Re: [ATM] Fiberglass Tube Fabrication

[NGC704@aol.com]

Hi again, Ed!

(I hit 'reply' originally, instead of 'reply to all' as intended. Since I 
believe this banter is worth submitting to the ATM archives, I have reposted my 
first reply to you.)

Anyway, you say "I'm intrigued with your suggestion of a cedar 
strip/fiberglass tube", and I (now) reply that you OUGHT to be! Again, the beauty of strip 
construction is that you do not throw your mold away, therefore wasting that 
wood (or whatever material you might have used); that the cedar tube will be 
easier to build; it will be  beautiful; it will be lightweight; and finally, that 
the composite result will be exceedingly satisfactory for a telescope tube in 
every regard -- cheap, light, lovely, durable, and rigid!

Hey, if it makes for the strongest and lightest kayaks going outside of 
radical Kevlar racers, it ought to do likewise for a telescope tube. So why don't I 
build one? Easy: I don't want a traditional closed tube telescope. But if I 
did, this is how I'd build it.

Fabrication is super-simple. The strip-built kayak is built using forms on a 
strongback. The strongback is often a plain old pine 2x4 supported on a pair 
of sawhorses. The forms, typically spaced every 12" along the strongback, are 
actual cross section shapes of the hull. When the forms are covered with 1/4" x 
3/4" strips, bango! You have a basic kayak hull and/or deck ready for 
fiberglassing. But for a telescope tube, it is much simpler yet, because you are 
dealing with a constant round shape as opposed to a complex boat shape.

Again, assuming a tube for a 12" f/6 'scope, four forms ought to do, maybe 
three. I would make two half-tubes, using a 2x4 strongback and 180-degree 
semicircular forms. I would strip the first half-tube, sand it smooth, fiberglass 
it, pull it off the forms, and then fiberglass the inside, using one layer of 
6-oz cloth for each surface. Then repeat. Then join the two halves, proceed with 
fill coats on the exterior (the cloth-textured inside would be *perfect* as a 
baffled interior), then varnish, and finally, enjoy one spectacular telescope!

Man, I'm tellin' you -- as an old ATM, and newer, but fairly accomplished 
amateur kayak maker, mixing kayak building techniques with telescope making is 
where it's at!! By God, I ought to write a BOOK on the subject. Just think, I 
could very probably sell *dozens* of copies!!!

Check out this website: http://www.outdoorplace.org/paddling/Guillemot1.htm

John is a friend of mine who builds unbelievable boats, knows how to use 'em 
in a wonderful way, and puts together a pretty good website too. If you find 
his information handy, I hope you'll write him, tell 'im what you're doing, and 
who sent you. I'm pretty sure he'd get a kick out of knowing his 
contributions to the collective knowledge was going into deep space.

Cheers,
Kurt Maurer
League City, Texas
http://members.aol.com/NGC704/

In a message dated 4/19/2005 4:09:10 PM Central Daylight Time, 
eheiny@yahoo.com writes:

Kurt,

Thanks for your response and suggestions.  I'll check out Raka's web site.
I'm looking for a low cost durable tube, so I thought fiberglass was a good
choice.  Carbon fiber, while great for strength, is also very expensive. I
may go with polyester resin if the performance is similar to epoxy because
it's cheaper and available locally.  I'll try the project in the garage with
a respirator and gloves.  Since the large tube will take a lot of material,
I may try a smaller tube first to gain experience and not end up with a
large pile of expensive scrap.  

I'm intrigued with your suggestion of a cedar strip/fiberglass tube
particularly since I don't have a form yet.   Are there any web sites with
construction tips or pictures?  Thanks.

Ed

_______________________________________________
ATM mailing list http://www.atmlist.net/