First timers want to build a super strong rocket. "Super Glues make it super and stronger, right?" WRONG!
WOOD GLUES
For LPR rockets, use white or wood glues for most of the wood to Kraft paper construction.
Don't use School Glues. Those are meant to be washed out of a child's clothes.
Elmer's White Glue is thinner than it once was, the "New Stronger Formula" doesn't allow couplers and engine mounts to slide into position like it did years ago. Couplers can "lock" in the wrong position.
PLASTIC GLUES
Use a real plastic glue for plastic to plastic or plastic to wood joints.
"Kid Safe" tube plastic glues won't hold up at launch. Get the red tube glue, the stuff that stinks of Acetone. Stay away from the light blue tube plastic glue.
That or Beacon Fabri-Tac glue for plastic fin cans and plastic adapters to tube joints. Beacon Fabri-Tac has acetone in the mix, essential to slightly breaking down the plastic joint.
SUPER GLUES (also known as CA, CYA or cyanoacrylate adhesives) DON'T use super glues to attach fins or launch lugs. While the initial bond might seem strong, the glue becomes brittle over time.DON'T "tack" fins down with Super Glue, then come back and add wood glue fillets.
The Super Glue will harden up and seal the root edge of the fin. Thin super glues have a capillary action, they soak in farther than you might think. A wood glue fillet added afterwards can't soak into the hard, CA glue sealed wood.
DON'T use Super Glues to "set" a knot. The glue will run up a shock cord or shroud line making it hard, brittle and very easy to break. A correctly used knot doesn't need a drop of glue to lock it in place.
DO use CA glues to stiffen up card stock shrouds after they are glued in place.
DO use CA glue to strengthen body tube ends. Wipe on with a Q-tip about 1/4" in the inside edge.
Plan ahead - do this after the engine mount is glued in. Remember, wood glue will not soak in or stick to a hard CA glue sealed tube edge.
I still build large RC planes and never use super glues, just plain old white glue for me. I refurnish old wood furniture and recently found an Aliphatic Resin Glue that is white and dries clear. Behaves just like Titebond and Elmers Yellow Aliphatic glues. The glue is Roo glue and where I buy my maple ply sells it for 5 dollars, great glue so far.
ReplyDeleteHi Scigs,
DeleteI'll keep an eye out for the Roo Glue! I can probably find it at the exotic wood store on the other side of town.
Haven't gotten around to picking up some Fabri-Tac -- one of the things I'll have to try is if it is compatible with expanded polystyrene foam. Regular plastic cement is far too "hot" to bond that material.
ReplyDeleteHi Naoto,
DeleteThe Fabri-Tac would probably eat right through expanded foam. The acetone can be pretty aggressive.