Saturday, November 17, 2007

If There Is Anything Messier And Less Elegant Than Learning to Lay Up Fiberglass Tubes

If There Is Anything Messier and Less Elegant Than Learning to Lay Up Fiberglass Tubes

It must be appendectomies done with a hatchet. I'm back to working on Big Bertha's weight reduction program. (She's not fat; she just has big bones--too much wood, not enough aluminum.) I decided to use two pieces of Sonotube, each about 12 inches long and a bit more 20" inside diameter. One will hold the mirror cell, and the other will hold the focuser, diagonal, and finder.

This stuff isn't as stiff as I would like (but it was $5.75 per foot), so I decided to try and improvise fiberglassing. I bought a fiberglass repair kit and a big bag of latex gloves (absolutely necessary for this job), and tried to fiberglass these pieces.

I suspended both of them on a piece of wood between two chairs, then painted the exterior surface with the epoxy mix as quick as I could, then put fiberglass matting on the outside, and tried to paint another layer of epoxy mix on top. It is really ugly. I am beginning to wonder if I might be better off spending the money to buy these sections from someone who doesn't mind (for some big bucks) getting his hands messy. Yuck.

UPDATE: A reader pointed me to this account of fiberglassing a cardboard tube which I remember reading. I remember the part about using a stick to hold the tube. I didn't remember the part about the temperature needing to be 60-80 degrees. That may be why the resin was so thick that it kept grabbing the fiberglass mat and pulling it loose--making a really ugly mess. This is a more ambitious effort that doesn't involve starting with a cardboard tube at all!

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