CA or My Way

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CA glues must be stored at a temperature of 5 degrees Celsius, or lower, (40 degrees Fahrenheit or less). They are perfectly safe in your food freezer. Note that CA does not actually freeze, and can be stored for at least three years with no thickening or loss of strength.

Once removed from the freezer, the bottle of CA should be allowed to warm to room temperature for several hours. Moisture will condense on the bottle's exterior and should be wiped dry before opening. Moisture is a big enemy of CA adhesives.

The shelf life of pure CA glue at room temperature is about 60 days. After that, the integrity of the glue joints begin to drop off slowly until about the 180th day point, and then much more rapidly until 360th day point, where the glue becomes unusable.

Commercially available hardware store CA glues have additives to extend this time frame, but such glues are only 30-50&@37; as strong as they could be.

I have noted poor adhesion with hardware store CA and with older stock from hobby shops. One might wonder if CA adhesives with expiration dates on the container might be a good marketing tool for one of the manufacturers.

Applied Knowledge - CA Adhesives

The following information is included with Model Research Laboratories' Premium CA:

1) A proper CA glue joint will not fail; the substrate (usually wood) fails in stress, The more the CA penetrates the substrate, the stronger the joint.

2) The better the parts fit the stronger the glue joint.

3) The strongest CA glues are water-thin.

4) CA glues are very heavy. Piling on coats of CA glue as a "fillet" does not add strength to the joint.

5) The thicker the CA, the less penetration and the weaker the joint.

6) The more catalyst used, the weaker the joint.

7) Good CA has a maximum shelf life of three to six months at room temperature. Long-term it must be stored in a freezer.

8) CA glues can be chemically modified to extend shelf life, increase viscosity, or increase flexibility, but such modifications will decrease strength. A typical unmodified thick CA that is two or three years from the original vat has about 20% of the original strength.

9) CA will not bond to anything with an oily or waxy surface. If you cannot get rid of the oil or wax, at least rough up the surface.

10) When the CA begins to thicken in the bottle, toss it.

11) The known solvents for CA glues are nitromethane, MEK methylethylketone), and acetone.

12) The best way to remove CA from fingers is to soak them in soapy, warm water. There is also a De-bonder on the market that works well.

13) The most difficult wood to glue is very thin plywood (1/64 - 1/32). It is very tight grained, and often oily from the processing. Spruce should have the turpentine and other oils sanded from the surface before bonding.

Applicator

Steve Lang

I built my first CR with the bottle supplied in the kit. What a mess. I could not get the glue where I wanted it nor the right amount.

Now that I build 2-3 CRs a month for others, I have found the perfect tool. A long snoot, bulb end, plastic applicator. If you get the kind with a very small tip, you can put just the finest amount of CA where you want it. The long snoot allows you to reach in and squeeze just enough into place.

Look for them in your local hobby shop - or contact Model Sailing Center to get yours - don't build your boat without it!!

Edited 4/1/01

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