Adhesive's

[billrcpilot]

I know a lot of builder's use Elmer's Probond wood glue, today i came across Elmer's Probond Polyurethane Ultimate Glue, has anybody used this glue in building sailplanes before and what is your opinon of it. I've used CA glues on all of my sailplanes but what i've read i maybe changing my mind about glues

Thanks
Bill :)

[Iguana]

I have used urethane glue just like that. It soaks into the wood and foams around it. Pretty tough stuff. I think it's the best for wing joiners and big stuff that will take a lot of stress. It will flex more than CA.

[billrcpilot]

I have used urethane glue just like that. It soaks into the wood and foams around it. Pretty tough stuff. I think it's the best for wing joiners and big stuff that will take a lot of stress. It will flex more than CA.
Iguana: thanks for the reply, did you use it in your complete building of your plane or just on the wing joiners.

BIll :confused:

[evan]

Bill, I've been thinking about how this glue will perform if used in building the whole plane. It works great on foam and repairs because it fills voids, and is very tough but the cure takes a long time and you have to apply a very thin layer since it's heavy and quite messy because of the expansion characteristic.

[ferincr]

I've read somewhere in these threads about it.
Someone said that it's good because fills in gaps but you have to be careful with the weight 'cause is quite heavy.
In my experience with woodworking is that if the surfaces do not match this glue wont add any resistance to the gaps but just fill them. So don't count on it's strenght if the surfaces are not in contact. The other downside I'm thinking of is that glue needs the parts to be humid to set, so be careful with warping problems.

[fprintf]

Every glue has its uses. When building my 3M Marauder sailplane last winter I used quite a few of them.

-epoxy for the critical dihedral breaks and joiners
-CA for the fiddly, hard to attach bits or when I was in a hurry to apply fiberglass to a broad area
-polyurethane glue for a few joints

But most of all, on perhaps 95% of the plane I used good old Titebond yellow wood glue. In my crash where my wing fluttered at the bottom of a zoom there was not a single failed glue joint, in each case the wood itself fractured. I think the choice of glue mostly comes down to convenience, price and the working qualities. For me yellow glue worked the best. Polyurethane glue has no advantages that I can see over epoxy on a good fitting wood joint. It is not as fast, the swelling does not enhance the strength of the joint, and it requires humidity (which we do not get a lot of in the winter here).

[billrcpilot]

Every glue has its uses. When building my 3M Marauder sailplane last winter I used quite a few of them.

-epoxy for the critical dihedral breaks and joiners
-CA for the fiddly, hard to attach bits or when I was in a hurry to apply fiberglass to a broad area
-polyurethane glue for a few joints

But most of all, on perhaps 95% of the plane I used good old Titebond yellow wood glue. In my crash where my wing fluttered at the bottom of a zoom there was not a single failed glue joint, in each case the wood itself fractured. I think the choice of glue mostly comes down to convenience, price and the working qualities. For me yellow glue worked the best. Polyurethane glue has no advantages that I can see over epoxy on a good fitting wood joint. It is not as fast, the swelling does not enhance the strength of the joint, and it requires humidity (which we do not get a lot of in the winter here).Very good point, still think i will stay with the old CA and Elmers Probond Wood Glue.

Bill

[schrederman]

This urethane glue is good in certain instances. I used it to build an entire Legionair 100. It worked well, but doesn't like to stick to aluminum too well. It expands and penetrates the wood grain very well, but has to be clamped well or it can push the joints apart. The only place I use it now is attaching the top sheet on built-up wings. It is excellent for that, but be sure to stack the phone books on evenly and leave them all day. The label says 100% solids. That means nothing evaporates, and the weight you add is there to stay. I used a brush to apply it the last time I used it, with good results. That way I was able to use just what I needed and no more. I also wet a paper towel and wiped the tops of the ribs with it before applying the glue. That helps with curing the glue. It's good, but really no better than CA or other wood glue for our purposes. It's great for sheeting foam wings with balsa or obechi.

Enjoy

Jack Womack