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Theory

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What temp do you like for post cure and how long?

I have never used the aeropoxy laminating epoxy. Looks like it cures relatively clear. Am I correct in that?
 

plugger

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Nominally 0.059"
So 1.5 mm. Thats the same thickness as my level 3 project but with a 6 inch airframe. On a 3 inch airframe that should be WAY overkill for strength. Just the way I like it! :)
So back of the envelope that's probably 4 wraps of cloth and the weight of the fabric is roughly 200gsm? If it's 4 and you're expecting to push this thing to approach Mach 3 (say with a M2245) if I were you I'd consider adding some internal stiffening to any point of the airframe where you only have the CF airframe load bearing. I say this as I flew a very similar vehicle last year in April that ended up coming apart when it was approaching Mach 3. There was a 1.75" space between the AV Bay/NC coupler and the 75-6GXL casing where the forward closure threaded onto a bolt to provide positive motor retention for the casing. And that's where my rocket decided to fail when it approached Mach 3.

Of course ymmv and most likely your airframe is better made than the one I made but I use CF from Soller (3k aero 2x2 twill, 200gsm) and the Renlam/Kirkside/Araldite K3600 epoxy system that benefits from a post cure like your Aeropoxy does. So they're probably not that much different to one another. So in my example if I had used a ~1.75" cut of FWFG coupling tube in front of my forward closure I suspect my vehicle would have had a much better chance of holding together. My replacement nose cone and new mandrels are on the way from Wildman as I type this. Hopefully they'll show up before August, the global air travel situation is seriously impacting international shipping, expecially down here where we've shut the borders to international travelers. I'll be trying this flight again in the future but it'll be 2021 at the earliest, so I've got some time.

Another not so pro "pro tip", make sure your rocket is aligned on the rail if you're going to use a FARG. Mine wasn't and it spend the first second or so under boost wobbling before finally straghtening up and flying true. I know it's a dumb thing to get wrong but I had never used them before that event and didn't consider it until a mate pointed it out to me in photos of the rocket on the rail after the flight had already gone pear shaped.
 

schworer

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What temp do you like for post cure and how long?

I have never used the aeropoxy laminating epoxy. Looks like it cures relatively clear. Am I correct in that?
Aeropoxy laminating resin is clear when it cures. The 3" and 4" CF tubes I've made using both CF cloth and CF sleeves have been cured in 5 degree F increments for a half hour or more in a step up to 190 F and a similar step down cooling fashion. An employee of Aeropoxy suggested this process a number of years ago when I gave them a phone call for asking for advice. The CF tubes have all worked out very well for minimum diameter L and M flights at Balls.

The rectangular box curing oven made out of rigid 2" aluminum foil backed insulating foam, a heat lamp with circulating fan, and a digital temperature controller. The tube is supported in the oven by a long dowel that runs through the tube so that hot air blows around and through the tube.
 

rfjustin

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So back of the envelope that's probably 4 wraps of cloth and the weight of the fabric is roughly 200gsm? If it's 4 and you're expecting to push this thing to approach Mach 3 (say with a M2245) if I were you I'd consider adding some internal stiffening to any point of the airframe where you only have the CF airframe load bearing. I say this as I flew a very similar vehicle last year in April that ended up coming apart when it was approaching Mach 3. There was a 1.75" space between the AV Bay/NC coupler and the 75-6GXL casing where the forward closure threaded onto a bolt to provide positive motor retention for the casing. And that's where my rocket decided to fail when it approached Mach 3.

Of course ymmv and most likely your airframe is better made than the one I made but I use CF from Soller (3k aero 2x2 twill, 200gsm) and the Renlam/Kirkside/Araldite K3600 epoxy system that benefits from a post cure like your Aeropoxy does. So they're probably not that much different to one another. So in my example if I had used a ~1.75" cut of FWFG coupling tube in front of my forward closure I suspect my vehicle would have had a much better chance of holding together. My replacement nose cone and new mandrels are on the way from Wildman as I type this. Hopefully they'll show up before August, the global air travel situation is seriously impacting international shipping, expecially down here where we've shut the borders to international travelers. I'll be trying this flight again in the future but it'll be 2021 at the earliest, so I've got some time.

Another not so pro "pro tip", make sure your rocket is aligned on the rail if you're going to use a FARG. Mine wasn't and it spend the first second or so under boost wobbling before finally straghtening up and flying true. I know it's a dumb thing to get wrong but I had never used them before that event and didn't consider it until a mate pointed it out to me in photos of the rocket on the rail after the flight had already gone pear shaped.
I very much like the idea of double-wall the weak link. I did on my Wildman Mach 2 at Airfest in 2018 to make sure it didnt fold on the way up. :) This will be considered for sure.
 

rfjustin

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Aeropoxy laminating resin is clear when it cures. The 3" and 4" CF tubes I've made using both CF cloth and CF sleeves have been cured in 5 degree F increments for a half hour or more in a step up to 190 F and a similar step down cooling fashion. An employee of Aeropoxy suggested this process a number of years ago when I gave them a phone call for asking for advice. The CF tubes have all worked out very well for minimum diameter L and M flights at Balls.

The rectangular box curing oven made out of rigid 2" aluminum foil backed insulating foam, a heat lamp with circulating fan, and a digital temperature controller. The tube is supported in the oven by a long dowel that runs through the tube so that hot air blows around and through the tube.
This is right in line with my post curing experience as well. Anything > about 160 degrees cures Aeropoxy rock hard (and no longer tacky). :)
 

BryRocket

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Awesome!

Do those fins go all the way to the end of the airframe? Does a thrust ring hit them at all?

looks great!
 

rfjustin

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Awesome!

Do those fins go all the way to the end of the airframe? Does a thrust ring hit them at all?

looks great!
The fins are flush with the end of the airframe. Thrust ring is not a concern, this is a sustainer of a two-stage with snap ring motor doubling as internal coupler. :)
 

BryRocket

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The fins are flush with the end of the airframe. Thrust ring is not a concern, this is a sustainer of a two-stage with snap ring motor doubling as internal coupler. :)
Oh my! That is what my endgame is with a rocket I’m working on right now. So cool! That’s a 3” sustainer correct? Do you intend to do a 3” booster or will you be going to a larger 4” and aiming 100k+?
 

crossfire

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Jf once the weave is filled and sanded what is the next step?
 

rfjustin

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Did you not use peel ply on your tip to tip? That will almost eliminate the need for the body putty.
Negative. I didn't have enough peel ply laying around and was too impatient to order/wait for it. I wanted to proceed. :)
 
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crossfire

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Very nice looks orange to me.
 

SMR

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Build thread to be short on text and heavier on pics. :)
I'm liking this build, Justin. A picture is worth a thousand words. IIRC, Popular Mechanics used to have a feature called Wordless Workshop. I have always been tempted to do a thread with all pictures and no text.
 

jd2cylman

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I'm liking this build, Justin. A picture is worth a thousand words. IIRC, Popular Mechanics used to have a feature called Wordless Workshop. I have always been tempted to do a thread with all pictures and no text.
Well, now that you're retired, maybe it's time... ;) 🤪
 
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