Has anyone successfully polished-out the scratches on old Bomar hatches, as on a 1984 Catalina 36? Are windows in the hatches acrylic or polycarbonate? Thanks, jv
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Ron Mills
Easier to replace than polish
out in my opinion. You can take the old ones to a plastic supply house and have them make new ones. Reseal with Dow Corning 795. Sd to the second part of your question there are two schools of thought. I went with polycarbonate per the plastic supply recommendation. Others prefer lexan.
out in my opinion. You can take the old ones to a plastic supply house and have them make new ones. Reseal with Dow Corning 795. Sd to the second part of your question there are two schools of thought. I went with polycarbonate per the plastic supply recommendation. Others prefer lexan.
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Gord May
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Jim Quibell
lexan is softer
Lexan (Polycarbonate) is softer than acrylic plastic, and more easily scratched. There is a polishing kit available that has a range of papers that start at about 250 and go up to 3000 (if memory serves me correctly) My kit is out on loan to another boater who is polishing all his hatches and ports. This is the same kit that is used by the airlines to polish out scratches on their airplane windows.
Lexan (Polycarbonate) is softer than acrylic plastic, and more easily scratched. There is a polishing kit available that has a range of papers that start at about 250 and go up to 3000 (if memory serves me correctly) My kit is out on loan to another boater who is polishing all his hatches and ports. This is the same kit that is used by the airlines to polish out scratches on their airplane windows.
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MArk
Lexan 28 times stronger
Lexan has 28 times the impact strength of acrylic and 250 times the impact strength of glass for the same weight. That's why it's used for crash helmets (and space helmets), power tools, Jeep hardtops and bullet proof glass. There are different grades (formulations) of Lexan depending on what properties you want. Another advantage of Lexan over acrylic on a boat is its resistance to UV depolymerization.
Lexan has 28 times the impact strength of acrylic and 250 times the impact strength of glass for the same weight. That's why it's used for crash helmets (and space helmets), power tools, Jeep hardtops and bullet proof glass. There are different grades (formulations) of Lexan depending on what properties you want. Another advantage of Lexan over acrylic on a boat is its resistance to UV depolymerization.
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Jim Quibell
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Jim willis
I want to replace all my hatches with lexan.
I made (cut to size at TAP plastics in Fremont CA) half inch lexan stormwindows to cover the plexiglass (acrylic) pilot hous windows of my Gulf 32. Yes Lexan is Polycarbonate. It is so tough that ultracentrifuge tubes are made of the stuff. The sufaces do oxidize (yellow) but this can be fixed bey removal and polishing. They do not "craze" like my acrylic hatch and portlights that will now be "brittle". That is why I would like to replace them. However Lexan is not as rigid as plexiglass and would need to be thicker or better supported. I had small offcut of lexan from my storm window job and I tried bending it back and forth to try to get it to break- never could- it's sort of like "toffee". Thanks Jim W
I made (cut to size at TAP plastics in Fremont CA) half inch lexan stormwindows to cover the plexiglass (acrylic) pilot hous windows of my Gulf 32. Yes Lexan is Polycarbonate. It is so tough that ultracentrifuge tubes are made of the stuff. The sufaces do oxidize (yellow) but this can be fixed bey removal and polishing. They do not "craze" like my acrylic hatch and portlights that will now be "brittle". That is why I would like to replace them. However Lexan is not as rigid as plexiglass and would need to be thicker or better supported. I had small offcut of lexan from my storm window job and I tried bending it back and forth to try to get it to break- never could- it's sort of like "toffee". Thanks Jim W
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Ron Mills
Sorry, I replaced mine with acrylic
per the plstic supply house recommendation. I wasn't concerned about being hit by meteors.
per the plstic supply house recommendation. I wasn't concerned about being hit by meteors.
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John Visser
So Bomar is...?
Lexan? Is this is a safe assumption? I couldn't figure it out looking at theri website. The polishing kit I've found is Micro Mesh. See the link. They have different kits for different materials, such as Lexan and Acrylic. The web site is tough to decode. jv
Lexan? Is this is a safe assumption? I couldn't figure it out looking at theri website. The polishing kit I've found is Micro Mesh. See the link. They have different kits for different materials, such as Lexan and Acrylic. The web site is tough to decode. jv
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Jim Rushing
Watch Out for Lexan
I have worked with both Lexan and plexiglass on my two airplanes and there are major differences. Lexan will graze over time if it is stressed. Also because it is much softer than plexiglass, it will scratch easier and is harder to refinish. Because it is softer, it will not shatter like plexiglass. After playing with Lexan, I will stick with plexiglass for its ability to be repaired. Jim
I have worked with both Lexan and plexiglass on my two airplanes and there are major differences. Lexan will graze over time if it is stressed. Also because it is much softer than plexiglass, it will scratch easier and is harder to refinish. Because it is softer, it will not shatter like plexiglass. After playing with Lexan, I will stick with plexiglass for its ability to be repaired. Jim
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Jim Quibell
All plastics have their benefits.
Strange how something so tough (polycarbonate) has a number of weak points. All plastics have different properties - when you gain something, you have to give up something in the plastics world. I recall many years ago when we were developing polycarbonate (Lexan) food storage boxes at Rubbermaid Commercial Products that we came up with some interesting findings. While the clear storage boxes were virtually indestructible, leave them overnight in a cooler with either tomatoes or a tomato product and the next day you have a useless distorted crazed bin. Sometimes even cracks would appear. We developed a polycarbonate bussing box on which we gave a life-time guarantee against breakage. Boy, that was a mistake. They cracked like crazy because of ketchup etc causing them to breakdown. Cheers, Jim Quibell - G-26 - Sam's Closin'time - BHYC
Strange how something so tough (polycarbonate) has a number of weak points. All plastics have different properties - when you gain something, you have to give up something in the plastics world. I recall many years ago when we were developing polycarbonate (Lexan) food storage boxes at Rubbermaid Commercial Products that we came up with some interesting findings. While the clear storage boxes were virtually indestructible, leave them overnight in a cooler with either tomatoes or a tomato product and the next day you have a useless distorted crazed bin. Sometimes even cracks would appear. We developed a polycarbonate bussing box on which we gave a life-time guarantee against breakage. Boy, that was a mistake. They cracked like crazy because of ketchup etc causing them to breakdown. Cheers, Jim Quibell - G-26 - Sam's Closin'time - BHYC
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Harry
Plex. & Lexan are diferent for a reason
In a past life, I was a salesman for a plastics distributor, and sold both Lexan (G.E.'s polycarbonate), and Plexiglas (Rohm & Hass's cast acrylic). Polycarbonate is extremely strong, due to it's "softness"; it gives rather than breaks...which also makes it highly suspectable to scratching. Cast acrylic is harder, therefore less strong, and also LESS likely to scratch. Both will scratch; acrylic, less. The benefit of acrylic over glass, is that it will not shatter, but will break in larger pieces. The benefit of lexan is it will not break at all. Surface scratches can be buffed out of acrylic using jeweler's rouge. If you are really good...and extremely careful, you can also "melt" scratches out of acrylic using a moving flame. Not sure if a hair dryer will reach required temperature. You can also bake it in you oven.. danger there is too hot distorts. There was a product used mainly for military applications called Plexiglass II, which had a harder surface, and therefore more scratch resistant than plexiglas. I don't know if it is still available, but it would be ideal for marine applications. Any distributor in the phone book could speak to it's availability & price. One more piece of advice, NEVER use ANYTHING other than mild soap (dish detergent)& water to wash either product, and don't dry with anything other than a soft rag. Paper towels will leave slight scratches. Hope this is of some help.
In a past life, I was a salesman for a plastics distributor, and sold both Lexan (G.E.'s polycarbonate), and Plexiglas (Rohm & Hass's cast acrylic). Polycarbonate is extremely strong, due to it's "softness"; it gives rather than breaks...which also makes it highly suspectable to scratching. Cast acrylic is harder, therefore less strong, and also LESS likely to scratch. Both will scratch; acrylic, less. The benefit of acrylic over glass, is that it will not shatter, but will break in larger pieces. The benefit of lexan is it will not break at all. Surface scratches can be buffed out of acrylic using jeweler's rouge. If you are really good...and extremely careful, you can also "melt" scratches out of acrylic using a moving flame. Not sure if a hair dryer will reach required temperature. You can also bake it in you oven.. danger there is too hot distorts. There was a product used mainly for military applications called Plexiglass II, which had a harder surface, and therefore more scratch resistant than plexiglas. I don't know if it is still available, but it would be ideal for marine applications. Any distributor in the phone book could speak to it's availability & price. One more piece of advice, NEVER use ANYTHING other than mild soap (dish detergent)& water to wash either product, and don't dry with anything other than a soft rag. Paper towels will leave slight scratches. Hope this is of some help.
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Bob Howie
Try glass
Same problem as all the rest; replaced mine with gray-tinted 1/4" tempered safety glass -- it's done all the time in higher-end hatches with great success -- and have had good results. Oh, sure, you can break it...but only if you really, really try! Have even drop'd 3/8" socket drive from top of mast -- 42' -- and it bounced right off...and then overboard, of course, but the glass didn't break!! And, glass is stable; doesn't warp and all that stuff and if you clean the frame well and then bed it with 3M Silicone marine seal, it's great.
Same problem as all the rest; replaced mine with gray-tinted 1/4" tempered safety glass -- it's done all the time in higher-end hatches with great success -- and have had good results. Oh, sure, you can break it...but only if you really, really try! Have even drop'd 3/8" socket drive from top of mast -- 42' -- and it bounced right off...and then overboard, of course, but the glass didn't break!! And, glass is stable; doesn't warp and all that stuff and if you clean the frame well and then bed it with 3M Silicone marine seal, it's great.
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