I am ready to laminate 4 pieces of Ash- 3/16 x4x68. Wanting a recommendation on what type of glue to use. I know that polyurathane has a long open time, but I might be covered from head to toe with foam before I was finished. I will have some help so that will speed up things a little. Also, should I start from the middle and work out both ways with the clamps, or should I start on one end and work toward the other end?Open to all input—WW57
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Depends a little what the object will be, and whether its interior or exterior. For interior, I would just use regular Elmer's carpenter's glue, applied with a shortnap roller to both faces to be glued. Most times it would be best to start clamping in the middle, but there might be reason to start at one end, if you had to align something like grain pattern or a boring for example. I've found that with the carpenter's glue, there is often a little springback after unclamping, so I slightly overbend, but guessing how much is an artform, based on wood species, laminate thickness, and intended radius, plus having blown it a few times. I believe I read on an old thread that someone recommended a glue that eliminated springback, perhaps they will chime in with that information. For exterior use, I would use slow set West Epoxy, or Tightbond III. Definetly practice your clamping process dry, and it might not hurt to leave your stock clamped up dry overnight, to pre-set a little bend in the wood. That will make the glue harder to apply, but the bending will be easier.
Edited 10/6/2008 11:24 pm ET by thumbnailed
Baby bed headboard ,obviously interior. Thanks for the quick response. WW57
Also, I am assuming that you apply glue to both of the boards that are mating ?
Speaking of the BED, it is past my bedtime---Will check back tomorrow--Thanks again--WW57
The group wisdom seems to be to use plastic resin glue, and I have no problem with that, but, other than springback , I haven't had any creep problems myself. Besides, unless your lamination is free floating, any crossrail you have will eliminate any spreading. And, yes, glue both sides, to make sure glue is fully worked into the grain on both sides.
Edited 10/7/2008 4:06 pm ET by thumbnailed
OOps, I just read the answer to my question, as one of the respondents refered to this product as a powder.
>> other than springback , I haven't had any creep problems myselfSpringback is caused by creep. No creep, no springback.Howie.........
I always understood creep to be long term slipping of the glueline, leading to shape change over extended time, hence the word "creep", implying slow movement. Springback usually seems to be the result of the straightening force of the wood laminated, lessened by glue stiffness and laminate thinness. Thats how I've always understood the usage. Otherwise there would be no need for two words. Anybody else want to get in here on definitions ?
Spring back, other than the small amount experienced just after removing from the form, is a result of the adhesive allowing the glued up sections to slowly slip past each other. This is what is referred to as "creep" when discussing adhesive. It's function of what is technically known as the shear strength of the adhesive. PVA adhesives are not full "hard" when cured. They are always a little flexible and are known as "creepers". Other adhesives that have high shear strength also are very hard--and almost brittle--when cured.A formed laminate glue up made with a high shear strength adhesive will have negligible movement back toward straightness over time where as the same glue up made with a PVA adhesive will have a tendency to straighten out. Of course, the engineering of the laminate can have an affect on the amount of spring back. The more and thinner laminates, the greater tendency of the glue up to stay in a curve.Howie.........
It still seems to me that the concept of creep and springback come from diametrically opposed time frames, slow and fast. Whatever, usage is more important than word origins, so I'll accept majority rule. Still, I laminated a chair back hoop with Elmers, left it lying around the shop fo a couple of weeks while making other parts of the chair, and the hoop was within a few sixteenths of its original spread when I went to assemble the chair back. My point would be, sure the resin glues would be a better technical glue for a curved lamination, but the white glue was entirely good enough for the job.
I think that springback is due to the inherent elasticity in the wood and glue layer and occurs immediately the tension is removed. Creep on the other hand occurs over a period of time as the glue layer, or layers, very slowly release tension and the wood layers move slightly relative to each other.
Howie,First of all, I appreciate your contributions over time to this column. They are always interesting and helpful.On the subject of laminations, I do differ with you on definitions. Springback is the slight relaxing of the glued lamination after the glue is set and the lamination removed from the form. There will always be some springback with a bent lamination, even with a perfect glue, and the springback amount is a function of the number of laminates only. So, springback can be reduced by using a higher number of thinner laminates in order to achieve a given thickness.Creep is the strain in the glue layer over time, when the glue layer is under stress. So, in a bent lamination that is not constrained, the bending stresses create a shear stress on the glue layer. If the glue layer doesn't resist shear stress, the lamination will slowly straighten over time. The rate is a function of the stress level and the glue properties.To other posters, both urea resin and polyurethane glues are good choices. I have used gorilla glue with success, and I reduced the amount of foaming to a tolerable level by controlling the amount of glue applied. I spread the glue and then removed most of it with a spatula.Best regards, Tom.
I guess that it depends on your definition of "long-term". I use the term creep to describe pieces of wood moving from their original position after the glue has been applied but before it cures.
I have always used the term spring back to describe what happens to a laminated piece after it is initially removed from the bending form.
See my response to "thumbnailed".Howie.........
I will offer my personal experience about spring-back and no-spring-back:I was laminating a 60" diameter semi-circle (arch). I cut my lams at 3/16 and needed 7. It worked with the "dry" clamp-up BUT - as in almost all glue-ups. things did not go as planned. I was using Gorilla Glue (polyurethane) because "it does not creep".What a mess! It was a Chinese Fire Drill. With all the mess I couldn't get all 7 clamped to the form, so I did 4. After an overnight cure, I removed the clamps and had a 2' to 3" spring-back. (I'll just change my design dimensions I thought.)The next day I added the remaining 3 lams and bent the whole arch around the form. After a 24 hour cure, I removed the clamps and I had NO spring-back. The 3" spread was gone!A few months later I attended a Michael Fortune seminar at a Woodworking Show. He explained that more lams means no (or less) spring-back) Since that time I've used PVA for laminations with no problems - just plenty of laminations.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
Frost!
I have made more than a few Archery bows using Gorilla glue! I guess we love spring back?
Yes, they are not that wide. AS in 'before' whittling.. To final form. I do not use it for everything but it works great! I have found that alternating wood species helps. I use thin strips of alternating Ash and Hickory.
Never had a complait from one of my bows! But I do not sell to experts!
You're a brave man. I don't think I would try laminating a bow - Gorilla glue on a Grizzly bow sounds neat. (Is Fred Bear still living?)Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
Died in 1988
http://www.fredbear-online.com/quotes.html
Strongest pull I make is 50 pounds. Because... I can't pull one larger! No way to test it. My boys are just for fun.. Nothing professional but they shoot OK...
Someday I'll make a 'self' bow if I find the right hunk of Orange Osage.
Thanks for the answer. I used to drive by his factory in Grayling.I had a 50# Grizzly bow. Stringing it was a tricky task.The first time I tried a "compound bow", I thought I had broken it when I pulled back.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
I don't knooow. I love Elmer's carpenter's glue but I would investigate the term "glue creep".
See Lon Schleining's article and then decide. Please.
http://www.taunton.com/finewoodworking/FWNPDF/011164054.pdf
Edited 10/7/2008 12:49 pm by roc
From my experience with I offer the following:
You are right about the Poly; you will have foam EVERYWHERE!
If it is not too late, use more and thinner lams. Spring back is a function of the # of lams.
I have Zero spring back if I go up to 5 or 7.
Check Michael Fortune's FWW article on laminating. He starts from the end.
Frosty
"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
Are you going to be creating a curved type lamination? If so, using a yellow PVA adhesive is not the best choice. PVA adhesive has relative weak shear strength meaning the plies will slip by each other over time and the curve will become less. However, if you have some type of construction that supports the curve independent of the laminate itself, PVA is OK. For an unsupported curve, use a urea formaldehyde adhesive like DAP/Weldwood Plastic Resin. This type of adhesive has high shear strength and the curve will be maintained.
I second the vote for plastic resin glue.
Depending on the size, and if you plan on doing more, you can buy a small tub of "veneering" plastic resin powder at Woodcraft. Otherwise search for a large tub.
One of the benefits of plastic resin glue, other than the strength and lessened springback, is the long open time. after you mix it up, you will have a good 1/2 hour+ to get everything set; plenty of time to do multiple plies and get them clamped up.
One thing to be careful of, when it has cured overnight (give it a good 24 hours), the dried squeeze out will be extremely hard and SHARP! Make sure your pieces have enough extra to cut off on both sides. I would not want to have to scrape this stuff off.
Good luck.
Is this stuff a liquid or a powder?
Plastic resin glue for laminations.
Beat it to fit / Paint it to match
Another recommendation for Plastic Resin glue. However, if you don't plan to use it very ofter, buy the smallest container you can. It has about a 1-year shelf life. Beyond that, it gets a progressively harder to mix.
I agree with the plastic resin (pre-catalyzed urea formaldehyde) recommendations. Along with the other cautions (I have cut myself many times with dried glue!), wear a dust mask while mixing because it is a carcinogen. Such a shame because I really like the smell.
Check out the new G-Flex from West System. All the advantages of traditional epoxy with long open time.
http://www.gougeonbrothers.com/G-flex/
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