Poor Man's Fiberglass

[techrat]

Howdy group....

Just watched a youtube video where some guys built their own camping trailer from a $100 used open trailer. After completeing the structure, instead of fiberglassing the outside, which would have cost a fortune, they instead used wood glue and cloth. Using a few gallons of wood glue and some cloth painting tarps, they first laid on the glue, pressed down the cloth, then gave the whole thing another layer of glue and let that harden.

I was wondering if anyone has tried this on a rocket yet? Obviously this would only work for a Body Tube that's cardboard. As long as the cloth is thin, I can't imagine it adds any more weight than the actual fiberglass and epoxy method. The only question is durability.

Other suggestions for fiberglass alternatives have been women's pantyhose for very light/small rockets and used fabric dryer sheets from the laundry as sheets of material that will soak up the epoxy and add stiff structure to an existing rocket. Can anyone think of anything else that might work?

 

[Steve Shannon]

Howdy group....

Just watched a youtube video where some guys built their own camping trailer from a $100 used open trailer. After completeing the structure, instead of fiberglassing the outside, which would have cost a fortune, they instead used wood glue and cloth. Using a few gallons of wood glue and some cloth painting tarps, they first laid on the glue, pressed down the cloth, then gave the whole thing another layer of glue and let that harden.

I was wondering if anyone has tried this on a rocket yet? Obviously this would only work for a Body Tube that's cardboard. As long as the cloth is thin, I can't imagine it adds any more weight than the actual fiberglass and epoxy method. The only question is durability.

Other suggestions for fiberglass alternatives have been women's pantyhose for very light/small rockets and used fabric dryer sheets from the laundry as sheets of material that will soak up the epoxy and add stiff structure to an existing rocket. Can anyone think of anything else that might work?

Linen phenolic is a similar material.

 

[SolarYellow]

Dope and fabric was a thing for a lot of decades.

But in reality, fiberglass and polyester resin are pretty cheap, especially when you compare results of the final product. Epoxy would be another story.

 

[prfesser]

Dope and fabric was a thing for a lot of decades.

But in reality, fiberglass and polyester resin are pretty cheap, especially when you compare results of the final product. Epoxy would be another story.

Depends on where you get it. If you want brand name, maybe the difference is important. OTOH US Composites has polyester resin for about $50/gallon. A 5-quart kit of laminating epoxy+fast hardener is $92, a 6-quart kit with slow hardener is $100. Yes, more expensive but not prohibitively so, and much less smelly. I've used polyester once. A little too much or too little catalyst and you have a sloppy mess/hard lump of plastic. Even if one were to use 10 gallons for a project, I'd think that the cost differential would be less important than the ease of use. Go with the cheaper slow curative and let it sit in the midday sun to cure.

 

[Daddyisabar]

Depending on your level of bulletproofing, just soaking lowly, cheap, LPR kraft tubing with thin CA will plasticize it enough to handle most motors that will fit. I call it Poor Boy Phenolic.


Warning: You might receive pained looks on the faces of the high power elite at the mere mention of such "cheapskateness." "Son, just opt fer some light glass and save yer image!" Flying it off a quarter inch rod will put them over the top.

 

[Daddyisabar]

Dope and fabric was a thing for a lot of decades.

But in reality, fiberglass and polyester resin are pretty cheap, especially when you compare results of the final product. Epoxy would be another story.

I think smelling all that dope has affected the old dude's minds. Working in that WWI aircraft factory made you real dopey! Super sharp sheers to cut that Irish linen. Dye that dope red and get this Triplane out to Manfred Von! Those were the days!

 

[SolarYellow]

Wipe the glassine off with a damp paper towel, then CA the kraft. I dig it. On the other hand, if you look here

https://www.erockets.biz/body-tube-sizes/
there are thicker-wall body tube options at most size increments.

That list doesn't include the Quest sizes they sell, plus there is BMS, LOC and @hcmbanjo's BT-20H. And maybe some others out there.

I kinda like the oddball, no longer popular sizes like BT-40, ST-10, etc. They are typically heavier wall and allow TTW and other heavy-duty construction methods on slightly-above-MD rockets.

 

[Daddyisabar]

Wipe the glassine off with a damp paper towel, then CA the kraft. I dig it. On the other hand, if you look here

https://www.erockets.biz/body-tube-sizes/
there are thicker-wall body tube options at most size increments.

That list doesn't include the Quest sizes they sell, plus there is BMS, LOC and @hcmbanjo's BT-20H. And maybe some others out there.

I kinda like the oddball, no longer popular sizes like BT-40, ST-10, etc. They are typically heavier wall and allow TTW and other heavy-duty construction methods on slightly-above-MD rockets.

I just soak the rough, bare inside of the Kraft tubbin' till it starts smokin' and I start coughin' and cryin'!

Spread the super thin and hard to handle CA around with a scrap piece of balsa. Work fast, no dilly dallying! Leave the outside pristine to fill the spirals to perfection and finish like glass.

Then get out the lovely dope fer those old school balsa fins and nose cones!

 

[SolarYellow]

Makes me wonder about the old model airplane procedure of painting the engine mount area and fuel tank compartment with epoxy thinned with alcohol. Fuel proof and, thinned enough, it is like a heavy varnish that leaves wood grain showing. It isn't as strong as unthinned epoxy, but that's not the point. Might have to try that on some MD thin-wall BT. Probably want to go CWF in the spirals first so you're not trying to sand epoxy blush out of the grooves to get anything at all to stick.

Would be pretty straightforward to run some bending, crippling, buckling, denting, and pressure containment tests to characterize the results. It at least shouldn't be brittle like phenolic.

 

[ThirstyBarbarian]

These kinds of DIY hacks are sometimes fun and interesting to try, but the trade offs are kind of like the trade offs I’m sure are being made by the trailer guys — proper fiberglassing costs more but gives a good result that lasts a long time, while alternatives cost less but give poorer results. A fiberglass trailer can last decades. A wood glue and tarp trailer? Maybe not so great.

That doesn’t mean there’s no place for alternatives — just do it when it makes sense. To me, if you want a fiberglass rocket, buy good fiberglass tubes. Or if you buy good quality cardboard airframe tubing, you probably don’t need to glass it, or if you feel you do, then a legit fiberglassing job is probably in order, and then a real fiberglass tube probably makes more sense.

I feel like the main reason to use fiberglass or other strengthened over cardboard is when you are using a cardboard tube that is NOT high-quality airframe tubing, and it needs to be strengthened. And there are plenty of examples of that.

One example would be when you are making a truly huge rocket out of sonotube or something of that kind. In that case, I’d probably lean toward a real fiberglassing job with fiberglass and laminating epoxy.

Another example is “trash building” with things like wrapping paper tubes or other repurposed materials. That’s probably a great opportunity for strengthening on a budget. Plus it can be fun to experiment with that kind of technique. I’ve built a few wrapping paper tube rockets, and I’ve usually stiffened the tubes by wrapping them in label paper. It adds some strength (not a lot, but some), and you can print a design on them before wrapping the rocket, so you don’t actually have to paint the rocket. That’s a papering technique, like papering fins, so I think a wood glue or white glue technique might work too. You could use white glue and paper, or you use glue an cloth if you wanted to give it a shot.

Another technique you could try on a trash tube is a pantyhose and a hardener I can’t remember at the moment. I think it’s called pseud-glass. I’ll try to look that up.

EDIT: Here’s the thing I was trying to remember. The technique is called “Quasi-glass”, not “pseudo-glass”. Silly me! Here’s a post about it. https://www.rocketryforum.com/threads/quasiglass.164093/ I haven’t tried it myself but was curious about it.

Also, I have used the technique mentioned by others of soaking tubes with thin CA. That stiffens them up nicely.

 

[techrat]

EDIT: Here’s the thing I was trying to remember. The technique is called “Quasi-glass”, not “pseudo-glass”. Silly me! Here’s a post about it. https://www.rocketryforum.com/threads/quasiglass.164093/ I haven’t tried it myself but was curious about it.

Yes... I used the quasi-glass method on two rockets I built over the winter -- "Queen Bertha" and "Der Rust Max". I feel that they were able to stiffen the body tubes just enough to survive a little more abuse and didn't add that much weight. Bertha in particular as that rocket uses Estes thin-walled BT-80 tube, and wouldn't have stood up to the high-power F motors I've been running in that bird. I used the built-up balsa fins, but I gave the entire rocket including the fins a final coating of thinned laminating epoxy, and I have to say that they are tough enough to survive a hard landing.

I also recently built a Star Orbiter and after hearing that the BT-60 tube sometimes folds under higher power 29mm motors, I wrapped the body tube in 1.5oz Fiberglass, as I'm interested to see what happens when I try something stupid like running an F52 in a $22 Estes kit.

 

[Daddyisabar]

When you are doing really stupid things with BT 80 Kraft tube the best way to go is to simply make it thicker. Glue in some couplers, fast, easy, cheap. I know that is scary with the Titebond grab, but fear is the mind killer. I had to strengthen a section of thin BT80 oddroc tube for three 29mm F motors ejecting into a small space supporting a ridiculously heavy nose cone. A section of scrap coupler with Titebond worked well.

P.S. if you are doing a longer tube see if you can get longer coupler stock. Or drop unglued or slightly tacked sections down on top of your reinforced motor mount.

Coupler stock too expensive? Just use sections of crashed and recycled tubing from your past failures. Cut a slot out and drop it in. I bet if roughed up friction alone would keep it in. Improvise and survive! Cheapskate LPR fliers moding to HPR unite!

 

[Daddyisabar]

Yes Mr. Highly glassed, Level Two RSO, i did not glass it for awesome high power strength. It is reinforced from the inside. Just little me, some paper and cow glue from the school.

Awwwe. Give the kid a far far away pad assignment, we want to see it collapse under thrust!

The expressions on the high power guys after a perfect flight...priceless.

Disclaimer: The story above has been fictionalized and may be based on a true story. Names have been changed to protect the guilty.

 

[cerving]

I wonder how that trailer is going to look after a season of sitting out in the rain...

If you don't want to use epoxy resin, you can get by with polyester resin, and it's cheaper and easier to work with too. Just don't expect the same strength as as filament-wound epoxy fiberglass tube.

 

[ZEDL1]

Linen phenolic is a similar material.

Canvas phenolic as well

 

[Ogre3713]

I have used gauze bandages layered up with carpenters glue to fix a broken balsa fin on my Duece. It's ugly as Hell but it worked.

 

[techrat]

You should stick two band-aids, criss-cross, right over that. It would look hysterical!

 

[cbrarick]

sometimes I wonder if these "cost saving" hacks really are.
If your time has no value, then maybe.
If you value your time, well probably not.

 

[Bruiser]

I have used my version of quasi-glass on my 3" Goblin, 3" Raytheon Peregrine, 3" Lockheed Cuda, 3" Doorknob and 3" Big Red Der Max. All were built using Estes pro series tubing.

I use a leg from a small pair of nylons, followed by two coats of water based poly which is then sanded followed by a top coat of water based poly. A little more sanding followed by filler primer. It goes pretty quick, doesn't stink, has easy clean up, doesn't cost a lot, gives a smooth surface for your paint and does slightly strengthen the tube. Oops, just remembered. I used a knee-high on the Goblin and the Big Red Der Max

-Bob

 

[BABAR]

I have used my version of quasi-glass on my 3" Goblin, 3" Raytheon Peregrine, 3" Lockheed Cuda, 3" Doorknob and 3" Big Red Der Max. All were built using Estes pro series tubing.

I use a leg from a small pair of nylons, followed by two coats of water based poly which is then sanded followed by a top coat of water based poly. A little more sanding followed by filler primer. It goes pretty quick, doesn't stink, has easy clean up, doesn't cost a lot, gives a smooth surface for your paint and does slightly strengthen the tube. Oops, just remembered. I used a knee-high on the Goblin and the Big Red Der Max

-Bob

So do you save the fishnets for the really sexy rockets?

 

[Bruiser]

I have thought of using those for some type of "reptilian" paint scheme

Bob

 

[techrat]

So far the best idea I've seen on this thread is the used fabric dryer sheets. That's brilliant because it re-uses something we'd normally throw away, and their smaller size makes it easy to layer and put on without hassle. Definitely trying this on an upcoming rocket. As for the fishnets, if you build a slim, shapely rocket with dual nosecones in the right place, go for it!

 

[BABAR]

So far the best idea I've seen on this thread is the used fabric dryer sheets.!

Plus if you use the name brand then when the rocket lands it will bounce!

(I mean, who builds a rocket to snuggle? And downy just doesn’t sound good either.)

(lemme know if it keeps that black powder smell away!)

 

[rokit]

People make watercraft like canoes and kayaks using PMF.

Here's a great resource for building camping trailers using PMF over foam board insulation:
https://www.tnttt.com/viewforum.php?f=55&sid=1311caa5d56ab1f397b92b6519bbdd4f
Many of the people who post in that forum get many years of use out of their trailers.

You could do it for a rocket. But as previous posts have mentioned, there are other methods that may be a better fit for our application.

 

[ep29030]

In alternate materials, people have used wood glue and tissue paper on glider wings. Have also seen articles where people used epoxy and vacuum-bagged brown paper from grocery sacks on glider wings to stiffen them. I use typing paper and wood glue on fins, placed under weights to stiffen fins on a regular basis. As said earlier, there are lots of alternate materials and adhesives you can use. The hard part is knowing when to make trade-offs in cost and performance. Know-how is often second to know-when.

 

[techrat]

So far the best idea I've seen on this thread is the used fabric dryer sheets.

Well, I covered a portion of a rocket with the used fabric dryer sheets and tried it. It didn't come out so well. Too lumpy. And even after much sanding and a coating of thinned epoxy and then more sanding, still too lumpy. So I painted that area copper/gold and made it look like the crinkled foil of the LEM. I'll slap a NASA sticker on it and call it a day. It was a good experiment though.

 

[CameronMakesRockets]

Makes me wonder about the old model airplane procedure of painting the engine mount area and fuel tank compartment with epoxy thinned with alcohol. Fuel proof and, thinned enough, it is like a heavy varnish that leaves wood grain showing. It isn't as strong as unthinned epoxy, but that's not the point. Might have to try that on some MD thin-wall BT. Probably want to go CWF in the spirals first so you're not trying to sand epoxy blush out of the grooves to get anything at all to stick.

Would be pretty straightforward to run some bending, crippling, buckling, denting, and pressure containment tests to characterize the results. It at least shouldn't be brittle like phenolic.

Is there a proper ratio of epoxy to alcohol to thing the epoxy out? Would too much alcohol ruin the epoxy completely?

 

[SolarYellow]

AFAIK, the proper ratio is "TLAR." Once it gets paintable and acts like a thick varnish, soaking into the BT readily, that's probably good.

Just to note, I still haven't tried this yet. I wrote it just after seeing an MD BT-20 that had really nice, smooth paint before launching get permanent witness marks of the spirals after launching. There's also BT-20H and Quest 20mm tubing. I currently am making plans around the Quest stuff, since it's available from BMS.

To the second question, yes.

 

[CameronMakesRockets]

he proper ratio is "TLAR."

I am not familiar with the acronym of TLAR, can you explain further please?

 

[SolarYellow]

That looks about right.