Makrolon?

[John, CD28]

After 30 years the skylight, and the old Bomar hatch are looking pretty tired, and I'll be reglazing. I found a guy (popdisplays) on eBay selling remnants of "Solar Gray Makrolon" which I think is a tinted UV stabilized polycarbonate designed for skylights and fixed windows on buildings. Does anyone have any experience with Makrolon? I'm thinking I'll bed them down with Dow 795.

Any advice/opinions on Solar Gray Markrolon? or Dow 795?

Any and all advice much appreciated.

John
CD28 Tantalus

[Hirilondë]

I have used it on hatches. It stands up well and the tint works well for horizontal glazing like hatches that get a lot of direct sunlight. I have yet to find a brand of polycarbonate that was inferior. The only thing that effects my decision on brand is customer wants for tint color.

[John, CD28]

Thanks guys, much appreciated.

Yeah, I think a nice tinted and UV stabilized polycarbonate is the way to go for hatches.

And where this eBay seller is offering remnants I don't have to pay for full sheets. Throw in his free finish cut size service, and it looks like a winner.

Thanks again!
John
CD28 Tantalus

[Hirilondë]

In theory acrylics have come a long way structurally. Some hatch manufacturers and repair companies claim it is the choice of material now. I am still skeptical.

[Maine Sail]

In theory acrylics have come a long way structurally. Some hatch manufacturers and repair companies claim it is the choice of material now. I am still skeptical.

Most hatch manufacturers, Lewmar, Hood, Atkins & Hoyle, Manship, Goiot and many Bomars use cast acrylic. Bomar is one of the few makers that has ever used polycarbonate. If your Bomar hatches have cross support bars then the hatch was intended to be polycarbonate. It is potentially dangerous to use polycarb in a hatch not intended for polycarbonate. While LOTS more impact resistant polycarbonate is also far more flexible than cast acrylic. When stepped on or pounded with green water it can flex enough to go all the way into the cabin or at the least break the seal when it foreshortens/flexes. If your hatch frame does not have cross supports it was likely made with cast acrylic not polycarbonate. If your hatches have cross supports like the Bomar 100 series then your perfectly safe to use polycarbonate. If they lack supports be very careful not to step on them or take big green water if converting to polycarbonate...

Our dodger windows are Makrolon AR and it is beautiful stuff but our Goiot hatches are cast acrylic..

[John, CD28]

I didn't realize acrylics were in vogue. Nor did I know polycarbonate was more flexible that other materials, great detail to know. But yeah, this is going on a late 1970s Bomar with two support beams to lend support to the new 3/16" Makrolon polycarbonate that's replacing the old 5/32" mystery sheet product.

<image when I get around to it ;) >

The skylight is different; it's just a cap screwed down over a 12"x17" hole in the cabintop over the main salon. I don't know what the old 11/32" material was, but I'm hoping the 1/2" thickness of the new Makrolon is sufficiently rigid to keep the bedding watertight. I'll bed it down with Dow 975, let it cure, then step on it a few times & see how much it sags. If it looks like trouble, maybe I'll swap it out for acrylic.

Thanks again guys - your collective knowledge is truly impressive, and my old boat is the greatest beneficiary!

John
Cape Dory 28 Tantalus

[Maine Sail]

I didn't realize acrylics were in vogue. Nor did I know polycarbonate was more flexible that other materials, great detail to know. But yeah, this is going on a late 1970s Bomar with two support beams to lend support to the new 3/16" Makrolon polycarbonate that's replacing the old 5/32" mystery sheet product.

<image when I get around to it ;) >

The skylight is different; it's just a cap screwed down over a 12"x17" hole in the cabintop over the main salon. I don't know what the old 11/32" material was, but I'm hoping the 1/2" thickness of the new Makrolon is sufficiently rigid to keep the bedding watertight. I'll bed it down with Dow 975, let it cure, then step on it a few times & see how much it sags. If it looks like trouble, maybe I'll swap it out for acrylic.

Thanks again guys - your collective knowledge is truly impressive, and my old boat is the greatest beneficiary!

John
Cape Dory 28 Tantalus

John,

CD used a lot of Bomar 100 series hatches and they are and were polycarbonate with the support bars. That is why they fog over pretty quickly. Acrylic was never in or out of vogue it has pretty much been to go to product in the industry for years with the vast majority of manufacturers using it. Even today the only hatch series Bomar makes with Lexan/polycarbonate is the 100 series. All their other hatches, SS, plastic, extruded aluminum and the 190 series cast aluminum are all acrylic lenses. Hop on a new Morris, Hallberg-Rassy, Grand Banks, J Boat, Sabre etc. and you'll see acrylic hatches.