Aluminium Corrosion in Concrete

G

George7941

Joined
May 10, 2005
Messages
2,737
Location
Toronto, Canada
I am installing two of these pathway lights in my garden. I am going to pour a small pad of concrete into the ground and insert the light base nto the concrete before it sets so that I have a firm mount for the light and do not have to be constantly straightening tilting lights. The mounting spike for these lights are pathetically short and the lights do not stand up straight for long in soil.

Being that the lamp is contructed out of thin aluminium, I was wondering if corrosion would eat away at the aluminium buried in concrete.
www.rona.ca

Vision Home LED Garden Path Light - Metal 5.51-in Black

Add style and enhance the beauty of your home and garden with this garden light. The black finish is universal and will fit most decors. This light o...
www.rona.ca www.rona.ca
Pathway Light.jpg
 
Yes, it can. Even more fun, the corroding aluminum can crack the concrete.

There are coatings made for aluminum in such applications.

Public service announcement: aluminum is not the lightweight, corrosion-resistant miracle metal some people think it is.
 
So, give the base a few layers of primer/paint, like rustoleum or equivalent.

Its a cheap light. How long do you expect it to last? I'd wager the corrosion will be the least of you problems. Have seem plenty of LED driver problems failing or trashing the LED.

Buy a few spares.
 
I agree with another poster, this is probably not gonna work out very well. I would come up with some kind of steak and wire tie it to the lamp shaft for a longer and more solid mount into soil. Mounting the shaft into concrete will just about guarantee the arrival of Murphy’s Law. 🤷‍♂️
 
^ In that case, maybe lay some conduit before pouring the concrete.. though I might want the conduit horizontal runner deeper under the concrete, if in it would result in concrete being too thin to hold up over time... I'm not a concrete guy so can't tell you the depth vs other variables, but seems easy enough to make a rut for it ahead of time.
 
I am currently leaning towards not using concrete, after hearing about corrosion issues. I am planning on hammering black iron pipe into the ground and tying the light fixture to it to ensure stability. This also enables easy replacement in the future, if necessary.
Will post pics when I am done but it might not be for a week or two.
 
I installed the two pathway lights this morning. 3/4 copper pipe (7/8 in OD) was a nice very tight fit inside the aluminium tubing, so I used the copper pipes as the anchor and fitted the lights on to pipes. Used 1/4 in stainless steel bolts to tie the aluminium to the copper. I started with a 18 in length of copper but the soil was very soft and I switched over to 3 ft lengths and hammered them into the ground. Now the lights are stable. The copper also adds height to the fixtures and enables them to shine over the bushes lining the walkway, instead of being hidden by the bushes. Lights will be easy to replace if they burn out.
Used adhesive lined heat shrink to protect the wiring splices.
The lights are bright. Have not seen them at night yet, should illuminte the walkway well.
Pathway Lught 1.JPGPathway Light 2.JPG
 
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