Anodising At Home, Advice or Experiences Wanted

[Ianb]

Pretty much as per title, I have never tried it, but been watching youtube videos.

I have (or will do) 2 aluminium trailing arm ball joint bushes I am making and wish to anodise them to help protect them and improve the appearance.

Any one with experience or advice I would like to hear it, thanks.

 

[bricol]

Always found it easier to get a professional to do it.

Be aware anodising will close the tolerance up a touch.

 

[Ianb]

Doubt my accuracy making them will be that close!

Probably would get better results getting them professionally done, just wanted to have a go for the fun of it.

 

[sako243]

My father bought a kit to annodise some one-offs for some systems we had to build and it's worked out very well. I can ask whether it was a complete kit, I think it was.

 

[Ianb]

yes please do, also if you can find out which company it came from.

I was just going to use printer ink as dye as seen this can work, it is hidden under the car so will never be seen really.

 

[Tom O]

Check out https://www.caswellplating.com/electroplating-anodizing.html

 

[Lewis_RX8]

Bit pricy this stuff , Looks like that's a kit for a more serious hobbyist or small business venture or i hope so anyway at that price

 

[sako243]

Got this kit: https://classic-plating.co.uk/product/aluminium-anodising-kit/

 

[hotponyshoes]

If it's a hidden part I don't think there is any need to dye it other than to show the anno has taken correctly although there are other ways of checking that. For corrosion protection only clear anno and sealer is just as good.

It is fairly easy to put together a diy setup with parts found locally. A whole ago (over 10yrs) I had a full line set up for production parts and sourced/setup everything myself. There are 'household' alternatives to all the proper chemicals although sourcing a large quantity of battery acid was an issue even back then.
I did end up with a massive constant current power supply, bank of chillers running at -15c and so on but the initial trials done using a car battery charger etc. produced decent results.
Trying to dye colour was a problem, red would come out pink etc. I was trying diy methods though and I think I would have got better results with the proper dies in proper quantities (ie. expensive)
I was only really doing hard anodizing on 2k series alloys. A mate of mine was making motorbike parts and sending batches off one a week for colour anno so I would just chuck those bits in with his order and it was easy/cheap enough for me not to try it myself. I only bothered doing the hard coats myself as I could not find anybody else to do it.
I will still have all the notes somewhere if you want me to look them out.

Don't underestimate how much space you need to do it either. For a one-off job you might get away with tipping stuff into a tray and then putting it back into the bottle but I ended up with a whole workbench racked out with 10 or so tanks...

 

[hotponyshoes]

Always found it easier to get a professional to do it.

Be aware anodising will close the tolerance up a touch.

You do need to account for this as well.
I was anodizing parts with anything from m6-m80 threads and they were all still screwing together fine and hard anno is a thicker coat than normal anno.
I don't remember the exact numbers but if you were building a 2mi coat half of the coating is etched into the surface and half is built up so the part ends up 1mi larger overall. That's normally fine for threads etc. But in your case, if it is to hold a press-fitted bush with a metal outer sleeve you might want to make an allowance for it. Not least because you could easily end up damaging the finish when pressing the bush in.

 

[Ianb]

T
Thanks, I will bear that in mind, on a side note, any links or knowledge on calculating sizes for push fit/interference fit, the arm is steel and the round opening the aluminium is to be fitted to is 60mm diameter.

 

[Ianb]

Just finished up anodising the 2 balljoint housings, each is made of 2 parts.

Very pleased with how they came out but have a question. I hung a large part on the end of a wire and the smaller part along the wire that attaches to the +ve supply, did this for both exactly the same, so had 2 wires each with 2 parts attached.

After dying them I noticed that both smaller parts took the dye better and are slightly darker.

Is this because most of the current passed through the first smaller part rather than carrying on along the wire to the second part? This is just a guess as I cant think of any other reason. Should I have attached just one part to a wire?

Thanks

 

[m_c]

I'd hazard a guess it's more to do with how good a contact the wire had with each part.

If each contact point had similar resistance, then it would limit the current going through the larger part, reducing the surface current.

 

[hotponyshoes]

That's part of the reason you need to use a constant current power supply rather than a constant voltage type.

 

[MattH]

Both parts would have an equal current path so would share the current.

the smaller part has less surface area so therefore has a higher surface current that the larger part.

 

[hotponyshoes]

The parts will heat up during anodising, if the smaller parts were hotter than the big ones when you dyed them they might have picked up the colour better.
Or you have not used a fixed current power supply so the smaller parts have built up a deeper layer of the anno coat hence have deeper pores to hold more dye. Or a bit of both.
Did you measure the parts before/after coating?

 

[Ianb]

No didnt measure the parts, I dont have anything accurate enough.

I used a constant current supply, using the 720 rule to calculate current, peak voltage and time. I also kept a close eye on the tank temperature keeping it between 60-70 F and had a 'bubbler' that seemed to be recommended.

If anything the larger parts on the end of the wires had a better contact as I folded over the wire and pushed it into the hole so they were jammed on, the smaller parts were just resting on the wire as it passed through ahole in them.

All parts were same temperature when I dyed them as washed them off and added them into dye together.

The difference in colour isnt an issue in this case, I was just interested why it may have happened.

 

[Ianb]

Both parts would have an equal current path so would share the current.

the smaller part has less surface area so therefore has a higher surface current that the larger part.

So are you saying if they each had their own wire they would have come out the same?