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+-- Thread: veneer from end grain and burls (/showthread.php?tid=7351241)
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veneer from end grain and burls - TomFromStLouis - 11-14-2019
I just suffered another defeat from some end grain veneer I made from an eyeless maple burl. It was 1/16" thick and laminated to both sides of 1/4" MDF with Old Brown Glue. The finished box is sitting indoors and when the heating came on strong for a few days cracks appeared, edges curled up and the box is ruined. darn, it really looked nice...
I've had this happen once before but I concluded that my veneers were too thick and so I thought 1/16" would be thin enough. Wrong? Or will tweaks like Unibond instead of hide glue and baltic birch instead of MDF be enough to tame this beast?
RE: veneer from end grain and burls - TomFromStLouis - 11-14-2019
Here is what Joe Woodworker says on his veneer site about shop sawn veneers:
Use his Ultra-Cat Powdered Urea resin exclusively because "Other woodworking glues do not have the strength to keep a thicker veneer from delaminating over several seasons of humidity changes."
Not sure if this explains how Ruhlmann managed so well before modern adhesives - maybe his veneers were way thinner than 1/16"? - but I guess trying a modern urea resin is next...
RE: veneer from end grain and burls - mikefm101 - 11-14-2019
I’ve only researched veneering, including workshops at North Bennet Street, and Urea Resin is consistently suggested. Even pros I’ve met have said the same.
Mike
RE: veneer from end grain and burls - Stwood_ - 11-14-2019
Are your shop cut veneers actually dry? Have you checked?
RE: veneer from end grain and burls - TomFromStLouis - 11-14-2019
Yes the veneer was dry. Just not as dry as it got after 3 days of indoor heating. Shrinkage happens.
I wonder what they are doing that makes urea resin so different than hide glues (which I understand to be collagen plus urea)?
RE: veneer from end grain and burls - fredhargis - 11-15-2019
I've no idea what the answer is to your question, but I've always used the urea glues for veneering (I've never veneered with end grain veneer, tho'). I've also used the Ultra Cat glue. It's very good, but truthfully I couldn't tell the difference between it and the one I typically use: Wedwood Plastic Resin glue. Another one that gets lots of good press (and is a liquid) is the Unibond glues. It's a guess, but I'd bet they would work better in your application. To be honest, I like the UF glues so much I'd use them for everything if they weren't so inconvenient.
RE: veneer from end grain and burls - Stwood_ - 11-15-2019
Ok, so it was dry.
Was it wrinkly, and did you have to wet it for it to lay down?
Just mulling things over here....
RE: veneer from end grain and burls - jteneyck - 11-15-2019
How low did the RH go in your house? I've had a couple of seam cracks show up in 1/16" shop sawn veneer, on both MDF and composite plywood glued down with PRG, when the RH in my house got down below 30%. I bought a humidifier and keep the house at 35% minimum now (40% setpoint). No more seam cracks.
The RH never got that low in European castles where that fine French furniture was housed. But I do think their veneer with thinner than 1/16", too. Stuff I've seen with pealed up corners looked to be much thinner. But good grief those guys were good with the tools they had, and some of their pieces look as good today as when they built them.
John
RE: veneer from end grain and burls - Steve Altman - 11-15-2019
(11-14-2019, 11:21 AM)TomFromStLouis Wrote: I just suffered another defeat from some end grain veneer I made from an eyeless maple burl. It was 1/16" thick and laminated to both sides of 1/4" MDF with Old Brown Glue. The finished box is sitting indoors and when the heating came on strong for a few days cracks appeared, edges curled up and the box is ruined. darn, it really looked nice...
I've had this happen once before but I concluded that my veneers were too thick and so I thought 1/16" would be thin enough. Wrong? Or will tweaks like Unibond instead of hide glue and baltic birch instead of MDF be enough to tame this beast?
Hi,
The thing that makes Unibond 800 different is that it has no water. Makes an extremely rigid glue line. But it requires at least 70 degrees (more is better, and faster) and a good press (manual, vacuum, power, whatever).
If your veneer is crinkly at all, relax it.
Not sure about MDF since I haven't used it in a very long time and don't know what it's like anymore. If you're concerned about it, cross veneer it on both sides before using.
Another thing you might try is creating a "two ply" with your face veneer and a cross veneered backer using Unibond 800 before pressing the two ply onto both sides of your core. That's probably the best way to prevent any problems.
RE: veneer from end grain and burls - TomFromStLouis - 11-15-2019
(11-15-2019, 09:19 AM)Stwood_ Wrote: Ok, so it was dry.
Was it wrinkly, and did you have to wet it for it to lay down?
Just mulling things over here....
They were fresh sliced from an air dry piece of burl and soon after glued down. Honestly I think I did everything right except I used the wrong glue.
The first time I ever used end grain veneers I think I used PVA glue and everything went fine. The piece is still intact. Next time same approach and some sections delaminated after a winter indoors. This looks like it might be harder than I thought... I switched to hide glue because the bleed through would not be an issue and thought I had this problem licked with veneers significantly under 1/8" thick. Not so.
Dang this hobby can be humbling. I've been doing this long enough that I truly should not be having these problems. I must be a slow learner.