Quote:
Originally Posted by h0ughy
Dennis,
I don't know why I didn't think of it earlier but I went to an art supply place this afternoon and purchased some black 5mm foam core board. two A3 size sheets were about 8 dollars. it is light, black and you can easily cut it with a scalpel. I have asked Alan if he would be able to make a screen print up for the larger sizes to print directly on the larger (8" and above) masks - then cut it out. Hopefully this will work.   that way the cost for the baoard is under $10, easily made with some TLC and a bit of time and hopefully specifically designed to the scopes requirements. What did you think of the alternate design? |
Hi Dave
I am inexorably being driven to a laser cut metal solution right now, in order to spend less time focusing and more time imaging. Having experimented now with the following materials and designs:
- Overhead transparency (gaps not cut out)
- Overhead transparency (gaps cut out with Stanley knife and steel rule)
- MDF 3mm thick cut with a router (phew!)
- Black plastic computer binders (gaps cut out with Stanley knife and steel rule)
I am left with the following conclusions:
- Floppy material, such as overhead transparency and black plastic is likely to stretch, sag and not lie in a single plane.
- Materials such as MDF, foam core board, etc may absorb water and over time, become frayed around the edges.
- The process of rapidly converging to and locating precise focus is such a key element that it is worth obtaining and using a well manufactured, stable and rigid mask.
- Ideally, it is best to remove all “easy” variables under your control, such as a sagging mask, furry edges, etc so that you can concentrate on other matters such as eliminating flexure in the focus train, etc.
So, at the moment, I favour either a stainless steel or aluminium thin sheet mask, laser cut for accuracy and cleanness of cuts. I enjoy tinkering so don’t regret the time I have spent just playing around with various designs and implementations, but I am strongly leaning towards a laser cut metal solution right now, in order to spend less time focusing and more time imaging. I’ve had my fun and now its time to get more serious!
Cheers
Dennis
PS- I suspect that those with permanent set ups, temperature controlled focusers that can be indexed, etc. may be scratching their heads at these shenanigans! Oh the joys of setting up and tearing down each night, as well as manually pushing motor focus buttons. LOL!