L1 in my future

Very helpful tip on the JBWeld - I'm going to get some for the motor mount assembly and the retainer (bought the 38mm AeroPack). I bought the West Systems epoxy (quart of 105-A resin, 1/2 pint each of the 206-A slow and 205-A fast hardener, plus the pumps) - should be enough for many rockets.

Update: the kit arrived in the mail yesterday morning. Couple of observations on the Super DX3 that I'd appreciate comments on:

1. It only uses two centering rings for the motor mount. But given the length of the mount, and where the fin tangs will attach, I can easily see adding a third ring and positioning it so that the tip of the fin tangs butt right against the (added) middle ring. Seems a bit flimsy without a 3rd ring...

2. On that same topic, if I were to follow the instructions that came with the kit, I would fully construct and then install the motor mount before mounting and bonding the fins. This would make it impossible to get any fillets where the fins bond to the motor mount tube. Assuming I go with 3 centering rings, I am considering:

- assemble and bond the two forward rings to the motor mount tube
- install and bond this partial assembly into the main body tube
- use some wood shims to temporarily center the aft end of the motor mount tube (though it should be pretty well centered from the two forward rings)
- install and bond the fins
- then (since the aft centering ring is off) get fillets on the fin tang - motor mount tube interface
- finally, install and bond the aft centering ring and the AeroPack retainer.

3. The more I read about motor-based single deployment, the more nervous I get. I am seriously considering modifying the kit to be altimeter-based dual deployment. It would be pretty straight forward and (at least from my back of the envelope calculations) would still be a stable configuration.

Chances of getting this bird in the air before spring are pretty slim, so my feeling is that I have a couple of months to get all of this right.

Thanks,
- Matt

On the JBWeld, I'm thinking about using the 'original' cold weld formula steel reinforced epoxy for everything that touches the motor mount tube. Seems like strong stuff, heat resistant to 550F. Should finally get to work on the kit this week.

Good progress on the DX3. Used JBWeld to assemble the motor mount & on the fin tangs that hit the motor mount; 2-step (quick unthinned layer followed by thickened) West Systems 105/205 (fast) epoxy on everything else. If my test bonds on scrap plywood and body tubes are any indication, this should be a pretty solid can. Getting ready to do the fin fillets (will again use the thickened 105/205 for this). Could be ready for prep-for-finishing this weekend!

I found the West Systems 205 to be pretty easy to use. It is workable for about 15 minutes, which is more than enough for this (fairly simple to build) rocket. I tried the 206 (slow) on some of my test bonds, but it was way too slow to set.

Thanks again for all the tips.

Hah! Just noticed that! We pretty much live in a toy store, care of our 6yr old son!