sportflyer-RCU

My Feedback: (35)

Plse advise how to use gorilla glue to repair a cracked foam wing ? I think the gorilla glue is better than epoxy for this application because it will expand and fill the gaps . Can I bend the wing slightly so that the crack in the foam is open a bit ( 1/16 inch) then inject the gorilla glue into the cracked foam wing with a syringe along the crack line ? Should I wet the gap before applying the glue? I have never used gorilla glue before so not sure whether wetting both mating surfaces and then applying the glue between would work . I know the usual method is to apply the glue to one surface then wetting the other . In this particular case it is not possible to do so. Is wetting the surfaces necessary ? Would heating the gorilla glue slightly iomprove the flow characteristics so its easier to inject the glue from the syringe?Thanks

spokman

My Feedback: (2)

I would wet both surfaces then just inject the glue or just push it in with a popsicle stick. Then just wipe off the excess as it foams out. Alchohol and a paper towel works good. You really can't screw this up with this glue. By wet I mean just a cue tip with water on it. If you don't do that it would probably be fine also. Are you in a humid area?

SST

My Feedback: (2)

Water makes the glue 'fizz', thin & expand more than without, and it will cure quicker, but it will work fine without it. Get the Elmer's ultimate glue at Home Depot or wherever you like to go, as it's the same stuff as Gorilla glue at about 1/2 the price. I've been learning about this stuff as I build my 8' SST out of pink foam, and have found that it's easy to waste glue by adding too much. A little bit goes a long way with this stuff. I have 16 ounces into this plane, and could likely have done it with 8...

tucker1865

My Feedback: (6)

Gorilla glue is poly-urethane glue and humidity is the catalyst. It is strong because is does not get brittle. Be carefull this stuff expands a lot. Alcohol is the solvent used for clean up. I close the cap, wrap it in a heavy plastic bag and put rubberbands on the bag. The shelf life is about a year with care but if the humidity gets to it, it's gone in no time. Its about the same consistancy and workability as foam when it dries.

BasinBum

My Feedback: (2)

Also because it expands you want to be able to clamp or weight down whatever you use it on. You don't want the expansion to alter the shape of the piece.

BBW Walt

My Feedback: (11)

Is this wing already sheeted? or is it a core? I have repaired some serious fractures in both and I have come to find that it is best to completely break the fracture and epoxy it back on. This is the only way to get 100% bond. Styro breaks with a very irregular fracture allowing a good glue surface. Alignment dowels can be used also. I have glued horizontal stabs back on using this method that were cracked at the fuse side. It ended up being stronger than the before fractured piece. In my opinion polyurathane glue is not the best way to go in this situation, epoxy!! I would break it loose, completely saturate the break with 30minute epoxy and mate the surfaces back together. If epoxy ozzes from the break its 100%. If the core is not sheeted Do the same but alphetic glue will work fine..This is from my experience which does work..walt

Fletch124

My Feedback: (7)

Ok i don't get it what is the point in wetting the surfaces that your going to glue together? What happens if you don't wet the surfaces? and wetting the surfaces?

BBW Walt

My Feedback: (11)

Gorilla/polyurethane type glues set up from moisture. Its a common practice to apply moisture on the glue surface to speed things up a bit. There is enough humidity in the air to work without doing the wetting thing, it just sets up slower

Shogun

My Feedback: (2)

In my experience with the poly glues it really depends on what you are attempting to achieve that will be the deciding factor when it comes to applying moisture or not.

Poly glues applied without moisture will still cure but not as quickly, they also will not foam up and expand nearly as much so the gap filling properties of the glue are diminished if you don't moisten the area first. OF course there are times when you might not want the glue to foam up on you and fixing foam certainly could fall into this area.

As for the moisture in the air being adequate, well that might hold true for some but bear in mind that if you live in the desert southwest of the US or it's the middle of the winter and sub zero outside, there is very little moisture in the air to begin with.

The quick and dirty of it is that if you have a need for a glue with gap filling properties, wet the joint and get ready with the towels and alcohol to wipe up the ooze. IF you just need to bond something that fits together well forgo the added moisture. Poly takes longer to cure without moisture present so working times can be quite long, often overnight. Adding moisture will change the cure ties dramatically and 45 minutes isn't unusual in my experience, no it isn't rock hard after that length of time but you can't pull the joint apart either.

Sir Fliesalot

My Feedback: (2)

Poly glue has no strength in a gap wider than 1-2mm. If you just want to fill a large gap use poly glue. Just add extra glue and dampen the surfaces and you'll get lots of foaming. It only needs a min. of 8% moisture to cure. That's really dry wood!. If you want to fill a gap AND have strength, use epoxy. Where poly glues excel is end grain glueing because of the penetration of as much as 2" of end grain.

That said, I'm talking from a wood workers point of view. As a modeler, Poly glues does penetrate foam very well and tends to harden it. It's the best for glueing something to foam. If the sheeting is intact and a tight wood to wood bond can be made and the filling is cosmetic only, then the poly glue would be ideal.


Mark