What is the difference between Marine and PT plywood?

[chrisg]

Thinking of replacing some rotted out seat frames. I can easlly get PT plywood. So what is the diff? other then price?

Thanks

 

[oops!]

Re: What is the difference between Marine and PT plywood?

lots.....2 different animals....

marine....aval in different drynesses....and has little or no "voids" petween the ply......this gives it more stregnth and less resistance to rot and or moisture build up between the plys........=$$$

pressure treated plywood.....or pt....

chemically treated plywood....this will serve as an "anti-rot agent"
pt is sold very wet....(i dont care if it looks and feels drypt will not accept resin unless it is very dry....it uasually takes a month in great conditions to dry....when drying...it tends to warp......great caution must be taken to dry flat....

it has more voids than marine ply.....

pt also does not like alumimimum....it causes a galvanic responce....and will "eat" it self or the material it does not like........you must use special screws...........

exterior grade plywood.....(not chip board)
has more voids than marine grade.....but easily in the acceptable range...
comes dryer than pressure treated wood...there fore....it requires less drying time....uasually just one week....... cheaper than the above

there is some basic info on wood....take your pick

 

[salty87]

Re: What is the difference between Marine and PT plywood?

very basic-
marine is going to be better quality wood. if there are any voids in the ply's, they'll be drilled out with a hole saw and filled-in.

pressure treated is lesser quality wood that has been soaked in whatever chemical they're using.


do some googling, there's tons more info on the subject...number of ply's, sanded on one or both sides, etc...

 

[chrisg]

Re: What is the difference between Marine and PT plywood?

Thanks, sounds like I should use marine or exterior grade plywood before considering PT. for repair on boat seats. Actually, think I will just go with getting new seats which have plastic frames.

 

[Labman]

Re: What is the difference between Marine and PT plywood?

Up here the difference is about $52.00 a sheet (4x8x3/4), $37.00 for Ext. 3/4(Fir) vs. $89.00 for the marine. Special order, two week delivery! For the $52.00, I can put alot of Glass on the Ext.