Diablo-RCU

My Feedback: (1)

I've put together firewalls with Probond Polyurethane Glue - no issues at all. It can be messy, but bond strength has never been a problem.

budgetdude

My Feedback: (6)

I just did some bending and flexing on my cap. It defintely feel like the stab is going to give before the joint does.

Panzlflyer

My Feedback: (15)

Bond Strength ASTM D-905
(On Hard Maple)
Temperature Strength psi % Wood Failure
Room Temperature 3,500+ 60
150°F. Overnight 3,000+ 50

This was for Titebond Ultimate or Polyurethane at titebond.com, cannot fing anything on Gorilla Glue

Panzlflyer

My Feedback: (15)

Bond Strength ASTM D-905
(On Hard Maple)
Temperature Strength psi % Wood Failure
Room Temperature 3,750 72
150°F. Overnight 1,750 6

This was for Titebond II Wood glue.

subarubrat

My Feedback: (1)

This is very odd. Allot of people here have used GG and similar and this is the first negative thing I recall reading. I have used it allot in the build of a Dynaflite Decathlon and a vintage ducted fan plane I am building now and none of the joints seem to be suspect. I will give them all a close inspection but thus far they seem to be rock hard and deep bonded.

jsm77777

My Feedback: (4)

I have never had an issue with Gorilla glue, or Pro-Bond. Have used it for all my foam sheeting, and even on firewalls. I flew a 40% Laser with Gorilla glue all over for 3 years and over 1200 flights. Solt it, and as far as I know it's still going strong. I have no problems on continuing using it in my airframes. Scott

pcsol

My Feedback: (2)

GG glue has a somewhat limited sheer strength by nature of its design. With that said its compression and expansion properties are tremendous.
If you were to glue a couple of four inch squares together per instruction, then try to pull them directly apart you would destroy the wood before the joint would break. However if you twisted the joint, it would be quite a bit easier to get the joint to fail (with a very loud POP sound !). For gluing irregular, porous, compression and expansion type joints this stuff is the greatest. Or if expansion of the adhesive is a requirement or of benefit than GG IMO is the way to go.
If there is any question as to whether or not the joint will be placed under a sheer (side) load , it would be best to use a traditional aliphatic or epoxy.
a little off topic:
Has anyone tried the Gorilla tape ? That stuff is INSANE!! (haven’t found a modeling use yet, but is great to have around the shop if for nothing else but to amaze people)

Panzlflyer

My Feedback: (15)

To put my mind at rest I glued 2 pieces of Ply with GGlue and left them overnite. The only way to seperate them destroys the ply and in fact its the ply laminate that is the weakest point.
IMO epoxy is still better for Firewalls and landing gear

subarubrat

My Feedback: (1)

I checked the joints and all was well. Balsa and ply would definatly break before the glue joint.

Randy M.

My Feedback: (38)

You guys ever use BVM Aeropoxy? Or Hysol? It's unbelievably strong. I went over alot of the joints in my 46% ultimate. Most of the jets guys use it. It's a twin cartrige used in a special gun with a mixing nozell. Kinda pricey, but I think it's worth it.

ben beyer

My Feedback: (23)

I used Gorilla Glue to fill in and secure a gap in a playwood mounting plate once on an US 40. I haven't had problems, but it may not be seeing as much stress as I thought it might. Either way, I took everything out of it and put it in a Funtana 40.

Lowlevlflyer

My Feedback: (3)

It always amazes me that when one or two people have a failure with a product, everyone is immediately scared to use it. I have two aircraft that have the wings joined with Gorilla Glue. They get wrung out pretty hard every time they are in the air. They both have over 100 flights on them, and there is not one hint of a glue joint failure on either one. I just made up four sets of two mixing sticks glued together with GG and clamped. Two sets are made up with a bottle I have had for about 6 months, the other two are out of a brand new bottle. I will let them set overnight and check them in the morning.

budgetdude

My Feedback: (6)

I just hit 30 flights on plane built entirely of this stuff (ARF). I stress it out and I dont think its going anywhere. I was worried at first but Its fine, although if it burns in I will be back on here to blame the glue. Does Gorrilla glue even know we use it for this, you never see them advertise in the mags!!

subarubrat

My Feedback: (1)

I wouldn't be surprised if Horizon bought it in bulk and sold it at hobby shops for 2x the price.

Lowlevlflyer

My Feedback: (3)

Why not... companies do the exact same thing with Epoxy and CA! Neither one was ever purpose-designed for the model aircraft industry.

Tired Old Man

My Feedback: (1)

Andyt,

Thanks for doing the leg work for the numbers. And to you others that have helped to ease a lot of minds.

Panzlflyer

My Feedback: (15)

No problem, self serving really as I have a Ultimate wing joined with the stuff.

I did see that at higher temps the Probond types ratings go way down compared with normal roon temp.

stuk_at_work

My Feedback: (111)

CG also works really well for gluing foam, and in particular blue foam together. Just be sure when gluing blue foam to remove the outer plastic skin from the foam wherever you want a glue joint to be (or it won't be for very long).

Ratt Belly

Has anyone had any Epoxy joints fail? I haven't read, in this thread, about epoxy joints failing, and if that is the case why chance it with GG?

Maudib

My Feedback: (51)

GG doesn't fail anymore than getting expoy mixed wrong. It's an alternative with it's own benefits.

1) It foams filling crevises and permeates foam and wood
2) Water cleanup
3) No mixing
4) Stong as all get out... stronger than epoxy... well we'll never know because whatever it's normally used to glue will fail before the glue does.
5) Lighter

Just because one guy did a test and it it "failed" doesn't mean we should get our panties in a bunch and run around saying the sky is falling...

Knowing the properties of poly glue, I'd say his test was tainted... old glue, too much water, etc.

There is simply nothing wrong with poly glue... it IS best used in applications where clamps or weights can be used, or in insertion applications like a hinge in a hole... the foaming action is strong (what makes it rock) and can even push surfaces apart... coupled with some other problem like past-dated glue etc... could cause them to be peeled apart... the glue was not set, that was plain to see. What caused it I don't know... but I've seen old GG take a lot longer to set up...

Ratt Belly

Fair enough.

But please, never ever use Gorilla Glue or any other Poly U adhesive to bond two or more tongue depressors or popsickle sticks together. It has failed in the past and the results have been demonstrated to have been catastrophic.

Maudib

My Feedback: (51)

ROTFL...

I'll have to remember that... and acually perhaps that was the problem... them sticks are sometimes very smooth, hard and resin filled (pine I think)

GG is designed for more porous amterials... balsa, liteply, aircraft ply, etc...

I guess that 40% design idea made of entirely popsicle sticks is out the window now... my osn will be SO disappointed.

ZoomZoom-RCU

[8D]Interesting thread. I've stayed away from GG, but I do use Pro bond poly often, and it is awesome, I have never had any issues with it. In fact, I have a large ply spar in an 80" foam wing bonded in with the stuff, and nothing short of a blow torch is gonna move that guy! From what I've seen in the photos, it looks as though GG doesn't foam as much as pro bond does though. Anyway. my two bits.

ZZ.

bonedaddy41

My Feedback: (2)

I am impressed. I honestly expected people to "attack" and "flame" my post. A few people have gotten close because they don't want to believe the results that I found in my little test. Maybe a little more detail is needed. In my professional life - I design cross platform business systems in the IT industry (computer nerd) ... and have done so for 25+ years. One thing that is stressed in that industry is test test test ... and then verify your tests. As far as hobby experience, 30+ years RC air, land and sea ... and I have been known to do a little woodworking around the house This little stir stick test was done .... 6 times .... with 3 different bottles of GG ... purchased from 3 different stores (Lowes, Ace and Home Depot) ... each store in a different town (Denton, Lake Dallas and Lewisville). Each test "failed" in the same manner. The first test cured for about a week. The others for 2-3 days. The picture I posted was the ONLY one that included a stick breaking. In the other tests, I was able to seperate the sticks without breaking a stick ... but I knew how to do it by then ... a slow twist and bend at the same time will do it every time ... kind of like the stress on a wing joint

It is important to set your feelings aside and look at the results closely. If you will load that first picture I posted and look very close .... GG bonded to the sticks completely. Both sticks have a good even coat that covers the entire bonding area. It was the glue itself that seperated. Listen to that closely. The glue itself seperated. It did not fail in the bonding area with the wood. It penetrated the wood just fine. I was able to pull the glue itself apart. If you will look at the picture that andyt posted, he experienced the same thing in one area of his test with ply. I will repeat what I said in the first post. I did the same test using epoxy and could not seperate the sticks even by using a knife or screwdriver. GG stronger than epoxy? I'm afraid not. Not by a long shot. Do your own test. Put equal amounts of GG and 30 minute epoxy on a piece of scrap and let them cure ... then poke them with your fingernail and see which it stronger. That is a simple test that anybody can do.

How can this be? Simple. Gorilla Glue cures into a porous structure. Any porous structure has a lower sheer strength that the same non-porous material.

The bottom line: I had read on RCU that people were using GG to build entire planes (join wings, install firewalls, everything). I used GG to repair a split in a balsa block on my 27% biplane and have seen no problems. However, joining a wing or installing a firewall is a bit more critical than a balsa block used for contour. In any application of any glue, the whole point is to create a structure that is stronger ... or at least as strong ... as the surrounding material. That is fairly easy with balsa. Pine and poplar ply should be fine. But on any hardwood block or ply (birch, maple, etc) go with epoxy. If you are joining wings that have balsa root ribs I am sure GG will do fine becaus ethe balsa will be the weak point anyway. If those root ribs are ply, I would recommend something a bit stronger. I would go with a glue that is as strong or stronger than the wood you are joining. I am not a safety cop ... and I enjoy watching crashes just as much as anybody else but I would prefer to put one in when I want to ... and I would prefer it to be an old beater and not my $2500 30% Yak. Make your own choices but make those choices based on facts.

Panzlflyer

My Feedback: (15)

I think youre right, use the RIGHT glue for the application and materials. Each has its advantages and disadvantages.


One thing to note is that my test was overnite and I didnt spread it out just S shaped it on from the bottle.