countilaw -> RE: Adhesive Question? (5/23/2012 10:25 PM)
Here is a list of adhesives and their applications:
Thin CA good for balsa to balsa, balsa to plywood, balsa to epoxy glass and balsa to fiber glass
not good for: foam , ply wood to ply wood, ply wood to hard wood, hard wood to hard wood, plastic to plastic or for high stess areas.
Thick CA Same as above, but used for more a gap filling or for more work time.
Ambroid: Good for most everything except foam, polyesters and epoxy glass. (We used this for everything before there was epoxy or CAs. )
5-minute epoxy: Good for Balsa to balsa, balsa to plywood, balsa to epoxy glass , plywood to plywood, plywood to hardwood, hardwood to hardwoood and foam.
Not good for: high stress joints, or use on fiber glass. (5 -min epoxy will not stick to polyester resins.)
30- minute epoxy: Same as 5 -min epoxy except best used on high stressed parts such as spars and motor mounts, joining foam wings and form stabs. (polyester resin will not cure over 30-minute epoxy)
White wood glue: Good for: Plywood to plywood, plywood to hardward, foams,
Not good for: laminating balsa to balsa, or laminating plywood to balsa, or anything to epoxy or fiber glass. (white glue is water soluble and will cause balsa to expand. Warping the lamination.
Yellow wood glue: Good for: everything white glue is good for, plus laminating, and joining wing skins. Not water soluble after it dries.
Water base contact cement works great for applying wing skins to foam. (if it is white, mix your favorite color of food coloring in it, to be able to see it on the foam and obtain an even coverage.
If you are building a plane that has a fiber glass (polyester resin) fuselage, you must use polyester resin to glue to it.
If you are building a plane that has a epoxy glass fuselage you can use 5-min or 30-min epoxy to glue to it.
If you are using thick CA (Gap filling) or thin CA and you need to kick it, baking soda works well.
If you are going to use polyester resin and glass cloth to wrap around a wing joint, seal the seam (joint) with 5-min epoxy. Polyester resin will not cure over 30 minute epoxy.
DO NOT use large amounts of 5-minute epoxy to join wing halves. The heat generated by the curing process will melt the foam.
There are some exceptions to the above schemes, but these are the general guide lines.