It's never too late to learn something new. I needed a plywood back for the hammered dulcimer I'm building. I could have gone out and got some walnut/cherry/etc. plywood, but I had some Baltic birch and a lot of veneer of various sorts I picked up a few years back. The size was too large for my little press I use for box tops and the like, and I have neither the space nor the money to get into vacuum veneering so hammer veneering was the only option.
I have three books on veneering plus all I could learn from online sources. Naturally they disagreed on more than one thing. For example, one book used veneer tape to join the pieces while a second said don't ever do that, the tape comes loose and you have a mess. Of course I followed the first book and the second was right!
Both a book and an online video showed spraying both sides of the veneer with water immediately before use. The book said let it drain for a minute, the video used an iron on it. I tried both. Would you believe veneer expands across the grain about 3/4" per foot when wet? At least the stuff I was using did. One piece actually developed stress cracks in the middle of the sheet after drying.
I don't have a heat gun to warm up the plywood, but I found that using the iron worked just as well.
I didn't have much luck with the "overlap and cut" technique. Jointing the edges by clamping them between pieces of MDF with factory edges and then sanding them straight worked much better.
The first try was a disaster. Not only did I have the aforementioned veneer tape all over the place, the glue was too thick - I followed the wrong book again. Then there was the expansion bit and my inexperience.
I think I'm finally getting the hang of it, although I won't be sending in photos in to Fine Woodworking any time soon. Here's my procedure:
- A day or two before the actual use, flatten the veneer with water and the iron and keep it pressed flat.
- Joint it with the mdf/sandpaper.
- Cut the veneer with about a 1/8" overhang on all edges not jointed - usually the ends.
- Get the glue pot and iron working. Make sure the glue is thin enough and keep adding water throughout the process to replace that lost.
- Use the iron to warm the area of the plywood for the first/next sheet of veneer.
- Spread the glue with the largest appropriate brush.
- Put down the veneer, carefully butting it against the prior piece if not the first.
- Use the iron to warm things up again.
- Hammer the veneer. Why isn't it called a veneer squeegee?
- Repeat steps 5-9 till done.
I do have one question. I know I can use urea to lengthen the open time of the glue, but the amounts specified seem all over the place. Some folks even make their own liquid hide glue - I sure don't want to go that far.
So if there are any hide glue experts out there, how much urea should be added to half a pound of ground hide glue just to extend the open time by a minute or two? Or would I do better to increase the open time by thinning the glue instead?
BTW, hide glue does *not* stink - there's almost no odor unless you overheat it - then it smells awful.