CA glues

Will the CA glues you buy at non-hobby stores like the *MART stores work for building planes?


Reply to
Randy A. Hefner
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Yes, but they are very expensive, since the S-Mart stores only sell them in small tubes. I'm not sure if they sell a thin CA, usually they are in a gel form. I've used them in a pinch, late at night when the hobby stores are closed.

Reply to
Normen Strobel

They sure act like hobby shop CA. They seem to be a lot cheaper and more available too. Same applies to epoxy glue.

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The only problem.... Some are afraid of heights and may go to pieces at altitude.

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Reply to
Raymond Giddens

They MAY be the same and maybe not. There are a LOT of different formulas made for different applications. Some plastic formulas don't work worth crap on wood and vice versa.

I would stick with something known to work.

Reply to
Paul McIntosh

When I was building to pay for my hobby, I bought the 8oz bottles and a bunch of tips from Bob Smith. It worked out to a little over $1.00 an ounce.

You can store larger bottles in a refrigerator for a year or more.

Reply to
Paul McIntosh

The best place to store unopened bottles of CA is in the freezer compartment of the frig. I have some that is over a year old and it still works OK. allow to get to room temp before opening


Reply to

According to the manufacturers (when I was usimg POUNDS of the stuff a week), it should be stored between 35-40 deg F. Looking at current manufacturers web site, none recommend freezing. All recommend COOL storage with none I could find recommending storage below 5 deg C.

I am not saying that your experience isn't valid, only what the manufacturers say.

Reply to
Paul McIntosh


I had to do some research on "CA"s for an industrial (product assembly) use and I do a lot of RC building. I am by no means an adhesive expert, but here is some information.

"CA" (Ethyl Cyanoacrylate) is actually a "plastic" that starts as a liquid and then polymerizes into a solid when it is in contact with a catalyst. The environmental catalyst is water moisture that is present in or on the surfaces to be bonded. That is why we see CA curing much more slowly when the weather and the materials are very dry. "Kickers" are formulated with additional chemical catalysts that speed the cure. Accelerating the cure too much can adversly effect the properties of the joint.

CAs "don't like" an acid environment. CAs formulated for use with wood are designed to better cope with the acidity found in wood material than is the "X-mart" and other general use CAs. As a side note: When we use a dusting of baking soda at the joint, the soda contains moisture AND creates an alkaline environment and this speeds the cure.

The initial quality of the CA and the curing environment will determine the

Personally, I never use CA on any of the flotation areas of sea planes.

The purity of the liquid adhesive in the container (percentage of the active chemicals versus general impurities and moisture) has a huge impact on the bond strength. The better the purity, the higher the cost to formulate and the higher the cost of the packaging container. There is no "cheap" way to manufacture and package high purity CA. Generally speaking, adjusting for "what the market will bear" retail pricing and pricing based upon "logo reputation", the retail cost of the CA reflects the purity and the cost of formulating for special viscosity properties.

Extremely high purity CAs formulated with very low inherit packaged moisture (super dry CAs) may be great for critical product assembly, but have a shorter life once the container is opened. I received some samples from Germany that were as "pure" as possible and they were very difficult to use for building models. They started to "kick-off" too quickly and required special applicators in our humid environment.

Manufacturers who market to the model aircraft industry formulate for our applications. When you see a big difference in the retail cost in CAs in our market it usually means that the cheapest stuff has some of the quality or characteristics compromised. Calculating the strength of the bond with various levels of CA purity and "general use" formulations can be difficult. If you compare the cost of purchasing high quality CA that has been specifically engineered for our applications with the total cost of the model materials, engine, and radio equipment - why compromise the structural integrity of your model to save a little money.

CA is very strong in tension and very poor in shear. We do use CA in some applications where the joint experiences shear forces. The higher the quality of the CA, the better chance you have of the adhesive being able to deal with a minor shear component of the joint stress.

When CA "cures" it forms a polymer joint between the two materials. If the CA is "wicked away" from the joint, the amount of the polymer left may not be sufficient to have the strength required at the joint. That is why balsa joints where one of the members to be joined is end grain can be significantly weaker than "face" grain joints. Capillary action in the balsa can wick all of the CA away from the joint. The "medium" and "thick" CAs are better suited for end grain joints than the "wicking" formulations. However, there are times when the joint can be made even stronger by first using "thin" CA to wick a little into the end grain and then quickly applying thicker CA to the joint faces.

There is a caution about wicking CA into the end grain of small structural members to "make them stronger". Unless specially formulated, CA doesn't like "shock" stress at all and wicking it fully into a length of soft balsa can reduce the elasticity of the balsa and cause a "brittle"failure. Also, using "gap filling" CA to bridge spaces at poorly fitting component joints can make the joint more susceptible to brittle failure.

I hate kits that are shipped with longeron or spar stock that is smaller than the cut-outs in the formers or ribs. This defect couples the difficulty of making good CA joints in end grain with the limitations of "thick" CA joints. I always take the time to cut balsa shims to fill the gaps.

High quality, true "aircraft ply" with face laminations made from wood with tight grain can present another problem with CA joints. This ply is fabricated under a lot of clamping pressure and the face laminations can have a "shine" from the compression. You will often see this with Birch ply. It is a good idea to "rough up" the gluing surface with some 220 abrasive paper. This permits the penetration of the CA that is required. Conversly, some "laminated wood products" that are shipped with kits have face laminations that are so porous that thin CA will wick away from the face joint. This is where you need to use "medium" or "thick CA" to get a good joint.

Finally, some notes on storage of CA. Moisture is the enemy. This moisture can be a "as packaged" quality issue. But, it is often a major issue once the container is opened. High quality UNOPENED containers of CA can be stored in the freezer and then slowly thawed, unopened, until they reach room temperature. Many manufactures say this is a no-no even with unopened containers. Most manufacturers will tell you to NEVER put opened CA into the refrigerator or freezer because of condensation of moisture in the container "headspace".

You must be very cautious of moisture condensation in the container when you have kept the CA in any chilled environment. This even applies to having the CA in an airconditioned house and moving it into a higher humidity environment like a garage shop.

Once you have opened the container, use both the inner cap and the outer cap on the container when ever you are not actually applying the CA to a series of joints.

If you are using a "kicker" - never store the kicker in the same area as the CA. And, never spray the kicker toward the container on your bench.

I store opened bottles of CA in small "zipper closing" plastic bags into which I have placed a small package of dessicant. I save all of the little bags of dessican that come with electronic items and some food items. Friends/neighbors know to save theirs for me. It is interesting to note that without the dessicant in the bag, I have seen a "blush" of CA on the inside of the bag even with both container caps in place. This means that the caps don't seal perfectly once the inner cap is opened and CA vapor escapes into the bag.

I hope some of this will be of use to you.


Reply to

Just want to agree and add that I've used the stuff for field repairs before and it's not as good. They tend to not penetrate the wood as well and form a very brittle joint. You're also going to pay a lot more per once for the stuff.

Reply to
John Alt

You would be in danger of losing your AMA card.

Reply to

BAD PAUL!!!! I could have gotten a few days out of that one :)


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