As I am new to veneers I have just a couple questions.
1. How should veneers typically be stored? Can they be left rolled up or should they be kept flat or some other way?
2. When applying the veneers do you do one side at a time or both sides at once?
3. Is it ok to apply the veneer then trim your substrate after the veneer has been applied or should the substrate be cut to finish dimension then trim the veneer?
Thanks in advance for all your help!
Ron
Replies
This is far from the final word on veneers, but it is what I have done with pretty good luck so far.
You can probably store it both ways. I store it flat if I have a space suitable. I wrap it in corrugated cardboard for storage. I have a roll of walnut that I have stored for 30 years. It seems to be OK.
If I use PVA or other glue containing water, I veneer both sides at the same time. I figure that will keep the moisture in balance better than wetting each side at a different time. If I use solvent type contact cement, I can do only one side at a time. Usually, I only veneer one side with contact cement. I NEVER, EVER, EVER use water-based contact cement! My one time to do that was twice too many!
You can do your trimming either way also. I prefer to veneer on oversized substrate then trim together. That is sometimes impossible to do. It is more tedious to trim veneer to an edge, but it can be done with a little practice. It is much more difficult with some woods than others. The PVA glue squeezed out gets in the way or tackiness of contact cement is a small problem also.
LOL!!
Cadiddlehopper
Ron,
I prefer to store my veneer flat. But it can be left rolled up. When you unbind the roll, let it unwind slowly by itself before you try to flatten it. I put the unbound, but still very curled sheet or collection of sheets in my oven (turned off!) with a 16 oz measuring cup full of the hotest water from my tap. That humidifies the oven and the wood rapidily unwinds to just about flat (it usually expands against the walls) as it absorbs the moisture. Then I lay it down on a flat surface and weight it as it equilibrates with the room air. It just stays flat then.
If you use white PVA glue in the dry, iron down process (which I highly recommend, second only to hot hide glue) you can coat the substrate and the veneer such that you can veneer right to the substrate edge, trim excess veneer to the substrate edge, or trim the two together. Any one of those operations will be easy to do as there will be no glue squeeze-out.
Also, keep the glue-down method of using the adhesive sheets made for fabric in mind. There are two types, a fusable web, and a non-web type. They work very well for veneer adhesion.
Rich
Rich,
How do you prevent the veneer from curling when you apply the glue to it?
Thanks,
Don
Don, Start with flat veneer. Spray the face side with water from a spray bottle just before spreading PVA with a brush on the back side. Keep spraying water on the face as needed to keep the veneer sheet flat as the PVA dries. Don't stop spraying as needed until you are sure the sheet is stable and dry, about an hour.
Rich,
I am confused after reading your answer??
Wait for the glue to dry? Is this in or out of the press?
You say Just before you spread the glue with a brush and then it sounds like to spray and wait??
Don,After PVA glue dries it is activated by heat. You spread the glue on both substrste and veneer, allow it to dry. Then you iron it down with an ordinary clothes iron set to cotton (high) - no steam. This is an excellent method, arguably, second only to hot hide glue.Rich
Edited 12/6/2006 8:09 pm ET by Rich14
It worked well for me when I did it too.
I had a large project with hard, white maple, and when I ironed it, my whole shop smelled like pancakes. Well, okay, syrup. It was nice!
Hal
DonC,
I'm not sure that Rich answered your question for you.
Using an iron, you don't use a press at all. Instead, the glue is spread on both the substrate and the veneer. They are then both allowed to dry completely. Personally, I use a paint roller rather than a brush to get a more even coat. You don't want any lumps. The reason for spraying the other side of the veneer with water is so that the veneer doesn't roll up from the moisture on one side. It gets crazy pretty quickly.
Then when everything is totally dry, you place the veneer where you want it, heat it with an iron, and iron it down. It really works best if you run a veneer hammer over it while the veneer is still hot.
The way it works is that the glue is thermoplastic, which means it turns to liquid if it gets hot enough, and will stick to itself instantly.
I hope this makes more sense to you now.
Hal
DonC
Have you had any problems with the expansion of the veneer from all of the moisture? I know that you wait for the glue to dry, but how long is necessary to wait for the moisture to leave the veneer? Or do you worry about it?
I have done long (12'), narrow (16" wide) pieces this way and didn't have too much of a problem with it.
But I have also vacuum pressed wide pieces (7' x 8') and just the PVA applied to the substrate caused maple veneer to expand so quickly that it folded over itself inside the bag before the vacuum was up (I have a fairly fast vacuum pump. It only takes about 15 seconds to pull all of the air out of a large bag.). Quite a mess!
Hal
http://www.rivercitywoodworks.com
You aren't asking me, but I had a similar experience with maple. I use a clamp press. I lay the veneer on the platen, butter the substrate, then lay the substrate onto the veneer panel. The weight of the substrate prevents the maple from curling. Also, the veneer is wetted for only a short period before it is clamped. I don't know how you could do this with a vacuum bag. My largest piece has been 2x5 feet, the limit of my press. I wonder if your reference to a 7x8-foot piece is a mistype. That is huge!Cadiddlehopper
No, it really was that big. I made a huge vacuum press with a frame hinged over the top of two sheets of melamine glued together. Then I did the same as you. I spread the glue on the substrate, laid it on top of the veneer, shut the top and turned on the vacuum. It was only a matter of a few too many seconds until things went south.
You should have seen the mess getting all the glue and veneer off before it got too gooey. I had a lot of work in the substrate so I couldn't afford to waste it.
This project was actually for a serpentine desk that went in a corner, so the veneer sheet wasn't completely 56 square feet as it had some cut out of it for a place to sit, but the press was 8' x 8'.
The scary thing is, I had to do it again. The second time was a charm. I used a bit less glue and got the air out of the bag a little sooner. But even more scary was the fact that I still had to do the veneer on the top, which was a $380.00 sheet of quilted maple. It actually went pretty well, except that I think a bit more glue would have been better. I still worry about it, but it is still down tight.
And now I'm happily married to the client that hired me to build that desk. Things always seem to work out!
Hal
Great story! I hope the ending remains happy forever.That was a risky procedure, as I would have thought and as your semi-catastrophy verifies. Surely, you had an assistant on hand. How did you spread glue? Working alone, 8 to 10 sq ft of glue area is all I can handle and still feel safe about the joint.Anyway, if the veneer bubbles, maybe you can iron it back in place. Perhaps you should make a veneer hammer in your spare moments to be ready for that event. Maybe both of us should look into catalyzed glues. I bought a gallon once, but its shelf life was so short that it solidified in the jug. I know no local source, but if I did, their stock would probably be stale just as was the liquid hide glue I tried.Cadiddlehopper
So far, so good on the story of my life. I don't think I've ever been happier.
Spare time? What is that exactly? If I'm correct in my calculations, the statistics for people who are alive that will die someday is right at 100 out of 100! So for me, if I have any "spare time," I go windsurfing, skiing, golfing, or dancing. Sometimes more than one a day. Maybe I am actually using my "spare time" to work, and my main time to play. I like that idea!
No, no assistant at that time. To spread glue, I almost always use paint rollers. Small for small jobs, full sized for large jobs. I think it gives the most even results.
The veneer bubbles I got on this particular mess were not ironable. The veneer actually doubled over on itself because it started to tack on the outer edges rather than just expand. It was a mess!
I used Unibond 800 once, the glue that is recommended by the veneer press people, and didn't like it. With cherry veneer, it actually discolors the veneer, giving it sort of a greenish tone. I've heard it does the same with maple. So I only used it once, and the rest is on the shelf.
I've also used epoxy in a veneer press. It didn't work. I spoke with a really knowledgeable plastics and epoxy expert about it, and he said that in a really strong vacuum, the vacuum will sometimes separate the molecules in the epoxy so that they don't cure. When I tried it, I pressed a sample in my vacuum press, and with the same epoxy, pressed some with cauls and clamps. The vacuum pressed epoxy never did cure, the other was fine. I was using West System epoxy, which is one that is often used for cold molded boat building, often used in a vacuum press. I think I had too little penetration and too much vacuum. Maybe I needed to thicken the epoxy. Regardless, it never did cure.
I personally don't think too much of liquid hide glue. I don't think they totally figured it out. It seems like more of a marketing thing than a gluing thing. Hide glue is good, liquid hide glue is not good.
Hal
I think that I share your philosophy of life. I never figured out which was spare time or otherwise either. Being retired, it is now all the same.I have a veneered piece approaching 40 years old on which I used contact cement. I know that the experts condemn such a practice. On the other hand, if it works, why not embrace it? It is sensitive to some finishing materials, but take that into account before using it. I recently did a repair job using contact cement. It could have worked for your desk top, but as large as it is, you still would face difficulties.Had I begun with the hammer veneering process, I would probably do that exclusively. At my age, I don't wish to purchase the equipment (though it doesn't require much) nor to spend the time perfecting the technique. It is a process that might have taken some of the thrill out of your desk top job though.Thanxx for the warning about the urethane. Guess I'll stick to PVA. I've got that process under control. I spread glue with a rubber roller very quickly. I presume that your paint rollers have short nap.Cadiddlehopper
Many years ago, I also used contact cement to glue paper backed veneer for a new surface on an old desk. Then the painter used lacquer based stain, sanding sealer, and finish coat. Of course it lifted in a few places.
Since Titebond Type II works so well, I don't know why anyone would use anything else.
I have used a lot of contact cement though, and for all plastic laminate projects I now use 3M's water based product for all of it. It is truly amazing, easy to use, very low emissions, and incredible strength. Plus it goes a long way.
Hal
http://www.rivercitywoodworks.com
Unibond http://www.vacupress.com can be expected to stain cherry and often maple, sometimes walnut. Testing first is always recommended.To address the Unibond staining problem, a thickening agent called Unibond Blocker was created. Never used it, but others have found it stops bleed through and therefore stops staining.Another two part urea formaldehyde glue is Pro-Glue, http://www.pro-glue.com. To the best of my knowledge there are no known staining issues with this UF glue, although it does bleed through like Unibond. With the light powder catalyst, it is also almost as white as maple.Either one can be purchased in half gallon as well as gallon quantities. Two part UF adhesives have a shelf life, like PVA's and many other products. If stored in a refrigerator (that does not contain food, since the liquid resin could offgass chemicals) the liquid in my experience lasts at least nine months without thickening (which indicates it is no longer "good"). Don't know how long the resin will stay "good" if stored in a fridge.With either UF adhesive, there should not be any moisture-caused veneer expansion as there can be with PVA.
In my experience, it isn't the bleed through glue that is the problem. Something in the fumes (probably urea) actually discolors all of the veneer whether it bleeds through or not. So I don't believe that thickening the glue would help.
I have glued identical veneer in side by side tests with Titebond II, and the Unibond definitely changes the color of cherry.
It probably isn't a problem if the cherry is going to be stained, but I seldom stain it when I am veneering things.
Hal
http://www.rivercitywoodworks.com
PS: My wife just came in the room and told me to tell all of you that duct tape is what she uses for just about everything.
Edited 12/9/2006 10:40 pm ET by Hal J
Awesome! Thanks so much for the feedback. It's kinda what I was thinking but then again I have done that before and... well the results have been less than steller.
thanks again,
Not looking for arguments about the best adhesive, simply mentioning that for veneering a lot of people have great success with two part urea formaldehyde glues such as Pro-Glue and Unibond. There have been several articles in FWW on using them, and tons of info on the forum at http://www.vacupress.com. No water issues as with using PVA, no delamination issues as with contact cement. Pros and cons of each adhesive. You might experiment with each, including hot hide glue if so inclined.
Don,
I actually just used some PVA on some paper backed curly maple and so far so good as far as I can tell. Thanks for the link to the Vacupress site it looks pretty interesting!
Thanks
Ron
Isn't the shelf life of these glues extremely short? Or maybe I got mine from the wrong source.Cadiddlehopper
Don't have a specific period in my notes, but the liquid resin will thicken over time at room temperature. I store the resin in a small fridge that does not contain food and have found the liquid resin good for at least nine months. I generally buy a gallon at a time and use it in 6-9 months, depending on the amount of veneering being done.
The gallon I bought had an expiration date printed on it. I presume that you buy from the source to which you made reference. I won't buy in advance for my next project and I'll try that source. Thanxx!!Cadiddlehopper
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