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Straight Al finish over time, will it pass the white glove test?

rons

Diamond
Joined
Mar 5, 2009
Location
California, USA
I polish the little square plate and then when I rub it with a finger. Metal easily wipes off. (The spot near the hole)

The larger plate does not rub off so easy. It's been sitting around for years.

Probably all 6061. Will a freshly brushed finish on a piece like this take some time to oxidize and be resistant to the white glove?
Or is there some liquid like vinegar (guess on that one) that would etch and make a suitable surface?
Or just paint?

DSC_1115.jpg

The swivel is to be mounted in-between the two plates. The swivel is Al with a anodize or powder, not made to take apart. Painting it would not cover the
sliding surfaces and maybe be ok for a common-folk-person and not a perfectionist. Paint everything or just scratch a finish on the plates and wait a few
years before a white glove attack? I choose black because a black part will be bolted to the small plate.

(I have no affiliation to U-SCREW, or I mean U-Haul. I remember back in the day they had ownership or profits from gasoline stations and had no interest
in getting more fuel efficient gas guzzlers).

(I didn't post this in "general" this time. Here because of paint, maybe. Want to see if the first time responders catch this one...) :drink:

Caught in less than 2 hours. :leaving:
 
I polish the little square plate and then when I rub it with a finger. Metal easily wipes off. (The spot near the hole)

The larger plate does not rub off so easy. It's been sitting around for years.

Probably all 6061. Will a freshly brushed finish on a piece like this take some time to oxidize and be resistant to the white glove?
Or is there some liquid like vinegar (guess on that one) that would etch and make a suitable surface?
Or just paint?

View attachment 327519

The swivel is to be mounted in-between the two plates. The swivel is Al with a anodize or powder, not made to take apart. Painting it would not cover the
sliding surfaces and maybe be ok for a common-folk-person and not a perfectionist. Paint everything or just scratch a finish on the plates and wait a few
years before a white glove attack? I choose black because a black part will be bolted to the small plate.

(I have no affiliation to U-SCREW, or I mean U-Haul. I remember back in the day they had ownership or profits from gasoline stations and had no interest
in getting more fuel efficient gas guzzlers).

(I didn't post this in "general" this time. Here because of paint, maybe. Want to see if the first time responders catch this one...) :drink:

Caught in less than 2 hours. :leaving:

Alkali Etch the parts. Degrease the parts then proceed with the Alkali etch. Dip in a solution of Sodium Hydroxide and Sodium Carbonate in a 50-50 solution. Operating Temperature 140 F. Specific Gravity at operating temperature 12 Be. Checked at least once a month. Additions due to drag out losses shall be equal amounts of Sodium Hydroxide and Sodium Carbonate. This will provide a clean even matt finish.
 
The electrode on the left was positive in test #1.
The middle electrode is always negative.
The electrode on the right was positive in test #2

1. The left and middle pieces are in solution with about .250 A flow. Bubbles occur and after a while the examination shows no
difference.

2. The right and middle piece left in solution for 1 1/2 hours with .25 A. The right piece was just a zinc plate bolt.
After removal the bolt was covered in black sludge and could be wiped off. It has rusted since yesterday.
You can see the vertical line of color on the middle piece. The backside of the middle piece was not getting transfer.

The measurement across the middle piece (opposing sides with new plating :skep:) is .001 greater. So .0005 thickness.
Thickness of what? Have not done anything about the suggestions for chemicals in the above. And where to get them?
And not sure about what should be positive or negative and what the sacrificial piece should be.

DSC_1116.jpg

It would be nice to just walk over to a tank of solution and turn on a power supply, wait or watch TV, come back and it's done.
Instead of setting up for painting each time. Like Mauri said in Goodfellas, "Henry my dream come true, no more bullshit..."
 
Can't say for sure about the product you linked to, but the aluminum-black for guns from Birchwood Casey is incredibly soft and pretty much worthless unless you can cover it with a polyurethane clear coat, etc.

Would blasting with sand or Ballotini impact beads make the surface more wear resistant?
The work hardening done by blasting stainless should carry over to blasting Aluminum?
 
I doubt it. It seems the film itself is very weak. In fact, you can wipe a lot of it off with a finger! Its been quite a while since I used it and maybe I was doing something wrong. For sure, I didn't think it worth buying another bottle.
 
looks like you might be zinc plating the alu :)

If you want to anodise the alu, you'll need to strip the existing oxide layer off (sodium hydroxide will work), then add a new one by passing a current through a sulphuric acid or sodium bisulphate solution with a piece of alu as one electrode and your work as the other. Can't remember off hand which way round they are. Current depends on part surface area and time in the bath - Caswell plating has a bunch of really good info, plus they sell good dyes for pretty reasonable money.
 
looks like you might be zinc plating the alu :)

If you want to anodise the alu, you'll need to strip the existing oxide layer off (sodium hydroxide will work), then add a new one by passing a current through a sulphuric acid or sodium bisulphate solution with a piece of alu as one electrode and your work as the other. Can't remember off hand which way round they are. Current depends on part surface area and time in the bath - Caswell plating has a bunch of really good info, plus they sell good dyes for pretty reasonable money.

This was just a test to see if I could transfer material. If I can tune it better and up scale it then maybe it can make good looking finishes.
I first tried the sacrificial piece as AL but didn't measure the deposit on the plated piece. I'm going to try AL to AL again but for a longer time.
The AL pieces are just cut-offs that I bought, $1 for a baggie full...
 
Using Sodium bicarbonate (1/4 tsp per 8oz).
Current was .5 A for a little more than 1 hour.
Both pieces are aluminum.
Piece was rotated at intervals. The wood piece was notched to rest on the top of a jar.
Just had to rotate the screw at the top every 5-10 minutes.

DSC_1117.jpg

Upgrade to this process is use distilled water instead of tap water.
Etch two pieces briefly to clean them. Rather than wipe them clean with a rag.
Maybe polish a side first and see how the plate looks.

As it is it reminds me of parkerizing.
 
Alkali Etch the parts. Degrease the parts then proceed with the Alkali etch. Dip in a solution of Sodium Hydroxide and Sodium Carbonate in a 50-50 solution. Operating Temperature 140 F. Specific Gravity at operating temperature 12 Be. Checked at least once a month. Additions due to drag out losses shall be equal amounts of Sodium Hydroxide and Sodium Carbonate. This will provide a clean even matt finish.

I have a 5 gallon bucket of that Sodium Hydroxide. It is in crystal form. Touching it burns skin.
I have used this stuff at above boiling temperature to blacken steel.

DSC_0682.jpg

May try your suggestion tomorrow.
 
Sodium Hydroxide is lye. It will etch your eyes corona if it gets onto them. Be careful! thicker skin like you fingers will take a few seconds to turn to soap so you can no longer hold the parts and will drop them..
Bill D
 
seems like someone is reinventing a wheel...

pretty much every process that can be easily done with aluminum has already been described in number of books (if you don't trust internet forums), small kits to anodize, chromate, and deposit metal on al already exist, stuff that is proven to work reliably enough to be worth the money it costs to buy and set up

experimenting with this just isn't worth the trouble, especially so if you plan to sell the part or service, the risk is your process failing before expected end of life of the product is just too great
 
For some strange reason the perfectionist in me says I would have the parts anodized by reputable shop. And stop wasting time asking a question online that everyone knows the answer to.
 
The Birchwood Casey stuff will blacken most non-ferrous metals. I used it to blacken some brass hooks, and then used Minwax Finishing Paste wax for a sealer. It's held up pretty well.
 
seems like someone is reinventing a wheel...

pretty much every process that can be easily done with aluminum has already been described in number of books (if you don't trust internet forums), small kits to anodize, chromate, and deposit metal on al already exist, stuff that is proven to work reliably enough to be worth the money it costs to buy and set up

experimenting with this just isn't worth the trouble, especially so if you plan to sell the part or service, the risk is your process failing before expected end of life of the product is just too great

You're right about that. And 98% of anything else on this forum has been written in books, journals, etc. The rest is just 2% or two cents.
 
Not sure of your end use but polished aluminum holds up quite well against finger smudging if waxed. I never chromed the cases on my Harley but just polished everything and put a good paste wax over it.

The mill finish on "as received" aluminum bars is quite dirty. At a minimum use a fine Scotchbrite on it and then wash with hot water and dish detergent.
 








 
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