19. Back from galvanic zinc plating

I got the parts - around 70 pieces - back from galvanic zinc plating. Most of them look really good.

The first bath is a pickle which removes rust and everything else what is not metal from the parts. I prepared the parts with a glaspearl blasting, which gives a clean smooth surface. After the pickle bath all the rusted areas, which are smoothed by blasting, were there again. Not so nice to look on, but ...

The second step was tiled in two different processes:
- hang bigger parts side-by-side on a rack
- put smaller parts in a barrel ( simmilar to rotofinishing )
and galvanise them all with zinc.

Third step was, that the parts will get a passivation which improves the rust protection and give a black coating to all parts.

As I know now, casted alluminium can not be galvanized. The pickle fretted the alluminium itself - not only the dirt and rust ( if you can name it rust... )

As the surface is only rough, I paint the hubs, so that the small hohles at filled. I will use them anyway.

See here the good parts :

side-by-side at a rack

done in a barrel

 

After a close inspection, I see some more areas, which are not looking quite good:

Some areas are like a faraday cage - means there is no flow of current which prevents the coating. I have to paint this areas. Mostly these areas are not big.

Another bad thing is, that if you have a part with a hollow space the liquids of the different processes will fill the hollow. You have to drill a hohle with around 4-5mm to allow the liquid to exit the part
- or the hollow space is sealed completely.

Hello company Spydercars,
your upper front wishbones are from a very good quality - on the first view !
All the welding seams look good, but after I got them I hear, that something is inside.
It was pickle - entered the wishbone through the not welded bushing. See here:

The small hohle in the middle was drilled to get an exit for the pickle...

And one wishbone has a really small cavity, which is not solid as well:

I flushed the wishbones with break cleaner several times and seals it with body cavity wax. The black coating from the passivation is gone at the areas, where the pickle comes out... paint it and OK...

The zinc plating was 200 €. It was done from Nicrola in Tettnang, Germany.
For that fee - I think - I would not get a 2K paint