Marine grade vs PT vs exterior experiment

[geedubcpa]

I am doing a highly scientific experiment for the benefit of all the boat restorers who visit this site.

Today I am placing three small pieces of wood in a bucket of water in my garage.

1) marine grade that cost 97 per sheet
2) PT that cost 39 per sheet
3) exterior grade that cost 20 per sheet

I had small scraps of each in my garage.

The experiment goes like this - At the end of 7 days I will pull the pieces from the water and photograph them and share with the board the degree of damage to each piece - then I will follow up at 30 days 60 days and so forth.

 

[ajgraz]

Re: Marine grade vs PT vs exterior experiment

Throw a scrap of interior ply in there too, just as a control.

 

[jspano]

Re: Marine grade vs PT vs exterior experiment

my ext grade cost more than that. there are diff ext grades

 

[Friscoboater]

Re: Marine grade vs PT vs exterior experiment

This ought to be good. One questions. If we coat the wood with resin, doesn't this become moot?

 

[jspano]

Re: Marine grade vs PT vs exterior experiment

it's kind of like me spending alot of time and effort painting the bottom of my hull. if someone can see it i'm in trouble!!!!!!!!!!!!

 

[68C15]

Re: Marine grade vs PT vs exterior experiment

subscribed, gotta see this.
thanks

 

[Chuck Gibson]

Re: Marine grade vs PT vs exterior experiment

Someone near a coast needs to do this with saltwater!

 

[erikpn]

Re: Marine grade vs PT vs exterior experiment

Someone near a coast needs to do this with saltwater!

Saltwater inhibits the growth of the bacteria that causes rot. I live near the coast and would do a test if I had the wood. And TS, please remember to put in a piece of regular interior grade ply to act as a control.

 

[Huron Angler]

Re: Marine grade vs PT vs exterior experiment

my ext grade cost more than that. there are diff ext grades

I agree, I've bought it for $15(HD) and $20+(Lowes) and the better stuff cost more.

As mentioned...to do anyone any good you would need to coat each in epoxy resin to compare. But they would all be fine after 60 days anyway.

Smart money is on ext grade for the odds

 

[jspano]

Re: Marine grade vs PT vs exterior experiment

I agree, I've bought it for $15(HD) and $20+(Lowes) and the better stuff cost more.

the exterior ply here had some discription with them like exterior but covered from exposure and exterior exposed i paid like 30.00 for 3/4

 

[geedubcpa]

Re: Marine grade vs PT vs exterior experiment

Update - I know I was supposed to get back sooner on this post, but I forgot.


All 3 pieces of wood are still soaking in the water, none are protected with paint or any resin. At this point all 3 pieces are still solid, although the big surprise is that the marine grade plywood has a little edge that is lifting up. I will leave them all in the water and get back in a few weeks with updates.

geedub

 

[wallybme]

Re: Marine grade vs PT vs exterior experiment

Great experiment, but all you are doing is to test the strength of the glue. Nothing else. wood rot occurs over time and with varing degrees of temperature, light and humidity. Some fungal growth occurs in moist, dark and with high humidity. Besides this too there are various microbes that causes wood decay(feed on the wood) and we sure have to be certain which one is present during the decay process. Pressure treated IMHO would be ideal since it is treated with organism killers. Couple this with the glue in the marine ply will be outstanding. If it takes a couple of years (at least10+) before you actually see deck decay, then this will tell you how long you would have to continue this experiment for rottage. Even with this experiment immersing the wood in water may not give the rottage result. Temperature, humidity and orgamisms would have to be present, and I do not know which types of organisms (aerobic or anaerobic) does speed up rottage.

 

[PiratePast40]

Re: Marine grade vs PT vs exterior experiment

If the marine grade is separating, at least they'll replace it under the lifetime warranty. A moot point if you have to tear everything out but at least they offer a liftime warranty.