2 Part Foam....

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Electrode

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Has anyone used any of the 2 part foam?
In building my 4" V-2.. I'm a little worryed about my fin can/tail cone. Really it is probly all right, as I've added 1/4" square stock that lies on both sides of each fin. There is inturnal fillets on all four points on the fin as well as fillets on the exturnal joints of the fin's. All done with West Bond System Epoxy.
In intention of doing the foam in the fin can. I cut porthole in the TTW tabs, in hope that the foam would flo through them and lock everything together.
Anyone have any experance in this area, or any thoughts? This rocket will be fly'n with motors up to a J.
:D
 
Originally posted by Electrode
Has anyone used any of the 2 part foam?

This is great stuff, but a little difficult to deal with. The stuff I have (from Tap Plastics) expands to 30 times its pre-mixed volume so you really have to be ready. It takes about a minute (certainly less than two) to start expanding all over the place.

Make sure that everything fits perfectly and be ready with your aft centering ring. Mix the stuff as quickly as you can and just until it's a uniform color. Pour it into the fin can and install the aft centering ring. The stuff doesn't exert a huge amount of force, but be sure that the C.R. is a tight fit or you have some mechanical means of attaching it until the foam cures.

This stuff sticks to everything! Wear gloves and cover your work area with newspaper. Also, if your rocket is already painted, cover the outside with masking paper or plastic. Really!
 
Thanks for the comments John.. I'll post how it all goes after I have the foaming complete.
 
I have just used this on a PML 3" AMRAAM for fin root encapsulation. I found on test pieces if you first use 12 hr epoxy for the fillets internally then apply the foam. the epoxy soaks into the foam and forms a bloomin rigid bond.
 
Originally posted by Electrode
Thanks for the comments John.. I'll post how it all goes after I have the foaming complete.
Tim,
What ever happened with your foam experience? I'm getting ready to build my new BSD Diablo and I'm planning on using the PML foam for the fin can.

Mark
 
Hay Mark, Thanks for reminding me. I've now done 2 projects with the foam. I'm still not conviced as some that say that you can use it with out anyother adheises in fin cans, but I do like it.

My first project was the boat tail for my 4" V-2 I used a LOC Nose Cone and there was quite a bit of void area to fill. Something I did to give it added streatgh ( I think, maybe) was clut oval slots in the fin tabs so the foam could flow from one cavity to the other and join it self. This worked out great. I did it in 4 pours about 3 oz. each time (1.5 oz of ea. liquid) The model hasn't flown yet, but hopefully it will on Oct. 27th if the crops are out of the field.

My second project I did with the foam was a project for my MOD Big Daddy. I wanted to put a beeper in the Nose Cone as I modifyed it to a 29mm motor and plan on flying it on a G125w to around 4k. Well with the added motor, I needed nose weight, so that was the obvious place to put the 2 9v battiers. So what I did was cut a hole in the Nose Cone to take a BT-80 tube epoxyed this in place. Next I took a 6" long BT-80 coupler tube and then put a 38mm motor tube in side of that. I made a cardboard centerring and CA'd it inplace to keep the tubes centered to each other. Then I filled the cavity with the 2 part Foam. It took about 2 pours. So really in this project the foam is the only thing holding it together and it does seem to be doing a great job. This too will be flying it's first flight on the 27th as well.

Something I do need to mention on the use of the foam is that, you need to be ready to work when you mix it. Once you mix the two together, start stiring, it will turn a milkies color and once that happens you'v got about 15 sec. to start pouring it. The total cure time is online like 5 min. I would suggest doing a .5 of each part as a test, just to see how much time you have and how it sets up.

I've got a Binder Excel Plus that I'm thinking about filling the nose cone completely with the foam as it is an ACE nose cone and as most know, these are very weak, and thin cones.

Good luck on your project Mark, I've heard the Diablo is a great little rocket.
 
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