Fiberglass or carbon fiber? Nah. I'm thinking pants.

[ebruce1361]

Okay, this one is really out there and consumption of alcohol may or may not have contributed to this train of thought, but I had a weird idea last night.

First off, I have never really worked with hardened fiberglass or carbon fiber for anything, let alone rockets, but I understand the basic concept of a thin and lightweight fabric that is already pretty strong being soaked in epoxy to give it rigidity. So what about other fabrics? Could a tube be rolled just like fiberglass or carbon fiber but use a different material plus the epoxy? Like say...denim? Maybe cotton?

I realize that a denim rocket would almost certainly be much heavier than fiberglass, but I'm not thinking about optimized materials here. I'm thinking novelty. What about your favorite band tshirt that has been kept for sentimental reasons but you don't wear any more because it has too many holes in it? Why can't that be measured out, cut, stretched over a pipe or other form mold, soaked in epoxy and made into rocket parts?

Maybe it's because I've never worked with fiberglass or carbon fiber that I am naive and therefore thinking so outside-the-box that I am in a different zipcode altogether and not realizing an obvious flaw that more experienced people know of. So, tell me: am I crazy or am I "crazy"?

 

[ThreeJsDad]

TOO FUNNY !!!!

Some 10 years back when I was new to rocketry but not resins that thought occurred to me. Our field has a low waiver so my thought process was low and heavy was good. I made quite a few rockets using 1yd fabrics from Wally World..... They were heavy but they were also very tough.

So, yes it can be done but you will be putting a G motor in the same size rocket I fly on a D.....LOL

The comics from the Sunday paper works as well.

 

[ebruce1361]

The comics from the Sunday paper works as well.

Paper, huh? Like paper mache but stronger. Okay, what about ... ready for this one?... DOLLAR BILLS? It would be the perfect joke at a club launch. You have to be made of money for this hobby.

 

[manixFan]

Okay, this one is really out there and consumption of alcohol may or may not have contributed to this train of thought, but I had a weird idea last night....<snipped for brevity>...
I realize that a denim rocket would almost certainly be much heavier than fiberglass, but I'm not thinking about optimized materials here. I'm thinking novelty. What about your favorite band tshirt that has been kept for sentimental reasons but you don't wear any more because it has too many holes in it? Why can't that be measured out, cut, stretched over a pipe or other form mold, soaked in epoxy and made into rocket parts?
...<snipped for brevity>...

Oh man, if my wife heard I could turn my old t-shirts into rockets, she'd take them all out to the garage and start cutting them up herself. I have bins full of them. I like your admission that beverages may have influenced your thinking.

Actually there is no reason why you couldn't laminate a tube with a t-shirt or denim. It would be mostly decorative but would certainly add some rigidity. Actually a 6" rocket covered with old rocket t-shirts is a pretty cool idea.

In my mind, that's a good king of crazy.


Tony

 

[ThreeJsDad]

Paper, huh? Like paper mache but stronger. Okay, what about ... ready for this one?... DOLLAR BILLS? It would be the perfect joke at a club launch. You have to be made of money for this hobby.

Laminate some Monopoly money into a rocket...Now that would be a riot.....

 

[Kelly]

I have a nosecone, for a 3" rocket, that is turned from foam and strengthened with a layer of epoxy over nylon panty hose.

 

[ThreeJsDad]

I have a nosecone, for a 3" rocket, that is turned from foam and strengthened with a layer of epoxy over nylon panty hose.

That is Brilliant. I have used HL60 in my shop for years but never thought of using stockings and resin as a hard finish !!

 

[heada]

Linen in phenolic is pretty standard stuff and is used as the liner in several reloads by some vendors.

Fiberglass, carbon fiber and kevlar are normally used for their combination of strength/weight/wear-resistance but there's no reason you can't use some other material like cotton. I add milled cotton fiber to my epoxy to bulk it up for fillets.

 

[ThreeJsDad]

Linen in phenolic is pretty standard stuff and is used as the liner in several reloads by some vendors.

Fiberglass, carbon fiber and kevlar are normally used for their combination of strength/weight/wear-resistance but there's no reason you can't use some other material like cotton. I add milled cotton fiber to my epoxy to bulk it up for fillets.

You make a good point because even those "hi-tech" materials have their strengths. Kevlar is super tough as in if something is crushed it can be pushed back out, wetted out and good as new. Carbon Fiber is better in elongation than compression. It is also the most brittle of the three. Fiberglass is like an old Pick up truck, nothing fancy but it is the work horse of the composite world.

I very rarely lay up something using just Carbon Fiber. I will almost always have a layer of kevlar or Fiberglass with it to make the finished item tougher.

Another material I really like but is harder to find is Basalt. It was developed by the Russian space program as a heat shield. It is easier to cut that Kevlar and is super easy to wet out. It is also Very tough.

 

[Nytrunner]

What canvas is canvas phenolic made out of? there's a question

 

[BABAR]

Probably waaaaay out there, but what about the flip side. What about using fiberglass (or denim) cloth and something OTHER than resin? Would standard white or wood glue work?

 

[ebruce1361]

Probably waaaaay out there, but what about the flip side. What about using fiberglass (or denim) cloth and something OTHER than resin? Would standard white or wood glue work?

I have seen fabrics soaked in white Elmer's glue to give them some rigidity for visual use. My high school once did a play where a ghost was in a hooded robe kind of like the grim reaper, but was otherwise invisible. The drama department took a black bed sheet and draped it over a mannequin and slathered Elmer's glue all over it and let it dry for a few days. Then they cut it away from the mannequin, cut off the sleeves and reattached them with black shoelaces so they could move and covered the joints with more fabric. Essentially, they ended up with a life-size puppet with movable arms and screwed the whole thing down to a wooden furniture dolly. It did have problems though. The whole thing was heavy enough that the back would fold inward and make it topple. Also, it wasn't truly rigid. The dried glue still had some flex to it that would make the sleeves droop if they were held up for too long.

So for rocket applications, I don't imagine Elmer's glue would work well. However, wood glue might work a whole lot better. I always put a small dab of wood glue on my kevlar cord knots to keep them from coming loose, and it cures nice and hard. Also, soaking CA into fabric makes for a solid piece, but it is often very brittle. I wonder what Testors model cement would do in fabric.

It sounds to me like this whole thing could use some old-fashioned experimentation. We may be on the cusp of the development of a whole new materials science here. Redneck grade composites.

 

[BABAR]

I suspect most of the High Power folks work either in garages, sheds, barns, or other dedicated rooms where resin and other epoxy fumes, lots of dust, etc., are not a problem for SWMBO . Aside from painting, which I either do outside or in small amounts in the unfinished part of my basement, I build at a table while watching movies or listening to audiobooks with my girlfriend, so something that is more user friendly to an armchair builder than resin would be nice.

 

[Kelly]

Oh, one more thing. I used to make knives, and remember reading some articles about making scales (the handle, basically) out of denim and epoxy. Here's one of many links you can find:

https://www.offgridweb.com/preparation/making-a-diy-knife-with-denim-handle-scales/

 

[ebruce1361]

@Kelly
AWESOME! That's pretty much exactly what I had in mind! Now that I know it has definitely been done before and not turned out to be a total mess, I think I will try with some denim fins and then maybe attempt to roll a tube. I'm not sure how I could do a decent nose cone quite yet, but this is a great start.

 

[dhbarr]

I've been wanting to make a blue jean bertha for some time now -- was just planning on laminating many layers then lathing down.

 

[kuririn]

What canvas is canvas phenolic made out of? there's a question

Don't know (I'm a phenolic newbie), but the phenolic fins on the MAC Black Fly are tough.
Canvas soaked in resin. The phenolic tube and fins appear every bit as durable (and heavy) as fiberglass.
That reminds me, I have to do internal and external fillets on this and wrap it up.

 

[mike2wander]

What canvas is canvas phenolic made out of? there's a question

Cotton.

 

[Nytrunner]

every bit as durable (and heavy) as fiberglass.

Durable yes, 30% lighter

 

[cwbullet]

Cotton and nylon will work. I can confirm it.

 

[ThreeJsDad]

I suspect most of the High Power folks work either in garages, sheds, barns, or other dedicated rooms where resin and other epoxy fumes, lots of dust, etc., are not a problem for SWMBO . Aside from painting, which I either do outside or in small amounts in the unfinished part of my basement, I build at a table while watching movies or listening to audiobooks with my girlfriend, so something that is more user friendly to an armchair builder than resin would be nice.

Other than the mechanical properties of the resin I use I also like the low odor. It has a very mild and kind of sweet smell. It is nothing like polystyrene resin (Bondo) or even polyester resin.

I do have a garage shop with a curing oven but for small parts I can sure them in the kitchen oven set at 150deg and nobody in the house smells anything. I do use parchment paper to keep the resin from getting on anything. I have been dong that for 15 years.

 

[ThreeJsDad]

Cotton and nylon will work. I can confirm it.

I have used nylon for live hinges on planes. By this I mean I put it in the lay-up and then cut through to it. After a bit of wiggling the resin breaks loose from the nylon. The best way to tell if you can use nylon is to get it wet in some water. If it readily soaks up the water you should be okay.

 

[ebruce1361]

Over the weekend, I assembled a simple frame made from a scrap 2x4 similar to the one seen in the knife video @Kelly posted, and selected a suitably uncomfortable pair of pants for a fabric donor. Hopefully I can get some free time tonight or tomorrow to try to make a 3" x 6" rectangle four layers thick. I have wax paper, but no mold release. I could order some, but from carbon fiber fabrication videos I've watched, I think I can get away with a thin coating of graphite powder or even PAM cooking spray. I'll do this first test with some cheapo Harbor Freight 15 minute epoxy since this is more of a proof-of-concept test than the creation of actual parts. But, if the piece turns out to be plenty sturdy, I might just cut it up and make fins for a little low power rocket because why not?

Stay tuned!

 

[heada]

Mixwax paste wax. Put it on and buff it. That very thin coating of wax has worked as a mold release for me. I also have a can of Mann 400 which is great stuff.

https://www.aircraftspruce.com/categories/building_materials/bm/menus/cm/moldrelease.html

 

[dr wogz]

I've done the stockings over a mold for airplane cowls & such. easy, light.. just takes a proper mold to mold over.

I recently fixed a 4:" zipper in my Super DX-3: i sanded the zipper fairly flat. I then inserted the payload bay into the tube, with wax paper in between. i then added epoxy, and layered in about 8 or 12 layers of .5 oz glassing cloth. The added a bit ore epoxy, and filly a piece of waxed paper, then an old short piece of 4" BT , slit, to fit over the original 4" BT, then secured it all with elastics & let cure. Results were a super strong fix that barely needed any sanding. Still debating whether I want to paint it, or leave it as proof of a great fix.

Back int eh college days, a friend forced his younger brother to wear a shirt soaked in plaster of Paris. after a few hours of sitting still, he had a T-shirt sculpture; the t-shirt looked like it was being worn by an invisible boy! very cool!!

 

[ebruce1361]

Well, experiment #1 is underway! I cut out five pieces (one extra in case I messed one up) of denim from the donor pants, measured out some epoxy by weight, mixed it up, added a splash of acetone to thin it out a bit, and proceeded with my layup. The first thing I learned is acetone soaks right in to untreated paper plates where it won't do very much to help. Next time, I'll try a coated one so the acetone can actually get into the epoxy. Since i didn't know how much epoxy to use, I just guessed and squirted out 12 grams of each part. Well lo and behold, 24 grams of epoxy isn't enough to cover all four pieces. I was only able to get three pieces covered. This is good science! I can't imagine any other way to have determined how much epoxy is needed to cover and soak into denim, but it turns out a 3" x 5.5" (had to cut half an inch off the length because the denim was flush against the ends of the mold, and I wanted room for it to expand in all directions) single piece rectangle of it takes 8 grams. That comes to 2.06 grams per square inch (front and back)! Also, I was curious just how much of a hassle removal would be with just the wax paper, so I added no additional lubricant/mold release. I realize that there is a chance the paper ripped in the corners and the epoxy may have oozed into the mold itself, but this mold can be disposed of and replaced easily if necessary. Still, I tried to be careful with the wax paper for both the top and bottom layer, so hopefully I can remove the finished piece. Finally, I secured the whole thing with five clamps and left it to sit for 24 hours. I did the layup last night around 11:00, so I might just let it sit for even longer and open it up tomorrow morning for a good 30+ hour cure.

 

[Nytrunner]

You've heard of BlueTube, but are you ready for....BlueJeanTube?

 

[ebruce1361]

Here are the results as of 6:45 this morning; almost exactly 31 hours of curing.






The finished piece has some wax paper stuck to the middle on both sides, but the whole thing came out of the mold with no problem. It has some minor surface imperfections that need to be sanded out as well as the edges trimmed, but right now it's a bit under ⅛" thick and the piece is about the same weight as basswood for the same size. It's not as brittle as I expected, rather it's got some flex to it but is still plenty rigid and doesn't deform when flexed. I'll clean it up at home tonight and do some stress testing to see just what it takes to break it.

 

[heada]

If you already have it, parchment paper might work better than waxed paper. Parchment paper is impregnated with silicone. Some things release better from waxed paper, some things better from parchment paper. Not sure which would work better for you.

 

[ebruce1361]

I don't have any parchment paper, but I will try that!

I tried to upload a video from this morning when I first inspected the piece, but my phone didn't want to do it, so on to my youtube channel it went.