Metal protective coating
- Thread starter antero
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mts0628
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Hey antero:
Just looking at the video, it looks like a finicky application. Using it on a back plate may be different and may be simple enough at first glance but the concern would be ensuring the product gets into the exposed surfaces of the holes and grooves. And the bottom line is that it looks like a surface application.
Now anodizing is a process that penetrates the surface of aluminum. You can vary the penetration and protection to suit your needs. The longer the time spent in the anodizing bath, the deeper the penetration and the deeper the protection (with a couple of other variables). Also, anodizing (if done correctly) applies evenly and thoroughly. You could get a metal preparation shop to do it for a few bucks or you could even get a kit and do it yourself. The Alchemist has a few examples of some anodizing, and it looks pretty neat.
And finally, there is powder coating. You can pick up a powder coating kit form Sears, I think, and use an old oven and get pretty good results. The back plate would be a good item for powder coating (no moving parts). Because the process deposits a thickness of the paint on the item, anything that requires a tight fit (threads for example) will not fare well and if you remove the coating to accommodate the fit, well then you just removed your protection.
I'd go with the anodizing.
I hope this helps,
Thomas
Just looking at the video, it looks like a finicky application. Using it on a back plate may be different and may be simple enough at first glance but the concern would be ensuring the product gets into the exposed surfaces of the holes and grooves. And the bottom line is that it looks like a surface application.
Now anodizing is a process that penetrates the surface of aluminum. You can vary the penetration and protection to suit your needs. The longer the time spent in the anodizing bath, the deeper the penetration and the deeper the protection (with a couple of other variables). Also, anodizing (if done correctly) applies evenly and thoroughly. You could get a metal preparation shop to do it for a few bucks or you could even get a kit and do it yourself. The Alchemist has a few examples of some anodizing, and it looks pretty neat.
And finally, there is powder coating. You can pick up a powder coating kit form Sears, I think, and use an old oven and get pretty good results. The back plate would be a good item for powder coating (no moving parts). Because the process deposits a thickness of the paint on the item, anything that requires a tight fit (threads for example) will not fare well and if you remove the coating to accommodate the fit, well then you just removed your protection.
I'd go with the anodizing.
I hope this helps,
Thomas
R
redacted
Guest
It is a backplate!!! Why bother???
Bolts that attach tanks to the back plate are stainless steel. This causes a noticeable corrosion around the holes where bolts are coming thru. While I neglected to pay extra for the anodized back plate because it is priced unreasonably higher I still would like to find a way to protect my gear.
colbar
Registered
If you use SS fasteners, you really need to isolate the aluminium from the SS, otherwise the aluminium become a sacrificial anode to protect the steel component - its all about electrolysis and the chemical nobility of the materials. Go to your local auto supply shop and buy some suitably sized red fibre washers. You need to set up the fastener/nut with a flat washer and a fibre washer on either side of the aluminium plate. I use this set up extensively on my aluminium boat when installing/replacing new parts/componentry and it significantly reduces the build up of the white oxide and the tendency of the fasteners to "freeze" together.
R
redacted
Guest
Yes, there may be corrosion. I built and 1/4th inch aluminum BP about 8 years ago and used SS screws threaded into the aluminum plate to fashion a STA. And they are corroding - Still holding just fine; but corroding. I'm afraid there is a good chance that before I am too old to continue diving, the corrosion may get bad enough to actually start compromising the connections and I will have to repair it. But so far (about 500 dives, 50% SW) a good soaking after SW dives seems to be limiting the corrosion.
gert7to3
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Isolating the ss screws from the al bp is the way to go. There are any number of plastic, fiber or rubber washers and plumbing bits available at a good hardware store. You could make your own by cutting out sections from a plastic bottle.
If you have a threaded ss/al component it should probably be sealed with marine bedding compound, silicone or even grease.
If you have a threaded ss/al component it should probably be sealed with marine bedding compound, silicone or even grease.
qrpc
Contributor
Attaching a zinc sacrificial anode might help too.
Since the area to be protected is small, you would not
need much surface area on your anode. If you know a
boat owner that is replacing his zincs, there is probably
more than enough material left in the scrap.
Since the area to be protected is small, you would not
need much surface area on your anode. If you know a
boat owner that is replacing his zincs, there is probably
more than enough material left in the scrap.
Jon Nellis
Contributor
A couple small teardrop zinc anodes and you can skip the plastic washers altogether.
Anodes are actually better than anodizing for things that will take some abuse. Once you put a small chip or scratch in anodizing, that little scratch of exposed aluminum becomes the anode surface for the entire part and corrodes much faster.
If you do decide to anodize something for saltwater use, go with hard anodizing .001" minimum thickness and round off any sharp corners.
.
Anodes are actually better than anodizing for things that will take some abuse. Once you put a small chip or scratch in anodizing, that little scratch of exposed aluminum becomes the anode surface for the entire part and corrodes much faster.
If you do decide to anodize something for saltwater use, go with hard anodizing .001" minimum thickness and round off any sharp corners.
.
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