Darryl Keil Last Activity 2025-09-09 11:09 AM
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Brent Longtin

Posts: 37

Joined: 2007-10-09
Location: Natick, MA

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Subject : back veneering
Posted : 2007-10-11 8:04 PM
Post #34084

I'm confused about when to do back veneering. I veneered some solid maple drawer fronts and didn't back veneer. They seem fine. And I'm now face veneering some half inch panels about 14" by 22" which are going to be edge glued and screwed into a frame. No back veneering. Is this ok? Or is some problem likely to develop over time?


 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: back veneering
Posted : 2007-10-11 8:49 PM
Post #34085 - In reply to #34084

There are some cases where you can get away with it, but honestly, I can't remember what they are because I just pretty much always veneer the back of any project.

Two exceptions that come to mind....real small panels, and tubes.

The bottom line here is that veneering the back of a panel is almost always the best way to do it.

Two things are happening to the adhesive. It will shrink, and it will create a water barrier.

Maybe your drawer front hasn't changed at all, but have you had it through a humid summer and a dry winter? A panel will not warp until the humidity changes. This happens with the seasons.

If you are screwing down the 14 x 22 panel, maybe you'll get away with it, but why put the stress on the project? 14 x 22 x 1/2 thick will definitely warp if you are only going to veneer one side.

It's not that much of a pain to simply cut another sheet, and then you can be sure...my 2 cents.




 
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Brent Longtin

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Joined: 2007-10-09
Location: Natick, MA

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Subject : RE: back veneering
Posted : 2007-10-12 1:47 AM
Post #34086 - In reply to #34085

Does it matter that the panels are plywood? I would have guessed that all the layers of glue alredy in the plywood plus the basic stability of plywood would prevent warping.


 
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Brian Gray

Posts: 339

Joined: 2004-01-21
Location: Sandusky, OH

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Subject : RE: back veneering
Posted : 2007-10-12 1:34 PM
Post #34087 - In reply to #34086

No matter what substrate, use a backer.

The next time that you are in the hardware store, take a close look at the plywood.

You will notice that all plywood will always be balanced in the number of plys, and identical in ply thicknesses.

The reason is for balance. If you add another layer that is not balanced, you are asking for it.

Try this. Make a scrap panel from your 22 x 14 x 1/2" and only put one layer of veneer on it....no backer.

Then put this under your couch and leave it there. Take a look at it each month. Pay particular attention to the changes especially from summer to winter.

You might be surprised.

My 2 cents - always use a backer, with a few exceptions. It's only an extra ten minutes of work.


 
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Don Stephan

Posts: 825

Joined: 2003-07-18
Location: Cincinnati, Ohio

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Subject : RE: back veneering
Posted : 2007-10-13 7:25 PM
Post #34092 - In reply to #34084

I agree with Brian, and I always veneer both faces. Any savings in time and materials from not veneering the other surface is inconsequential when compared to the cost of re-doing a project.

If the drawer front is relatively small, any cupping would be harder to see, and the joint with the drawer sides will help hold the front against horizontal cupping. If your larger panel is firmly trapped in a strong frame, the frame may be able to hold the panel flat, but the stress will be present.

When possible I veneer both sides at the same time, but occasionally it works out easier to veneer one surface in the morning and the other in the afternoon. One time the morning glue was very slow to cure (I think the heating pad wasn't switched on) and it was so late I decided to let the panel sit vertically and veneer the other surface the next day. By morning there was a noticeable cup. Fortunately the vacuum bag was able to flatten the panel, and with the other surface veneered the panel stayed flat.


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