Tube material

I am going to put together a 4.25" f10 newt.

Questions:

Do they make Sonotube in a 5" ID?? If not what material do you recommend?

The spider assy I got for my 6" had a 1.3" secondary hold and it is apparently the smallest made??

Thanks

What size secondary would be best?? A 0.8"??

I once made a 4.25" f/13 newt to use as a guide scope. I used a .8" secondary on a homemade spider. PVC tubing makes a good secondary holder, and a curved spider would also be a good choice. A recent S&T article has some good pointers on the curved spider. Naturally the mirror can be left spherical and it should give pretty crisp images. I believe Apogee used to sell 5.5" OD rolled steel tubes, but don't know if they made them in 45" lengths. You might find a mailing tube that would work after several coats of polyurethane. Good luck!

Walt

Too bad. I have a stripped Newt with the right ID, but not nearly long enough as you would need. I know there is a company named Acme Spiral wound paper products that can make you sonotubes to ANY custom ODs and IDs within reasons. I would keep this in mind as a last resort, as it is not your cheapest option, and to be honest their service is really terrible. Only use them if there is a specific tube that you absolutely need to be a certain size, and you can't find it anywhere else. Their website is "acmespiral.com"

Evan