What filter for 4" PVC homemeade pelican case housing?

[RandyRobbins]

Hi all,

I'm making a camera housing out of an "Apache" case from harbor freight (cheap pelican case alternative). For the "lens" part of the case, I'm using a 3" to 4" PVC adapter fitting... so the 3" goes into the case, and then it widens out to 4" so none of the PVC is in the field of view of the camera. It will be pretty slick when I'm done, but I'm wanting to fit a large clear round glass filter in the end of the 4" PVC part for true weather-proofing. The PVC is marked as 100mm, but I'm measuring the internal diameter at more like 107 or 108mm... I'm assuming someone else has done this same thing, so I figured I'd ask... what size filter will be the closest fit? I'll seal it with silicone gasket stuff, or epoxy, or both... so close but not perfect is OK... anyone done this as a front lens element on your housing?
Thanks in advance....

[RandyRobbins]

I'm not seeing filters much bigger than 77mm out there... I haven't broken out the epoxy and fiberglass cloth yet, so I could fit a straight 3" PVC in there instead of the step up to 4" if no such thing exists.... but I'm worried about to narrow of a field of view and catching some of my PVC in the frame of images...

[RandyRobbins]

OK I found a 95mm... is that the best I'm going to do? Suggestions on what to fill the gap with?

[-jeff]

I usually take a 86mm to 95mm filter adapter and epoxy that into a 3" PVC coupling. This makes it easy to replace the 95mm filter when it breaks.

[RandyRobbins]

I usually take a 86mm to 95mm filter adapter and epoxy that into a 3" PVC coupling. This makes it easy to replace the 95mm filter when it breaks.

Oooh, that’s a good idea. So same concept.... if I epoxy’d a 95mm filter with a threaded front (for stacking on another filter)into a 4” pvc fitting, could I just in theory break out the glass from the first filter when it breaks, and use the “frame” of that filter as a threaded attachment point for a new 95mm filter? That should work, yeah? Kind of hoping the outer diameter of a 95 will get me close to 4” PVC size....??

[buckhuntertrailcam]

I bought a bunch of thin flash light lenses at times off ebay and used those. I recommend GOOP to install them. I just did a quick ebay search and found toughened glass lenses in various sizes up to 120mm so you should be able to find one no problem. Just search "flashlight glass lens". The other option is to cut one out of a bit of scrap glass, firstly cut it square then cut the 4 corners off, sandpaper the sharp edges. Hope this helps.

[eeisenhaur]

If you have a 3D printer or access to one I have been 3D printing lens snout that fits a 77MM filter. At 18mm you won't have any issues if you're almost touching the filter with the lens.

20210826_171055.jpg

20210420_174708.jpg

20210904_075704.jpg