For years I’ve been making radius cabinets with hardwood veneers. We set up a cold press system of positive and negative forms that seems to work fine. So far, so good – no problems.
We were hired to do some mahogany veneer work on some 10′ tall radius walls in a study and so we didn’t have the option of clamping the veneer to the substrate.
I am not happy with the results.
Has anyone else had the opportunity to do something like this? If so, what method did you use?
Thanks,
Ed.
Replies
This sounds like a vacuum bagging job to me.
Keep in mind that the form does not have to be in the bag for everything. I almost never bag anything that has the form in the bag, because the form only has to be strong enough to support the weight of the parts and resist their bending force if it is outside, while if it is inside, it needs to be able to support a ton PSF if it is inside.
It would be helpful if you would give more than one dimension of this three dimension object. Remember we don't have the plans in front of us like you do. The more you can share the less I have to guess at what you are wanting to know.
Like are there studs behind this that it is attached to, or is this the end of a carcass? how thick, and what were you planning on using for substrate? What kinds of adhesive are you using now etc.?
Is you veneer raw single ply, or paper-back, or three ply?
Rootburl,
It's the walls to the room. Already framed and drywalled. We covered the radius sections with bending luan to give us a wood substrate.
Here's a floor plan I made in MS paint. We used a spray adhesive and paper back veneer. The substrate was smooth, but now that the veneer is on, I'm getting all kinds of bumps telegraphing through - not air pockets, but solid bumps. It's the strangest thing I've ever seen. The layers of substrate plywood were glued and stapled to the drywall very securely.
I'm not sure it can be repaired - it will probably have to be replaced. I'm interested in a better method if anybody has one, and I'm open to ANY ideas.
Thanks,
Ed.
The lumps are probably in the glue. some of that paper back veneer is so thin, that it will show the glue pattern. You need to either learn to vacuum bag, or find someone who can make you a three ply face that you can use spray contact with. It would be stiff enough not to show every irregularity under it.
You should go to http://www.vacuumpress.com or find an article to learn how. I am trying to get the finish on a piece tonight, and can't give all of the details now.
Root,
I'm afraid that those vacuum machines are a bit out of my league and pocket book. I was considering one of those bag setups with a little vacuum motor. You can still get large bags for large projects.
We sis use spray adhesive, so I'm not sure it was an accumulation of glue although that makes sense. I didn't do the spraying personally, so I can't be sure.
I didn't get pictures today - we had an ice and snow storm all day. Yesterday it was 70° and sunny. That's Texas for you. But I will get by there tomorrow.
Ed.
If your air compressor has a screw-on intake filter, and uses oil in the crank-case, all you have to do is open the tank, and hook a hose to the intake, you have a vacuum pump.
A little sheet vinyl and carpet tape will make a cheap bag.
A whole new world of possibilities are open to you, but only if you open your mind first.
I've got an old Emglo that might be perfect as a dedicated vacuum pump. Excellent idea. Thanks.
Ed.
Well all right. So are you going to give it a try?
If you are willing, I can give you some tips to help you get started, but I don't have time to spend if you are not open to giving it a try.
Just so you can know what to expect, here are some stats.
You will be using the weight of the air over your shop in big D all of the way up to the vacuum of outer space as your clamp. If that emglo pump is capable of drawing say 28" of Hg. You will get 1 pound of pressure on the outside of the bag for each 2" of mercury that your pump will draw, so 28'' Hg will give you 14 # per psi X 144" per sq. ft. =2016 # per sq. ft.
If the part that you posted in your photo was 1,5' wide by 7' long that is equal to 10,5 sq. ft. X 2016# you would have had 21,168 lbs of perfectly even pressure clamping your parts together, and your form sides could have been made out of 1/4" mdf with only about half of the ribs that you used, and you only needed the male part to do the same thing.
Still using your photo as an example. Each of those pipe clamps is good for about 800 # X 8 clamps = 6400# but most of that pressure would have been focused or concentrated along the form edges, and some along the ribs, and almost nothing in between.
Let me know if you are going to give it a try, otherwise I will stop here. Keith
Keith,
Thanks for the info. I'm sure I will give it a try on the next project. As this is a business, I have to wait for the next radius order. However, I may try a test or two before committing myself to a paying job. What mil is sheet vinyl?
Here is the problem I have at hand. Do you know how to solve it without just replacing the veneer with factory plywood? These panels are flat. The radius ones seem fine. Why the carpenter I was using decided to veneer the flats when 1/4" Honduran is readily available is beyond me.
Thanks, Ed.
I apologize for the large size files, I still don't know how to size them down.
Ed,What glue did you use? Have you tried "ironing" the veneer flat with a warm iron or heat followed by a veneer "hammer?"Rich
Edited 12/26/2004 10:30 pm ET by Rich14
Resized for you.Scott C. Frankland
Scott's WOODWORKING Website"He who has the most tools may not win the race of life but he will sure make his wife look like a good catch when she goes to move on."
If this works, they've been re-sized to 10% of your original files.
Leon Jester
How'd you guys re-size those pictures?
Rich,
We used the spray can kind of glue (sta-put), and heat was going to be my first try at a repair. How should I do this? Keep a cloth between the iron and the bubble? How hot does it have to get? When we use iron-on edge tape we just turn the iron up as hot as it will go. Do I have to use a veneer hammer or will a laminate roller work? I have access to a veneer hammer, but was curious if a roller would work.
Ed.
Ed,Heat softens most glues. I would experiment on some scrap veneer/substrate, using the same glue. If heat softens it, you probably are going to succeed in correcting the problem. It may be a lot of effort, but that should be all that's between you and flat veneer. You will have to experiment with various methods of heating and temperature. An ordinary iron may work, a hair dryer may work, or you may need an industrial-strength blower. Be careful with those, they can heat metal up to soldering temperature!A veneer hammer exerts far more pressure than a roller can ever do, as all the force is concentrated in the narrow line of contact. If the glue gets very soft, very easily, then a roller may do the job. Get one that has 2 handles, one for each hand. But I think you will have better results with the hammer. It's going to be a lot of work to hold the handle with one hand and the back of the head with the other in order to exert pressure on that vertical surface. Most veneering with a hammer is done so that you can lean down on the hammer, letting body weight do the work as you drag the hammer over the veneer surface.Rich
I'm sure you guys have a good idea, but it looks to me like this stuff already has a finish on it. Do you have any tips for keeping the finish from getting soft and ruined while trying to soften the glue under the veneer.
There's no way to know for sure the effects of heat until Ed tests on some scraps.Rich
Well............
No go. The heat didn't seem to help re-activate the spray-on glue, but it sure did take the finish off.
So it looks like it's remove and replace. Good thing the house isn't finished yet and I've been nice to the painter.
Thanks to everyone.
Ed.
Ed,That's a tough one. Good luck with the re-do.Rich
Ed:
I copied them into Photoshop 6.0, then sized to 10% of the original dimension, saved to my file, reposted them as a attachment.
If you have Photoshop, bring the image up, click on "Image"on the top toolbar, then click "Image size" in the drop-down.
This will bring up a window that lets you re-size either up or down, go to the "document size" part of the window, delete one size and enter the new size. You only have to change one dimension, the other will be automatically resized if the "constrain proportions" box is checked, click "OK" and then save the image to your file again.
You may also alter the resolution to decrease file size, 72 pixels/inch is pretty standard for internet use.
Good luck.Leon Jester
so we didn't have the option of clamping the veneer to the substrate.
Does this mean you are having to laminate the venner to the existing wall or can you apply the veneer to a bendable substrate and then attach it to the wall?
There are products called wiggle wood(3/8" bending luan) or other products that are kerfed on the back and you laminate the veneer to the face, and an English product that I can't remember. You can also buy real wall paper that has a wood veneer face. Another is to make a template of the curved wall and vacuum press a curved panel with 1/8" bending poplar and then apply the veneer to it in the vacuum press.
A little more explaination might help
Migraine,
How do I get the bending luan or bending poplar (what is that?) to hold it's shape? Will it hold it's own after coming out of the vacuum press without a form behind it? Just a curved panel to match the radius that I can attach to the wall?
The upper panel is about 4' x 7'. I don't seem to be having the same problem on the smaller panels below the chair rail.
I'll get pictures tomorrow.
Ed.
When I used to do alot of pressing, we would make a one sided mold of the the wall(or cabinet) and glue 6 sheets of bending poplar which is 1/8" thick 3-ply made of poplar. The sheets come in 4'x8' or 8'x4', depending on the way you want to bend it. We used a 2 part urea glue(as in plastic resin) and when the part had cured, we would size the panel and then veneer during a second press. When you are done pressing 6 sheets together, you then have a rigid panel with the builtin curve.
The 3/8" wiggle wood is made from 2 thick exterior layers of luan(a type of Phillipean mahogany) and one thin cross band of luan. This bends/flexes easily. You can veneer right to the sheet and then attach it to the wall with panel adhesive and nails/screws
One of the biggest complaints about glue bubbles is that you need to apply a caul over the face of the veneer to help create an even pressure on the veneer. Basically is squeezes the uneven glue thickness to a more unifrom glue thickness. With out the caul, the vacuum bag will contour aroung the inconsistant glue thickness.
Try contacting Anderson International Trading in Anaheim, Ca. http://www.aitwood.com They sell all the above products.
Migraine,
Thanks for the link. Great supplier.
That's bad news about the vacuum bags and glue bumps. I assumed that the pressure would even out the glue.
I've had great success with the plastic resin glue as well - in a clamping application. But it wasn't an option on a vertical wall. Next time, I'll make the form and bend the ply.
I've been hesitant to veneer the lucan bending ply flat and then creating the radius. I just figured it would crack or distort the veneer when you bent it to a tight radius. I haven't used the 1/8 bending birch or poplar. We can buy 1/8 birch here locally in Dallas, but it's not referred to a "bending birch" like they refer to on the web site. I'm not sure if it's the same thing. I do use it for radius work over 3' or so, but I use the luan as the core and clamp it all up at the same time with plastic resin glue in a positive and negative form. I put in some pictures of our method, but they're BIG! Sorry. I had no idea they would come out so big, and I couldn't figure out how to delete them without deleting the intire post and starting over.
I guess this vertical wall application should have been made up in the shop and then nailed to the wall.
Next time for sure.
Ed.
The bending birch that Anderson Int. sells is a 2 ply material. A thicker, pliable luan on the back and a birch veneer on the face.
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