fzeller

What kind of glue do you use to glue large areas of foam.? Someone told me he used sumo glue, I have never heard of it and I can't find any around here. Thanks in advance for your help. Fred

Sir Raleigh

Sumo Glue is by Loctite and is similar to Gorilla Glue. They are both similar in the way they cure and foaming is a product of this curing. Sumo Glue foams about 1/4 less than Gorilla Glue and cures white, while Gorilla Glue foams more and cures yellow (although Gorilla has come out with a white curing glue.) Also, this type of glue does not cure rigid like Epoxy and Super Glue but remains slightly flexible. These glues also allow about 10 minutes to get the parts aligned before the real curing begins.

I keep 3 types of glue in my 'first aid kit'. They are: Sumo Glue, 5 minute Epoxy, and foam safe CA (Super Glue). I don't use hot glue on airplanes due to its additional weight.

jdetray

Sumo Glue and Gorilla Glue are both polyurethane-based glues. I just discovered that Gorilla Glue is now available in a faster-curing white formula, too, in addition to the yellow version.

- Jeff

Time Pilot

How large is large?

I'm a big fan of GWS glue for gluing pieces of foam together. I let it dry until tacky, like contact cement is supposed to be used, and then press the pieces together.

Sir Raleigh

If there is a large surface to glue together, Elmer's White Glue (not the School Glue) works great. Takes a while to set, though, but you have plenty of time to get things aligned properly.

Hatty

Basically any glue will work for a part with a large surface area. I would use Elmers like recommended above. Its cheap and pretty light. When you try to glue parts without a lot of surface area, thats when you run into problems and need stronger glues like epoxy or those that penetrate like the polyurethane glues and thin CA.

Just to remind you, if the foam has a covering on it (like most foam planes come with) you need to try to get that off and glue foam to foam and not covering to covering. That joint will be much weaker.

PilotSmith

My Feedback: (1)

I've recently discovery the Loctite Sumo glue. It is inexpensive and very strong. I believe it is better on foam (BluCore / Depron) than CA or epoxy. It is lighter and absorbs shock much better. It does foam up some so you have to use it right so it doesn't foam out all over the place. On bulkheads I actually put on a little more than needed and when it foams out the sides it creates an even stronger structure as it makes a reinforcement on both sides of the bulkhead. Sets up in a few minutes but takes a few hours to reach full strength. You have plenty of time to properly position pieces. I think I got a bottle at Lowe's Hardware store. (If not Lowe's it was Home Depot but pretty sure it was Lowe's.) Best glue for foam I have found so far. Unlike CA you can also trim it with a razor and sand it. Very similar to Gorilla glue but dries faster and does not foam as crazy like Gorilla glue. I've often seen on a hard landing or crash where the joint glued with CA fails. This stuff on a foamy airplane will not come apart at the seams as the seams will be stronger than the rest of the structure!

Wing on my airplane smacked a power line yesterday and my Sumo glued airplane held up pretty well. Despite the cable cutting through the depron up to the CF rod in the wing, none of the Sumo joints failed.

The photo shows a bulkhead where I intentionally did not clean off excess glue and let it expand around the joint. But you can make very clean joints with no glue showing if you put the right amount down and wipe the excess off a couple minutes after it sets.

pfatz

I have just received a G-flex (2 part) Epoxy kit by West Systems. It is in-expensive @ $16.20 for 8 oz. It is very interesting.

It says it will will glue, wet or oily & hard to glue Woods. Aluminum, Fiberglass, ABS, Masonary, Metals, Plastics, PVC, Polystyrene, Polycarbonate, Polyethylene. I wonder if this covers Depron & Epron? I think that I read somewhere that it will work with StyroFoam & Polyurethane foams. I will check that out if I can.

The kicker appears to be 45 min. working time, 7-10 hours initial cure/24 hours total cure. Slow but strong. 150,000psi modulus of elasticity (whatever that is). Sounds like a heck of a glue if you can hold the project until it sets up.

It states it is formulated to: Absorb the stresses of expansion, contraction, shock and vibration & to be a bit more flexible than other standard Epoxies and Polyester glues. Ideal for bonding dissimilar materials.

I think I will find a use for it. There is a lot more to it than this but this will give some idea of its attributes.