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#1
posted to rec.boats
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Marine grade? or salt-treated plywood?
"mmc" wrote in message g.com... "Califbill" wrote in message m... "mmc" wrote in message ng.com... wrote in message ... On Tue, 20 Jul 2010 12:10:34 -0700 (PDT), Tim wrote: I was wondering abotu using salt-treated plywood on the Marquis deck. I'm not a feared of paying for marine grade, but Jimmy the carpenter told me that the newer salt treated woods are about as worthy as marine grade at a fraction of the cost. So, what's the opinion? I'm even wondering abotu using hybrid decking like you'd use on a porch. synthetic mylar etc mixed with wood. The stuff is weather resistant as all get out! I looked at everything when I decked my pontoon boat 20 years ago. We had a Wolman plant here at the time and they offered to pressure treat any plywood I would bring them but the guy who ran the plant said PT really only protects it from bugs. If water is your issue, save your money. I ended up with MDO plywood (one side) and it is still going strong after 20 years in salt water. That is basically 7 layer exterior grade plywood with one MDF layer. You would probably have the same luck with BC The main thing is to be sure everything is sealed before you put it in and seal all penetrations. The only bad spot I have found in my current rehab is from an unsealed penetration. Cut all of your pieces to size, paint them on all 6 sides with 2 coats then install them. Paint it again to cover the screws. Bristol Palin will be running for president before that plywood goes bad. I worked on a sailboat once that had a PT plywood sole and where it met, the aluminium mast was badly pitted. I thought it may have been caused by the cyanic acid? Nope, the copper is not friendly to aluminum in a wet inviroment. Is ther copper in pressure treated plywood? Yup. Used to be copper arsenate (CCA). Now it is a copper only solution. http://www.strongtie.com/productuse/PTWoodFAQs.html |
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#2
posted to rec.boats
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Marine grade? or salt-treated plywood?
"Califbill" wrote in message m... "mmc" wrote in message g.com... "Califbill" wrote in message m... "mmc" wrote in message ng.com... wrote in message ... On Tue, 20 Jul 2010 12:10:34 -0700 (PDT), Tim wrote: I was wondering abotu using salt-treated plywood on the Marquis deck. I'm not a feared of paying for marine grade, but Jimmy the carpenter told me that the newer salt treated woods are about as worthy as marine grade at a fraction of the cost. So, what's the opinion? I'm even wondering abotu using hybrid decking like you'd use on a porch. synthetic mylar etc mixed with wood. The stuff is weather resistant as all get out! I looked at everything when I decked my pontoon boat 20 years ago. We had a Wolman plant here at the time and they offered to pressure treat any plywood I would bring them but the guy who ran the plant said PT really only protects it from bugs. If water is your issue, save your money. I ended up with MDO plywood (one side) and it is still going strong after 20 years in salt water. That is basically 7 layer exterior grade plywood with one MDF layer. You would probably have the same luck with BC The main thing is to be sure everything is sealed before you put it in and seal all penetrations. The only bad spot I have found in my current rehab is from an unsealed penetration. Cut all of your pieces to size, paint them on all 6 sides with 2 coats then install them. Paint it again to cover the screws. Bristol Palin will be running for president before that plywood goes bad. I worked on a sailboat once that had a PT plywood sole and where it met, the aluminium mast was badly pitted. I thought it may have been caused by the cyanic acid? Nope, the copper is not friendly to aluminum in a wet inviroment. Is ther copper in pressure treated plywood? Yup. Used to be copper arsenate (CCA). Now it is a copper only solution. http://www.strongtie.com/productuse/PTWoodFAQs.html Ah galvanic action. Good reason not to butt up to, bolt or clamp to aluminum. Thanks. |
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#3
posted to rec.boats
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Marine grade? or salt-treated plywood?
wrote in message ... On Wed, 21 Jul 2010 18:27:24 -0400, "mmc" wrote: "Califbill" wrote in message news:I5GdnVHTnL2ExdrRnZ2dnUVZ_tmdnZ2d@earthlink. com... "mmc" wrote in message g.com... "Califbill" wrote in message m... "mmc" wrote in message ng.com... wrote in message ... On Tue, 20 Jul 2010 12:10:34 -0700 (PDT), Tim wrote: I was wondering abotu using salt-treated plywood on the Marquis deck. I'm not a feared of paying for marine grade, but Jimmy the carpenter told me that the newer salt treated woods are about as worthy as marine grade at a fraction of the cost. So, what's the opinion? I'm even wondering abotu using hybrid decking like you'd use on a porch. synthetic mylar etc mixed with wood. The stuff is weather resistant as all get out! I looked at everything when I decked my pontoon boat 20 years ago. We had a Wolman plant here at the time and they offered to pressure treat any plywood I would bring them but the guy who ran the plant said PT really only protects it from bugs. If water is your issue, save your money. I ended up with MDO plywood (one side) and it is still going strong after 20 years in salt water. That is basically 7 layer exterior grade plywood with one MDF layer. You would probably have the same luck with BC The main thing is to be sure everything is sealed before you put it in and seal all penetrations. The only bad spot I have found in my current rehab is from an unsealed penetration. Cut all of your pieces to size, paint them on all 6 sides with 2 coats then install them. Paint it again to cover the screws. Bristol Palin will be running for president before that plywood goes bad. I worked on a sailboat once that had a PT plywood sole and where it met, the aluminium mast was badly pitted. I thought it may have been caused by the cyanic acid? Nope, the copper is not friendly to aluminum in a wet inviroment. Is ther copper in pressure treated plywood? Yup. Used to be copper arsenate (CCA). Now it is a copper only solution. http://www.strongtie.com/productuse/PTWoodFAQs.html Ah galvanic action. Good reason not to butt up to, bolt or clamp to aluminum. Thanks. It may be somewhat of a concern but not a huge problem. These aluminum brackets have been on my .8 CCA PT dock for over 20 years http://gfretwell.com/ftp/aluminum%20and%20PT.jpg |
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#4
posted to rec.boats
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Marine grade? or salt-treated plywood?
wrote in message ... On Wed, 21 Jul 2010 18:27:24 -0400, "mmc" wrote: "Califbill" wrote in message news:I5GdnVHTnL2ExdrRnZ2dnUVZ_tmdnZ2d@earthlink. com... "mmc" wrote in message g.com... "Califbill" wrote in message m... "mmc" wrote in message ng.com... wrote in message ... On Tue, 20 Jul 2010 12:10:34 -0700 (PDT), Tim wrote: I was wondering abotu using salt-treated plywood on the Marquis deck. I'm not a feared of paying for marine grade, but Jimmy the carpenter told me that the newer salt treated woods are about as worthy as marine grade at a fraction of the cost. So, what's the opinion? I'm even wondering abotu using hybrid decking like you'd use on a porch. synthetic mylar etc mixed with wood. The stuff is weather resistant as all get out! I looked at everything when I decked my pontoon boat 20 years ago. We had a Wolman plant here at the time and they offered to pressure treat any plywood I would bring them but the guy who ran the plant said PT really only protects it from bugs. If water is your issue, save your money. I ended up with MDO plywood (one side) and it is still going strong after 20 years in salt water. That is basically 7 layer exterior grade plywood with one MDF layer. You would probably have the same luck with BC The main thing is to be sure everything is sealed before you put it in and seal all penetrations. The only bad spot I have found in my current rehab is from an unsealed penetration. Cut all of your pieces to size, paint them on all 6 sides with 2 coats then install them. Paint it again to cover the screws. Bristol Palin will be running for president before that plywood goes bad. I worked on a sailboat once that had a PT plywood sole and where it met, the aluminium mast was badly pitted. I thought it may have been caused by the cyanic acid? Nope, the copper is not friendly to aluminum in a wet inviroment. Is ther copper in pressure treated plywood? Yup. Used to be copper arsenate (CCA). Now it is a copper only solution. http://www.strongtie.com/productuse/PTWoodFAQs.html Ah galvanic action. Good reason not to butt up to, bolt or clamp to aluminum. Thanks. It may be somewhat of a concern but not a huge problem. These aluminum brackets have been on my .8 CCA PT dock for over 20 years http://gfretwell.com/ftp/aluminum%20and%20PT.jpg Still look pretty solid! |
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#5
posted to rec.boats
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Marine grade? or salt-treated plywood?
wrote in message ... On Wed, 21 Jul 2010 13:27:06 -0700, "Califbill" wrote: Nope, the copper is not friendly to aluminum in a wet inviroment. Is ther copper in pressure treated plywood? Yup. Used to be copper arsenate (CCA). Now it is a copper only solution. http://www.strongtie.com/productuse/PTWoodFAQs.html You can still get CCA lumber at a marine supplier. I know, but at least here, could not find any in the San Francisco Bay area. Maybe Oregon. |
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