Thread: Aluminium problem

Originally Posted by OxxAndBert

I can't think of anywhere you'd get them off the shelf.
Have you got any boat builders locally, or an aluminium fabricator? They might have some extrusion that you could make some from, or be able to fabricate some for you from flat (either bent or welded).

Steve

Thanks Steve.
Ok, I've got it. I'll try to find out. Thanks for the idea.

Originally Posted by Michael G

I like the Wattyl 'killrust' system of paints. Visit an outlet and discuss with them. They will probably recommend an etch primer for the Al and then a top coat, but see what they say.

I'm a bit concerned by the steel bolts used to attach the Al post to what looks like an Al plate. Even if you are not remotely near the sea, pollution in the air will set up a galvanic cell and make any corrosion worse. Personnnaly I would replace those angle pieces and weld the replacements to the pipe rather than bolt them. Extra effort, but less likely to result in corrosion.

Michael

Hi Michael.


Unfortunately I never welded aluminium before. I reckon it's a job for a TIG welder, which I'm not. My friend is close to the sea, around 4 ks.
For the paint I went to Lonsdale paints and they have recommended almost the same stuff as you do, just a different brand. Thank you for the tip.

Originally Posted by OxxAndBert

I can't think of anywhere you'd get them off the shelf.
Have you got any boat builders locally, or an aluminium fabricator? They might have some extrusion that you could make some from, or be able to fabricate some for you from flat (either bent or welded).

Steve

I found some ALU brackets that are used to hold electrical roof panels. What do you think, can they be a better choice?

Ahhh - yes. Solar panel mount brackets. I was racking my brain as I knew I'd seen some brackets somewhere that would likely do the job. That was them.

I'd say they would be a good choice.

Steve

Originally Posted by OxxAndBert

Ahhh - yes. Solar panel mount brackets. I was racking my brain as I knew I'd seen some brackets somewhere that would likely do the job. That was them.

I'd say they would be a good choice.

Steve

Thanks Steve.

Originally Posted by China

"Powder coating is not a good thing outdoors." with all due respect Rubbish

It baffles me how people don't see the abundant evidence that PC lacks long term durability. Never seen the piles of discarded garden furniture etc, at any council street cleanup campaign?

Some say that, done properly, it will last. It may be true, I don't know. But, how to know if an item you see for sale has PC that has been applied properly? I don't think it would be something that could be checked visually.

I recently bought a tractor implement, and asked if I could have it enamel painted. "Sorry, they come in powder only. Besides, ordinary paint gets knocked about more during transport." So now I know another reason for PC's apparent popularity.

Photo is a friend's fork attachment that is stored outdoors, less than 8 years old, hardly ever gets used.
This is surely typical of powder coating?

Hi Guys,

I didn't realise that powder coating was so frowned upon !

I'm told that when powder coating steel, the steel has to be clean and rust free, otherwise the rust underneath spreads and breaks up the coating over time allowing more rusting. I assume that new clean aluminium doesn’t have that problem.

With correct pre treatment as with any steel product, powder coating will out last out doors pretty much anything other than plating

I wish I knew how to find out that something has been properly prepared before it was powder coated.
But even if it has been, the PC eventually gets punctured. No matter how clean, the underlying metal is then exposed to the elements.
It's what happens next that is really bad. Corrosion grows under the PC, causing large flakes of it to bubble and break off.
Unlike enamel, it can't be brush touched or otherwise repaired. It cannot be successfully painted over either.
I can't understand the enthusiasm for it, speaking as a consumer.

10 years ago I had a couple of talks with a guy that did the powder coating for the company I worked for.
"I does not matter the type of coating, surface prep is the key". That and he "would back powder coating against any other coating if done properly except maybe baked enamel he did his time doing during the 60`s".
The parts coated by him went underground into a harsh environment. We could get 2 or 3 cycles out of them before needing to be coated again. This was a lot better than the previous coater were the coating was starting to flake off after one cycle. It cost more up front but we made up for it at the end.

Back to the OP.
I`d weld new brackets to the pole, coat it then isolate it from the concrete. As mentioned before a layer of sheet between the pole and concrete. I have seen sleeves used on the bolts to the concrete so they don`t touch the brackets and washers made from the same material as under the pole backed up by gal steel washers to tie it all down.

Tony

Here are a few pictures of the mast at it's current location. The idea is to get it down, fix the corrosion issues, change some rusted parts at ground level, paint it and erect it back again and then attach a new antenna to it.

Hi Guys,

I had a 75 ft Strumech three section base plate crank up tower, erected in 1972, the year that I got my ham licence. It was galvanised steel. Apart from replacing the cables with stainless steel ones and a winch, which rusted away, there wasn't any rust on it ! Nobody was interested in buying it a couple of years ago, so apart from the base plate, I cut it up for scrap metal. The only reason the base plate is still there, is because the wife has her washing line tied to it.

Originally Posted by bts

10 years ago I had a couple of talks with a guy that did the powder coating for the company I worked for.
"I does not matter the type of coating, surface prep is the key". That and he "would back powder coating against any other coating if done properly except maybe baked enamel he did his time doing during the 60`s".

So someone whose business it is to do powder coating backs it against other methods. There's room for a little suspicion there.

Nadroj - like you, I've seen lots of crap powder coating.
I've also seen lots of crap welding.
I have also seen a lot of good powder coating and welding, so IMO its not the product as such, its the application.

A mate of mine makes 4WD accessories - bull bars, wheel carriers etc. All of his gear is powder coated (by the same coater) and as far as I'm aware he's never had any issues with it.
I've personally got powder coated bull bars (ARB brand) on a couple of vehicles. Both bars are at least 20 years old and live outside in the weather 99% of the time. The coating has started to oxidise and they have scratches in the coating which have surface rust on them, but haven't flaked. At least as good as any painted coating I've come across.
I think if you look at PC that has flaked like the photo you posted earlier you'll find that there has been zero prep done on the part before coating. Likely not even been degreased is my guess.

Just my 2c worth...

Steve

Originally Posted by OxxAndBert

Nadroj - like you, I've seen lots of crap powder coating.
I've also seen lots of crap welding.

I believe you Steve, but you can at least usually see if welding is crap when it's new.
The part in the photo is a genuine Kubota, although it's possible it was made here in Oz, sadly.