Quote:
Originally Posted by Garyh
I might try making one of these up?
How do they work on fast f/ scopes? Also where can you buy foam board?
cheers Gary
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Hi Gary
I’ve not yet tried foam board, but what I can say, is that the overhead transparency material seems to make a very good mask.
H0ughy has posted some standard sizes and if you can print one of these on A4 overhead transparency, then the slots are reasonably easy to cut out with a sharp Stanley knife and steel rule. The transparency material is surprisingly tough and doesn’t seem to tear easily. I always cut with the steel rule lying on the black bar, leaving the clear slot visible – it seems easier to see the edge that way. I then cut all the slots along one long edge and turn the work around and do the other long edge. Finally, I cut the narrow edge at the middle bar and at the inner circumference.
I bonded the mask (once cut out) onto a closed cell foam ring made from those camping tent door mats that interlock together. I used contact adhesive.
Here are examples of my C9.25 mask and Mewlon 180 mask. The C9.25 has a central aluminium bar to help with stiffness and a nylon bolt to allow me to place the mask on and remove it with the dew shield fitted. When fitted, the C9.25 mask sits on the metal frame surrounding the corrector plate. The Mewlon mask just sits over the end of the OTA. The last file is a printed but uncut A4 transparency.
Cheers
Dennis
EDIT:
The C9.25 mask required 2 sheets of A4 transparency paper. I printed the central bar + left hand horizontal bars on 1 sheet, then the central bar + right hand angled bars on the 2nd sheet. After cutting out the slots, I overlapped the central bar and glued them together.