Windshield wiper mechanism (Soft metal) melted by zinc plating

[JamesE30]

Ok this may seem obvious to some people, but it was my first time getting parts zinc plated and I overlooked the fact that some of the parts I dropped off were not only made from steel...

As you can see I had these windshield wiper mechanisms plated. They came back looking good as new, except that the tiny drive gear must be made of some soft metal and has melted in the process..

Let this serve as a warning to anyone getting parts plated to make sure exactly what metal you are dropping off.


I also lost some pins from my window winder mech mechanism which i will have to fabricate. This picture was before plating, the spring was removed but the pins not.. now they are gone.

Now, I was lucky enough to find some replacement parts for a reasonable price. But as you can see they’re not so petty..

Is it possible to remove the little gear off the replacement and transfer it to my already plated parts?
If not, how should I go about restoring these parts without plating them?

 

[deQuincey]

Ok this may seem obvious to some people, but it was my first time getting parts zinc plated and I overlooked the fact that some of the parts I dropped off were not only made from steel...

As you can see I had these windshield wiper mechanisms plated. They came back looking good as new, except that the tiny drive gear must be made of some soft metal and has melted in the process..

View attachment 64715

Let this serve as a warning to anyone getting parts plated to make sure exactly what metal you are dropping off.


I also lost some pins from my window winder mech mechanism which i will have to fabricate. This picture was before plating, the spring was removed but the pins not.. now they are gone.

View attachment 64717

Now, I was lucky enough to find some replacement parts for a reasonable price. But as you can see they’re not so petty..

Is it possible to remove the little gear off the replacement and transfer it to my already plated parts?
If not, how should I go about restoring these parts without plating them?

View attachment 64713 View attachment 64716 View attachment 64714

well you learnt the lesson just the hard way, yes you can not chrome or plate those bland metals or semimetals like zamak and so on

as to your last question of course you can remove that delicate little gear from the top and exchange parts

if possible use an extractor

 

[JamesE30]

well you learnt the lesson just the hard way, yes you can not chrome or plate those bland metals or semimetals like zamak and so on

as to your last question of course you can remove that delicate little gear from the top and exchange parts

if possible use an extractor

Thanks for the reply. I would assume it is possible, just not sure exactly how to go about it.
It appears the spline that the gear sits on has been pressed and flared out to prevent it from ever coming off.
Was wondering if someone’s done this before and has a trick for getting it off, maybe deforming the “flare”back, or just used and extractor of sorts and went to town..
obviously don’t want to destroy another one haha

 

[Markos]

Hi James,

Keep your eyes peeled for a new linkage. The e3 parts will work for you. The M16x1.0 threaded collar is the same for both, as is the splined part that melted. You can use a small puller to removed the splined end. I use a battery puller. Then you can plate the necessary parts independently. Note that the e3 ball joint is different, and it is welded to the shaft that is inside the threaded collar. Lastly, there are plastic bushings in there that most certainly melted as well.

Notice the thread condition. This is caused by the thread rubbing against the body. This is why I know the diameter and pitch.

 

[eriknetherlands]

Thanks for both warning and tips.
These posts have prevented another meltdown ( or two)

 

[deQuincey]

Thanks for the reply. I would assume it is possible, just not sure exactly how to go about it.
It appears the spline that the gear sits on has been pressed and flared out to prevent it from ever coming off.
Was wondering if someone’s done this before and has a trick for getting it off, maybe deforming the “flare”back, or just used and extractor of sorts and went to town..
obviously don’t want to destroy another one haha

whenever you need to know anything about the e9, just check the DQ list,...

https://www.e9coupe.com/forum/threads/windscreen-wiper-mechanism-renewal.16493/

http://www.e9coupe.com/forum/showthread.php?t=7794

 

[eriknetherlands]

I read it yesterday, but it kept me busy apparently.

I don't think the temperatures of a normal galvanic (both for anodic or kathodic proces) electroplating process are too high of the metal that was lost is zamak (or zamak)
Either the metal was not Zamac, or it happened from another reason then temperature.

The various forms of zamac all have melting points above 375 Celsius, about 700 Fahrenheit.
https://en.wikipedia.org/wiki/Zamak
When I asked at my plating company about their process temperatures, their answer was that it did not run higher then 75 Celsius maximum. I asked I because I wanted to plate the fuel sensor which has plastic parts to isolate the electrical connections; after plating that plastic (Polyamide, melting around 180-220 degrees Celsius ( ~400 Fahrenheit) was still ok, (but the part looked horrible due to too much rust; the attached picture shows the part om the left prior to Zinc treatment).

Was the part perhaps tumble plated, or was it suspended on a hook in a basin? Both processes are used; if you drop off buckets of nuts and bolts they usually dump everything in a tumble electroplating machine. If you bring them large panels, frame parts etc, they usually hang them on racks.

If zamac gets tumbled for 2 hours, then it gets massive abuse as it is a softer metal; steel wins. Kind of like the kids game 'rock-scissors-paper'.

 

[Gary Waggoner]

Most of the time the dissolving of pot metals in the plating shops is caused by the acid used to clean the parts before plating. This has happened to me several times with similar results.

 

[JamesE30]

Just to follow up on this, I made a small puller tool and was able to easily remove the gears. Now I can clean these parts properly before assembling again.

 

[teahead]

Maybe do small parts yourself?

https://www.eastwood.com/ew-electroplating-system-tin-zinc.html

 

[Wladek]

Zinc plating also doesn't accept Aluminium parts, so all parts that have aluminium rivets etc., need to be diassembled first.

yes you can not chrome or plate those bland metals or semimetals like zamak and so on

actually, you can chrome zamak, you just can't zinc plate it because of acid bath.