Gel stage?

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BrAdam

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I probably should have asked this before I started. This is my first shot at fiberglassing a tube. I am using west systems 105/205. I am glassing a paper tube. How long does it take to reach the gel stage where I can trim the end flush with the tube?


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If there was any excess when you were done use that to tell. It will be when the epoxy is still plyable but not sticky to the touch. This will be when you want to trim the glass.


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I probably should have asked this before I started. This is my first shot at fiberglassing a tube. I am using west systems 105/205. I am glassing a paper tube. How long does it take to reach the gel stage where I can trim the end flush with the tube?


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If I was glassing a cardboard tube, I would be tempted to first give it a light coat of epoxy to "water proof" it. Otherwise, the cardboard might soak up the epoxy in your fiberglass such that you end up with a dry layup. On the other hand, 105/205 cures so quickly that there might not be much time for that to happen. Unless it's a small tube, you'll have to work very quickly.

Jim
 
If I was glassing a cardboard tube, I would be tempted to first give it a light coat of epoxy to "water proof" it. Otherwise, the cardboard might soak up the epoxy in your fiberglass such that you end up with a dry layup. On the other hand, 105/205 cures so quickly that there might not be much time for that to happen. Unless it's a small tube, you'll have to work very quickly.

Jim

I will respectfully disagree with that advice - you WANT the epoxy to soak into the tube so the tube/epoxy/fiberglass become a single matrix as it cures. In fact, it is recommended to first remove the glassine layer on the tube to increase the epoxy absorption which will create a better bond.

To avoid a dry layup, simply wet out the tube prior to applying the fiberglass. It won't soak up any appreciable amount of epoxy after that. I apply a Teflon Release film on the last layer. I give it a "test tug" on a corner after a few hours. If it breaks cleanly free, I pull the rest off and trim the overhang with its still green. If its still gooey, I wait another half hour and try it again.

I would also recommend switching to the West 206 slow hardener to give yourself more working time if you are glassing anything bigger than a 4" tube. On a hot day in Florida, I've had the slow epoxy get gummy by the time I had applied two layers on a 7.5" tube.

Good luck and happy glassing!
 
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I took the glassine layer off and applied epoxy to the bare tube first to let it soak some up then took off the extra. Then I applied the cloth like the John Coker video showed. Went on well. Just wondering on timing for the trim. Thanks for the replies. All the advice I get helps.


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Also, I'm in Wisconsin and the thermostat is set at 65 so the temp is on the low side. No materials for a wrap so I will likely apply a coat of epoxy to fill the low spots later. Like glassing a wooden boat.


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65F is plenty warm for the resin to set up. I would estimate 3-5 hours after mixing for West 105/205.

Like Jim said, 205 sets up pretty fast for glassing; I personally very much prefer 206 for glassing as it's a bit thinner and pot life is longer. Both will work fine however.

As for "testing" when the layup is ready for trimming, I would tend to not rely much on the leftovers in the mixing cup....105/205 will kick off and harden fairly quickly if confined to a mixing container; however when spread out (ie saturating glass cloth), it will cure at a much slower rate. I find it easiest to wiggle the overhanging fabric after a few hours; when it becomes stiff, yet still pliable, it is ready for trimming. I tend to err on the side of caution, I don't trim unless its somewhat cured; cut too early and you can manipulate the fabric in undesirable ways. Even fully cured, I don't find trimming ends difficult; use a dremel cutoff wheel if needbe and sand flush/flat post cure.

-Eric-
 
I will respectfully disagree with that advice - you WANT the epoxy to soak into the tube so the tube/epoxy/fiberglass become a single matrix as it cures. In fact, it is recommended to first remove the glassine layer on the tube to increase the epoxy absorption which will create a better bond.

For typical rocketry tubes, I agree. When fiberglassing "found" tubes or concrete forms, I disagree completely.

Tubes made for the hobby don't tend to soak up a lot of epoxy, so the odds of a dry layup, if the fabric is properly wetted, are very low. "Found" tubes and concrete forms tend to soak up a LOT more epoxy -- a thin coat which is then allow to cure to the tacky stage will dramatically reduce the amount of epoxy used. This is significant when building large rockets, both due to cost and added weight.

A 24" x 144" piece of sonotube will suck up a lot of epoxy....

-Kevin
 
Also, I'm in Wisconsin and the thermostat is set at 65 so the temp is on the low side. No materials for a wrap so I will likely apply a coat of epoxy to fill the low spots later. Like glassing a wooden boat.

I'd suggest using a space heater to bring it up to 70F. Some epoxies will cure at 65F, but it tends to be very slow and they take an eternity to reach a full cure. Most epoxies I'm familiar with don't recommend using them below 70F.

-Kevin
 
Tubes made for the hobby don't tend to soak up a lot of epoxy, so the odds of a dry layup, if the fabric is properly wetted, are very low. "Found" tubes and concrete forms tend to soak up a LOT more epoxy -- a thin coat which is then allow to cure to the tacky stage will dramatically reduce the amount of epoxy used. This is significant when building large rockets, both due to cost and added weight.

A 24" x 144" piece of sonotube will suck up a lot of epoxy....

-Kevin
Was that learned on the Delta III?
 
For typical rocketry tubes, I agree. When fiberglassing "found" tubes or concrete forms, I disagree completely.

Tubes made for the hobby don't tend to soak up a lot of epoxy, so the odds of a dry layup, if the fabric is properly wetted, are very low. "Found" tubes and concrete forms tend to soak up a LOT more epoxy -- a thin coat which is then allow to cure to the tacky stage will dramatically reduce the amount of epoxy used. This is significant when building large rockets, both due to cost and added weight.

A 24" x 144" piece of sonotube will suck up a lot of epoxy....

-Kevin

Kevin, I think you've nailed it. I was helping someone put fiberglass on a larger tube. I'm afraid I don't remember if it was a sonotube or not, but it might have been. We simply couldn't apply enough epoxy - it kept on soaking it up. Yes, you need some to soak in to get a good bond, but not to this degree. Saturating a cardboard tube with epoxy just results in a heavy tube.

Jim
 
I'd suggest using a space heater to bring it up to 70F. Some epoxies will cure at 65F, but it tends to be very slow and they take an eternity to reach a full cure. Most epoxies I'm familiar with don't recommend using them below 70F.

-Kevin

Not a bad suggestion at all; most epoxies benefit somewhat from a post cure.

That said, I'm also in America's Dairyland, most of my building is done in our basement which pretty much stays below 65F year round; 105/205 cures plenty fast for me without raising temps. I do utilize means of elevated heat for curing when necessary; but with that particular West combo, I've never found it necessary. As mentioned earlier, with West 205 curative, I find that it cures too quickly for my tastes when it comes to glassing.

Your mileage may vary:).

-Eric-
 
I'd check it around 4-6 hours. Ish.



Later!

--Coop
 
That said, I'm also in America's Dairyland, most of my building is done in our basement which pretty much stays below 65F year round; 105/205 cures plenty fast for me without raising temps. I do utilize means of elevated heat for curing when necessary; but with that particular West combo, I've never found it necessary. As mentioned earlier, with West 205 curative, I find that it cures too quickly for my tastes when it comes to glassing.

Try West outside on a 100F day....:eyepop:

West Systems may cure fine at 65F and below, but in my experience most epoxies do not.

-Kevin
 
So the answer is 5-6 hours. At least in WI in one of the worst springs in a while. Thanks to all that replied. Lots of help for future projects. Eric my basement is 53 degrees so not very conducive to the work at hand. Good for aging home brew though. Did not feel like getting the wood stove stoked up earlier but thinking now that is a good idea. Good luck to all attending Thunderstruck, have to miss this years event. And again thanks.


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Try West outside on a 100F day....:eyepop:

West Systems may cure fine at 65F and below, but in my experience most epoxies do not.

-Kevin

Somewhere I have a video from my college daze.... We were working on a fully composite SAE AeroDesign plane. I mixed up a batch of 105/205, added pigment and some other filler (either fairing filler or fumed silica). The batch kicked off early, began smoking, and someone had the bright idea to pull the gelatinous epoxy blob from the mixing cup. It fell from the grasp of the grasper, and began bouncing off the concrete floor like a super ball. It was hilarious, to this day I don't understand how it happened, but this concoction had come alive, it was like a jumping bean.

Epoxy on a hot day: smoldering in no time! I've burned myself on warm days with epoxy!:facepalm:

-Eric-
 
Somewhere I have a video from my college daze.... We were working on a fully composite SAE AeroDesign plane. I mixed up a batch of 105/205, added pigment and some other filler (either fairing filler or fumed silica). The batch kicked off early, began smoking, and someone had the bright idea to pull the gelatinous epoxy blob from the mixing cup. It fell from the grasp of the grasper, and began bouncing off the concrete floor like a super ball. It was hilarious, to this day I don't understand how it happened, but this concoction had come alive, it was like a jumping bean.

Epoxy on a hot day: smoldering in no time! I've burned myself on warm days with epoxy!:facepalm:

-Eric-

That is an advantage of dedicated adhesive epoxies like Aeropoxy ES6209 and apparently Rocketpoxy as well. They don't go crazy in high heat. But at the same time, you can use heat to accelerate a cure without issues; I used a 114 degree Black Rock day plus sunlight to cure Aeropoxy in under five hours instead of 24.
 
Somewhere I have a video from my college daze.... We were working on a fully composite SAE AeroDesign plane. I mixed up a batch of 105/205, added pigment and some other filler (either fairing filler or fumed silica). The batch kicked off early, began smoking, and someone had the bright idea to pull the gelatinous epoxy blob from the mixing cup. It fell from the grasp of the grasper, and began bouncing off the concrete floor like a super ball. It was hilarious, to this day I don't understand how it happened, but this concoction had come alive, it was like a jumping bean.

It's the pigment. Unless you use really small amounts, it tends to turn epoxy rubbery.

Epoxy on a hot day: smoldering in no time! I've burned myself on warm days with epoxy!:facepalm:

Only some epoxies. One of the reasons I no longer use West Systems -- it doesn't deal well with heat. I use Fibreglast System 2000 and AeroPoxy on 100F days with no issues at all.

-Kevin
 
That is an advantage of dedicated adhesive epoxies like Aeropoxy ES6209 and apparently Rocketpoxy as well. They don't go crazy in high heat. But at the same time, you can use heat to accelerate a cure without issues; I used a 114 degree Black Rock day plus sunlight to cure Aeropoxy in under five hours instead of 24.

Though I use Aeropoxy laminating, I have yet to try the ES6209; you and others report favorably so I'll give it a shot somewhere down the road. Rocketpoxy is da bomb; as a natural born skeptic, this product won me over in quick fashion! It is nice that the cure is not exponentially exothermic!

-Eric-
 
It's the pigment. Unless you use really small amounts, it tends to turn epoxy rubbery.



Only some epoxies. One of the reasons I no longer use West Systems -- it doesn't deal well with heat. I use Fibreglast System 2000 and AeroPoxy on 100F days with no issues at all.

-Kevin

Ah, the pigment; that would explain why I haven't replicated the experience. Thinking back, it was CST sky blue powdered pigment.

I normally use West Systems or Aeropoxy for laminating; one of the determining factors is temperature. If I'm in the cold basement, more often then not I use West for simplicity; if I'm in the garage (or similar) during summer OR I want a seemingly neverending cure schedule:wink:, I go with Aeropoxy.

A fun thread this is; glad your 'glassing went well Brad!

-Eric-
 
While we're on the subject of epoxies, how do people here feel about Aeropoxy ES6220 (the fast-cure stuff)? Useful, or better off just using Ye Olde BSI for quick work and ES6209 when the cure time is tolerable?
 
Somewhere I have a video from my college daze.... We were working on a fully composite SAE AeroDesign plane. I mixed up a batch of 105/205, added pigment and some other filler (either fairing filler or fumed silica). The batch kicked off early, began smoking, and someone had the bright idea to pull the gelatinous epoxy blob from the mixing cup. It fell from the grasp of the grasper, and began bouncing off the concrete floor like a super ball. It was hilarious, to this day I don't understand how it happened, but this concoction had come alive, it was like a jumping bean.

Epoxy on a hot day: smoldering in no time! I've burned myself on warm days with epoxy!:facepalm:
Related story on West 105/205:

A while back in Darren's basement, Todd and I were putting nose weight in Shake Weight the morning of its first flight. We had the weight set in the tip and just needed to encapsulate it with epoxy. We needed to leave so we used West 105/205 and let it sit in the cup for a bit before pouring. Just as we began to pour from the cup, it started smoking, so we poured faster-- in the time it took for the liquid to fall down the length of the cone it solidified into a solid blob and thunked into the tip.

Backup plan: wait about 20 fewer seconds and then leave the nose cone, tip down, sticking out of the sunroof on the drive to the launch. (You wouldn't believe how many bloody-- literally-- mosquitoes that thing attracted during the trip. Yuck.)
 
While we're on the subject of epoxies, how do people here feel about Aeropoxy ES6220 (the fast-cure stuff)? Useful, or better off just using Ye Olde BSI for quick work and ES6209 when the cure time is tolerable?

Slower cure times usually create a stronger bond. Aeropoxy ES6209 is a thick structural epoxy, while West 105/206 is a thin epoxy usable for lamination ( in context with other posts). Aeropoxy makes a laminating epoxy which I have used, and really like. BSI 30 minute is great stuff for 'quick' jobs. I always try to allow 24 hours for full cure no matter what brand or type of epoxy I am using.
 
While we're on the subject of epoxies, how do people here feel about Aeropoxy ES6220 (the fast-cure stuff)? Useful, or better off just using Ye Olde BSI for quick work and ES6209 when the cure time is tolerable?

I'd regard it as less noxious than BSi. I've never used it myself, but based on the datasheet, it's in the same awkward viscosity regime where it's too runny to stay put, just like BSi.

I'd try it if they sold it in smaller quantities than a quart.
 
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