Dew Shield for C90 MAK

[Stub Mandrel]

Here's an idea which worked for me. 3D print a cylinder 107.5mm internal diameter and 110.7mm external diameter (for a 4mm nozzle and 0.8mm skin thickness - gives four layers with no fill) and 100-120mm high.

Mine failed half way through as stray wires caught it and pulled the unsolidified filament off! Sorted and printed a second bit and superglued them together.

Covered outside with 'The Range' 1mm black high density foam and the inside with Wilko's online only black velour, aside from a 10mm section that slips on the end of the lens.

Print a short test ring first, to check the fit.

Would post a pic but it just looks like a black cylinder.

[Mr niall]

Good idea - is it tough though or brittle?

[Stub Mandrel]

Reasonably tough, and it keeps it shape where a foam-only one doesn't.

[theropod]

I made a dew shield for my C90 using standard 4" pvc sewer pipe. I heated the end of the pipe and slipped it OVER the plastic apature end. It fits snuggly and requires just enough force to remove so it can't fall off. I epoxied a zip tie in place so my DIY Baader solar filter (mounted on a hunk of 1" insulation foam) wouldn't bottom out. The lens cap fits the pipe perfectly.

[Stub Mandrel]

That must have taken a bit of persuasion, even with heat :-)

[theropod]

On 9/19/2017 at 16:34, Stub Mandrel said:

That must have taken a bit of persuasion, even with heat :-)

Not really. I just held the pipe over our gas cooking stove and gradually warmed it until well soft and it just slipped on. I did use the "swelled" end where another pipe is supposed to fit, and wobbled the warmed pipe as it cooled so it didn't "mate" with the scope permanently. After it cooled in place I took it off the scope and cut 4 short slits down the swelled portion about 1" long so it doesn't require much force to install or remove, but there remains plenty of clamping action so as to be quite sturdy. I still need to paint it flat black, but it works very well.