Trailer Bunk Boards

[its an addiction]

Hey Fellas,

My bunk boards are in need of replacement. I've talked to people who say you have to use pressure treated wood since it will be exposed to water and pressure treated is rot resistant. Well, it appears that one of the materials that the wood is treated with is copper. Most treated wood requires hot dipped galvanized fasteners and I've read that most of it is corrosive to aluminum. Apparently there is a newer pressure treated process called Micronized Copper Azole, opposed to the ACQ(Aresenic Copper Quaternary) that is supposedly safe with direct contact with aluminum, but upon further research I've found this from a manufacturer website of the MCA ...

Aluminum building products can be placed in direct contact with ProWood Micro CA pressure-treated wood products used for interior uses and above-ground exterior applications such as decks, fencing and landscaping projects. Examples of aluminum products include siding, roofing, gutters, door and window trim, flashing, nails, fasteners and other hardware connectors. Aluminum contact is not recommended when ProWood Micro CA treated wood products are immersed in water or are subject to frequent and prolonged wetting or other severe exposure conditions. In such cases, a moisture-resistant protective barrier should be placed between the aluminum products and ProWood Micro CA treated wood.

The wood will be covered with marine bunk carpet I've purchased from Cabela's. But does anyone have knowledge or experience with replacing bunk boards and what type of wood they have used or what type you would recommend and why.

And thanks for anyone who stuck through and read my lengthy post.

[JWheeler]

We replaced one on my BIL's trailer, we just used treated and fastened the carpet back onto is. Cheap and easy

[Priority1]

A hole could develop in the bunk carpeting and the wet wood come in contact with the bottom of the aluminum boat. I wouldn't chance it. It would probably be OK with a FG boat. Regular wood will last 10 years.

[Nailer]

Like Frank said; just use SPF and replace when needed. It will last a long time.

If your really worried use Cedar, and coat it with Sikkens before the carpet goes on.

Cedar is not as strong, but it can withstand water. My dock is made out of cedar, and it's wet all of the time, with no rot..

[its an addiction]

Thanks for the input guys. I was leaning towards getting what you all suggested, but had a buddy who insisted I needed treated our my regular SPF lumber would rot out in a year.

I ended up going to Home Depot yesterday and got the untreated SPF lumber. I didn't want to risk it like you all said. Took me forever to find a good looking 2x4 at Home Depot yesterday.

Would it be worth it to stain the 2x4's, or just unnecessary work?

Thanks guys.

[mj6131]

It wouldn't hurt to seal the end-grain with whatever. (sealer, paint, wax...)Just something to slow the uptake of water.

[sherman51]

if you ever go through this again try to find a lumber supply store that carries or can get you some hard wood ie oak, just make sure its hard wood. it will last for 20 yrs. i have oak beams on my trailer then cut them at the same angle as the bottom of the boat. then bought the little roller bunks from bass pro shops and mounted on top. its as good as having an easy load trailer. but ive had these hard wood boards on my trailer with no coating or paint for atleast 10 yrs and they are still just as good as the day i put them on there.

you,ve heard of marine grade plywood, well all it is, is its made with hard wood. thats what makes it last so long.

as for the wood you used, yes you want to use a good exterior paint and put a good coating of paint on them. it will just make them last for a few more years. or thats what i would do if it were me. good boating.

sherman

[salmonquest]

I wouldn't recommend oak for bunk purposes. It has open pores on the surface which promotes mold growth as well as being reactive with many metals plus it's prone to shrink. Plus being a lot more $$$

Every bunk I've seen has been made of treated lumber. The carpet covering should be enough to protect the hull. Even if a small hole develops the hull will still not be on direct contact with the board. I would recommend double dip hardware though.

[sherman51]

I wouldn't recommend oak for bunk purposes. It has open pores on the surface which promotes mold growth as well as being reactive with many metals plus it's prone to shrink. Plus being a lot more $$$

Every bunk I've seen has been made of treated lumber. The carpet covering should be enough to protect the hull. Even if a small hole develops the hull will still not be on direct contact with the board. I would recommend double dip hardware though.

i dont know where your getting your info on oak boards. now i could see where any green wood might react to metal. but a seasoned oak board is one of the most weather resistant woods there is. but there is alot of other hardwoods besides oak. redwood, ash, birch, walnut, cypress, and many many more. and any of them will outlast treated wood. and like you said yourself its going to have carpet on it.

the biggest reason most people dont use hard wood is its just not readily available. and so many people believe the treated lumber is so much better, but it is just so much cheaper. than say oak or redwood. the oak on my trailer has been just great with no problems at all. but then i put the roller bunks on mine. but i havent got any mold or rot whatsoever, and its been on there atleast 10 yrs. but then your intitled to your opinion just like me.

i,ll never use anything besides some kind of hard wood. and all marine grade plywood is made with some type of hardwood. birch, oak, ash, walnut, cherry, teak, just to name a few of the woods used in marine grade plywood. but its all seasoned and not green.

sherman

[salmonquest]

You Are correct oak is very acidic but reacts with iron so should be safe for aluminum applications, however it is very porous and prone to swelling, and splitting. Those who have restored wooden boats know the first thing you do when you are done is sink the boat. This causes the oak to swell and the craft to be more water tight. Plus oak tends to be heavy. I am glad the application worked for you. If you are going to stick with hardwood I would recommend: teak, mahogany, or cypress a more suited for this application, although really i think a material like manufactured decking such as azek would be best although perhaps need to be structurally reinforced.

http://en.allexperts.com/q/Woodworking-2320/black-spots-hardwood.htm

http://forums.iboats.com/showthread.php?t=238336&page=1

[sherman51]

i think alot of what you say makes sence. and you may be right about other woods working better. but then on the other hand the boards are not left to sit in the water long enough for them to swell very much. not enouh to hurt anything as a bunk board. and it wouldnt hurt anything if it did swell alittle.

i could be wrong but i believe any wood boat works better if allowed to swell and seal all the small cracks. but just about any wood will swell if left exposed to water for along peroid of time.

and this just gives you an idea how long these hardwoods will last with no coatings at all.

and they do make building materials now that could be used for bunk boards that should outlast both of us,LOL.

hey its been very interesting talking about this on here. but i think we,ve hyjacked his thread long enough.

and like most trailers just plane wood with a good paint and carpet should last you for a few years anyway. or the plane treated wood with a good bunk grade carpet should last for years. and as far as being in contact with your aluminum boat if you got a hole in the carpet. you would have to load the boat to the very same spot every time you loaded it. or leave it sitting for a few years to do any real damage.

sherman

[its an addiction]

Thanks for all your input guys. I'm going to go with the SPF that Nailer and Priority1 suggest. I sure did learn a lot about the different types of wood throughout this whole process though.