wood veneering question

[Fred Voorhees]

Fooling around in the shop...I decided to get around to using some of the wood veneer that I bought as a bulk package on some tops of two small boxes that I am fabricating. I have never veneered before and I don't have a vacuum press. The two pieces are approximately 4 1/2" x 9 1/2" and 7" x 9". The material for the boxes is red oak. I will be using some red oak 1/4" plywood for the bottoms and I also used it for the tops with the red oak side opposite the side that I glued the veneer onto. I used yellow pva glue...didn't get sloppy with it and overapply and didn't underapply. Just a nice even coat and all of the surface was covered on both the plywood face and the veneer. Not having a vacuum press, and being that the pieces were so small...I simply covered perfectly flat pieces of scrap wood with saran wrap for glue protection and placed these on top of the veneered pieces and weighed them down considerably with some masonry block. I did tape the edges of each piece to avoid any creeping of the veneer while fooling with it and setting up the weights.

Upon inspecting the pieces a few hours later, the larger piece had significant "wrinkling" while the smaller piece had just a minor amount. Not sure what the heck went wrong. Like I said...I have zero experience in veneering prior to this really, so I am looking for an answer to what happened here. Is it possible that the veneer "hydrated" from the moisture in the glue and since it was taped at the edges that the excess veneer material that resulted from the hydrating had nowhere to go and hence the wrinkling? There was significant weight on each piece and I thought it would be sufficient to keep things flat.

I looked around on the internet for veneering tips and methods and I did notice that there was a hint that when applying to plywood...to give the plywood a coat of glue to act as a sealer and then when it is dry, go forth with your veneering job..applying coats of glue to both surfaces. This I didn't do. Would this be the cause of the problem? Or is there something else causing the grief.

Actually, the smaller piece has barely any noticeable wrinkling and the larger one has it pretty good, but honestly, between the figure of the wood in the veneer combined with the wrinkling - it really makes for an interesting effect. Any answers would be greatly appreciated.

[Larry Browning]

Fred,
I also am wanting to learn all about veneering. My last project could have really used a good veneer instead of purchased veneered plywood. There is a great resource on the web: http://www.joewoodworker.com/
There are plans on his site for making you own veneer press, which looks like a really fun project. The best I can tell, you really need a vacuum press in order to have good success.

Also, is the veneer you are using backed or is it just the wood? If it is not backed, I "think" using the press may be about the only way to avoid the wrinkles, but I really don't know that for sure.

[Ernie Miller]

Iron the veneer with a household iron set to medium high. Don't let the iron stay in one place for a long time or you will scorch the veneer. The heat will soften the glue and should un-wrinkle your veneer.

[Montgomery Scott]

a few blocks of concrete is wholly insufficient for the pressure needed. Next time you will either need to use a vacuum press, lots of clamps and cauls or a traidtional veneer press. Vacuum veneering makes the process much easier, though it's not cheap.

As far as the recommendation to apply glue and let it dry, I've not heard that one before except if you are intending to do an iron bond method.

[Jim Tobias]

+1 on Ernie's idea of using a warm iron to soften the glue and flatten. In the future, if you are going to attempt this method, you should definitely use cauls with clamps to get as much even pressure as possible across the entire surface.
You can also use this http://www.betterbond.com/heatlock/heatlock-FAQ.htm. It is made for iron on application and works pretty well.
BUT, if you break down and get a vacuum bag, it will open up endless veneering possibilities (and make the process soooooo much easier).

Jim

[Chris Luna]

I highly recommend the website mentioned above. I built a venturi based vacuum press system from the plans on the site. (I bought the parts from him too. It's the least you can do for so much free information!) It works like a champ and is very easy to build. You just hook it up to an air compressor and it cycles on and off depending on how much pressure you want. While I still prefer working with solid stock, it has opened up a whole new world of opportunities for different designs and construction techniques. For a few hundred dollars you can be setup with a complete system and a decent sized bag. It's one of the best investments I've made in my shop. Now that I have it I use it all the time.

If you plan on getting into veneer work you should pick up some cold press glue. Yellow PVA doesn't dry as hard as cold press glue and can creep over time. I have a project that I did a few years back that is now suffering from this. It's not horrible, but I can tell a distinct difference between the final product based on the glue that was used.

[Steve Peterson]

The maximum pressure that a vacuum press would be able to achieve would be around 14psi. For the 7" by 9" piece that would equate to 882 pounds of pressure. A block of wood on top and a couple of clamps could easily provide more pressure than a vacuum press.

I have heard that PVA glue can creep and allow the veneer to loosen over time. Many people (including myself) have used it without issues.

Titebond makes a cold press veneer glue that is supposed to be better. They recommend 100-250 psi of pressure to create an ideal bond. This would require a hydraulic press to generate around 6000 pounds of pressure. It probably performs good enough with normal pressures.

Steve

[jim gossage]

I have successfully used the press method by sandwiching the veneer and substrate between 3/4" mdf and using slightly curved cauls and many clamps. Its a little tedious but has worked well for me on pieces up to 18x24".

[Mel Fulks]

Veneering had a modern era long before vacuum bags. Plastic resin glue mixed thinly and applied to both surfaces will pull down just fine without much pressure. Piece of plastic over veneer,then piece of plywood ,spring clamps around edges,some weight in middle. The glue pulls down as it sets. This method seems to work ONLY with plastic resin glue.

[Chris Padilla]

The maximum pressure that a vacuum press would be able to achieve would be around 14psi. For the 7" by 9" piece that would equate to 882 pounds of pressure. A block of wood on top and a couple of clamps could easily provide more pressure than a vacuum press.

I have heard that PVA glue can creep and allow the veneer to loosen over time. Many people (including myself) have used it without issues.

Titebond makes a cold press veneer glue that is supposed to be better. They recommend 100-250 psi of pressure to create an ideal bond. This would require a hydraulic press to generate around 6000 pounds of pressure. It probably performs good enough with normal pressures.

Steve

While clamps and cauls could provide more pressure, the beauty of the vacuum clamp is UNIFORM pressure across the surface. However, for such a small part as in this example, I would think clamps and cauls ought to be able to provide relatively uniform pressure. For larger pieces in the 2x2 foot+ regime, vacuum bags work much better unless you have a dedicated veneer press or special cauls.

Joewoodworker sells veneer glues that work great and dry hard. In fact, I've sliced my hands on many a sharp squeeze-out of the glue. And the glue he sells doesn't need that insane pressure that Titebond calls out for their veneer glue.

[Fred Voorhees]

Great information guys and thank you. As I said...I am completely new to the veneering and am looking to become more involved in it. I am now retired and have a nice fistful of discretionary cash on hand every month and if all it takes to be set up nicely with a vacuum situation is a few hundred dollars...I might have to look into it. Recommendations to this end?

[Larry Browning]

Great information guys and thank you. As I said...I am completely new to the veneering and am looking to become more involved in it. I am now retired and have a nice fistful of discretional cash on hand every month and if all it takes to be set up nicely with a vacuum situation is a few hundred dollars...I might have to look into it. Recommendations to this end?
Fred,
I think I am headed down the same path as you on the veneering thing. But sadly I have not retired yet (That will come in 3-4 years) so will probably be a bit behind you. I will be very interested in reading about your journey down the path. Please keep us all posted with your progress. I have been roaming around in the Joe woodworker web site and think I am going to follow much of the advice over there.

[Chris Luna]

I am very happy with the press that I built. http://www.veneersupplies.com/categories/Vacuum__Press__Items/Vacuum__Press__Kits/

$150 for the kit, another $20 in misc, and a bag will get you going. He sells cold press glue too. I haven't been able to find a local source so I get this from him as well.

I built the auto-cycling venturi system. Joe sells a kit that has 75% of what you need. The rest is easy to find stuff like pvc pipe, scrap plywood, etc. You don't need a crazy huge air compressor for it to work, but you definitely need something bigger than a pancake. Mine is a standard issue 20 gal 110V and it's more than you would need. That and a couple hours is all you need.

I picked up a 4'x4' bag and it works for most stuff, but I would like to pick up another bag or two down the road. They are a little cumbersome to work with so it would be nice (but not necessary) to have a couple different sizes. The vinyl ones are a lot cheaper, but I would recommend sprining for a poly bag as I hear they are a little easier to work with and will form contours a little more easily. I also built some vacuum clamping pads out of some extra UHMW that I had. They really come in handy when I'm trying to belt sand a table top, etc. I really can't recommend this project enough.

[HANK METZ]

Great information guys and thank you. As I said...I am completely new to the veneering and am looking to become more involved in it. I am now retired and have a nice fistful of discretionary cash on hand every month and if all it takes to be set up nicely with a vacuum situation is a few hundred dollars...I might have to look into it. Recommendations to this end?


I have one, crawl before you walk, walk before you run, this following is about as inexpensive yet effective a device as you can build to replicate those small jobs you did, in fact the solution is stored in your trunk:

254380

- Beachside Hank
Improvise, adapt, overcome; the essence of true craftsmanship.

[Steve Peterson]

Great information guys and thank you. As I said...I am completely new to the veneering and am looking to become more involved in it. I am now retired and have a nice fistful of discretionary cash on hand every month and if all it takes to be set up nicely with a vacuum situation is a few hundred dollars...I might have to look into it. Recommendations to this end?

I have the EVS auto cycling kit from Joe Woodworker coupled to the $104 pump that he sells. You need to add some PVC tubes and end caps for the vacuum chambers. It goes together in about a day.

I bought the cheper vinyl bags, but will spring for the much more flexible polyurethane bags if I buy another bag. My nephew is really into skateboarding, so I would buy a 2'x4' bag next so he can make a skateboard deck.

Steve

[Mike Henderson]

If what you're working with is flat, you can press it with cauls and clamps around the perimeter. For cauls on small stuff, I use 3/4" MDF with plastic (or waxed paper) between the cauls and the work. If your work is curved, fill a box with sand, and put plastic between the sand and your work. Clamp the work down into the sand box.

When gluing, you normally would not put glue on the veneer - just on the substrate. One reason is that some veneer turns into a potato chip when it absorbs water. So you put glue on the substrate, lay the veneer on top, and get it into clamps immediately.

Regarding glue, white glue (Elmer's Glue All) is a good glue for small stuff. One big advantage of it is that you can wipe off the glue on the show face with water, even after it sets. I use white glue on all my small work, as long as it's not going to be exposed to lots of water.

Otherwise, I use ProGlue, which is a Urea Formaldehyde (UF) glue. The advantage of white glue is that you can take it out of press in 30 minutes to an hour, while UF glue will often require a heating blanket and overnight press. There are other good UF glues.

But let me add one important thing: there's quite a bit to learning how to do good veneer work. Taking a course from someone experienced will help you avoid problems and speed your learning. If you don't want to take course, the best book is "Woodworker's Guide to Veneering and Inlay (http://www.amazon.com/Woodworkers-Guide-Veneering-Inlay-Techniques/dp/1565233468/ref=sr_1_1?ie=UTF8&qid=1360987379&sr=8-1&keywords=a+woodworkers+guide+to+veneering+and+inla y)". (Disclaimer: I do a lot of veneer work and teach classes in veneer)

Mike

[thomas eaves]

Fred,
To answer your question, the glue you use has too much water in it. You think the oak wrinkle try maple! So from the time the veneer touches the glue to the time you start to weigh it down the veneer will absorb the water and start to swell. At this point having a vacuum press would not have flattened it without help.
Books, video and classes are advisable if one is serious about learning the art of veneering. Tom

[Jim Becker]

Fred, I use vacuum to press panels, but have also used platten and clamps for small pieces. I agree that "weight" alone is not sufficient to do a good job with veneer application. There are other techniques for small projects, such as "hammer" veneering using hide glue, etc, too. Do be sure you're using glue designed for veneer work, too. I buy mine from Joe Woodworker.

[Alan Lightstone]

I went with a dedicated electric vacuum pump instead of using my compressor. Only downside (besides cost) is that it runs continuously. But it is FAR quieter than my air compressor, so that's not a big deal.

I think it goes up to more like 25.5psi, not 14psi as was said above, but I usually use it at 21psi as was suggested.

I also get all of my supplies from Joe Woodworker. I prefer their cold press Better Bond veneer glue to the powdered Ultra-Cat PPR pre-catalyzed resin. While that resin glue is arguably superior (it is waterproof and I work with a lot of shop-sawn veneers), it is a real pain to mix, messy, and gets all over. Plus I find I'm fighting the clock with it to get both the backer veneer and the show veneer done before it sets. Plus hard to get rid of lumps. The Better Bond is plug and play, like PVA glue, but better. I'm especially fond of the dark color for mahogany, sapele, cherry, etc. I've never tried their Unibond 800 glue.

[Mel Fulks]

Alan,glad your system is working for you. Have to defend the powdered plastic resin glue simply because ,as I have posted before it works well with little pressure. It does not have to be messy ,it is helpful to follow the mixing instructions exactly.Using the right amount of water in the initial thick mix ( before adding the rest) is critical to avoiding lumps. The working time is one of the best . It is best used thinner than most glues. Some are put off by the high price in small quantities. We buy 25 pounds at a time. Shelf life is pretty unlimited with extra storage care, I checked with a tech rep. I keep silica gel in it , keep the package inside a thick plastic bag. In hot weather it is kept in the office,not the shop. Care is taken to get the top back on fast.

[thomas eaves]

Alan, You can extend the life of your pump by retro fitting it to make it a cycling pump for around $30.00. Also I think you got mixed up on the pump Vacuum pressure which is 0 to 30 hg and the outside pressure on the bag which is 14 psi. Tom

[Erik Christensen]

+1 to all the advice to checkout joewoodworker.com - great source of info and if you decide to buy he has pretty much everything at prices that are very good. I built my own pump system from a kit he sells - easy to build and very reliable. I have done 'some' veneer work and discovered that with a good pump & bag the only challenge is cutting, edging, book-matching, etc the veneer itself. Vacuum bag glueups are pretty much goof proof.

One point I want to make is that in the 3 years I have had my vacuum system I have used it many times more for everything else but veneer work - ie. making a torsion box or my latest - I needed 12/4 hard maple for legs for my new bench but could not find it - pretty easy to take a piece of 8/4 & 6/4, face joint them, HEAVY glue applied (squeeze out is a good thing & no harm inside the bag), vac bag for 30 minutes, dry overnight & plane to final thickness. Less work than driving around looking for the mythical 12/4 supplier.

A good vacuum bag/pump will be a tool that you will be amazed at all the ways you can use it besides veneering.

[Mel Fulks]

We've seen those ads...

[Chris Padilla]

Alan, You can extend the life of your pump by retro fitting it to make it a cycling pump for around $30.00. Also I think you got mixed up on the pump Vacuum pressure which is 0 to 30 hg and the outside pressure on the bag which is 14 psi. Tom

Right. 1 psi is about 50 mmHg (51.7 mm of mercury to be a tad more precise) or about 2 inHg (2.036 inches of mercury to be a tad more precise), which is likely the unit used on your vacuum pump gauge.

[Alan Lightstone]

Alan,glad your system is working for you. Have to defend the powdered plastic resin glue simply because ,as I have posted before it works well with little pressure. It does not have to be messy ,it is helpful to follow the mixing instructions exactly.Using the right amount of water in the initial thick mix ( before adding the rest) is critical to avoiding lumps. The working time is one of the best . It is best used thinner than most glues. Some are put off by the high price in small quantities. We buy 25 pounds at a time. Shelf life is pretty unlimited with extra storage care, I checked with a tech rep. I keep silica gel in it , keep the package inside a thick plastic bag. In hot weather it is kept in the office,not the shop. Care is taken to get the top back on fast.

Thanks, Mel. I must be making the mix too thick (though I thought I was following the directions closely). No doubt the powdered resin is a very strong glue, just not as easy to use in my hands as the Better bond.

Whoops on the psi / hg mistake. I should have known better.

[Mel Fulks]

Kind of you to reply . My only purpose is to say that anyone who doesn't want to buy a vacuum press can still do good veneer work .

[Doug Cook]

I have just started working with unbacked, curly Walnut veneer and it was not flat by any means. What I have found to work with this veneer is to first soften it. I can't remember the site, but one recommended a mixure of 6/3/1 water, denatured alcohol, and glycerine. I made up this mix, generously sprayed both sides of veneer, then after about 3 minutes, wiped excess mix. Then I placed the veneer between two melamine boards, with newsprint on both sides of veneer. I used cauls and clamps to keep the melamine tight, but didn';t need to clamp too hard. Let it stand for about 5 hours. Then took the veneer, which was still "damp", let it air dry for about half hour, then cut to size. I noted that the veneer did "expand" a bit, so doing a rough cut before wetting is ok, but you will need to tweek the cut after drying. Then, I used BetterBond glue on substrate, put 3/4" plywood with melamine surface both sides on top of veneer, then clamped the heck out of it. The more pressure you use the less chance of bubbling. Clamps work well provided you use as many as you can fit over piece, and let it sit for about 4 hours before removing clamps. I did small pieces (1' square) to relatively large (2' square) and was successful in every case. Do not rush the glueing after removing the veneer from the drying press; if you glue too soon, the glue will bleed through the veneer and will show up as little shiny spots which can not be sanded out.
I am a neophyte at this veneering process; but after going thru the glue and bubble routine, this process worked for me.
DC

[thomas eaves]

Doug I thought by now someone would have commented on your above post? The only reason I’m saying anything is that if you haven’t seen for yourself, the two layups you did, well are bad. Before we begin there are two things that must be remembered. No matter how thin a piece of wood is it’s always on the move and has memory.
So let’s look at your post, you said that the veneer was wavy so you mixed up a homemade brew of softener, which is fine. Next you applied the mix and removed the excess before putting the paper on both sides of the veneer (next time don’t use news print the ink will show up on the veneer) then put it under pressure. Ok. You waited 5 hrs, made your first and only paper change and mentioned the veneer was still damp.
Here is where you went wrong; the veneer needs to be completely dry. Depending on the time of year it will vary how many times you need to keep changing the paper, but only once it’s dry can you safely proceed.
As things stand it will take couple of days for the effects to start to show up, but they will, the seams will start to open up, cracking and warping. Sorry this project didn’t work out but remember veneering is a learning process like anything else.
Fortunately there are many great resources that can prevent most mistakes. I recommend sticking to books and videos; you can also look online but be careful, just because someone said it doesn’t’ mean it’s true.
Tom