Step 1 – Use the slotted main body tube to mark 3 evenly spaced marks around the shorter coupler tube. I did not get a photo of the process, but here is the result.
Step 2 – Use a door jamb to mark the full length of the coupler. This will help later when marking other tubes. I used a length of angle iron. It worked very well.
Step 3 – Sand the outside end of the coupler and the inside of the nose cone where the coupler and nose cone parts will bond together. Also sand the inside of the opposite side of the coupler where the bulkplate will be bonded.
No photos of me sanding, sorry. I tried to taper the end of the coupler that will go into the nose cone so that it could be inserted deeper and have more surface area in contact.
Step 4 – Mount the eyebolt with a nut and washer and secure with epoxy so it will not come apart later.
I am using West System with the slow hardener and for this particular step, I am using the 404 high density filler since it claims to be the best for attaching hardware.
Step 7 (done out of order) – Use lock-tite on the nose cone tip to make sure it does not come loose during transportation.
Since the nose cone bolt is not captured in any way, it would be impossible to secure the aluminum tip once the coupler and bulkplate are in place. I felt it would be best to epoxy the bolt in place, and secure the tip permanently.
Step 5 – Epoxy the bulkplate into the end of the coupler where you sanded the inside. Leave about 3/8” for a fillet. After the epoxy sets, apply a fillet around the inside edge. I applied a fillet to both sides of the bulkplate.
Step 6 – Drill a 1/8” vent hold in the bulkplate to let the air out while you epoxy the coupler into the nose cone base. Epoxy the coupler into the base of the nose cone and make sure you leave at least 4” of the coupler exposed. Also ensure you get epoxy on the whole area where the coupler and nose cone will contact to ensure a good bond. It is best to put epoxy inside the nose cone and not the outside of the coupler. Make sure you have a clean coupler so as to not interfere with the payload body tube later.
Yeah, not possible to leave less than 4″ of the coupler exposed in my case, the coupler would not fit any deeper.
The nose cone is done for now.