BillyGoat

I had heard that using an accelerator on a Ca glue will not provide as strong of a bond vs. letting the glue cure on it’s own.

Is this just a myth?

airega1

My Feedback: (204)

That is absolutely the truth, when you kick CA it crystalizes rapidly, thus becoming brittle. if you're going to use kicker, spray a very light mist from a distance and only the top surface of the glue will cure leaving the underneath CA still in liquid form, this method works much better.

Jerry Sigur

Well, I use ca and accelerator almost exclusively on every model I build.
I have some models that are in the 12 to 14 yr old range that are flown
regularly with no probs. I'd say that any brittleness is very minor based
on the longevity of my models and the models I've built for others.
Jerry

bentgear

While the bond strength may be less, if it is still greater than the strength of balsa, what does it matter?

Ed M.

Knighthawk2100

I use alot of kicker. I am very impatient,[>:] and have never had a problem. I agree with bentgear it is gonna be alot stronger than the balsa

jettstarblue

I use a bottle of distilled water with a teaspoon of baking soda dissolved in it. It works the same, but is much cheaper than accelerator.

CafeenMan

This is a frequent comment that makes sense. There is a difference and it should be addressed. When you think about it, there is almost no glue that is weaker than balsa - especially when you're talking about contest balsa. So why not just use Elmer's school glue? It's stronger than balsa.

There are a lot of things to consider if you want the structure of your plane to have its best strength and lightest weight.

* Flexibility of joint
* Stress points - hard glues create them
* Glue penetration into the joint. For example, end grain soaks up a lot of glue. Face grain hardly soaks up any glue and all it takes is a few fibers to pull from the face and the joint fails. If you epoxy the end of a 3/4" square block to a piece of face grain balsa, it will break free easily taking very little wood from the face of the balsa.
* Laminating
* Sanding ease
* Etc.

I'm not up for a whole gluing tutorial, but the glue type makes a difference even though they are all stronger than the wood itself. I hardly use CA at all because it's almost never the best choice. It's strong enough to hold a plane together, so that isn't usually an issue. But other glues are too and they have advantages over CA in many cases.

mikeboyd

When I can build a kit out of the box, to the flying field in less than 30 hours, with CA and Epoxy, when it used to weeks to build, waiting on elmers to dry and the new planes come out lighter, I'll always use good medium CA and let it soak in, without kicker. On planking, a light coat of kicker from a distance on the planking surface, then run medium ca on the ribs, align carefully and it's set in place forever. Soooo much easier than the old days!!!

CafeenMan

So you're saying that the drying time of glue made WEEKS of difference in your builds? I can't even imagine that.

This wing was built entirely with carpenter's glue. The glue made no difference at all in the time it took build. Ok, it took 15 minutes longer than it would have taken if I used CA.

http://airfieldmodels.com/informatio...tion/index.htm

Crash90

My Feedback: (17)

That surprises me cafeenMan. I recently started building a giant profile with the intent of using carpenters glue. What I found, however, was that a 5 minute job with CA many times turned into a few hours waiting for the carpenters glue to dry so I could unpin the assembly from the building board. This was my first attempt at using carpenters glue so maybe I am doing something wrong?

The last step I performed was gluing a piece of balsa stock to the LE of the wing. Had to wait till the next day to pull the tape off and sand it to shape. Added a whole day to a small step.

I too have found that carpenters glue added a few weeks to my build. As I read the link you posted, specifically, installing the LE sheeting on the wing, you let it dry for 24 hours. Considering that you had to do both sides of the wing, you added 48hours to 1 step in construction. Now, make it a 2 piece wing and you are applying LE sheeting 4 times. Now we have added 4 days to our build waiting for glue to dry. You can surely see how this can add up quite quickly.

Not arguing, just defending mikeboyd a little.

CafeenMan

Crash90 - No doubt that carpenter's glue takes longer to dry. I don't deny that. And please don't take my comments as an attack on anyone. I'm harmless so nobody needs to be defended from me.

I guess the point I'm trying to make is that glue doesn't slow me down. If I built in a way that I put a piece on and couldn't do anything else until the glue dried, then yes, it would take weeks to build. But I plan my projects so that I can be working on something else while glue is drying.

If I don't have a clear plan of something else to do, then I find things to do, such as starting to assemble radio equipment, deburring metal landing gear, make servo mounts or whatever.

As far as sheeting goes, I guess I could have put on one side and used thin CA because it was accessible, but I would not attempt to use CA for the other side. That wing has a lot of ribs and there's no way I could get CA on all the ribs and then get the sheeting in place before the CA was already setting up.

Anyway, I'm not anti-CA. I don't care for it a whole lot, but I use it on some things. I enjoy model-building more than flying, so getting my plane in the air quickly usually isn't part of the equation for me unless I'm out of airplanes.

CafeenMan

If it's a two-piece wing, build both pieces simultaneously. Then it's only 48 hours.

Seriously, I like to build matching components at the same time so that whatever I do on one is done to the other. My memory is getting worse and I find that if I build matching components at different times, then I often forget exactly what I did on the first one and sometimes I can't see it any more because it's enclosed.

I realize not everyone has the space to build two giant wings at once though.

Anyway, I've talked about CA on a few places on my site. I see that it has a lot of drawbacks, but I also recognize that a lot of people have good success with it. The only thing I really question is the time aspect. I haven't noticed much difference from when I used to build almost exclusively with CA to now that I build almost exclusively with carpenter's glue.

What I have noticed is that I make a lot fewer mistakes because I have more time to get things in place when I used to have to spend time cutting parts back out because they set up so fast I couldn't get them in place properly. I've also notice my structures are a lot cleaner. If you read the article, you can see that I don't have glue slopped everywhere. CA is uncontrollable in that regard - especially the thin stuff.

I like to look at my wood work through transparent coverings and seeing sloppy glue really bothers me.

Again, it's my personal thing. Everyone should do whatever works best for them.

Crash90

My Feedback: (17)

"What I have noticed is that I make a lot fewer mistakes because I have more time to get things in place when I used to have to spend time cutting parts back out because they set up so fast I couldn't get them in place properly."

Amen.

BillyGoat

I appreciate the discussion with CA bond in relation to balsa and model building. I use kicker religiously in model building without concern. However my question stems from not bonding wood but rather a plastic to metal and a need to set quickly.

So agreed its not a myth. Does anybody know of studies done testing tensile and torsional strength regarding the effects of CA being accelerated to cure?

The question now is how much loss of strength?

FLYBOY

My Feedback: (11)

The problem you will have with plastic to metal is getting the glue to stick to it. It lets go of the smooth surface becuase it can't penetrate it. If you want a good bond, you are more than likely going to have to rough up the surface or it will let go fairly quickly with vibration.

LSP972

My Feedback: (13)

mikeboyd, sounds like you need to explore ARFs...

Seriously, I use yellow glue a lot, because of the previously-mentioned slower set-up time and the fact that it sands so much better than CA. I'll take months to build even a simple sport kit; I do it to savor the enjoyment, not see how fast I can throw one together. That what ARFs are for; throw one together to fly while you build what you REALLY wanted...

But diversity is what this hobby is all about, eh?

britbrat

CA sticks to both metal & plastic -- don't you guys remember the old crazyglue adds where some bozo glued a hardhat to a steel beam & then swung from it?