What's the most that 30 minute epoxy can handle?

I'm going to start building a Madcow Super Batray for my L1 soon.
I'll fly it on a small H motor for it's first flight, but in the upcoming years I may fly it on bigger motors, and maybe even up to a J motor at some point.
Could 30 minute epoxy handle a J motor?

I'm just looking towards the future.


Thanks,

I used 5 minute epoxy in my Shadow and 5 Finger Death Punch, and they've both flown on J's. So, yeah.

Yep, you'll be fine. Surface prep is the key to a good bond.

I know someone who’s used it on his L3 with success.

timbucktoo said:

I know someone who’s used it on his L3 with success.

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I'm guessing you don't mean me, so now you know two people who did that. :wink:

My L3 flight was with a MAC Performance Radial Flyer on a CTI M1101. Went over Mach. Built with hobby store 30-minute epoxy.

Yes, surface prep is critical. Also, using a thrust plate takes all the stress off of the MMT/CR bond, and puts it on the airframe. Forward CR still need to bear the brunt of the ejection charge.

Bat-mite said:

I'm guessing you don't mean me, so now you know two people who did that. :wink:

My L3 flight was with a MAC Performance Radial Flyer on a CTI M1101. Went over Mach. Built with hobby store 30-minute epoxy.

Yes, surface prep is critical. Also, using a thrust plate takes all the stress off of the MMT/CR bond, and puts it on the airframe. Forward CR still need to bear the brunt of the ejection charge.

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Nope. Some guy up in Georgia built a Madcow DX3.

My L1 used 5-minute Loctite HD and it's going strong with mid I's.
Eventually I'll get my L2 and try a J in there.

Is that Batray fiberglass or paper/plywood? If paper/ply, a strong woodglue will hold to those materials perfectly and be a good deal easier to apply.
I'll throw in the standard advice: Your material will fail before your adhesive if you apply the joint properly.

Nytrunner said:

My L1 used 5-minute Loctite HD and it's going strong with mid I's.
Eventually I'll get my L2 and try a J in there.

Is that Batray fiberglass or paper/plywood? If paper/ply, a strong woodglue will hold to those materials perfectly and be a good deal easier to apply.
I'll throw in the standard advice: Your material will fail before your adhesive if you apply the joint properly.

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Mine is a paper/ply.
One of my brothers gave the kit to me for free.
Would Titebond III wood glue hold it together?


Thanks,

Does Andrew know the difference between 5, 15, 30, 3hr epoxy?

Andrew, you should always try to use the longest cure epoxy your assembly will allow. This allows the epoxy to flow / get into all the crooks & crannies of the materials to be bonded. The longer the cure time, the longer it has time to get "into" the materials. A thinner epoxy (such as West Systems) will further get 'into' the materials being bonded better than, say, a thick gooey 'peanut butter' consistency epoxy..

Heat will help speed the cure times, but also will make it more runny. And, inversely, cooling it will slow it's cure rate. People have added alcohol to epoxy to get it to flow, but doing so reduces it's overall strength. Don't do this..

The higher end epoxies tend to have a 5:1 or such mix ratio; 5 parts resin to 1 part hardener. This can get confusing when measuring up / mixing up a batch. The 'hobby shop' types are typically a 1:1 mix ratio, resulting in a hardener & resin with additives to get them to the 1:1 ratio.

at least, that's what I've been told / read..


And, know HOW to glue something is another subject!



And yes, I did know a guy who mixed 5-minute epoxy for 5 minutes..

rockets said:

Mine is a paper/ply.
One of my brothers gave the kit to me for free.
Would Titebond III wood glue hold it together?


Thanks,

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TBIII will work. Just make sure to read up on techniques for applying it to rockets.
Warning: Titebond is very tacky and has a history of seizing when couplers are inserted. When you're inserting couplers or motor mounts, make sure to mark exactly how far its to go in and use 1 smooth swift motion to insert it.
Go back when it's dry and put a bead around the edges to make a fillet.

Suggestions:
-Payloadbay.com Use its template generator to print out a fin jig template. Use that template to cut from corrugated cardboard or foamboard and it'll help keep your fins straight.
-Take your time. I know you've heard that a lot, but it still holds true. Make your L1 a rocket you're really proud of. Definitely not something you want to rush (like I did......)


dr wogz's info on epoxy is important ^^

dr wogz said:

And yes, I did know a guy who mixed 5-minute epoxy for 5 minutes..

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Best Billy Crystal voice: "I think your friend is you."

Some quick questions for my L1:

Can I use my Jr. L1 rocket as a dual deployment flight, or does NAR not allow that for the cert flight?

Can I use a fiberglass 4" E-bay for the cardboard Super Batray?


Thanks,

Bat-mite said:

Best Billy Crystal voice: "I think your friend is you."

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Actually.

"I" did manage to get a good amount in my hair once.. We were gluing skins onto foam wings (Sig King Kobra) and we mixed up a hefty batch of epoxy for the job. We slathered it on, and put the skin in place, then the top 'shuck'. I leaned over to check alignment (putting my head upside down), and low & behold, felt my hair 'grab' something. When I returned back to vertical, I pulled the note pad that was the epoxy mixing base off my head.. My friend had a good laugh, but since we were about 15 minutes into a batch of 30 minute, I had little time to 'clean up'..

Took about 2 weeks to get it all out..

rockets said:

Some quick questions for my L1:

Can I use my Jr. L1 rocket as a dual deployment flight, or does NAR not allow that for the cert flight?

Can I use a fiberglass 4" E-bay for the cardboard Super Batray?


Thanks,

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The answer you're looking for is found on the JR L1 info page from nar.org. Read section 5
vv
JR L1 overview

Look up the OD of the fiberglass Ebay, and the ID of the tubes used in the batray. A quick email to madcow could clear things up.

"What's the most 30 minute epoxy can handle?"


31 minutes......yeah, I know.LOL

I'm happy to announce that I am now a NAR member again.

Now I'm with NAR & TRA!


Thanks,

Nytrunner said:

The answer you're looking for is found on the JR L1 info page from nar.org. Read section 5
vv
JR L1 overview

Look up the OD of the fiberglass Ebay, and the ID of the tubes used in the batray. A quick email to madcow could clear things up.

Click to expand...

Yeah, I test fitted the E-bay, and it didn't fit.
I'll just have to buy a cardboard 4" E-bay.


Thanks,

rockets said:

Yeah, I test fitted the E-bay, and it didn't fit.
I'll just have to buy a cardboard 4" E-bay.


Thanks,

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Do read that link again before you buy some unnecessaries, and probably before you go further down certification lane.

If you look at section 5, Jr L1 flights are Not to be made using pyrotechnic charges other than what's in the motor delay charge. This is a legal issue since minors aren't technically supposed to be handling explosives.
You are unlikely to get other advice on a public forum.