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How Much Fiberglass Should I Use?

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I'm currently building a high performance 38mm, 56" tall rocket. This project will be my first time fiber glassing an air frame and fiber glassing fins tip to tip. I'm using Public Missiles phenolic tubes for the body. So how many times should I wrap the body with 3oz or 10oz fiberglass weave if I'm anticipating a top speed of around mach 2? Same question for the tip to tip fins. How many layers should I use for the fins?
 

markkoelsch

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I would look at 6 ounce glass,but the 10 would do. I would do two or three layers laminated in one continuous piece. Then a breather and heat shrink tape.

I think the 3 ounce is too light unless used as a single layer for sanding purposes.
 

markkoelsch

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I would look at 6 ounce glass,but the 10 would do. I would do two or three layers laminated in one continuous piece. Then a breather and heat shrink tape.

I think the 3 ounce is too light unless used as a single layer for sanding purposes.
What are the fin cores made of and what is the span?
 

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I would look at 6 ounce glass,but the 10 would do. I would do two or three layers laminated in one continuous piece. Then a breather and heat shrink tape.

I think the 3 ounce is too light unless used as a single layer for sanding purposes.
May I ask where you get 6oz fiberglass?
 

tfish

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I'd go 3 or 4 continuous layers of the 3 oz. For the fins I'd do 2 'layers. First piece of tip to tip would be 1/3 and the last layer would be just 2/3rds.

Tony

added. This is .097 G10 on a 54mm min dia...
 

markkoelsch

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I'd go 3 or 4 continuous layers of the 3 oz. For the fins I'd do 2 'layers. First piece of tip to tip would be 1/3 and the last layer would be just 2/3rds.

Tony

added. This is .097 G10 on a 54mm min dia...
Tony, as always a really useful video. Do you have one on laminating a tube for the OP?

A couple questions.

The Rakka epoxy- is it a room temperature cure,or do you put it in an oven?

Secondly, have you ever used a breather fabric to absorb excess epoxy +/- vacuum bagging?
 

Who_Cares

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Tony, as always a really useful video. Do you have one on laminating a tube for the OP?

A couple questions.

The Rakka epoxy- is it a room temperature cure,or do you put it in an oven?

Secondly, have you ever used a breather fabric to absorb excess epoxy +/- vacuum bagging?
That same guy actually has a tutorial for glassing tubes:
 

tfish

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Mark, I've not used any breather material. You can control the amount of epoxy as you go. I do add some extra (thinned) epoxy just before I apply the peel ply. It helps wet out everything and avoid pin holes. The Raka is room temp. I've seen where it's reall easy to get wrinkles in body tubes that are vacuum bagged. I've not tried it.

Years ago (2011) I did a thread on Rocketry Planet, for an all FG, hand layed, thinned epoxy thread. To prove most guys don't need to go over board on "things". it went 34k mach 1.8

Tony
 

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Mark, I've not used any breather material. You can control the amount of epoxy as you go. I do add some extra (thinned) epoxy just before I apply the peel ply. It helps wet out everything and avoid pin holes. The Raka is room temp. I've seen where it's reall easy to get wrinkles in body tubes that are vacuum bagged. I've not tried it.

Years ago (2011) I did a thread on Rocketry Planet, for an all FG, hand layed, thinned epoxy thread. To prove most guys don't need to go over board on "things". it went 34k mach 1.8

Tony
tfish I've got a couple of questions. Do you use the same method for glassing a 36" tube as you do in the video shown above? And where do you buy peel ply at?
 

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I'd go 3 or 4 continuous layers of the 3 oz. For the fins I'd do 2 'layers. First piece of tip to tip would be 1/3 and the last layer would be just 2/3rds.

Tony

added. This is .097 G10 on a 54mm min dia...
How many layers would you recommend if I use a 6oz weave for the body and the fins?
 

tfish

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tfish I've got a couple of questions. Do you use the same method for glassing a 36" tube as you do in the video shown above? And where do you buy peel ply at?
36" diameter? If so that's out of my realm. If you go with 6 oz I'd only do 2 layers. If you have some scrap BT laying around..play around with various number of layers to see what you feel like will work.

and the peel ply is the stuff Tim posted the link to.

Tony
 

AlphaHybrids

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I performed a small study on this very topic last year using 4” LOC tubing. I ultimately settled on 2 wraps of 6 oz glass.

https://www.rocketryforum.com/threads/glassing-my-first-tube.136266/page-2
I prefer the fiberglass sleeves from Soller Composites. I'm a bit of a kludge and with the sleeves I can easily glass a 5.5" airframe with a sock, sacrificial bulkheads and a ratchet strap. I don't think I'd have the patience to wrap a cardboard airframe with fiberglass fabric.

Edward
 

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36" diameter? If so that's out of my realm. If you go with 6 oz I'd only do 2 layers. If you have some scrap BT laying around..play around with various number of layers to see what you feel like will work.

and the peel ply is the stuff Tim posted the link to.

Tony
36" length
 

AlphaHybrids

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I performed a small study on this very topic last year using 4” LOC tubing. I ultimately settled on 2 wraps of 6 oz glass.

https://www.rocketryforum.com/threads/glassing-my-first-tube.136266/page-2
I prefer the fiberglass sleeves from Soller Composites. I'm a bit of a kludge and with the sleeves I can easily glass a 5.5" airframe with a sock, sacrificial bulkheads and a ratchet strap. I don't think I'd have the patience to wrap a cardboard airframe with fiberglass fabric.

Edward
 

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I prefer the fiberglass sleeves from Soller Composites. I'm a bit of a kludge and with the sleeves I can easily glass a 5.5" airframe with a sock, sacrificial bulkheads and a ratchet strap. I don't think I'd have the patience to wrap a cardboard airframe with fiberglass fabric.

Edward
Interesting. So if I used those sleeves I would pick the 1.5" option and slide it onto the tube and then just wet it with epoxy? What fiberglass would that be equivalent to? 10oz?

https://www.solarcomposites.com/NewSoller/FiberglassSleeves.html
 

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I prefer the fiberglass sleeves from Soller Composites. I'm a bit of a kludge and with the sleeves I can easily glass a 5.5" airframe with a sock, sacrificial bulkheads and a ratchet strap. I don't think I'd have the patience to wrap a cardboard airframe with fiberglass fabric.

Edward
Interesting. So if I used those sleeves I would pick the 1.5" option and slide it onto the tube and then just wet it with epoxy? What fiberglass would that be equivalent to? 10oz?
 

markkoelsch

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Mark, I've not used any breather material. You can control the amount of epoxy as you go. I do add some extra (thinned) epoxy just before I apply the peel ply. It helps wet out everything and avoid pin holes. The Raka is room temp. I've seen where it's reall easy to get wrinkles in body tubes that are vacuum bagged. I've not tried it.

Years ago (2011) I did a thread on Rocketry Planet, for an all FG, hand layed, thinned epoxy thread. To prove most guys don't need to go over board on "things". it went 34k mach 1.8

Tony
I recall as I was a mod on RP.

I have done a fair amount of laminating myself. I ask the questions as they are mostly questions I would have asked in the past.

Also, as a thought-these fins may or may not need tip to tip. The span is not that great. If fillets are good size and have proper amendment that may be enough.
 

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I recall as I was a mod on RP.

I have done a fair amount of laminating myself. I ask the questions as they are mostly questions I would have asked in the past.

Also, as a thought-these fins may or may not need tip to tip. The span is not that great. If fillets are good size and have proper amendment that may be enough.
Yeah they are pretty small fins, but I'm going to do at least one layer of tip to tip because I want to learn how to do it. This project is a lot of firsts for me and I wanted something challenging and rewarding after my level 2 cert flight. I would love to try for level 3, but I feel I'm a bit too inexperienced and that it is too late in the flying season to start.
 

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Yeah they are pretty small fins, but I'm going to do at least one layer of tip to tip because I want to learn how to do it. This project is a lot of firsts for me and I wanted something challenging and rewarding after my level 2 cert flight.
I would look at 6 ounce glass,but the 10 would do. I would do two or three layers laminated in one continuous piece. Then a breather and heat shrink tape.

I think the 3 ounce is too light unless used as a single layer for sanding purposes.
Does it matter what weave the fiberglass is?
 

rharshberger

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So if I get 3oz I would wrap it 3 or 4 times, if I get 6oz I wrap it twice, and if I get 10oz I only wrap it once?
With 10oz you may want to over wrap it with a lighter weight cloth, 10oz has a pretty large weave that will need to be filled. I would go with the 6oz as less filler will be needed later.
 

Steve Shannon

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May I ask where you get 6oz fiberglass?
Another source is Aircraft Spruce and Spar, the same place you can get all sorts of composite building supplies. I use the 5.7 oz. glass in a plain weave. The weave does matter for different high stress applications, but not so much for your application. Plain weave drapes nicely and wets out well.
 

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If it's your first time, I would probably just use a couple wraps of 6 oz.
 

markkoelsch

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So if I get 3oz I would wrap it 3 or 4 times, if I get 6oz I wrap it twice, and if I get 10oz I only wrap it once?
I generally do not think a single layer is all that great. I like two wraps and have had good luck. Tony has a lot of experience and uses 3-4 if the lighter cloth. There is not a hard and fast answer.
 
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