noseoil wrote:Attaching to the interior plastic skin of a door is pretty iffy. I think the best way would be to fasten from the outside, counter-bore from the inside & add a stand-off to keep from crushing the door itself with a block, tube or some type of insert which becomes part of the door & adds a compression member to hold things in place.
We used them in aircraft work when building with balsa-core or honeycomb panels for structural fastenings & assembly. Basically, drill a #30 pilot hole from the outside first, then counter-bore from the inside to make a hole for the compression insert (spool, tube, stand-off, threaded insert) & epoxy the insert in place. The curtain rod foot will cover the hole. It's a PITA for a simple trailer build, but it would be a nice permanent solution which is leak-proof & would look OK when it's finished.
There is a something similar done with cored boats when doing a thru hull, drill out the inside skin over sized by a little. Say a 1/2 inch hole for a 1/4 bolt. Then take a small allen key or wire bent at 90 degrees and put the long leg in a drill. Slip the short leg in to the hole and run the drill moving it in and out. This will eat up the core larger than just the hole and allow it to be vaced out, then coat with reg epoxy with a q tip, then fill with thickened epoxy. when its cured drill the 1/4 hole all the way thru the hull. this give you a solid slug of epoxy all the way thru the panel, so no way to compress it, and nothing that can rot can get wet. even if the bolt leaks, it just leaks all the way thru, not in to the core.
I have to do this for the rear hatch lifts I will take pics.
See this thread about doing it to boats, cut away pics are on page 2
https://www.pbase.com/mainecruising/sealing_the_deckFor curtains just stick a wood dowel epoxied in a drilled hole, if it ever needs to be replaced just drill out the old dowel and glue in another.