Foam and Fly ????

[Andy Greene]

Building a Q-Modeling RMS Nike-X . I wanted to try and use the F/F method on the flight fins but my concern is the way the motor mount is built. I'm afraid the expanding foam will crumble this type of mount as it expands ?
Anyone tried it ???


Here is what it looks like tucked in-

 

[ckreef]

That mount looks more robust then 95% of the rockets flying so why use expanding foam ???

 

[hornet driver]

That mount looks more robust then 95% of the rockets flying so why use expanding foam ???

Gotta agree with that!! As long as you don't over do the foam your good to go--plan on a little/lot of clean up--If you have enough releafs you should be good--I'd put a motor casing in though-just in case--no pun intended

 

[Andy Greene]

Was just looking for a cleaner way to lock the fins in.

 

[gdiscenza]

Assuming the glassine layer of the mmt is sanded through, a generous bead of wood glue will create a joint that is stronger than the surrounding material. In other words, the tube itself will fail before the joint comes apart.

Foam in this situation is extreme overkill.

If you want even stronger than the wood-to-wood and wood-to-paper joints within the body tube, rough up the airframe with 80 grit sandpaper around the fins prior to applying Titebond Molding & Trim Glue fillets. The wood glue will soak into the wood and the paper and create another joint that is stronger than the materials being joined.

Save the weight for the fore end of the rocket.

G.D.

 

[chadrog]

I'd agree with the above advice - with all of that wood-to-wood contact, wood glue alone will be bulletproof. Expanding foam has it's advantages, but it's most useful with composites that don't absorb adhesives. The foam acts as a surface adhesive, bonding to all available surface area. You'll bust that can to bits before you'd compromise just the joints glued with Titebond or Titebond II.

 

[Andy Greene]

Thanks for the replies, Tite-Bond it is.

Andy

 

[Andy Greene]

I'm sold- used the Titebond II Premium- nice stuff. I wont use 2 part epoxy unless I have too any more.
Thanks Guys

Andy