# Lamination Bending: Which glue?



## swied (Feb 6, 2008)

I'm trying to come up with a new design idea for building a hollow wooden surfboard, and am looking for some help from the wood bending experts.

I bought a book on wood bending from Rockler, and it stated that Expoxy and Plastic Resin glue were the two top choices for doing lamination bends. Most boat builders would probably suggest exopy, but I am not convinced yet. I don't have any experience in lamination bending, and expoxy is expensive, so her are my fears about using epoxy:

1) I'm going to have to cut the laminated pieces with my bandsaw. Will the epoxy gum up the blade? How long should I let it cure before doing any cutting?

2) I'm going to be using a hand held electric planer to shape the piece after it has been bent and glued. Will the epoxy in the glue joints harm the blade on my tool?

3) How toxic are the fumes and saw dust. I'll wear an organic resperator, but I'm worried about others in the house. My shop is in the garage below the living room.

Plastic Resin glue is much cheaper, so I would like to know if there is any reason why I can't use it instead of epoxy. Here are my fears about using Plastic Resin glue:

1) I have read that when the glue dries it is hard as glass. Does this mean that it won't flex? A surfboard is subjected to constant flexing. Will Plastic Resin glue hold up to this abuse?

2) Same as above-Will the Plastic Resin glue harm my bandsaw or power hand planer?

3) Same as above-How toxic are the fumes and saw dust.

Thanks in advance for your help.


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## Rich_S (Oct 26, 2007)

I don't know anything about surfboards but what I can tell you is that I use "plastic resing glue" which is really urea formaldehyde glue…DAP calls it plastic resin, but what you are after is UF and there are several manufacturers of it…..."plastic resin" is a non-flexible glue which is why I use it for bent laminations…you can sand it, plane it, joint it etc….the same rules for machining apply to it as most other glues in that if you run it through your planer or joiner you do run the risk of chipping your blades…but sometimes that is the price you pay for creativity…the fumes from UF aren't so much the harmful part…the dry material prior to mixing poses more hazards as would the dust from sanding it…I used UF glue to do the bent laminations for the box I entered in the Single 2×4 and Not Just a Box competitions…..UF glue is water resistant but not water proof…there is a big difference…last thing you want is your surfboard delaminating in the water…so you should add a 4) to your list…water proof


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## jcees (Dec 31, 2007)

Epoxy is the way to go for a what I assume will become a torsion box with a laminated skin. I use West Systems epoxy. It comes with handy pumps, each one specific to the hardener or part B. Get more info than you ever dreamed of here… http://www.westsystem.com/ As you'll discover, there are additives and resins and the how-to for just about any contingency here. One filler is called micro balloons and it lightens the mix while not giving up any strength. Something to keep in mind for a surfboard. Check it out.

Also, you should wear the respirator anyway. Some wood species dust are suspected of being carcinogenic, the humble pine among them. Good luck.

always,
J.C.

P.S. The nature of what you're trying to accomplish will be hard on your planer and saw. Go for carbide blades as you'll get the most life out of them and you might want to keep an extra set around too.


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## swied (Feb 6, 2008)

Thanks Rich and J.C.. It sounds like either will work. Epoxy is probably the best solution except for the price. I was many looking to see if using Plastic Resin or UF glue was a viable option for my project. A tub of DAP plastic resin glue costs about $8. The epoxy resin, hardener, and fillers will probably set me back about $75.


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## Islandwoodworker (Mar 24, 2008)

Well, I've done a fair amount of bent wood projects and I'll add one other glue: Polyurethane. I built a bent wood arbor and It worked great. I've built boats (frames) with epoxy and like the flexability. If it won't bend ~ it may break. As for any of them; once cured they are pretty much non toxic but of course dust has inherent hazards ~ even sawdust. Like don't be breathing Port Orford Cedar: causes liver damage and I'm sure there are others.

What I like about the epoxy besides relative flexability is that fits are not so critical. The glue line doesn't have to be too tight (not to say you should do sloppy work). I made some rocking chair rockers for a lady with epoxy; her grandkids like to "ride the rockers" on the back of grandmas's chair and broke them. She had a guy make new ones and they broke those too. The bent lam ones are still going strong. KEEP THE CATALYST OUT OF YOUR EYES ~ same with 5 minute epoxy sold at the grocery store.

I've had some failures with PR or UF which ever you want to call it. It can be a bit touchy.

Ironically airplane construction in Britian uses polyurethane. A bunch of guys realizing it was good stuff started importing it to US. (Gorilla) Now other companies are on the band wagon. I've used the Borden version and been very satisfied with it. Wet one surface and apply it to the other.

As for cost ~ what's your time and materials worth? especially if its a boat …. airplane….


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## schaney (Mar 30, 2008)

I use a fair amount of West Systems epoxy for kayaks and camping trailers, great stuff.

There are two benfits that may help you in your project. The long "open time" allows you plenty of working time, especially when trying to coat multiple pieces and get them in place when doing a laminates. There are different hardners available to adjust "open time" depend on conditions. It's gap filling properties make for strong joints even when the fit is less than ideal.


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