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New port lights - advice please

Started by SeaHusky, September 09, 2016, 01:52:47 PM

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SeaHusky

I am replacing the old plexi(?) port lights with new ones and I have chosen hard coated polycarbonate. As you see they are the simple "bolt onto the GRP cabin" type with a one inch overlap all round. You also see that the old ones were fitted with a bolt every two inches.
I wonder if I should simply copy the old ones or drill the new ones perhaps using only every other bolt hole or so? The holes in the cabin are already there but I will drill as many as I need in the new polycarbonate. I am thinking that forces will be pressing against the outside but the holes may weaken the design. On the other hand perhaps less holes/bolts put more stress on each bolt hole and therefore more is better?

I look for subtle places, beaches, riversides and the ocean's lazy tides.
I don't want to be in races, I'm just along for the ride.

CharlieJ

If it were me, I'd drill all the holes, slightly oversized (say a 64th), no countersink, and use pan head screws (or bolts)
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

Jim_ME

Agree with Charlie to reuse all existing fastener holes. One of the purposes of the close spacing is to keep the materials as flat and the pressure on the sealant as even as possible.

SeaHusky

Thanks! I will use all bolt holes as suggested.
Any tips on working with butyl in this case to make it look good and avoid a mess?
I also want to use some "shading film". Should I apply it to the outside or inside?
I look for subtle places, beaches, riversides and the ocean's lazy tides.
I don't want to be in races, I'm just along for the ride.

ralay

Out of curiosity, CJ, why no countersink?  Just to have the full thickness?

CharlieJ

Nope- countersinks in plexi or lexan act as wedges The screws expand and contract in both heat and cold, at a much different rate than the plastic. Countersinking would tend tom break out right at the edges. Also the reason I said drill slightly oversized holes NOT a snug fit.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

CharlieJ

Quote from: SeaHusky on September 09, 2016, 04:19:39 PM


I also want to use some "shading film". Should I apply it to the outside or inside?
On board Tehani I use a self cling vinyl I get from sign shops. You dampen the window, and sqeegee the vinyl on  When you want it gone, just peel it off- no residue. Then goes right back on with a damp sponge. When I don't want the ports covered, I store the vinyl under a bunk cushion

You can see what it looks like on the port in this pic

Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

doug

While not inexpensive we have been happy with these blinds:

http://www.zarcor.com/products/clozures/#gal-image-0

They used to be called peek-a-boo blinds. Had them 5 years now without any trouble.