fiberglass basics

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watermelonman

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I had been avoiding fiberglass for months, thinking it was some kind of scary voodoo substance. After learning a little more, it seems real simple, and I should have started a while ago. I thought I could get some basic questions addressed, though.

All it is, is sheets of fiber, with epoxy soaked through. Right?

In reinforcing a cardboard tube, do I want to lay down the sheet before hitting with epoxy, epoxy before shaping, or epoxy onto tube then wrap and press? I think the last option.

Is a single layer significant in reinforcing a cardboard tube?

Does one typically worry much about seams? Is it better to err on the side of overlap or a small gap?
 
I have exactly one fiberglassing project under my belt, a scratch built Maxi Alpha (Estes BT-80 tube, light cloth, don't remember the weight). Besides my local rocket buddies' advice, I used two excellent video tutorials from John Coker and Tony Alcocer.

[video=youtube;_gTxwEVK6IY]https://www.youtube.com/watch?v=_gTxwEVK6IY&feature=youtu.be[/video]

[video=youtube;bjZNyXsd8gw]https://www.youtube.com/watch?v=bjZNyXsd8gw[/video]
 
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I have exactly one fiberglassing project under my belt, a scratch built Maxi Alpha (Estes BT-80 tube, light cloth, don't remember the weight). Besides my local rocket buddies' advice, I used two excellent video tutorials from John Coker and Tony Alcocer.

Hah, I have been watching the Tony video on tip to tip, should have figured there was a cardboard reinforcement one too!
 
I had been avoiding fiberglass for months, thinking it was some kind of scary voodoo substance. After learning a little more, it seems real simple, and I should have started a while ago. I thought I could get some basic questions addressed, though.

All it is, is sheets of fiber, with epoxy soaked through. Right?

In reinforcing a cardboard tube, do I want to lay down the sheet before hitting with epoxy, epoxy before shaping, or epoxy onto tube then wrap and press? I think the last option.

Is a single layer significant in reinforcing a cardboard tube?

Does one typically worry much about seams? Is it better to err on the side of overlap or a small gap?


1. Yes, it is sheets of fiberglass saturated with epoxy. Most of the tubes you buy from a manufacture or that come in kits aren't made of "sheets" but we don't need to get into that for what you need to know.

2. I like put down a coat of epoxy and then lay my glass down. I then go back and apply more epoxy to parts that need to me further wet out.

3. Yes, a single layer will increase the strength of a tube. The amount of wraps you need really depends on your reasoning for glassing the tube in the first place.

4. Yes, always cut the cloth a little bit longer then needed to allow for overlap. You can use this equation for figuring out how long of fabric you need.

fabric length=(C)(pi)(1.1)

C=Circumference
 
Usually you want to coat the tube first...
Otherwise; the fiberglass cloth may want to slide right off of the tube that you are working on.

The only time I've ever apply epoxy last when using a fiberglass sleeving.
The stuff Giant leap sells is NOT fiberglass, It's polyester!


Circumference is: pi X r (radius) squared + 2 to 3" should work.
Also add another 4" in length for over hang on both ends of the tube.

Once you get the fiber glassing down you can move on to vacuum bagging.

JD
 
Usually you want to coat the tube first...
Otherwise; the fiberglass cloth may want to slide right off of the tube that you are working on.

The only time I've ever apply epoxy last when using a fiberglass sleeving.
The stuff Giant leap sells is NOT fiberglass, It's polyester!


Circumference is: pi X r (radius) squared + 2 to 3" should work.
Also add another 4" in length for over hang on both ends of the tube.

Once you get the fiber glassing down you can move on to vacuum bagging.

JD

JD, I think that equation is for area ;) C=(pi)D
 
JeromeK99 turned me on to Glassing stuff with Lightweight Glass Cloth.
I was using building techniques that were unnecessarily heavy, and using FG Cloth allowed me to move beyond that.
I can tell you this much, once you get to glassing stuff, you'll want to glass almost everything.
Right now for me this really sucks, because I prefer to cut the Cloth outdoors, and ofcourse I do my sanding of glassed stuff outside, and it has been too cold to work outside this winter.
I have all sorts of work "on the back burner" right now because it either needs glassed or is glassed and needs sanding.:(
Also, when you cut Cloth, if you use Scissors, it screws them up pretty quick, so use a blade of some type whilst holding the cloth down with a straight edge.
As soon as the Weather gets better, I'm gonna' be a glassin' machine!!!
I even cleaned up the workspace in one of my Sheds to use specifically as a Glassing Station. I'de be out there now if I had a way to heat it, but I'm patient.
Another thing, glass clothed Balsa is lighter than Basswood, and stronger too, so that is great for someone like me who likes durable Fins.

Last thing, I too thought it would be complicated to learn, or require some kind of special instruction, but it really is quite simple once you get started. Just make sure you have all your "Environmental Safety Equipment" in order before you get started. Safety First!
It'll be nice when my Shed is all set up for working with it out there.
 
I really want to do vacuum bagging but, still need some more supplies for that.
Hand layups will have to do until then...

He's what I did today:

2015-01-22 15.52.09.jpg


I used some extra Aeropoxy that have.
2015-01-22 15.52.29.jpg

JD
 
Another option for getting glass cloth to stay in place before adding the laminating resin is to spray the cloth with a mist coat of 3M 77 spray adhesive. Or you can mist the surface you are glassing.

Them simply apply the cloth to the tube or part and the mist cost of adhesive will keep the cloth exactly where you want it.

The 3M 77 in no way interferes with the epoxy bond.

Since you can lift and reposition the glass while it is dry, I find this gives the neatest results overall: cleaner seams, no wrinkles and more precise overlaps.

Then you can brush, squeegee or roll in the resin. I find I use less resin with this method.

We used to do a lot of foam and glass external layups at work in years past. I came up with a technique that I have not seen published elsewhere for vastly reducing the post fiberglassing finish work.

You need a container of micro balloons and a dry disposable chip brush.

After your external layup is complete, allow it to cure a bit, but not all the way to the tack free stage. Then, you simply dip the dry brush in the dry micro balloons and brush the powder on to the surface of the cloth, rubbing it in lightly. The slightly cured resin will still grab the micro balloons and a thin layer of slightly wetted and adhered micro balloons will build up on the surface of the layup. The slightly cured resin grabs the micro balloons and does not wet the brush.

Once you get the technique down, you end up with enough micro balloons on the surface to provide an easy to sand surface coat that will completely fill the grain of the glass cloth. This pretty much lets you skip the normal layer of body filler that is required to fill the weave of the cloth. You might need a few dabs of filler here and there, but not much.
 
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Another option for getting glass cloth to stay in place before adding the laminating resin is to spray the cloth with a mist coat of 3M 77 spray adhesive. Or you can mist the surface you are glassing.

Them simply apply the cloth to the tube or part and the mist cost of adhesive will keep the cloth exactly where you want it.

The 3M 77 in no way interferes with the epoxy bond.

Since you can lift and reposition the glass while it is dry, I find this gives the neatest results overall: cleaner seams, no wrinkles and more precise overlaps.

+1 for the spray adhesive tip. Makes for much easier handling of the cloth!
 
I've been meaning to buy some 3M spray adhesive.
Finally found one supplier that had everything I needed.

JD
 
Since you'll be finding out soon that Fiberglass Cloth is the Rocket Gods Gift to Rocketeers, I figured a Bump for this Thread is in order.
It has some great Info, and some good Tips for beginners like us to learn a lot from it if we keep it current.:)
I've been having the best luck lately when doing a single layer of lightweight cloth by coating the Tube in 20 Minute Epoxy, then placing it onto the Cloth, that is already cut to size and layed flat on a Piece of Parchment Paper that I hold onto the Benchtop with Weights, as it is a Non-Stick Surface, and masking Tape does not hold it securely to my Benchtop.
I fuzz up the edges of the Tube ends, so that as the overlapping Cloth is curing, the Epoxy does the work of absorbing into the Edge of the Tube and making the Cloth and the Tube one.
After the thing has cured, I cut away the excess on the ends with a Hobby Knife.
Before doing any sanding, I wet my Nitrile Glove clad Finger in Gorilla Brand Super Glue, and rub it into the ends thoroughly to ensure that when I start to sand I have a uniform and homogenized surface to which to apply my abrasives. Thin CA would be too messy for this Step, but it comes next.

ETA: Note of Caution on next Step! Do this part outdoors, as the inside of the BT with all that CA in it will put out some nasty Vapors, plus, you don't want CA Dripping out of the Tube onto your Floor or where there might be Pets or other Floor Hazards. Outside, with no Bystanders, and bring the safety Safety Glasses and Nitrile Gloves.
Sometimes, on my Super Thin CA, when I open it, there is a little bit in the Nozzle that shoots out. That's why the Safety Glasses.
After a very light sanding, I drizzle Super Thin CA down the inside of the Tube to seal it up inside, and on the Thin Wall Tubes that are glassed, you can usually see the CA soak from the inside to the inner surface of the Glass. There is no doubt that this inner hardening after Glassing enhances the Structural Integrity. It certainly adds weight!
Anyhow, FG is an absolute Joy to work with if you let it be. I am getting a great deal of Practice in on smaller Models. By the time I get Certified I'll have a few years of Experience under my Belt of proven Composite Construction Techniques.
Rocketry was starting to feel like Work before I discovered Fiberglass Cloth. Now I can build a Durable Rocket, but stay light enough to keep Weight Nazis out of my Build Threads.
If they want to question the Stability of my Builds I'll kindly point them to some of my Threads where I used my old Techniques, like papering everything. They see me using serious materials like Glass and even occasionally doing Computer Sims on Open Rocket, and they take me much more seriously. It's quite understandable really, and some of the Members here that I at first thought were sometimes rude or condescending, are actually now some of my greatest Teachers when it comes to broadening my Skill Sets as a Modeler.:)
 
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Here's a completed set of fins glassed with 1 layer on each side of 2.3oz. Cloth. They are for a clone of the Estes Kit #1944, D-Region Tomahawk in BT-60 Scale. They likely weigh less than if I had Papered them, and lighter and more rigid than Basswood.:)

More DREG 001.jpg
 
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It brings me great joy to see my padawan TopRamen has become an expert and teacher of the art of "Light Weight Fiberglassing"!


Some added advice to those new to fiberglass finishing. "Peel-ply"
Avoid the fillers, sanding and over lapped seams. Peel-ply use correctly gives a smooth finish!


Jerome :)
 
It brings me great joy to see my padawan TopRamen has become an expert and teacher of the art of "Light Weight Fiberglassing"!


Some added advice to those new to fiberglass finishing. "Peel-ply"
Avoid the fillers, sanding and over lapped seams. Peel-ply use correctly gives a smooth finish!


Jerome :)

I am by no means an Expert, but thanks Jerome. And thanks again for getting me hooked on the Glass!
I sent Watermelonman some samples to start with just like you did for me. Hopefully it takes!
I still have not used Peel-ply, but this is due to the fact that no matter how much I tried to research it, I still don't understand how it works.
There needs to be a tutorial Video made by someone that explains what it is EXACTLY, and why and how it works.
I'm quite satisfied with the results I get without it, so I'm in no hurry to learn Peel-ply.
 
I never really got to RP so I didn't see what all went on there for the Secret S
Santa. I was hoping for a Squirrel Works Red Baron but when I opened the package I found a MEGA-BARON! Whoo hoo!

Thanks Secret Santa! I hope to build this AFTER I build a Quest Flat Cat for practice. Hopefully by early summer if I get off my backside and get moving on some projects.

Peel ply is just another layer of material that gets laminated over the fiberglass. When the epoxy is cured it is pulled off leaving a surface with no imperfections and extremely smooth.
 
Peel ply is just another layer of material that gets laminated over the fiberglass. When the epoxy is cured it is pulled off leaving a surface with no imperfections and extremely smooth.

I've gathered that much, but I can't wrap my head around how that is any better than using the bare minimum of Epoxy necessary to fully saturate the cloth, and simply laying the dry cloth on top of the Epoxy covered Tube. The weave pattern will fill in with Primer anyhow. I immagine that if I relied on Peel-ply, the actual amount of Epoxy on the tube would be greater. If the peel ply simply fills the weave pattern with Epoxy, it does not seem like too big of a deal for the small scale and light weights that I'm using so far.
Likewise, when I do Fins, I simply cover the Fin with Epoxy, then press it onto the cloth that sits on top of parchment paper, then set the whole thing under flat surfaces. Rarely does the weave pattern show up as a textured surface with this method, but when it does I can just rub in a little more Epoxy.

I think the Peel-ply is probably more helpful when you start working at a larger scale. It is inevitable that I will learn it eventually, but for now I think it is unnecessary.


Why did you quote Peartrees unrelated Post???
 
I've gathered that much, but I can't wrap my head around how that is any better than using the bare minimum of Epoxy necessary to fully saturate the cloth, and simply laying the dry cloth on top of the Epoxy covered Tube. The weave pattern will fill in with Primer anyhow. I immagine that if I relied on Peel-ply, the actual amount of Epoxy on the tube would be greater. If the peel ply simply fills the weave pattern with Epoxy, it does not seem like too big of a deal for the small scale and light weights that I'm using so far.
Likewise, when I do Fins, I simply cover the Fin with Epoxy, then press it onto the cloth that sits on top of parchment paper, then set the whole thing under flat surfaces. Rarely does the weave pattern show up as a textured surface with this method, but when it does I can just rub in a little more Epoxy.

I think the Peel-ply is probably more helpful when you start working at a larger scale. It is inevitable that I will learn it eventually, but for now I think it is unnecessary.


Why did you quote Peartrees unrelated Post???

I think your right that it is probably useless for something on a small scale but it does help with larger scales. If your fine with what your doing now the. Stick with it :) I was on my phone so I guess I used the wrong quote
 
I tried to do a Coker style lay up but tried to use wax paper instead of butcher paper. It was messy and the glass seemed to pull sideways and try to deform as i was trying to tight roll it on the table. Also the end caps were a bit ackward to assemble and seat to overwrap the tube an inch.

Also tried to do composite fins Coker style, but folded a length of mylar across leading edge to make seamless and weighted down with porcelain squares and bricks instead of bagging.

Tube had dry spots and voids and pinholes. .but overall was happy with the result for 1st time - was usuable and weighed considerably less than FG tube and Blue Tube.

The fins did not come out with seamless leading edges because the mylar shifted slightly. .and there were some dry spots voids pinholes and the edges were lifting.

After painting and cristening as my daughters Mega Der Purple Max and it flew on a H400 vMax outta the gate.

Really like the elasticity and some bounce to the tube after a single wrap, will do my other pro series builds the same way. Next time will use 3m to stick the wrap and then whet out, will twist fg tight at ends and rubber band instead of using end caps and cut off last 1/4 inch of tube. Picked up a food sealer so may try to vacuum bag fins or may just do one side at a time weighted again.

Overall with in improving strength of a paper tube but without most of the weight penalty of substituting FW FG tubes or blue tube is worth it.

Kenny

1424985222641.jpg

1424985264203.jpg

20141206_141329.jpg
 
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I tried to do a Coker style lay up but tried to use wax paper instead of butcher paper. It was messy and the glass seemed to pull sideways and try to deform as i was trying to tight roll it on the table. Also the end caps were a bit ackward to assemble and seat to overwrap the tube an inch.

Also tried to do composite fins Coker style, but folded a length of mylar across leading edge to make seamless and weighted down with porcelain squares and bricks instead of bagging.

Tube had dry spots and voids and pinholes. .but overall was happy with the result for 1st time - was usuable and weighed considerably less than FG tube and Blue Tube.

The fins did not come out with seamless leading edges because the mylar shifted slightly. .and there were some dry spots voids pinholes and the edges were lifting.

After painting and cristening as my daughters Mega Der Purple Max and it flew on a H400 vMax outta the gate.

Really like the elasticity and some bounce to the tube after a single wrap, will do my other pro series builds the same way. Next time will use 3m to stick the wrap and then whet out, will twist fg tight at ends and rubber band instead of using end caps and cut off last 1/4 inch of tube. Picked up a food sealer so may try to vacuum bag fins or may just do one side at a time weighted again.

Overall with in improving strength of a paper tube but without most of the weight penalty of substituting FW FG tubes or blue tube is worth it.

Kenny
 
Lets not forget the best thing about glassing Tubes.
NO MORE FILLING AND SANDING SPIRALS!!!!! :clap::grin::w::happydeer::D
I've seen some folks, myself included, add so much Bondo and Primer to a Body Tube just getting it perfectly smooth, that we had added at least as much weight and then some versus what would be added and saved by simply glassing the Tube in lightweight cloth.
Not to mention you can spend hours sanding and filling. I have Arthritis and nerve damage in my right hand, so sanding things sucks the Joy out of building.
My builds progress at a better pace now.
 
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I've gathered that much, but I can't wrap my head around how that is any better than using the bare minimum of Epoxy necessary to fully saturate the cloth, and simply laying the dry cloth on top of the Epoxy covered Tube. The weave pattern will fill in with Primer anyhow. I immagine that if I relied on Peel-ply, the actual amount of Epoxy on the tube would be greater. If the peel ply simply fills the weave pattern with Epoxy, it does not seem like too big of a deal for the small scale and light weights that I'm using so far.
Likewise, when I do Fins, I simply cover the Fin with Epoxy, then press it onto the cloth that sits on top of parchment paper, then set the whole thing under flat surfaces. Rarely does the weave pattern show up as a textured surface with this method, but when it does I can just rub in a little more Epoxy.

I think the Peel-ply is probably more helpful when you start working at a larger scale. It is inevitable that I will learn it eventually, but for now I think it is unnecessary.

You pretty much have it dead on TR. Any smooth film that won't stick to your resin will work for something flat like fins as long as you are using mechanical pressure instead of vacuum. The peel ply serves the same purpose when using a vacuum bag and is porous so that trapped gas in the resin can escape. It looks like you are getting good results for what you need right now.
 
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