I am constructing a telescope optimized for high resolution CCD imaging applications and would like to use invar rod in the truss structure to minimize dimensional changes due to temperature fluctuations. Has anyone recently purchased a small quantity? If so where did you get it and how much did you pay?
I need four .500" diameter rounds, 65" Long. Invar 36 FM would be nice but not necessarily required especially if the price difference is dramatic.
Thanks,
Mike
While I have never purchased Invar, I quoted a tool for one of my customers that specified one component made of Invar (Invar 36, as I recall). The piece needed was small, a couple square inches at most. I had no clue where to obtain it, so I quoted the job with the customer supplying the needed piece. Imagine my shock to find out that I would have had to purchase a square foot of the stuff, which was ½" thick, at a cost of approximately $1,000. The cost of the tool I supplied was far and away less than that. This was back in the early 80's, so the material may be less expensive now, hard to say. I'd be interested in hearing what the material costs today, so if you find a source, be sure to let us know.
Harold
Mike This size of rod is commonly used in laser resonator frames. You may be able to pick up a dead (very) large frame ion laser from a surplus house, there are a lot of surplus laser dealers around. Martin.
Mike
Just found this page on Invar in the FAQ
--I'm thinking that by now there must be a composite component that has equivalent or better thermal expansion characteristics. Have you taken a gander at carbon fiber tubing, etc? It's probably a *lot* more common and much cheaper by now, too.
If anybody else is interested I got a quote today from Ed Fagan Inc for $10.80/foot FOB New Jersey (I'm in TN) for 24 feet of .500" Invar
36 FM.Not as bad as I thought it was going to be...
Mike
That is a VERY good price. One of my associates bought a 6" x 6" x .090" piece of Invar from Goodfellow for ~ $350 earlier this year. For future reference, does Ed Fagan Inc have a websight or phone #?
edfagan.com
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