delara newsDelaware Amateur Radio Association, Delaware OH VOL 36 NUMBER 11
Craig MIller W8CR
Acid Trip, ManMany years ago, I stopped in at a tower erecting company called CESCO in, of all places, Powell. I had grand plans of putting up a super cool tower to support some super cool antennas to do super cool ham radio stuff. Behind the building, in a chain link fenced yard, were the carcasses of antenna towers of every shape and design. I was hoping they’d part with a few sections, cheap, to an impoverished young amateur radio enthusiast.Fortunately, the counter man didn’t laugh in my face and kick me out the door when I inquired about the scrap steel out back. He directed me to the back door and told me to look around, which I did. In hindsight, I wish I brought a camera. Back then cells phones were non-existent except for the very wealthy and well connected (and those didn’t even have cameras). This scrap yard had towers and miscellaneous parts of every variety. He asked me how tall of a tower was I interested in. I replied that I was flexible, anywhere from 40 to 70 feet, not too picky. I didn’t have a very large yard to put up a super monster stick. They had a real cool, orange and white painted microwave tower where the base section was about 8 or 10 feet across and stood 100’ high. It was so beefy, it could have supported a treehouse or mini ham shack.I passed.Next to it, was a stack of 14 sections of commercial grade Rohn 45G including the expensive top piece that they pulled out of service. 14 sections x 10’/section=140 feet! That’s a little too high for my needs and property dimensions but if the price was right... I asked how much he wanted for it. We walked back into the office, he asked if I needed any guy wire. I said “Sure.” He tossed in a huge spool of cable and all of the hardware required for erection plus a commercial grade climbing harness. He even allowed me to snag one of those neat red blinking tower lights you always see on top of the big commercial towers. The final price? Basically, he gave me tower for free but I paid for the other things. Nice!It took several trips to haul it out with my old ’67 Chevy pickemup truck. I stacked the sections up nicely behind the garage dreaming of the day they will be brought back into service. One year lead to the next….and….the… next….After moving this stack of steel to a new house on a bigger lot, I’m committing to get this beast in the air, maybe not the whole 140’ but at least 60. Before anything can proceed, I wanted to re-galvanize the sections. I called around to hot dip galvanizing companies, some didn’t want my business, those that did were going to charge me about $1000 – ouch! I could just put a coat or two of Rustoleum on the bare metal but zinc is the ultimate in rust preventer.There are products on the market called “cold galvanizing compound” which purport to be just as effective as hot dip but can be applied by yourselve with just a paintbrush. One brand is ZRC. Expensive as all get out but advertised to be the best. I ordered a gallon for a meager $159 plus shipping. When the box arrived containing the “paint” I was amazed how heavy it was. It felt like picking up a car battery. It was heavy! This can contained basically pure zinc micro particles suspended in a solvent – literally liquid metal.The instructions informed me that the metal to be treated must be clean down to the bare steal, sandblasting preferred. Well, I ain’t gonna burn up my air compressor spraying silica everywhere and I sure as h*** not going to wire brush all of the tiny crevasses. An alternative is to treat the sections by some rust-removing acid like Navel Jelly. The jelly is also a pain to use plus it’s rather expensive for the quantities I need. I’d rather do some type of dip tank and let chemistry do the hard work.The tower sections are 18” wide by 10 feet long. To dip the whole thing under some type of acid, I’d need a vat of those dimensions holding 15 cubic feet (112 gallons!) of nasty acidic goo. In reality, I determined I only needed to treat one side at a time, requiring only a few inches of depth to soak the legs. So, I built a dip tank using some 2”x6”x12’ lumber, 1/2” plywood and heavy duty PVC sheeting.I sat the tower sections on ½ pvc pipe to prevent gouging the plastic sheet and allow fluid to come into full contact with the tower leg pipe.Go to the friendly construction supply store and buy out their Muriatic (HCL) Acid stock:Dilute with a several gallons of water and watch the surface rust just separate from the steel.I said “separate” as opposed to dissolve, I ain’t no chemistry brainiac but my observations conclude just that: the rust particles loosen from the steel and settle to the bottom of the solution. I honestly use an old toothbrush to gently dislodge the crud from the metal. The legs come out spotless after soaking each side for a day or two. I averaged almost two sections a week using this cleaning process. An extra bonus, it cleans the inside of the vertical pipe sections as well.When the sections are ready, I pull them out, without chemically burning myself alive, spray off with water, dry and apply the magic ZRC cold galvanizing compound with a brush.I then fabricated a swab to paint the inside of the legs using a small paint roller and fiberglass rods:I may apply a top coat of Rustoleum before assembly to pretty things up, or just leave it dull grey. All-n-all I’m really pleased with the outcome and the costs were surprisingly low. And frankly, this is probably the easiest part of the project. Next, digging the hole… Any volunteers?