Getting started with composites.

[ghost]

Hi,

I have a bit of HPR experience and want to get into high performance composite rockets after learning that my club is willing to lend out Rocket Hunter equipment.
For my first project, I was thinking of a minimum diameter 38mm rocket. I want to scratch build it. Also, I don't have that much money to spare, so the cheaper the better
For a min diam 38mm, I don't think I need CF... Fiberglass is enough, right? I found https://www.aerosleeves.com/Fiberglass_Biaxial_Sleeving_p/fg-slv.htm
and it seems pretty cheap at 4.00 a yard. Also, I won't need vacuum bagging.

So far, I have only used DEVCON epoxy (1:1 mix). I've heard West Systems is much better for epoxy, and my local store carries it... but it is expensive! Can DEVCON work?

Thanks!

 

[sailmike]

I am interested in minimum diameter also, but these rockets can go awfully high and land pretty far from the pad. I've put that on hold till I learn more about dual deployment and also figuring out ways to make it easier to see it when it reaches apogee.

I've been working more and more with composites lately, but still don't have much experience. Whatever epoxy you use, make sure it's long cure to give you time to layup the fiberglass/CF. I think the most common fiberglass is plain weave 2-4 oz. For fins, you can put a thin layer of epoxy on the fin and then lay the fiberglass on top of that and use a brush or piece of stiff cardboard to get all the air bubbles out. Once that's done, put some wax paper on top then lay some books on top of that till the epoxy cures. This is just one way. Hopefully, someone else will chime in here with other methods.

Hope I helped some,
Mike

By the way, I was at Lucerne last weekend also.

 

[ghost]

Thanks for the help!
Who do you buy the fiberglass from? Aerosleeve seems good, but they only sell sleeves. I guess I could always buy an extra yard and cut it for tip-to-tip.
Are you a ROC member? I'm pretty sure they let members borrow their RocketHunter gear (I'm not a ROC member, but will sooon be one). That way, you don't have to worry about dual deploy... Just follow the beeps.
Also, since you were at the launch last week, did you talk to Matt? He had a whole table set up with his min. diameter CF rockets. He was really nice and explained a bunch of things to me.
BTW, if it helps, I was the kid in the blue shirt with the blue hat... and I jr. level 1 certed. My rocket was the big green and black camo one (4" diam).
Did I meet you at the launch? Were you just a spectator? What did you launch? And did you see that awesome 2 stage HPR Estes upscale (AWESOME!!!)?
Thanks

 

[JDcluster]

Actually West is probably cheaper than your devcon per oz. ,
I usually buy mine by the gallon kit.


JD

Hi,

Snip

So far, I have only used DEVCON epoxy (1:1 mix). I've heard West Systems is much better for epoxy, and my local store carries it... but it is expensive! Can DEVCON work?

Thanks!

 

[sailmike]

Here are a few sites I know of for composites:

https://cstsales.com
https://aircraftspruce.com
https://www.acp-composites.com
https://www.uscomposites.com

I am not a member of ROC either. It's $50 for a year membership, I believe, but I don't go often enough to make it worthwhile to pay the membership fee. It's 10 bucks to launch all day. The 50 buck membership fee would equal 5 launchs and I don't go that often.

I was the one with the blue and yellow Explorer with hot pink chute and 10.25" saucer. I am scatch building a 20" saucer with a 54mm MMT. Will be adding lights to that for night flights. Gonna be cool. Hope to do the night launch this November, if the weather cooperates.

No I didn't talk to Matt, but I remember his rockets. They were cool. Besides there's something about dual deployment that attracts me. Why worry about tracking it when you could get it to land a short distance away?

Mike

 

[ghost]

In my case, I don't have access to BP... Pyrodex it is!
I also don't go to 5 launches a year, but if I was able to use the Rocket Hunter equipment, it would be worth it. I'll check out those sites.
Unfortunately, I missed your saucer flight, but my friend and dad kept telling me how awesome it was! I was out recovering my PML Pit Bull I launched on an engine slightly too big for it (at least for it without a tracker...)

 

[11bravo]

https://www.avtcomposites.com/

has the lowest price on AeroPoxy that I've found.
Guys name is Randy (IIRC) and he knows a bit about rockets.

 

[tennisace]

Don't for get Soller composites
https://www.solarcomposites.com/

 

[JoesRocketry]

Don't forget www.MrFiberglass.com

 

[sailmike]

There's a couple threads I've found that are talking about FG/CF and you should be able to pick up quite a few tips from there.

One is "3 " min dia" in this forum and the other is "Fiberglassing Wood Fins for K Power" over in the high power forum.

I certainly did pickup some tips there.

Mike

 

[jraice]

To start maybe you should just make a composite reinforced tube instead of a pure composite tube?

The sleeves are neat, I started with them but cloths are much more versatile... More types and leftovers are great for fin reinforcement! Also I think its easier (especially when doing multple layers) and stronger...

I think 3 wraps of like 5-6oz e-glass or 4-5oz s-glass should be stronger enough for a pure glass tube... Then use 1/16" glass fins, attach with epoxy and throw some glass tip-tip or tab'd on for strength... It will scream!

But you could also just take a thin tube, when adding composites you will want light and thin, not LOC or PML tubing... More like estes tubing. Sand it well and add a wrap or two of glass. That way you are just worrying about your application and finishing, not getting a mandrel out... And make a glass reinforced tube instead of a pure glass tube...

It will weigh a bit more but not much and the cardboard will insulate the motor heat better, protecting the fins.

Definetly get aeropoxy or west systems (they have pro's and con's)... Its cheaper per amount, you just need to buy larger quantities. Standard its great for wetting out cloths but I'd also get a collection of fillers. With 3-4 basic fillers you can make easy to handle (for fillets) and thick epoxy's, super solid epoxys and nice thick easy to sand epoxys for filling rough fillets etc... All with the same glue!

West has a lower heat rating, fine for 38mm but as you get larger its a problem. Aeropoxy is a bit higher but I have heard west cures quicker... The actual cure time is not much different but the aeropoxy can stay semi flexible and tacky for a while after the green stage, especially if its cold. I have had tubes that feel totally dry, as flexible as cardboard but after a week they are rock solid... That was in the winter though.

With a curing oven however (great for using heat shrink tape to make really nice tubes) you can cure it in 4 hours at 150 degrees and its ready to go.

I'd join the yahoo composites group, lots of great info for experienced guys or beginers.

 

[jraice]

Oh and Dave Triano's videos are amazing! First and second are a great resource, 3rd is a bit advanced.