Expanding Foam Question...

[gsanders]

Is it possible to use standard "home use" expanding spray foam in HPR? I was thinking of using it to mount my GPS tracker unit (mounted in sled / coupler tube) inside my nose cone? Will the hardware-store brands of expanding foam impede the GPS / tracker signals?

Thanks in advance...

 

[Steve Shannon]

Is it possible to use standard "home use" expanding spray foam in HPR? I was thinking of using it to mount my GPS tracker unit (mounted in sled / coupler tube) inside my nose cone? Will the hardware-store brands of expanding foam impede the GPS / tracker signals?

Thanks in advance...

The two-part foam used in rocketry is basically the same two-part foam used for home insulation but usually without the dyes or flame retardants added to home insulation.
It is not the same as the can-foam, which is a one part foam which reacts to the moisture in the air to cure. If you try to fill a large cavity with too much can-foam you could easily end up with the innermost foam taking an extreme time to cure, if it cures at all. You might be able to fill small areas, especially in a humid area.
Neither type of foam will do much to block radio propagation.

 

[blackjack2564]

NO!
Do NOT use any foam in the can from big box stores. It can & will continue to cure for months inside a rocket. Sit that bad boy on the pad or in the hot sun for any length of time and it will swell/bulge your airframe.
There are too many reasons not to use that stuff to list. suffice to say it's only purpose is for insulting issues around the house.

You want polyurethane 2-part foam from Wildman...PML .....many fiberglass supply houses and even boat building supply, they use it for foam flotation inside boat hulls.

I just wrap my tacker/antenna with bubble wrap & stick it inside cone.