Pure CF tube: first attempt

[cjl]

Well, today I tried to make a pure carbon tube. It was my first ever attempt, and I think it turned out rather well. It uses 2.5 wraps of 2oz carbon (originally wanted 2, but ended up with a little more), laminated with pro-set 125 resin with 226 hardener. I used a 29/360 case as a mandrel, which I wrapped in release coated mylar, and then covered the outside of the layup with more mylar, followed by shrink tape. The whole lot was in a curing oven for 10 hours at 180 degrees, and the final weight is 11.7g for 13" of tube (will be trimmed down to 8.5" for the final use).

So. What do you think

 

[cjl]

Here's a closeup of the best part of the tube:

 

[Rocketman248]

Looks pretty cool man! Nice job.

 

[ben]

Looks good. I have found you can turn Long wooden Block's on the lathe and tightly wrap mylar. Then CF them. Never tried it but it looks god. BTW congrats. Looks cool enough to add something to my Rocket "To-do list"

thanx, Ben

 

[Batman]

Hmm, i think you should loan it to me at our next launch for further examination and testing.

 

[cjl]

I've got a deal for you

You find the rocket after I launch it on a G80 for the single shot contest, I make you a tube of the same size of whatever strength you want- 2 wraps of 2oz carbon, 5 wraps of 5oz, whatever you want

Seriously, my biggest worry is finding the darn thing after the contest - a G80 will put this WAY the heck up there.

 

[Chris TNR]

Originally posted by cjl
Well, today I tried to make a pure carbon tube. It was my first ever attempt, and I think it turned out rather well. ...[Snip]
So. What do you think

Wow! That's your first time!!

( I'd probably get laughed out of the forum if I showed pics of
my first time)
Nice work..
Looks like you've definitely done your homework......you're well on your way.

Gotta do a build thread now, though!

-Chris

 

[cjl]

Well, it's not my first time working with carbon or glass, just my first pure carbon tube (not carbon or glass reinforced paper or phenolic)

 

[Rocket Guy 1317]

Originally posted by Chris TNR
Wow! That's your first time!!

( I'd probably get laughed out of the forum if I showed pics of
my first time)
Nice work..
Looks like you've definitely done your homework......you're well on your way.

Gotta do a build thread now, though!

-Chris

Same, I tired making fiberglass tubes the other day lets say the results weren't pretty. Sorry no pictures.

Oh yeah BTW great looking tube.

 

[rocketkyle]

cjl, I launched my USR Miniroc 1.2 (minimum diameter 29mm) on a RoadRunner G80 at Southern Thunder. I lost sight at ejection, but the streamer was easily spotted on the sod 3/4 a mile away. I just used a normal pink streamer, though I would reccomend mylar. Good luck finding it.

 

[cjl]

Here it is trimmed to length. The Dremel with a diamond cutoff wheel ($15 - ouch!) cut through the carbon like butter, leaving a clean edge and a nice tube.

 

[jraice]

Nice tube! Did you use the shadowaero video? After some more supplies come in I will be making some 54mm ones. I plan on making two tests... about a foot long. One will be made with mylar and heat shrink tape (smooth finish) and the other will use peel ply and a breather covered in heat shrink tape. I will cut them to the same length and see how they compare in weight and finish texture (mylar will be smooth, peel ply will have a uniform roughness). Then I will pick one method to use for the actual airframes...

 

[cjl]

I used the shadow vids as my main resource for the project, as well as some info from the yahoo composite rockets group. It was pure mylar and shrink tape - no peel ply or breather, and as you see it is how it came out of the oven. No sanding, polishing, or filling, just like that.

 

[jraice]

So you like the mylar method? I ordered some peel ply and breather and mylar, i like the way the mylar looks but still plan on doing 2 12" long tests, one with mylar and one with peelply/breather. What thickness of mylar did you use to cover the mandrel? What did you use to cover the outside (I have heard that a thicker mylar is better for the outside)...

 

[cjl]

I used .003" mylar for each, but that's because I had to get it around a 29mm tube. I would go thicker for a larger tube - .005 or .007" depending on the size (I even have some .010")

 

[jraice]

You would go thicker on the inside and outside? I am getting my mylar from TAP plastics, they have .002" and .007"... ill see what they say at the store, and how they feel...

 

[cjl]

Mostly the outside - the inside was fine with the .003"

The reason to go thicker on the outside is to more evenly spread the load from the heat shrink tape. Mine has faint spiral impressions on it - nothing that will impact strength or performance, and not even noticeable unless you look for them, but they probably wouldn't be there with thicker mylar.

 

[jraice]

Should I go thick for both? Or is it better to stay thin on the mandrel?

 

[cjl]

As far as I can tell, it is kind of irrelevant. I would go thin on the mandrel, as much as anything to make it easier to wrap.

 

[jraice]

So thin on mandrel and a thicker one for the outside to help squeeze epoxy out, sounds good (and give it a smoother surface)