[pearson424] bomar hatch plastic? and the goo that binds
Pete Dubler <pete@dublerfamily.com> Sun, Mar 12, 2006 at 11:12 AM

I am going to replace the plastic in my Bomar hatches.  I measured the thickness as best I could without removing the plastic and found it to be 1/8" thick.  That just seems very thin to me.  

Am I missing something here?

Pete
Quent Kinderman Sun, Mar 12, 2006 at 3:04 PM

Pete-

I think 1/8" is a bit thin to be safe.Bomar replacement is about 3/16" lexan or similar polycarbonate. They sold me one replacement "lens" that was acrylic but it wasn't as good. If you plan to do them all, and have the equipment to cut and shape the stuff, you might consider buying a sheet, and making your own. If you have Bomar cast aluminum opening port lights, they use same plastic.

Quent
Clairebuoyant, #132

Pete Dubler Sun, Mar 12, 2006 at 6:02 PM
I have a good plastics guy here with fair prices and great service.  So when I find out what the actual specified thickness is I have him cut them for me.  I did all the measurements while at the boat, but the thickness is kinda hard to be sure about without removing a piece or having a glass caliper (tools used for measuring thickness of windows with a deep offset throat to clear the frame).

Pete
Carter, Richard Mon, Mar 13, 2006 at 9:27 AM

Peter

I've had trouble with the aluminum frames on my bowmar hatches. Over time, they corrode and get brittle. Even though I regularly painted them, the hinge on two of them have broken. I replaced both of them with new Bowmar hatches. I replaced with Bowmar because I didn't want to deal with a different hatch opening size. The point I'm making here is that I suggest that you not spend a lot of money reparing these hatches. If the plastic is shot, compare the price of a replacement before you repair them.

Rich Carter
Lee Thurner Mon, Mar 13, 2006 at 12:48 PM
My experience has been the opposite of Richard's. Meridian still has her original Bomar hatches with the original Lexan lenses. When the Bomar-applied black paint began to flake off (actually this happened before I bought the boat) I cleaned the frames down to bare metal, primed them with Petit 2-part metal primer, and painted them with Easypoxy, gray ("Platinum") on the outside and white on the inside. The Easypoxy on the outside doesn't last longer than a few months before it starts chalking, but scuff sanding and recoating every spring has kept them looking better than they looked when new. The lenses are cleaned and polished with 3M Fiberglass Restorer and Wax, and they also have stayed looking good, even in the Florida sun. The only breakage I've experienced is a couple of the stainless screws that hold the retainers to the frames; they went the way of all such dissimilar metals that are installed without benefit of Lanacote or similar galvanic barrier. Bottom line is that my Bomars have held up well, but they're maintenance intensive.

Given the ridiculous prices of new Bomar hatches, I wouldn't replace my existing hatches with them, or with any other painted aluminum-framed hatch. For similar money I'd spring for stainless-framed hatches such as those made by Mariner's Hardware (www.marinershardware.com). No painting required, they are exquisitely made, and they would certainly complement the looks of the 424.

Lee
Meridian, hull no. 139
Carter, Richard Mon, Mar 13, 2006 at 1:01 PM

Lee

I would have expected that those hatches would last forever.  After all, they aren't in salt water and they are painted.  I had both of the larger hatches fail in the same way however.  They broke at the hinge. There is a stainless roll-pin in the hinge and I wonder if there was some problem with the dissimilar metals.  In both cases, I was left with a gaping hole in my deck.  On short notice, I was forced to run down to the local marine store and pick up something that would fit.  There's a place near where I keep my boat that has surplus marine stuff for sale. They had some of the newer style bowmar hatches in stock for about $200. All they had was white, so now I have two white hatches and one black. These hatches are lighter in weight and are made from extruded aluminum stock.

Your suggestion to go to a stainless frame hatch is probably a better way to go.

Regards
Rich Carter
Quent Kinderman Mon, Mar 13, 2006 at 1:34 PM

We found that the Bomar hatches were serviceable.The lenses are probably .177" thick tinted polycarbonate (Lexan) sheet.I'll confirm that tonight as I have some old stuff I can measure.Google reveals several sources, at about $30 for a 24" by24", or about $160 for 4' by 8' sheet.We used regular Tempo outboard motor spray paint on the frames.First a light primer coat, several color coats, then several clear coats.Lasts a few years.A local metal shop welded and redrilled a riser attachment lobe for us.I suspect the galvanic corrosion around the SS cap screw built up aluminum oxide, which eventually caused so much pressure the part broke off.A little paint and plastic, these things keep going and going.

Anyone found a cheap source ofportlight outside trim rings?I could use a few of those.

Quent
Piescik, Walter Tue, Mar 14, 2006 at 10:56 AM
I restored mine using Dupont Imron Primer and Isocyanate paint. 4 years now, and they shine like they are brand spanking new.I replaced the lexan, my brother runs a machine shop and sourced it for me. I sent him accurate measurements and he sent it pre-cut. I just had to round t he corners.My lexan has begun to craze, but I have done nothing to protect it. I will try the fiberglass restorer/wax that Lee suggests. I would have thought it was too abrasive, and that it would leave a scratched surface. I was planning to use the same Maguier's plastic cleaner de3signed for soft convertible top windows.
Quent Kinderman Tue, Mar 14, 2006 at 12:31 PM

I confirmed last night that my replacement plastic is the .177" (3/16") thick stuff.

Original lens was just a little bit thinner, maybe .168" or so.

Crazing is what happens due to UV degradation.

Quent
[pearson424] bomar hatch plastic - the goo that binds
Rick Dugger Sat, Jul 1, 2006 at 10:59 AM
 


I've got some 3/16" lexan on order for the front hatch (cracked while removing to re-bed).

What goo is best for sticking lexan to the Bomar hatch frame?

Rick Dugger
Eclipse (#73)

Lee Thurner Sat, Jul 1, 2006 at 11:19 AM
Auto trim shops sell a 3M urethane adhesive product used for installing automobile windshields.  I used it to fasten the safety glass lenses I retrofitted to my Bomar aluminum ports and it works great.  It's 11 years old now and no leaks.  I'd ask whether it's suitable for Lexan before buying it.

Lee
Meridian, hull no. 139
Pete Dubler Sat, Jul 1, 2006 at 2:32 PM

Rick,

I just did this job.  The definitive way is to use the sikaflex cleaner and primer (very expensive, find some friends to share, about $40 per bottle) and the silkaflex UV caulk.  It takes two tubes of caulk to do all the hatches on the 424.  

Here is a great article for reference:
http://www.sailingmagazine.net/technique0106.html  

I got the materials from Jamestown.

Pete