Public Enemy airframes

Mar 05, 2006 8 Replies

Does anyone have any pointers concerning sanding/finishing Public Enemy body tubes?



I have a Performer and the regular cardboard airframe (with spiral groove) is sort of shrink wrapped with a thin plastic overcoat. The owner of PE says you just sand and paint, but the wrapping is pretty uneven over the spirals in the tube. I'm worried that sanding sufficiently to even out the wrap will actually leave holes in it. Plus, how well will epoxy bond to the plastic (I plan to rough the surface with sandpaper and use Aeropoxy). Will the plastic delaminate from the tube?



Thanks


When I prep a tube for fiberglassing and stuff I just rip the glassine coating off the tube... you can carefully peel them off but dont do it too hard, or else you will unevenly peel them off or even worse, rip holes in the tube. You dont have to have a very even surface, in fact it is more desirable to have a rough surface for epoxy to bond to the paper. If you are going to go the trouble of coating a tube with epoxy might as well fiberglass it too... I think rocketry online has instructions on how to do it.

-- TAI FU

Rocketry Online has instructions on how to do something?

Odd. How old is the article?

Just use some moderately course sandpaper to rough the tube up and do the glassing. When weight isn't an issue, I do a modification of Rick Boyette's quasi glass procedure. Simply:

Prep the tube with sandpaper.

Use a nylon stocking or some other sleeve, depending on the size of the tube, to put over to the tube.

Use the water soluble polyurethane from Minwax to adhere sock to the tube.

Now here is where I depart from Rick. He uses spackle to seal the grain. One could use fiberglass resin I believe, but I use a two part epoxy sealer called Environ-Tex Lite. I slather it on, sand and apply one more coat and sand. Viola', ready for primer, prep and paint.

Now this will be comparable to a heavy "glass" job and I think might be a little bit heavier but I like the epoxy coating.

I believe if one wants extreme light weight and strength, they have to go to composite construction. I don't have any experience with that (yet!)

Kurt Savegnago

I think its called "info central" but im not sure if its still there... it was there years ago though.

Actually composite like carbon isnt practical for anything but Level 2 and up. The reason is its kinda hard to find carbon fiber cloth that is anything less than 5 oz and a 5 oz cloth is stiff as hell and almost impossible to get it to conform to a tube that is less than 3 inch diameter. I tried that using shadow composite's heat tape and it was a pain, but I did the cloth to a BT-50 or something. I think if you want strength fiberglass cloth is actually pretty good and if your technique is right you can glass them without using too much resin. I would peel off the glassine coating cause its kinda loose on the tube and you might as well peel them off to save the sandpaper from clogging. I find that shadow composite's video is very helpful to learn how to do fiberglass/carbon. If you are serious about it consider getting them (if they are still around that is...)

-- TAI FU

Is that why the competitors use CF to make tubes that weigh a couple grams?

sorry.. I didnt think of that, but I think shadow composite was selling some .1 oz carbon fiber paper for that purpose... but if a 1 oz carbon fiber cloth exists... that would be nice for competition.

(yet)!

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Sometimes you are MOST amusing, sir.

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