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How does one treat a cardboard tube?

Started by AllsWell, 08/09/2002 12:19AM
Posted 08/09/2002 12:19AM Opening Post
Fellow ATMers

I have a nice 80/1200 lens in a metal cell and I have a cardboard tube about 4 inches in diameter and with a wall thickness of about 1/8th of an inch, which I wish to use for a telescope tube. It needs to be made strong, very stiff, totally waterproof and painted attractively.

I have thought of painting the cardboard with a thinned 2 pot epoxy preparation (like that used on timber for construction of boats) and then having it spray painted.
Has anyone had success with a similar cardboard tube? How did you handle it??

Yes, I know I could spend megabucks on a nice CNC metal tube but there is a certain satisfaction to be had in shoestring budgeting.

Posted 08/09/2002 06:44AM #1
Remove any wax or plastic film that may be coating inside or out. Coat in and out with 2 liberal coats of polyurethane, either satin or gloss. When completely dry, sand lightly and then coat the outside with fiberglass resin. Apply two coats with sanding between each. Wet sand the final coat with 400 wet/dry sandpaper. Prime with a good auto primer then pain your choice of color. Should make a great tube. Cover the inside with flocking paper. If you can order from the states go to and check under fabrics. The black velvet without the adhesive backing is great stuff and cheap!! Use a good quality white glue to glue to the inside.
Probably won't even need baffles after using that stuff.