msumoose
Member
Alright guys, I have had a couple of requests for information, and I thought that this might be a good place to start.
As an intro, My name is Clay, I live in Mississippi, and I am a wood scientist. I have been working in the wood industry for about 10 years in various roles. I was degreed by Mississippi State (GO BULLDOGS) in Forest Products - Wood Industries Management and Wood Science. Currently I am a consultant about....you guessed it, wood science and plant management.
Anyhoo,
I was watching one of my favorite boating shows the other day (Ship Shape TV....check it out on FoxSports) and the host had the pres of World Panel Products on. He was espousing the superiority of marine rated ply, and how regular outdoor sheathing was not up to the marine standards. Well, being the nerd I am, I did a little research about the things and came up with some interesting thoughts....
1. The adhesives used are VERY close to the same...there may some minute differences, but all in all they are Coke vs. Pepsi. All outdoor sheathing is made from phenol formaldehyde resin (PF) and most marine ply is too. A small percentage may use melamine formaldehyde, but it is VERY expensive comparitively speaking.
There is a standard for marine ply called "WBP" and while I have been unable to find the tech documents on the test itself, the overview is that a part is boiled in water for some period of time. I can say that I have performed the APA (American Engineered Wood Association) test that does about the same thing. The way the test is carried out may be different, but I can assure you that all panels carrying an APA stamp have had a boil test performed for its adhesive.
2. All American made marine ply is made of Douglas Fir, and the standard that it adheres to allows football patches, and a small void in the core. This is where the difference between marine ply and sheathing is seen...Sheathing can have voids in the core. Is this good or bad? well, if I were making a transom that I were fiberglassing, I would definetley go with marine ply. There are too meny thru hulls that go in that area that a void could be hit and allow water to sit in the void. If I were making a deck for a tinboat....to Lowe's I would go.
There is some difference in the rot resistance of doug fir and pine, and especially some of the foregin woods used in marine ply. I believe that with the proper preparation that this can be overcome, though. I am sure that most of you have seen my little discourse on "water sealants" so I won't include it here, but I will say a pine board bathed in epoxy resin will last a LOOONNNG time. I would use West system 105 as the resin and varnish over for some UV protection, if you were leaving the wood natural, but that is just me.... :mrgreen:
I hope that this solve somes problems in the debate of marine vs regualr plywood...and these are just my opinions, and you know what those are like! :roll:
As an intro, My name is Clay, I live in Mississippi, and I am a wood scientist. I have been working in the wood industry for about 10 years in various roles. I was degreed by Mississippi State (GO BULLDOGS) in Forest Products - Wood Industries Management and Wood Science. Currently I am a consultant about....you guessed it, wood science and plant management.
Anyhoo,
I was watching one of my favorite boating shows the other day (Ship Shape TV....check it out on FoxSports) and the host had the pres of World Panel Products on. He was espousing the superiority of marine rated ply, and how regular outdoor sheathing was not up to the marine standards. Well, being the nerd I am, I did a little research about the things and came up with some interesting thoughts....
1. The adhesives used are VERY close to the same...there may some minute differences, but all in all they are Coke vs. Pepsi. All outdoor sheathing is made from phenol formaldehyde resin (PF) and most marine ply is too. A small percentage may use melamine formaldehyde, but it is VERY expensive comparitively speaking.
There is a standard for marine ply called "WBP" and while I have been unable to find the tech documents on the test itself, the overview is that a part is boiled in water for some period of time. I can say that I have performed the APA (American Engineered Wood Association) test that does about the same thing. The way the test is carried out may be different, but I can assure you that all panels carrying an APA stamp have had a boil test performed for its adhesive.
2. All American made marine ply is made of Douglas Fir, and the standard that it adheres to allows football patches, and a small void in the core. This is where the difference between marine ply and sheathing is seen...Sheathing can have voids in the core. Is this good or bad? well, if I were making a transom that I were fiberglassing, I would definetley go with marine ply. There are too meny thru hulls that go in that area that a void could be hit and allow water to sit in the void. If I were making a deck for a tinboat....to Lowe's I would go.
There is some difference in the rot resistance of doug fir and pine, and especially some of the foregin woods used in marine ply. I believe that with the proper preparation that this can be overcome, though. I am sure that most of you have seen my little discourse on "water sealants" so I won't include it here, but I will say a pine board bathed in epoxy resin will last a LOOONNNG time. I would use West system 105 as the resin and varnish over for some UV protection, if you were leaving the wood natural, but that is just me.... :mrgreen:
I hope that this solve somes problems in the debate of marine vs regualr plywood...and these are just my opinions, and you know what those are like! :roll:
