Inground pool, corroded ladder anchors

[Kip]

Our inground pool came with two ladders which consist of plastic steps mounted to what appear to be stainless steel tubes. The pool company supplied the ladder anchors which are now buried in the concrete deck, flush to the deck surface, and they appear to be aluminum. The concrete deck has small colored stones set into its entire surface. Over the years, the insides of the anchors have become more and more corroded, and they have now reached a point where I can no longer insert the ladder tubes.

The pool company's suggested solution to this situation is for me to call the company that did the deck, have them come out and cut out the old anchors and replace them. But I would like to avoid this if possible...I don't believe they would be able to do this without it looking like a patch.

I am thinking that if I had a proper tool, I could perhaps bore out the insides of the anchors to remove the corrosion and get an internal diameter that would again accommodate the ladder tubes.

Does anyone think this is a viable solution? Would anyone have a suggestion as to what tool would be appropriate?

Thanks very much.

[gfretwell]

Take the bolt out, remove the wedge, use a cylinder hone from the auto parts store to buff out the inside of the cup. If you do have them replaced, be sure they get hooked back up to the 8 gauge copper bond wire. That may be hard to do without chipping out a pretty good sized chunk of concrete, being careful not to break the wire. You will still be splicing on a piece and shoving it back into the hole with the cup. Be sure to attach the #8 correctly to the cup.

[Joe]

Isn't there a known problem with galvanic corrosion between aluminum and copper? Could that be the real problem?

Joe

[gfretwell]

cup.http://gfretwell.com/electrical/laddercu.jpg>

Not really. The lugs used just about everywhere with copper wire are aluminum. I would still use a bronze ladder cup though, just because the aluminum cups do go bad. quicker.

[DD_BobK]

What you refer to as "anchors".... aluminum pipe sections placed in the deck concrete?

If that is true you have a stuation with two no-no's

Aluminim in concrete.... bad for aluminum Aluminum contacting stainless in wet environment .... bad for aluminum

As per other post....cylinder hone with coarse stones

or change out the aluminum for PVC or stainless

cheers Bob

[Reno]

Kip wrote in news:4c348c05-12a9-4509-96b5- [e-mail]:

You might be able to clean the anchor tubes out - try a circular wire brush on a drill. The problem is these usually only come with a short shank, about an inch, so they can't reach far enough into the anchor tube. Try a short one just to see if it will do the cleaning well enough. If it does, then try to find a longer shank or use a shank extension like the ones that come with sets of screwdriver bits. The extension will be a real pain because the wire wheel will constantly fall out into the hole. Try gluing it in but best is to get someone to weld the two together. A fast job for a welder.

If it is really aluminum then the corrosion will never end because aluminum and steel form a galvanic cell where the higher noble metal, aluminum, will corrode which protects the less noble metal, steel, from corroding. Is the steel clean? If so that supports your thinking that the anchor is aluminum. The good news is that aluminum is a soft metal and thus easy to clean. It is even easy to grind up and remove, easier than steel anyway.

After grinding away corrosion a few times you may find that most of the aluminum is gone. Clean up the hole nicely and get a piece of galvanized pipe cut to length and replace with that. It, too, will corrode eventually but you could slow it down with some lead in the bottom of the hole. Get some scrap lead, wheel weights are good, pound and cut them into a washer that fits the bottom of the hole and will contact both pipes. The lead is the most noble metal and will corrode instead of the steel. Could last for many years - the more lead you use the longer it lasts. It's called anodic protection if you want to research it.

[Tony]

I recall learning that in very old city water pipes they would put a block of zinc at each joint to prevent corrosion. Similar but the zinc would react with any available oxygen before the oxygen could react with the pipes and causing rust.

[chaniarts]

zinc doesn't react with the oxygen. it corrodes because of the stray electrical currents set up between the 2 dissimilar metals.

[gfretwell]

These are ladder cups. They are required to be U/L (or other lab) listed and as far as I know they only come in aluminum or bronze. They are required to be part of the equipotential bonding system (the solid 8 ga wire). Simply shoving a sleeve of pipe in the hole will not meet these requirements.

[Mr. Land]

Thank you all for the excellent suggestions and information. You folks are great.

Best...

[DD_BobK]

I was unaware of the ladder bonding requirement.

I wonder how many pools in the US have unbonded metal ladders. I wonder how many unbonded ladders have proven to be a problem.

I'm interested in hearing the scenario where a pool ladder gets energized.

ahh, I can think of one...... overhead power line (more than 25') breaks and falls to the ground energizing the ladder?

In any case, aluminum in concrete is a bad idea, esp around a pool environment. How good is the electrical contact going to be between heavily corroded aluminum and stainless? Probably not great.

Of course PVC can't work as part of the grounding system but allowing aluminum in this situation doesn't sound like a great idea either.

If one is really serious about bonding a stainless steel ladder, it would seem that a means more positive than aluminum sockets should be used.

cheers Bob

[gfretwell]

They are still required to be bonded and it is part of the pre-concrete inspection. I think the question about how the ladder got energized but how bad it would be if it did. These are usually considered "stray voltage" problems where a buried cable causes a voltage gradient in the soil. I was at a seminar a few weeks ago where an instructors was saying you could get voltage gradients, just from electrolysis. I am not sure I go along with that.

BTW I bet that ladder is chrome over brass, not stainless. This whole "stainless" craze is fairly recent. If it is stainless it would explain the aluminum going to hell. Stainless and aluminum together, really hate water.

[DD_BobK]

The ladder in my parents pool (1959) was stainless tubing. I saved when my mom had the pool replastered in ~1995.

The new ladder system was "pool wall toe steps" and aluminum ladder arms cantilevered off the deck.

I saved the old ladder ( a hefty dude) thinking I might use it but my wife convinced me to sell if for scrap. :(

I learned about galvanic corrosion in my teens when I clamped an 1/8" sheet of alumimum to the ladder to divert the "pool sweep" so it wouldn't get stuck. The aluminum sheet was aluminum "lace" in less than a week!

I agree......buried cable or utility fault are way more likely than electrolysis.

Any idea when the ladder bonding requirement came to be?

Both replaster jobs I've been involved in 1995 & 2000 involved ladder replacement but no one mentioned it.

cheers Bob

cheers Bob

[gfretwell]

This has been in the code since at least 1962, the earliest reference I have found. Mike Holt may have something on it. This bonding thing has now (2008NEC) gone to the point that you have to bond the water if there are no other metallic paths. It requires 9 sq/in of metal, in contact with the water and bonded to the equipollent grid, that now includes any paved surface within 3' of the water. This is the steel in a concrete slab or a #8 copper ring under pavers. In 2005 that was a 1'x1' grid of #8 copper but they backed off of that.

[hrc.rddw60]

Great idea with the lead! I do imaging room shielding lead lining is very accessible.

[Mchamp]

replying to gfretwell, Mchamp wrote: Stainless in pool ladders and ramps in not a recent fad but a standard for over

60 years. Brass is too flimsy to be used for pool ladders or ramps. Moreover the chrome plating would not last long.