Antennas, Elevated Water Tanks, and Stud Welding 1

[sewerratt]

Anyone have any experience with the use of nelson stud welding to attach antenna mounts to elevated water storage tanks? The structural part is OK, but I'm trying to determine the extent of damage, if any, to expect on the interior coating of the tank. The proposed studs are 3/8" dia and the tank plate is 1/4" thick. Nelson says everything is fine and don't worry, but they'll be gone in a year and I'll still have a tank to maintain. Anybody have any problems with interior coating burn when a antenna was put on your tank?

 

[sbush]

It's definitely going to "brown" the interior coating in that spot. Will that compromise the coating? I wouldn't want to find out by trial and error.

The first time one of our welders forgot to install an exterior bracket for a tank name plate, I decided to have him affix the bracket with four low-heat tacks. The results: brown spots on the interior surfaces adjacent to the tacks. The tank was empty, at the time, so we were able to repair the coating. Now, if we forget to attach a name plate bracket and the vessel has already been coated, we use a high-strength epoxy (something like J-B Weld) to essentially glue it in place.

I would look for some other appendage (hand rail, ladder, leg, pipe flange, etc.), on or near the tank, that will allow for a good penetration weld.

Good luck!

S. Bush

http://www.water-eg.com

 

[greggy]

Have you considered magnetically mounted antennas? Check it out at

http://www.metal-cable.com/,

a product called "magnemount", which will prevent the need for welding and blistering the coating system on the interior of the tank.

 

[gerhardl]

If you look to (European) magnetic powder applied epoxy coating of valves allowed for drinking water, some of the best coatings will have a coating manufacturor limit of 70deg C for fluids and 120 deg C for dry air, but also a limitation of 70 deg centigrade difference between outer and inner wall.

Reason and by experience: at around or above 100 - 110 deg Centigrade for fluids the coating will not keep colour and small bubbels inside coating or slips against wall may occur. This is then a start-point for corrosion.

General conclusion: if by welding the coating producers max temperature for any quality or methode of coating is exceeded, the producers guarantee for the coating will not be valid. The coating will be weakened, and corrosion or damage of tank walls may start at the weakened point.

Mis-coloring is a sign that the max temp. have been exceeded.

From insurance and quality point of view your action should be obvious.

 

[mikeBoh]

You might want to review my web page wherein we explain the process of CD stud welding onto water tanks for the installation of cellular antenna. Years ago we ran into this problem and did extensive research and testing. We developed this method and it is now used my cellular companies and consulting engineers to design antenna attachment mounts to the water tank skin surface. See

http://www.kmengr.com

Mike

 

[Unotec]

Mike, is this method suitable for welding catwalks, nozzles and such into a tank without damaging the internal coating?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[scwaterguy]

We have welded antennae masts to our tanks in the past. There is damage to the interior coating, but we applied a Tnemec product (not at the office so I don't have the name) that's a paste and is applied by a trowel. It is designed to be applied in moist environments and is NSF 61 approved. Call your local Tnemec rep for the name.