Gluing wood to steel? Anyone tried this?

[cracker39]

Has anyone used gorilla glue to stick wood to steel? Does one dampen the wood and put the glue on the steel, then clamp them together?

I have an angled spar that I want to stick to the front and back cross rails of my chassis, then use it for attaching the front/back skin as well as anchoring the front edge of the floor to it. The body will be attached by glue and screws to the floor, which will be bolted to the chassis, so there won't be much structural stress on this angled spar. It looks much like the spar used by Dee Bee in the Zeyphy, as the front of it is similar to the front of my TTT.

I had planned on using the best construction adhesive I could buy, but if gorilla glue is better, I'll get some. Any ideas on which would work best?

[gman]

Try this stuff, http://www.coolchem.com/ code is MA7, saw it on StreetRodder from the SEMA show, they glued rubber to glass, glass to wood, leather to glass, wood, you name it.
_________________

[Chuck Craven]

Yes! Tried it with all kinds of glue! Always came apart for me.
Something about steel and wood have opposite explanation coefficients. Wisconsin temperature swings from +109F to
–29F and 100% to 15% humidity and somewhere in there it always failed, even when I sealed the wood. But there may be glue that may work! Not Gorilla Glue! I have encapsulated steel into wood with Gorilla Glue as long as it didn’t come in contact with the steel.
Wood on wood floated steel with in it, coated with epoxy worked super for outdoor use. Make sure the steel is protected from rust!
Chuck

[cracker39]

At least, in my application, the wood doesn't have to be stuck to the steel all that well. All of the wood parts will be glued together and reinforced with screws. Once they are joined, the wood spar can't pull away from the steel anyway. The wood spar really doesn't need gluing to the steel, but only needs a sealer between it and the steel frame to keep water out. I guess I'll use some construction adhesive which should waterproof the joined area. I'll probably put a coat of the fibered roof coating on the underside of the spar and frame cross member as well. All of the steel will be first protected with two coats of Rustbullet.

[madjack]

Dale , we used Al angle for all our cleats in the A Tears and screwed and Gorilla glued 'em...we roughed up the AL, applied the glue and moistened the wood...it has worked wonderful well...with the steel, I don't know but something like the sika adhesives would probably work well, they are available from Austin Hdw and other places
madjack

[cracker39]

Thanks for the replies and suggestions. Given what I have to work with, and that the wood spar will be attached to both the plywood sides and the floor, I'll just check with the local box stores to see what would work best just as a sealer between the spar and the steel cross member. I have the same situation with my plywood sides. They will extend down the outside of the side rails of the chassis. I had planned on using construction adhesive here too, mainly as a seal against moisture and whatever additional holding power it would provide.

The key to the body/floor attachment are the two 3/4" x 1" strips that attach to both the floor and the sides with glue and screws. And, the floor will be held in place by 13 carriage bolts through 7 gussets welded to the three 2" x 2" tubular cross members, and through 6 holes drilled through the two angle iron cross members. This is a view from the front. The angled spar is not shown in this diagram, but would run across in front of the side rail and cross member. I made one error in this diagram. The U-bolt would run up through the floor as well, holding it to the cross member.



This is a side view of the front cross member, the angled spar, the front skin and inside paneling. It shows how I would attach two U-bolts through the angled spar and floor for "insurance".



I'll just go to HD and read the labels on all of the adhesives to see what I can get that will work best.

As an afterthought, I may add some more insurance in the form of two U-bolts in front and two in back, fastening the tongue pieces and the bumper supports to those two spars.

[angib]

I gave a similar reply to another post a week or two ago, so apologies for repeating myself.

I would recommend a polyurethane sealant-adhesive - that maintains a watertight seal under deck fittings like winches on yachts, so anything on a trailer is easy by comparison. Two brand names are Sikaflex 221 and 3M 5200 (which DANL also believes in). Neither is cheap, both are good.

This is quite a flexible product, but do not confuse it with somemthing like a silicone sealant - this stuff really sticks and yuo would risk ply delamination if you tried to remove it.

Andrew

[Ira]

I used some lengths of L-aluminum to decure my AC to the TD, Although I used screws, I also used 2-part epoxy.

Granted, I have no idea how this will hold up stress-wise after a while, but for this small application, it seems solid as a rock.

[cracker39]

Andrew,

That is the sealer that Scot Adohen recommended I use to install the Fandastic fan he sent me. I thank you for providing the brand names, which I didn't have. For some applications, cost is not an issue...effectiveness and quality are. I'm another step closer to the total solution

[Sonetpro]

Dale, Couldn't you just drill a hole through the back of the cross member and screw it to it? You could put sealant between the to for a good seal.

[cracker39]

Dale, Couldn't you just drill a hole through the back of the cross member and screw it to it? You could put sealant between the to for a good seal.

That's the simplest solution...I tend to overengineer these things. Up to now, I've resisted putting any holes in my frame, but I don't think three 1/4" or 5/16" holes in the tubular cross member (one near each end and one in the middle would weaken it, and a 3" long 1/4" carriage bolt would sedure the spar just fine. I hadn't really thought of doing it that way, but It may be the most effective solution. Thanks.

[Chuck Craven]

Craker39 I took it as if you were going to use glue as a fastener.
You are really going to use it as a sealer! Then I think you should go with Andrew’s advice. Gorilla glue / Construction adhesive will not work as a sealer for it gets hard and eventual a bit brittle. As far as drilling small holes in the cross members should not weaken the frame.
Chuck

[cracker39]

Yes, Chuck, I did finally decide to bolt the spar to the end rails, so I just need a sealer, not an adhesive. A poly sealant was recommended (Sikaflex 221 or 3M 5200 ). That's what I will get. Since the floor is bolted to the frame and screwed to those two end spars attached to the end rail, I'll use a construction adhesive between the floor and the frame. I want to have it stuck down to avoid squeaks. The floor will be moisture protected from beneath with roof coating and foil-faced foam insulaton stuck to that. When I run the luan sides down along side the side rails, I'll probably use the poly sealant of gorilla glue between the plywood and the side rails. The end plywood will be glued to those two angled spars with Titebond II. The bottoms and inside face of the angled spars are getting a few coats of varnish now to seal the wood. I'll probably end with a touch up with some of the roof coating on all of the wood with exposed bottom surfaces after I paint the outside skin.

[Ira]

A poly sealant was recommended (Sikaflex 221 or 3M 5200 ).

Watch out for that 3M 5200.

It's unbelievable stuff, but I used it when the weather was warm down here.

And man...

Open up that tube in warm weather, and it starts to thicken up in like 15 minutes, making it really hard to work with. (Depending on your application, of course. I was doing finer work with it, and it wouldn't go where I WANTED it to go.)

So if it starts to stiffen up on you, just recap it, put it back in the house/AC for 20 minutes, and you're good to go again.

Also, DON'T get it on any surfaces you don't WANT it on. You'll never get it off.

[cracker39]

Thanks for that advice. One application is just on a piece 2" x 60", so that won't be a problem. Working with the whole floor might be if it hardens up too fast. It's only supposed to be up to 72 tomorrow, so maybe the working time won't be too short. I plan on getting the floor on the chassis, on pieces of wood, then lift and prop up one side at a time and put down the sealant on the chassis, so I'll probably get it on fast enough. I do need to be able to slide the floor around until I line up the bolt holes before it sticks too hard. I know I'll make a mess doing this by myself.