M750 build progress

Can ya tell it's a holiday weekend and I'm fired up?! Happy early Independence Day by the way, my vast readership.

Last week I used JB Weld to bond the 98mm Slimline motor retainer to the end of the 48" long booster section and this worked well. I should also note that it took me roughly 20 minutes to grind off the lip several months ago using a griding wheel. This is some seriously hardened aluminum!

Last night I got a second wind at about 8:30PM and, over the course of three hours I:

• Pre-cut all materials: 48x37.5" piece of carbon fiber cloth, 48x16" piece of waxed/buffed 14 mil Mylar™ film, and 17x13" piece of release fabric for the exterior of the fin section.
• Correctly mixed up a 180g batch of Aeropoxy
• Laid up three wraps of 6 oz carbon fiber on the exterior of the booster section forward of the motor retainer.
• Applied the blue, coated 17" release fabric directly north of the motor retainer lip. When removed this fabric leaves a perfectly rough surface for subsequent bonding of the fins.
• Wrapped the Mylar™ film around the part and applied many individual pieces of gaffer's tape to hold it in place. I employed a great deal of tension on each piece so this should be a smooth surface.
• Spiral-wrapped the exterior with 2.5" wide heat shrink tape and secured the ends with gaffer's tape.
• Placed this final part into my curing oven for only 15 minutes. I was trying to get the tape to shrink a bit and to kick off the epoxy's polymerization. I then moved this part back into my garage to finish its cure cycle overnight.

I checked the part this morning and it looks good through the films but no resin has squeezed out:

As such I'm guessing the aesthetics will rock on this part but the resin:reinforcement ratio will be much higher than desired. This will add weight but I can say that this sustainer section still feels comparatively light to me. I'll post pictures later today and then pop the excavated part in the curing oven for an hour to post-cure it.

Finally I also filled the surface-challenged payload section with SuperFil filler. That is some great stuff. I'll rough up the surface with some coarse grit sandpaper then apply two coats of UV Smooth Prime at some point this weekend: