Glassing unpeeled LOC 5.38 Tubes...

Am planning on 'glassing a LOC 5.38 tube, but don't want all the extra weight that you get when 'glassing a peeled tube. Anyone have experience (good or bad) 'glassing unpeeled tubes in this size?

thanks,
-bill

I'm sure you would fare alright...just rough it up a bit with a low grit sandpaper.

But here's my question--why would leaving the tube unpeeled make it lighter? Do peeled tubes soak up enough epoxy to significantly raise the mass?

yup, it will. I've seen it first hand 'glassing smaller (3" and 4") LOC tubes.

Have you actually glassed one like this before, or is this a supposition?

thanks,
-bill

Originally posted by wyldbill
yup, it will. I've seen it first hand 'glassing smaller (3" and 4") LOC tubes.

Have you actually glassed one like this before, or is this a supposition?

thanks,
-bill

Click to expand...

It's sort-of a supposition. Back in the day, when I didn't know what I was doing, I tried to glass a painted rocket--I thought sanding it real hard would work, rather than completely stripping it of it's paint. That did NOT work...but that was on a painted surface, ha. If you rough up bare LOC tubing I'm willing to bet it would work. Heck, buy a small piece and try it yourself.

Someone's probably actually done what you're asking, though...hopefully they'll chime in. I'd like to hear the result of the exact situation in which you are referring.

Wouldn't less absorbtion lead to a weaker tube? I would think that tubing soaked with epoxy is stronger than tubing without epoxy. After all the whole point to glassing is to strengthen.

Also, if you're worried about weight, put a bigger motor in it

The strength comes from the fiberglass. Epoxy is rather brittle without it and it can add a lot of weight very fast.


Edward

Isn't a cardboard tube just another substrate for epoxy bind with though? After all, phenolic tubes are cardboard impregnated with phenolic resin. Maybe that's an apples and oranges comparison, I don't know. But I would still think that a tube with epoxy resin truly soaked through it would be stronger than a plain tube. Whether it's worth the weight penalty is another question.

It's always better to peal the glassine off of the tube first.
That way the epoxy will soak into the tube. otherwise you'll end up with what happens to the Polecat kits; the glass bubbles up & peels off. I heard this from a couple people who have bought Polecat kits. Most of the time it comes off fairly easy if you are patient.




JD

Even if you sand the glassine, there will inevitably be spots that get missed. This may not be a *huge* deal... but it still becomes a weak point where the fiberglass can separate from the tube.

I've sanded a couple of 4" airframe tubes... and after burning through MUCH elbow-grease, came to the conclusion that it's easier to peel the glassine off entirely.

Just to clarify, I know how to peel glassine and 'glass a tube. I've done it and know that it's not difficult. I understand that it bonds better. In this particular case/design, I don't want to do that because of the added weight (which is real and significant). I was looking for real life experience from folks who have actually 'glassed LOC 5.38 tubes without peeling.

Yes, epoxy soaked tubes, w/o glass are stronger (than plain tube), but you've effectively made a phenolic-ish tube at that point which is much heavier than actual phenolic and no stronger (though perhaps a bit tougher).

As far as Polecat goes, I've heard the stories, but personally had good luck w/ their kits, as have other members of my club who've built them. But that is a completely different story, as Andy glasses his tubes more for finish than strength, and uses a gelcoat resin, not straight epoxy.

thanks,
-bill

Originally posted by wyldbill
JIn this particular case/design, I don't want to do that because of the added weight (which is real and significant).

Click to expand...

You've confused me a bit here. You're not going to be adding a LOT of epoxy to a peeled tube. Sure, a bit soaks in, but more remains with the fiberglass. Also, by peeling off the glassine... and probably a layer of paper with it... you're removing some weight from the tube - possibly enough to balance what's soaking in.

This is just my opinion, mind you... but I don't think you'll save much weight by not peeling off the glassine layer.

What kind of project is it, if you don't mind my asking...

I've glassed tube this size with and without the glassine layer, and I haven't really told much of a difference. there's a technique that works well to prevent the tube from soaking up a huge amount of epoxy.

Instead of coating the tube in epoxy and then laying down the fiberglass, use a spray on adhesive to attach the fiberglass on one end, then wrap the glass around the tube as many tmes as you need dry. THEN you add the epoxy, and it soaks into the fiberglass just as much as you need, and only the extra soaks into the tube...problem solved.

As for the comment about the epoxy just being brittle, this is true, but it's only as brittle as phenolic tubes, and people still use those right? Basically there's not much difference between them, but if you should chose to not remove the glassine layer, just sanding the tube with a real rough sand paper will get enough adhesion to where it really won't be a problem. I've done that before and had no problems at all.

Good luck with whatever you choose to do!

much appreciated, Nate.

what can I say? I'm a problem solver...

What is the sense of even wrapping the tube in fiberglass if you are taking away all the benifits in the first place???


JD

Originally posted by JDcluster
What is the sense of even wrapping the tube in fiberglass if you are taking away all the benifits in the first place???


JD

Click to expand...

What benefits are you talking about?

A stronger tube less prone to folding over from hard landings.
prevents zippers.



JD

no, I'm aware of what a stronger tube does, I meant what benifits are you taking away? I have no idea what "What is the sense of even wrapping the tube in fiberglass if you are taking away all the benifits in the first place???" means.

If you don't peel the tube it won't stick to it & the epoxy won't soak in! You'll have a higher chance of the fiberglass delaminating from the tube you just wrapped. Wrapping the tube in fiberglas/Carbon Fiber /Kevlar ; you want it you want it to bond with the substraight & not act like wrapping paper on the roll.



JD

I too found your comments to be vague at best, or simply unclear. Your last post OTOH was crystal clear.

The whole question was "can you succesfully laminate fiberglass to a tube (meaning it will bond, and not delaminate) without peeling?"

I don't want to peel, as it adds considerable weight when glassing because the tube soaks up much more epoxy than required to merely wet out the 'glass. While some folks believe this is a good thing, because they believe it creates a much tougher tube, I don't because the 'glass itself adds more than enough strength, and I don't want the extra weight.

Nate says he's had success with non-peeled tubes by sufficiently roughing them up. You say it's not possible, but you're never done it, or personally seen it fail, where Nate has done it and had success.



-bill

Originally posted by JDcluster


If you don't peel the tube it won't stick to it & the epoxy won't soak in! You'll have a higher chance of the fiberglass delaminating from the tube you just wrapped. Wrapping the tube in fiberglas/Carbon Fiber /Kevlar ; you want it you want it to bond with the substraight & not act like wrapping paper on the roll.



JD

Click to expand...

And I have never had a problem with it delaminating before. if you just put it straight on this may be a problem yes, but as long as you give it a good sanding with a very low grit sandpaper, the tubes will stay glassed for as long as you can fly the rocket. the whole point of epoxy it to bond to stuff. that's what it was made to do. it does bond to some stuff easier to others, but a well sanded glassine layer has a suffieciently rough surface for binding, take any upper level physics class and it'll be explained to you immediatley.

cheers

OK, please keep the discussion on-topic and refrain from personal attacks. I edited a bunch of the posts, since there appeared to be technical discussion going on. If I accidently botched up and changed on-topic content, please feel free to edit your posts. I hope this was better than pulling them.

As far as I'm concerned, just go ahead and lock it, Dick. I've got the info I needed and it'll probably just head off into the weeds again....

-bill

Done