Pressure Treated Lumber and Hardware

[TheRic]

I'm putting pressure treated lumber on a trailer. Been told the wood treatment eats away anything that's not dipped in zinc, or Stainless Steel. I was going to use T-Nuts, I looked at Stainless Steel ones, and zinc plated. The price difference is about 10 times the cost, around $7.00 for zinc plated, $90.00 for stainless steel (for 100). The bolts, washers, etc are also a lot more.

I guess my question is how soon would the pressure treated lumber eat away the zinc plated t-nuts. Are we talking months, years, decades? Do I have worry about things like handles, hinges, etc being Stainless Steel? Will a layer of plastic or a coat of paint on the parts touching the wood help (not talking about the T-Nuts, bolts, washers, etc)?

Edited: Changed count on T-nuts to 100, was 10 thanks to mschrank for pointing that out.

[mschrank]

I can't help with the amount of time it would take to corrode, but I wonder about your source for tee nuts.

Either you are looking at a monster size, or you are looking in the wrong place.

A quick search on McFeely's turned up these, only $16.00 for 10

[TheRic]

Mike: Thanks for pointing out that I had 10 on the T-nut count. I meant to say 100.

As you can see from the link you posted Stainless Steel t-nuts would cost about $150 for 100, while zinc plated would cost me about $12.

Not sure exactly how many I will need (might depend on the cost) but the final number I'm sure is going to be closer to 100 than 10, that is why I mentioned (tried to) the 100 count.

I don't mind spending a few extra dollars, but not sure I want to spend that much more.

[newbie2wood]

Hot-dipped galvanized or stainless steel fasteners are recommended for treated wood. Zinc plated fasteners are thinly coated and will rust faster than the other two coatings. However, corrosion is measured in mils per year. Depending on how long you expect to keep the trailer, the fasteners may outlast it.

Also, depending on the size of the t-nuts that you need, the prices for the s/s t-nuts are not always 10x the cost of the zinc plated nuts.

http://www.jamestowndistributors.com...eyword=tee+nut
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Peach

[TheRic]

Newbie2wood: Galvanized is what I was told not zinc. As soon as I read that it hit me. Somewhere I got dipped zinc in my head.

Not talking about getting rid of the trailer. My grandfather orignally made it. It's been slightly redone a few times in the last 40+ years. I'm replacing the sides with pressure treated lumber. If I have to replace the tnuts, and/or bolts, washers, etc. in 10 years I can live with that. If I would have to replace them every other year, well that's a different story.

Any ideal on how long you think zinc plated will last?

[newbie2wood]

Corrosion is a complex subject. I do not have an answer to your question about how long zinc plated nails will last. Zinc will react with the copper in the treated wood.

Looking at boxes of nails, stainless steel nails have a lifetime warranty against rust and the warranty for galvanized nails is less than 10 years.

If you have no plan of ever selling the trailer, I would go with the stainless steel nails - its a one-time investment. Shop around for the best price on the stainless steel nails.
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Marijuana card

[LarryG]

Galvanized fasteners were okay for the old, now-banned, CCA-based wood preservatives, but the new stuff that replaced it (never can remember what it is without looking it up) will eat 'em alive. This Old House talked about this fairly extensively on one episode, with Tom Silva saying that stainless is now the only way to go.

He mentioned how quickly a galvanized fastener would fail. Unfortunately I cannot recall exactly what he said, but it wasn't long at all ... I want to say 12 or 18 months, something like that. I do remember being amazed by how incredibly short a time it was.