by KCStudly » Tue Apr 25, 2017 8:12 am
As I understand it, if the window flange (outside flange) doesn't already have a rubber ribbed seal incorporated (and then even if it does, it is common practice to add) the butyl tape goes under the outside flange of the window unit, not between the clamp ring and window. The seal is formed at the exterior face of the wall, so adding butyl to the clamp ring just makes a mess and wastes material with no effect.
I suspect that the trim ring was inverted and nested over the inside shape of the window for more efficient shipping. The inner leg of the "Z" shape gets screwed to the inside face of the window. Normally no screws go thru the outer flange of the window, avoiding possible leaks, and it is the clamping action of the window frame and outer trim ring frame that sandwiches the wall. The trim ring offset has to be specific to your wall thickness otherwise it won't clamp (i.e. you want a small/minimal gap between clamp ring and inner window frame once everything is tight).
The dimpled piece is there to hold the two ends of the trim ring together. I don't think its supposed to be loose or adjustable, but may have loosened up in shipping. You can probably double check the fit to make sure it wants to be closed up tight, then just restake the dimples using a center punch to tighten it back up again (protect exposed surfaces by backing them up with a rag or scrap piece of foam, soft vise jaws, etc., as required). If you are going to exchange the trim ring for one with a different offset, this is moot.
On my side door windows, they came with trim rings for a thicker wall. I am making thin wooden trim/spacer rings matching my interior finish that will allow me to use a flat clamp ring that I will make from sheet aluminum. That way I can set the amount of clamping force by setting the thickness of the spacer and minimize any unsightly gaps.
Last edited by
KCStudly on Tue Apr 25, 2017 3:23 pm, edited 1 time in total.
KC
My Build:
The Poet Creek Express Hybrid Foamie
Poet Creek Or Bust
Engineering the TLAR way - "That Looks About Right"
TnTTT ORIGINAL 200A LANTERN CLUB = "The 200A Gang"Green Lantern Corpsmen
with pilot holes drilled on the inside of the frame's flange. My assumption is that the outward facing flange should be towards the inside of the trailer and the window sits on top of the portion with the drilled holes on the outside portion of the trailer 
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