[Kent F]

Use gorilla glue from any hardware store or CT.It will survive any destructive force and not break.Follow directions and let set over night.

[f4u]

Take a straight pin and punch littleholes not too deep. This will help the epoxy hold better.

[cassat]

Yeah, you would think the carpenter glues gives a superior bond and is stronger......
True, but it is water based and when you find that slight warp after it is all dry, you
will reconsider the second time around. Use 30 minute epoxy and clamp it tight.

[devo55]

So the common thought is that the carpenters glue creates a very strong bond, but due to the bonding properties it makes the material too brittle, wheras on the other hand the epoxy allows a strong bond while still allowing a slight flex to obsorb any impact forces during the possibility of a crash.

[hugh m]

Just my 2 cents but Weldbond (or some other PVA) is supposed to be waterproof (when dry) and flexible. It also bonds real well and can be thinned with water initially. A really great glue with all kinds of uses. Good for foam too.
Not sure about fuel proof tho as I haven't tested it for that. Perhaps someone else can comment.

Later
Hugh

[bobreib]

I have used epoxy, Carpenters glue ( the yellow stuff), and Polyurethane. I have used both epoxy and Polyurethane to bond the firewall to the fuselage and both worked well.
I have used all 3 for laminating with equal success. I usually use a rough ( 80 grit ) sandpaper to roughen the 2 surfaces before bonding. I have found that the slower setting epoxies are less brittle than the quick set ( 5 minute ) variety. Carpenters glue and Polyurethane will require clamping for several hours, and usually don't get full strength until after 8 or 12 hours ..

[Xanadu]

Epoxy is the best way to go, that is why it is recommended. It is not as brittle as carpenter glue, and really soaks into the wood much better. They call for it in the build manual for a reason, trust them.

Would you rather fix the entire plane later because the firewall separated, or just do the firewall correctly the first time. Besides, there is several other items in the build that require epoxy again. I just finished building the same cub. All these are scattered through the build, so not something you can do all in one sitting. Use an old phone book to mix your epoxy on, then tea off the one page to throw away, and you have a fresh mixing surface for the next round. Don't waste your money on mixing cups, etc. Go to the dollar store and buy a bag of Popsicle style sticks for mixing.

[DO335]

Different glues have different properties and work best in specific applications. If that were not the case, there would be only one glue for all uses on all materials.

Since the amount of epoxy required will be very small, if applied properly, there would not be any significant weight difference between it and the carpenters' glue. Prep the surfaces, mix epoxy parts accurately, mix thoroughly, spread thin and clamp the parts while the epoxy cures.

Most carpenters' glue is only water resistant, although people have told me that some of the new aliphatic resins (a.k.a. carpenters' glue, white glue) are pretty much water proof. However, as you have been cautioned, there is a great chance of introducing warps with it. It is water based. Epoxy is not.

You do not need to thin the epoxy for penetration. Thin epoxy is generally a surfacing or finishing resin. It's purpose is not strength. You get your geatest strength from a slow cure epoxy. The slower the cure, the greater the strength. Many modelers groan that they do not have time for it to cure (it does not dry- remember, it is not water based. It cures, which is a chemical reaction.). That's baloney. They have all the time in the world to fix a plane once it's been dorked. Just set up your slow cure epoxy before you go to bed. It will cure while you sleep and you can get on with things the next mroning.

To achieve the best strength, it is imperative to also prepare the surfaces to be joined properly - along with proper using proper ratios of resin to hardener and mixing. That means you wan to sand them with a fine sandpaper, not coardse, to make a good, even surface. Clean that off, so that you do not have oil, grease, dirt or any debris left behind. Try to keep your hands off too to avoid getting oil from your skin onto the surfaces to be glued. Think clean.

And yes, you can get a slow cure epoxy at Canadian Tire. However, there is no particular price advantage over that available at the LHS or mail order hobby supply.

One last point. USing an excessive amount of hardener for your quantity of resin does not improve the bond. It results in a rubbery, weak glue with a poor strength bond. Similarily, using insufficient resin results in a poor mix and bond. Accuracy is necessary for best results. To insure this, I use small kitchen measuring spoons. It's amazing how easy it is to use epoxy and how well it works when you remember to think clean, mix properly and give adequate cure time before dicking with the glued parts.

[AJCoholic]

Boy, a lot of discussion for gluing two pieces of wood together.. Thats good though... lots of options.

I can say, I have glued more wood to wood, and plywood together than most (its my job) and also have used pretty much every glue on the market.

Just plain old "carpenters glue", either Aliphatic (generally yellow) or PVA (white, yellow or other) is more than adequate for gluing ANY wood to wood joint. And especially when gluing face to face. You will NOT have a delamination - If you have actual wood to wood contact.

Warping shoule never be an issue - unless you are slopping the glue on way too heavy and leaving it un clamped. You have to apply pressure to a "wood glue" joint in order to keep the faces actually touching. If youhave air space, even though some aliphatics are semi gap filling, you wont achive full strength.

Epoxy is also fine, but very unnecessary IMO. And to clarify - there are MANY epoxies out there... the least of which I like are the 5/10/30 minute bottles you buy at either the hardware store or hobby shop.

If you want to use good epoxy, buy a small kit of West Sytems (or similar) resin, and a few different hardeners. it will last years in the shop and is always at your disposal. Its thin to penetrate (or glass if you want) yet can easily be thickened with various addatives (micro baloons for light weight and fillets, something like milled fibres or silica for a strength application).

And yes there are 100% water proof wood glues today - Titebond III is one of them. STill water based.

AJC

[TLyttle]

Epoxy can be thinned with alcohol. The thin epoxy penetrates farther, and is lighter. We used it to laminate skins onto foam wings. Full-strength epoxy is heavy, and it is best used in very limited quantities.

"Carpenters Glue" comes in various forms: the white glue is affected by water and other contaminants, but is fairly strong. The Aliphatic (yellow) glue is stronger yet, can be thinned with water, yet water only affects it under full, long-term immersion. The so-called "Gorilla" glues are very strong, but I find them difficult to use, due to the fact that it expands out of the joint and makes an awful mess IMHO.

I've built boats, furniture, even a car using aliphatic, and over the years I have NEVER had a glue joint fail for any reason. I have gone over many of my crashes (!), hoping to find a failed glue joint, but alas, I always find out it was my flying that was the culprit... Lots of busted balsa, no glue joint failures.