Painkiller 3 Build thread

So it's here the rocket I'll build for my L2 certification attempt.... What I need is advice from the CR to shear pins and I'll be putting updates on here... The first thing I need to solve is the epoxy to use I'm thinking of just buying some 5 minutes epoxy and use epoxy clay for the fillets... Thanks

For epoxy, I like to use Aeropoxy ES6209. It sounds expensive at first to put out $50 on glue, but it's much cheaper than buying the amount of five minute syringes you'll need. Also the one hour pot life gives you more time to work. With filler added it can also be used for external fillets. 6209 also injects very nicely.

Rocketpoxy and proline 4500 are also excellent choices. 4500 has a shorter pot life, is thicker, and a 5.5:1 mix ratio whereas rocketpoxy and Aeropoxy are 1:1. I do like 4500 for external fillets. Nice and clean.

I've personally had a difficult time with epoxy clay. I used it on my vulcanite and it was difficult to sand.

I would also grab a pack of regular old JB weld to mount Kevlar to the MMT, and the motor retainer

DizWolf said:

For epoxy, I like to use Aeropoxy ES6209. It sounds expensive at first to put out $50 on glue, but it's much cheaper than buying the amount of five minute syringes you'll need. Also the one hour pot life gives you more time to work. With filler added it can also be used for external fillets. 6209 also injects very nicely.

Rocketpoxy and proline 4500 are also excellent choices. 4500 has a shorter pot life, is thicker, and a 5.5:1 mix ratio whereas rocketpoxy and Aeropoxy are 1:1. I do like 4500 for external fillets. Nice and clean.

I've personally had a difficult time with epoxy clay. I used it on my vulcanite and it was difficult to sand.

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I don't use fillers in it at all anymore. In my experience a big fillet of neat resin worked fine.

CarVac said:

I don't use fillers in it at all anymore. In my experience a big fillet of neat resin worked fine.

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About how long did you let it sit before laying it in? I always seem to wait about 5 minutes too long. I've been meaning to get away from 4500. It's clean, but fairly brittle.

Yeah when you look at other options $45 is pretty good considering... I was watching videos from apgee components and the clay seems easy to sand but I might be wrong.... The thing that has been troubling me most is the ebay... Should I get one of those BT rings so the whole coupler is removable? Like epoxy in the bottom bulkhead with my Kevlar attached to the eyebolt on it with my drogue chute being deplyed via motor charge using shear pins.... Then attaching a piece of tubular kevlar on the eyebolt of the bulkplate of the nose cone coupler and the other end on the e bay bulkplate and shear pins and when the main deploys the ebay will come out as well... Or should I epoxy the coupler into the second BT? I wrote that whole post very very badly I know... My goal is to have the rocket ready by July 5th for my l2 cert at Orangeburg... Also my harness... Should I use kevlar with a nylon shock cord for drogue? Or just Kevlar?

DizWolf said:

About how long did you let it sit before laying it in? I always seem to wait about 5 minutes too long. I've been meaning to get away from 4500. It's clean, but fairly brittle.

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I lay it immediately, sometimes doing a small fillet first and then a larger one on top of the partly cured smaller one.

Many ways to do an av bay. I'd rivet it to the payload. Easier to assemble and load charges than if it's epoxied in. Rivets are remove able.

Hmmm never thought of that... I think I'll go rivets... Anyone know where I can get a G12 or G10 ring for a the outside of the coupler?

Also what is the cure time of Proline or Rocketpoxy ir Aeropoxy?

Good luck with 5 min.
It's too brittle with no work time at all!
If you blink, it will already be smoking in your mixing cup.

For fiberglass kits; use either Pro-Line or Pro-Set.


JD

Okay I'll be ordering what I need this weekend sometime

Alethins said:

Hmmm never thought of that... I think I'll go rivets... Anyone know where I can get a G12 or G10 ring for a the outside of the coupler?

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Not sure where to get a short piece. You can also go bandless. Just rivet the payload in, slide the body tube on, and drill vent holes where the tube meet. If you slide the coupler into the tail of the body tube first, you can use the fin slots to mark the coupler in three places for rivet placement. Drill the vent holes between the rivets so they don't disturb airflow over the vents. I'm not sure what you have planed for electronics (if any) but you can mount the switch to the sled, and access it through a vent hole with a tiny screwdriver. Or simply run the wires out a vent hole, twist them together and tape them to the airframe. Simple, solid, and proven. I did this on my L2. (tape it to the upper payload...not the booster, I nearly messed this up)

Alethins said:

Also what is the cure time of Proline or Rocketpoxy ir Aeropoxy?

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It's temperature dependent, but assuming 70 degrees my experience is that proline 4500 starts thick, get tacky in about 15 minutes but will still run if turned vertical, and sets to a point you can move the rocket around in about an hour or two.

Aeropoxy is workable for 30-60 minutes, then gets tacky. I typically use will lay it in, and let the part sit overnight. This leads to needing 9 days to do a set of 3 fins (tack in place, internal fillet, external) I generally tack them in with 4500, rotating and doing another fin every hour, then inject aeropoxy over 3 days, then 4500 external fillets rotating every 4 hours. You can likely tighten those times up, but it's worked for me.

Do you have a motor in mind, and do you plan on using DD for the cert flight?

DizWolf said:

Aeropoxy is workable for 30-60 minutes, then gets tacky. I typically use will lay it in, and let the part sit overnight. This leads to needing 9 days to do a set of 3 fins (tack in place, internal fillet, external) I generally tack them in with 4500, rotating and doing another fin every hour, then inject aeropoxy over 3 days, then 4500 external fillets rotating every 4 hours. You can likely tighten those times up, but it's worked for me.

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I run Aeropoxy in 12 hour shifts. Wake up a tad early and spend ten minutes to glue something, and then do something else in the evening.

DizWolf said:

Do you have a motor in mind, and do you plan on using DD for the cert flight?

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Yes I plan on DD for l2

Alethins said:

Hmmm never thought of that... I think I'll go rivets... Anyone know where I can get a G12 or G10 ring for a the outside of the coupler?

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I assume by "ring" you mean a short piece of airframe tube say 1.5' to 2" long? Just cut what you need from the lower airframe section. The ring you referred to is known as a vent band. You are going to turn the couple into your Av-bay right? Don't hesitate to ask questions, lots of good folks here eager to help out.

Would an 18" chute be a good drogue?

I fly drougeless. Others like to use them to keep the parts separate on the way down, in that case I'd imagine 18" would do the trick.

a good discussion of it here: https://www.rocketryforum.com/showthread.php?63948-Drogue-to-Main-Ratio&highlight=drouge

Okay cool thanks diz! I have found that rocketry warehouse will cut custom switch bands for people.. I'm assuming the coupler is 3" in diameter like the body tubes? So what diameter band would I get? What length if the coupler is 7" long? Thanks again guys I usually buy kits with instructions but I wanted to make the leap to mainly custom

The couplers fit inside the body tubes, so they're less than 3". Tell them you want a 3" vent band and they'll know what you need. An inch is plenty, inch and a half if you want. If you're externally mounting switches just make sure it's big enough for them. I've used 110/220 switches on inch bands. Also on 1.5" I tried to flush mount on the 1" not worth the effort to me, likely won't do that again.


RW also carries all the kevlar, nylon, and rivets you'll need (save on shipping, get it all at once.)

Okay thanks! I'll also order my chutes from there. The Kevlar will come from one bad hawk. I wonder if I post a wanted add if I can save save some money on things...

It's possible. Just remember shipping adds up fast and can eat savings. The time crunch will make it hard too. What types of things are you looking for? Can't hurt to ask and see what you can find.

Aeropack 54MM fiberglass retainer
CTI preferably 3 Grain hardware
Chutes
RRC3/2 or any dd capable Altimeter

I hate having to order my epoxy I would love it if Lowe's had epoxy!!!

What ebay hardware kit should I get?

Have a west marine in the area?

Yes I do

I've never used it for rockets, but search west systems on here. Several people use their epoxy for builds.

I was looking at it would I need to add something to it in order to make it suitable for gluing

Alethins said:

I was looking at it would I need to add something to it in order to make it suitable for gluing

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406 Colloidal Silica is probably the most commonly used filler in conjuction with West Epoxy; it should be available at the same place where the West Epoxy is available. It is all that is needed to tune 105 resin and 205/206 hardener to the desired consistency.

A touch of 410 milled fiber increases strength and decreases brittleness of the epoxy as well. Others use the 404 filler as a thickening agent instead of silica. These fillers are available, generally cheaper, under generic names....though West System quality is great and the convenience of having the line of products at one retailer is worth the extra cost at times.

I've used many, many different types of epoxy before. Everybody has opinions on them; most will work just fine (including the stuff you can indeed buy at Lowe's); some work better than others! Good luck with the build!

-Eric-

Or run a space heater next to the rocket. Your epoxy will cure much more quickly.

CarVac said:

I run Aeropoxy in 12 hour shifts. Wake up a tad early and spend ten minutes to glue something, and then do something else in the evening.

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You can get all of that from Wildman Rocketry. He also has both west systems and proline epoxy.

wildmanrocketry.com

Alethins said:

Aeropack 54MM fiberglass retainer
CTI preferably 3 Grain hardware
Chutes
RRC3/2 or any dd capable Altimeter

I hate having to order my epoxy I would love it if Lowe's had epoxy!!!

What ebay hardware kit should I get?

Click to expand...