ACQ vs CCA PT Lumber

MikePA · Jul 19, 2004

I used square drive stainless steel screws from McFeely's to install my fence. Someone on TBN recommended McFeely's and I concur. Using square drive was substantially better than using Phillips head.

I went with stainless steel screws because of the following information at the McFeely's site;

As most woodworkers are aware, as of January 1, 2004, the pressure treated lumber industry has voluntarily switched from CCA chemical processes to alternative treating methods such as ACQ. While significant testing has been performed on galvanized screws to ensure their compatibility with the new treatment processes, to date stainless steel is the only corrosion resistant material to have gained widespread acceptance for use with these new materials.

I have some other projects planned that will use PT lumber and decided to go with stainless steel nails. Used to be that only projects near salt water had to use stainless steel fasteners. Looks like they're going to be needed regardless of location any time PT lumber is used. /forums/images/graemlins/frown.gif

shvl73 · Jul 19, 2004

I think it may have to do with the much higher copper content in ACQ vs CCA, possibly a metalurgical reaction of some sort with the zinc galvanization.

JDgreen227 · Jul 19, 2004

shvl73 is correct about the copper....according to my latest issue of a woodworking magazine: "ACQ-treated wood has fastener corrosion rates up to three times greater than CCA-treated wood. As a result, manufacturers now recommend using hot-dipped galvanized or stainless steel screws and nails."

I was planning to use hot-dipped nails for my new deck, same as I used in the one built last year, which was CCA-treated wood. After reading the posts here and the info in the magazine, I think I will spend the extra $$ for stainless steel nails. After paying extra for the ACQ lumber, what's a few more dollars for the hardware.... what's funny is, I was congratulating myself on stocking up on 16D hot dip nails (50 lbs. worth) just before nail prices went sky-high.... /forums/images/graemlins/frown.gif

MikePA · Jul 20, 2004

I just bought a box of stainless steel nails for my coil framing nail gun here. I could not find stainless steel nails for air nailers at Lowes.

kevincook · Jul 20, 2004

I bought stainless nails for a cypress fence from these guys a couple of years ago. They seem to have everything imaginable and the prices look pretty good to me.

Stainless Fasteners

Kevin

EastTexFrank · Jul 20, 2004

I read the same thing and I started using the ACQ galvanized nails sold by Paslode in my framing gun for fencing. I figure if they do rust out in 5 or 10 years, I'll just shoot another couple in there. There has to be some sacrificial effect that causes nails and screws to rust faster. If I was building a deck though, I would probably go with the stainless.

Sorry Mike, I agree with you about McFeely's but I can't agree with you about the square drive screws, especially the 3" and 3-1/2". I know a lot of people like them, including a good friend of mine who runs a contracting business, but I personally have more trouble stripping the heads of those than any other type. I know it's my technique that is at fault. I don't keep everything aligned as I drive the screw and end up stripping the head and rounding off the bit which only makes the problem worse. I find other types of head more forgiving.

MikePA · Jul 20, 2004

I was putting in 1.5" SS pan head screws. 1,122 of them, into PT fence posts. I spun the square head out of less than 10 of them, probably because I did not get the bit in completely, and broke one square head bit. I was using a DeWalt drill/driver with a torque collar, which made things real nice.

I can see how the longer screws could cause problems.

JDgreen227 · Jul 21, 2004

As a carpenter by trade before retirement, I used to break or wear down standard phillips bits in my drills quickly. My solution was, when Sears was having a $1 sale on their Craftsman screwdrivers, I would buy several of the regular phillips drivers. It took only a few minutes to put one in a vice, cut off the plastic handle, and grind the tabs off the shaft with a bench grinder. It's almost impossible to break the tip off these and the shaft is longer than most of the bits you can buy.

AND, if you do indeed break one, take the handle and shaft back to Sears and they will replace it for free.

/forums/images/graemlins/smile.gif

bgott · Jul 21, 2004

I've thought about experimenting with the temper on those bits to see if I could get 'em to last a little longer.

ScottAR · Jul 22, 2004

I use to hardly ever have trouble breaking bits until I got one of those cordless impact drivers... Now I break em all the time... I just try to buy in bulk on common sizes, cuz I'm gonna break more... /forums/images/graemlins/tongue.gif