the finish which will be on the outside when the project is complete? With the best will in the world no-one ever sprays the inside of a chest of drawers to the same extent as the outside; and this will inevitably help cause cupping of the panel as moisture enters and exits to different degrees on either face of the panel.

I told him to go ahead and finish the panels before we assemble them.

Two questions;

Does anybody else do this?

and Does it have any effect?
 
Last edited:
Hi Duncan,
Interesting questions. Here's a few thoughts:

1. If you are going to finish the inside, especially if you are spraying, its wise to do so before assembly, to ensure good coverage in the hard to get to places like corners.

2. If you have a cross grain situation where parts will move differently, e.g. the drawer rails, finish those parts separately before assembly, to avoid a finish film cracking when the movement comes.

3. The rule that both sides of all pieces must be finished exactly the same way is in doubt in lots of places. For instance, Stickley did not finish the bottoms of tabletops. Personally, I seal both sides, but I don't worry greatly about getting the exact same number of coats on both sides. I don't seal drawers any more.

4. I usually route a sliding dovetail for drawer rails. That allows post finish assembly and also provides some mechanical protection against the panel cupping.

As always, just my 2 cents....
 
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