Darryl Keil Last Activity 2025-05-12 11:03 AM
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Harold Hough

 
Subject : Springback
Posted : 2006-06-05 2:16 AM
Post #33096
Thank you for this great forum. I don't know any place else where I could get so much practical info on veneering.
I'm about to attempt my first veneer job which is a laminated curved drawer front. The front is about 25" long and 5" wide. I do not know what the bend radius is since it is not a true arc but is eliptical. The apex of the curve is 3" high so the curve is moderate. I have a vacuum system which will pull down 20". I'm using a rigid foam insulation bending form and five pieces of 1/8" Luan. The adhesive is a pre-mixed Cold Press.The laminations were in the press for over 1 hr. No veneer yet, just laminations.
My problem is springback. From comments on this forum (I've read them all) I expected little or no springback. I was disappointed when I had over 1/2" on both ends.
Question: Does the number of laminations have any effect on springback.
Would it help to use more? Or less?
My next attempt will be with 1/8" oak laminations. Will that be
better or worse or no difference?
Should I change my form material? The foam was surprizingly
rigid for that amount of pressure but maybe it does compress
some.
Am I using the correct glue. The bond of the laminations was
very good.
Any suggestions will be very much appreciated. I am facinated with veneering posibilities and want to become as good as I can with it..



 
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Darryl Keil

Posts: 1454

Joined: 2003-05-22
Location: Maine

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Subject : RE: Springback
Posted : 2006-06-05 10:18 AM
Post #33097 - In reply to #33096
Harold,

Three things I would alter in your process.

First and foremost you need to leave the laminations in for MUCH longer. One hour is no where near enough hold your shape firmly. Let it stay in the press overnight. That alone would have changed your results dramatically.

Second, use bendable plywoods designed for making curved panels, they are very flexible and would have held your shape quite closely even taking it out of the press as soon as you did. 1/8" Italian bending poplar is my favorite.

Third, but not as critical, is to use a catalytic type glue. The three common glues in the category are urea resin, epoxy, and polyurethane with urea resin being the most rigid.

Do these things and you will have just about no spring back at all.

Sincerely
Darryl Keil


 
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Don Stephan

Posts: 825

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

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Subject : RE: Springback
Posted : 2006-06-05 12:37 PM
Post #33098 - In reply to #33097
Harold:

I'm a bit confused by your initial post as to what you want for a drawer front core. If you are trying to form a substrate to be veneered, Darryl's suggestion regarding substrate material is perfect. If you are trying for the look of a solid curved drawer front, as suggested by your idea of using 1/8" oak strips, consider laminations 1/16" thick instead of 1/8". You can saw those on a band saw with an appropriate blade, or you can purchase 1/16" thick veneer in a number of wood species, including probably oak, at veneer suppliers such as www.certainlywood.com. The thinner solid wood strips will bend much better.

We all benefit greatly from Darryl's willingness to pay the cost of hosting a forum and for his contribution of time and experience.


 
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Harold Hough

 
Subject : RE: Springback
Posted : 2006-06-05 7:39 PM
Post #33099 - In reply to #33098
Sorry about the confusion. I can see I was not clear on that point. Actually what I have is 1/8t oak faced plywood. I wasn't particular about the face, that just what was available. The lamination is a subtrate and will be veneered.I'm going to follow Darryl's expert advice but I'm wondering if I
can use 3/8 bending ply. I will have to buy on the internet since I doubt there are any suppliers here in Arizona. I've seen 3/8 and 1/4 on the net but not sure about 1/8t. I'll begin my search tonight. Thanks for the advice and information.


 
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Darryl Keil

Posts: 1454

Joined: 2003-05-22
Location: Maine

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Subject : RE: Springback
Posted : 2006-06-05 7:44 PM
Post #33100 - In reply to #33099
Harold,

If you go with 3/8" bending ply the lay up should look like this. Face veneer, cross band veneer, 3/8" bending ply, cross band veneer, 3/8" bending ply, cross band veneer and face veneer. This ends up being a 7 layer lamination. 3/8" bending ply is to rough to veneer directly on hence the cross banding.

Good luck with your project.

Sincerely
Darryl Keil


 
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Wemdell Hughes

 
Subject : RE: Springback
Posted : 2006-06-06 10:07 AM
Post #33102 - In reply to #33099
Try Woodworkers Source - stores both in Tucson and Phoenix as well as a couple of independent lumberyards in Tucson carry it.
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