MAC 4" Black Fly Build Thread

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Barkley

Well-Known Member
Joined
Jul 1, 2015
Messages
572
Reaction score
15
I'll just put this here for the moment...

attachment.php
 
Subscribed.... do you have a timeline for the build?
 
Subscribed.... do you have a timeline for the build?

It's on its way, and I want to fly it in the spring, so it should be a quick build. Don't know how I'm going to paint it given that I live in a condo, but I'll cross that bridge when I come to it.
 
And... the dry fit is absolutely PERFECT.

attachment.php
 
Last edited:
Can you say customer service? Granted there was some back and forth over this one, but Mike goes above and beyond.

attachment.php
 
I'm going to lay up the whole thing with epoxy, despite the fact that cardboard/wood joins are better with wood glue. With that as a given, I should really paint the wood/cardboard with epoxy to help everything join... but I'm not going to. I'd like to have this rocket done this week.

Marked the MMT. I doubt this will help anyone, but I slid the aft CR on, then tailcone, then put the Aeropack on until fully seated, then slid the tailcone and CR back down the MMT until it was all where it needed to be. This makes sure the CR placement gives the Aeropack a good join while making the most of the tailcone.

attachment.php
 
Hey Chris is this the nosecone coupler, are you doing an AV bay with HED?

Yes, that's the NC shoulder. Still unsure on HED or single break with JLCR, so I'm doing what needs to be done for both options while I think about it. I've tacked the coupling nuts down with 5 minute epoxy, but am going to mud them with West & cabosil, then glass them in. And yes, the shoulder will be the AV bay.
 
Sunday afternoon... time to take some next steps. I had my trusty junior rocketeer with me to assist.

attachment.php


West thickened with cabosil. Centering ring/ bulkhead:

attachment.php


And two of the 4 nuts for the av bay/ nose cone shoulder.

attachment.php


That last one looks ugly at the moment, but the plan is to glass those nuts in, so it'll be pretty enough when I'm done. The most important bit was to thicken it to the point that it wouldn't sag- the last thing you'd want is epoxy inside those nuts or out far enough to prevent the lid from closing.
 
Wow Chris no denying she is yours, that is for sure. One thing I would recommend, if possible, is to try to shape the epoxy before it hardens. Sure you can sand it however I don't know about you but for me sanding is the most painful part of the hobby. I coulnd't tell you how many tasks I have put off just because they involve sanding.
 
Michael, sanding cabosil is like sanding concrete. If there's an overly energetic ejection charge those nuts are all that attaches the nose to the body, so I'm intentionally making sure those nuts can't move.
 
That sounds as appealing as a root canal.

All I can say is you prep your surface and it holds. And that's what I want.

Mixing more cabosil for the other 2 nuts and to mount the MMT in the BT. I'm putting all the epoxy in the BT to make sure that when I place the tailcone on to keep things straigh, I'll be able to take it off again to apply the internal fillets. When mounting the MMT in the BT, make sure to align the recovery strong point in between the fin slots so that it doesn't interfere with fin placement. I'm going to place two fins to make sure the alignment works.
 
Popsicle stick, duct taped to angle iron for inner epoxy application.

attachment.php


2 more nuts about to be completely captured until the end of time. Make your own joke with that one.

attachment.php


Internal MMT fillet. Once it's set, it's not going to move.

attachment.php


And note - this is the bottom end of the tail cone. Make sure you have enough room there for the retainer. I marked mine to make sure all threads could seat but that I could still have the most amount of MMT inside the BT.

attachment.php
 
Yea, you have to make sure the nuts are firmly attached, or the booster will try to keep them in the deployment bag.

Working with large nuts like that is delicate work. Surface prep is critical. You really want to take your time. A nick will make for a bad day.
 
attachment.php


Initial bond of the fins. And for those who have wondered about the Tide bottle, if you pour your epoxy resin into one of these bottles it makes things much easier to pour and clean up.
 
Back
Top