Loose Coupler

[Crazyrocket]

OK, simple question, but wanted to find out what everyone does. I have a near minimum diameter 38 mm rocket and the couple in it is just loose enough that it can slide up and down the tube when inserted in the body tube. What does everyone do to tighten the fit. On smaller models I have used tape. I was thinking of using a thin coat of finishing epoxy. Is this too much trouble or are there other ways? Note that this will be going pretty fast (close to mach) and I do not want it to fail it this point. Thanks.

 

[Stymye]

split it down one side so it can expand to fit

 

[Crazyrocket]

That's a good idea, and would do it if the couple wasn't my ebay for electronics. Everything is done already (to the coupler) and don't want to do it over.

 

[gpoehlein]

Just how loose is it? Would a piece of, say, 20# bond computer paper fit all the way around without being too tight? If so, try two, three or four shorter pieces glued to the coupler to shim it tight. If a full wrap of 20# paper is still too loose, wrap further around until it is the right tightness. Once glued in place, the paper shim will be a lot more permanent than a piece of tape. Paper is also thinner than tape, so whereas a piece of tape might be too much, a layer of paper might be just right. You'll have to experiment a bit, but you can get it right.

Greg

 

[Crazyrocket]

I didn't think about gluing paper, that's another good idea. I'm sure that 1 piece of paper would be enough. If there are any other ideas, let me know. Thanks.

 

[Fore Check]

Thin strips of fine grit sandpaper glued on to the coupler to shim it up.

 

[uncle_vanya]

If the coupler is paper then CA it. If you CA it it will swell a bit. You may have to sand it back down but sanded CA is smoother than sanded paper. If the coupler is phenolic then I'm not sure this will help.

 

[Crazyrocket]

Well, to give you an update, I experimented to see how many wraps of paper I need to make the couple tight in th BT, one full wrap. So, I put a thin coat of epoxy on the coupler and put 1 wrap of printer paper on and allowed the paper to soak up the extra (it became translucent). I then wrapped two layers of wax paper around the coupler and then tightly wrapped masking tape around the coupler to squeeze out the extra epoxy. After it dried, I removed all of the tape/wax paper and had a nixe smooth finish. A little bit of sanding is all I need now. Thanks for all the input.

 

[sylvie369]

"Loose coupler" could be the title for so many different things I see on the internet, mostly in my junk email folder.