Peoples thoughts and experience with different glues

For me, I like using all three of the Titebond glues.
They dry slower but give you a good adhesion for balsa wood.
The CA (CN) glues are too brittle. A good example was I had built a stick fuse (rubber powered free flight), unpinned it from the board, everything was looking good, fuse looked straight, turned around a little bit with the fuse in my hands when I banged into the side of my bandsaw bench with the fuse and about 1/3 of the small sticks broke loose.

My wife laughed at me and said that I made a nice toothpick fuse.
Since then, I use Titebond to glue the sticks together, no more quick CA glue on those little 1/8" square stick guys!

As for the epoxy. I have found that the longer setting epoxy bonds much better to the harder woods like engine bearers than the quick 5 or 15min epoxy. You need the epoxy to really soak into the wood for a good bond.

If you did wing bagging, you used the slow setting epoxy for the time, but also the benefit was that the slow setting epoxy was absorbed into the balsawood to make a strong "foam" wing.

Just a summary, each and every glue has a purpose, you just have to select the right one for the right job (and stress?)

Years ago I used Ambroid. It is interesting to see that older models built with this stuff used to have glue fillets and these have pretty much sublimed away.

You have to admit that the smell was neat!

Hi Yabby,

What you are calling CN I've never seen...iI have seen CA:
Cyano-Acrylate super glue.

Before I jump into the deep end, I build for fun, not for forever.

I use CA for stuff that must be secured quickly, but not for any significant strength. The thinner stuff cures HARD and causes funny sanding. That is, the balsa around sands away, and leaves a hard pebble unless sanding with a sanding board. Even then, I find it hard (yuck, yuck, yuck) to ensure the harder spot sands down with the rest. I remember trying to use Super Glue brand CA as a kid for fixing my old plastic Cox airplanes, and it disintegrated when touched by nitro model fuel. Maybe the newer stuff is better. I'll use gel CA for gap-filling. Again, I am concerned about exposure to fuel. The stuff must be better 30 years later, because a lot of hobbyists use it for their builds. I may try the newer stuff sometime.

I remember Ambroid. While it is no longer marketed, look for SIG-Ment, which is basically the same stuff. I find it holds joints well, and sands like balsa. The only drawback is "glue a few tonight, sand tomorrow." A similar alternative is fletching glue for gluing feathers/flights to arrows. Purchased in bulk in this context, you are looking for "nitrocellulose" glue (yellow and stinky like Ambroid/SIG-ment). Way back when, this was also called canoe glue. Joints can be dissolved by dissolving with acetone, and re-glued later. This is quite useful for when a rib is glued in wrong. I find joints hold up to stress quite well...and can prove it by saying look for my 1960 Scientific P-40...it was done primarily with SIG-ment. This stuff can soak in well when thinned, and really grabs if thinned a bit for penetration, and double-glued full strength. In fact, the tail of the P-40 was wetted with thinned SIG-ment, and double-glued with undiluted glue. I believe this is lighter than aliphatic resins. I haven't warped any pieces with too much glue...but haven't tested to the point of ruining a part.

I use name brand epoxy for firewalls to balsa for the strongest joint possible...Bob Smith Industries is the name brand. The joint is a bit more flexible (or, really, less brittle) than the SiG-ment joint. This is why it is good for high-vibration areas. I use epoxy for any fiber-to-metal work, like landing gear wire secures to bulkheads, formers, and plywood platforms, and even fuel tanks to frames. Try to avoid the 5-minute stuff. While significantly more flexible, it develops a waxy surface that makes for poor dope adhesion. Find my BHM Mosquito in MS thread and observe the engine mounts. They were difficult to paint, but absorbed the abuse. The beams were epoxied to the balsa nacelles and plywood skins.

The yellow aliphatic resins, like the Tite-Bonds yield flexible, vibration-proof joints, and would be great for firewalls and engine beams. However, they sand rubbery and will peel out of the joint unless allowed to thoroughly dry...again, glue this morning, sand tomorrow. The best part is it CAN be thinned for maximum penetration, and strengthens after penetration by double-gluing with undiluted glue (post-penetration). It doesn't soak into really hard wood very well, so I consider epoxy for high surface strength
when penetration isn't very likely. Care needs to be taken when thinning, as parts can warp if too much is applied, like when gluing two 1/8" sheets to make a 1/4" sheet. For stacked sheets, I'd consider carefully which glue to use, as there are plus/minus on each for this purpose. End-grain on both sides of a joint would be done with thinned aliphatics for depth of adhesion, double-glued for strength, and scraped of excess from the exterior of the joint to lighten the structure. I would go back later to see if excess squeezed out, and scrape the exterior of the joint before dry. The Mossie was Tite-Bond for the balsa nacelles on the balsa wing.

Last thing...I use E6000 for plastic to balsa, like canopies and cowls. The stuff peels loose like rubber cement. Care.must be taken to roll the plastic off the wood. This isn't for a penetration area, but something that needs to stick like snot on a kid's fingers. It is difficult to remove, but can be rubbed/rolled off from the wrong place. It will glue bare plastic onto a painted surface, and generates heat as it cures.

I don't like white glue for any of this. It never seems to sand well for me.

Thanks heaps to all of you for such detailed and considered replies Yes, I do build them quick and fly them like I stole them. But, that said, I know a real weakness in my knowledge about building models, be that a quick build or slow build, is which glues to use where and even glue types etc. Whilst i dont build the greatest looking models, the assistance and advice provided from all of this input will help me build stronger models, as quick, as in elapsed time for a build is very false economy if your model disintegrates as you turn it really hard into a wingover. My planes are fast, twitchy, very maneuverable, and built very light to gain those features and launch off my launch table on my own. And I love flying them like that.

But a number of flying incidents and obvious post flight stress to the model(s) has made it obvious to me that I need to better understand the glue(s) being used in the construction of the models. I have also started improving my models from a strength perpective from observing these failures and looking to understand where I need a doubler or gussett or even slightly thicker balsa and I am learning! But all that said, I have become very aware from flight failures and post flight examination on quite some occasions, that the glues I am using in various places have definitely been a significant contributor to failures.

Thanks to all of you, all of it is great advice that may seem obvious to some people, but to me it simply is not. We all have stuff we are really good at and know about, and this is a real area I just really dont! I will be re-reading all of the posts and looking up the different glue names etc. on the net, and seeking them in Oz or the same glue by whatever name it is here. The posts present a very common theme about CA and its use and also about using the 24 hour epoxy as apposed to the five minute stuff.

This is valuable learning for me! That will help me do more of what I love which is flying my models like I stole them , or as my Lad says to me, Dad you fly your planes like an idiot... did you know it did..... Did you see it go like...... I think you had lost complete control Dad. Yep, the old fart equivalent of an 18 year old riding a "Boy Racer" through the hills, but with my heaps fun Half A models.


Yabby