I'm on the last mile of replacing my old aluminum
Bomars with NFM port lights. I agree with Minaret, given the way the NFM are installed. That said, that's a lot of epoxy filling. I ended up NOT decoring all the new holes but rather wetted them all out with epoxy, as I have 1.5" cabin
sides with two 1/2" ply sheets
I have a few tips that are not covered in their installation
1. Do NOT rely blindly on the template(s) that they send for the location of the bolt holes. I installed 8 5x20 ports
, and the holes were spaced a little differently on all of them. I ended up checking the bottom two middle ones (which seemed to always fit the template), drilling them, then fitting the port with dowels in those holes to hold it in place and marking the rest of the holes and drilling them individually. I was a bit irked to say the least, as if they send you a template with drill guides around it you would sort of expect them to at least tell you that they might not line up. The only port where they lined up was a small 5x12 one.
2. Clean the ports
and finishing rings well with mineral spirits and acetone before installation
. A significant amount of machine oil
, dirt, and polishing compound will come off of them.
3. Put rings of butyl around the studs on the finishing ring so they seal the countersunk bolt holes from the outside. NFM's method relies on injecting the holes with silicon from the inside, but it is virtually impossible to ensure that you've got it all the way to the studs.
4. Make sure that you have at least 3/16" gap between the port flange that you insert through the cabin
wall and the cutout, and check from the outside. Anything less makes it difficult to ensure that you have the butyl sufficiently packed in.
5. Keep the butyl that you're going to add from the outside, and to finish the finishing ring, in the refrigerator
, or a cooler, if possible. If it gets warm it will get messy. When it's cold it's easier to work with and does not start to stick to your fingers as quickly.
6. If you get squeeze-out of the butyl back to the inside flange and it starts to come out the bolt holes, just punch a #3 phillips head
screw driver in, twist it, and yank. It will punch a hole and pull out the excess.