TheSamba.com :: View topic - Plating hood hinges and torsion spring. Good or bad idea?

Sat Jul 25, 2020 7:20 pm

As the title says I'm thinking of plating my front bonnet hinges and torsion spring in silver zinc plating. I don't much like the idea of painting them and trying to keep the paint without chips or scratches during installation. Im also unsure of the 2k paint's ability on the torsion spring to twist without cracking.
What's your thoughts on this idea?
Does anyone have pics of what I'm suggesting? Plated hinges, do they look OK? I can't recall seeing any done like that but I'm sure its probably been done before.
Cheers, Paolo.

Sat Jul 25, 2020 7:56 pm

Yabbadubbadoo wrote: As the title says I'm thinking of plating my front bonnet hinges and torsion spring in silver zinc plating. I don't much like the idea of painting them and trying to keep the paint without chips or scratches during installation. Im also unsure of the 2k paint's ability on the torsion spring to twist without cracking.
What's your thoughts on this idea?
Does anyone have pics of what I'm suggesting? Plated hinges, do they look OK? I can't recall seeing any done like that but I'm sure its probably been done before.
Cheers, Paolo.

NO....NO....NO!

The hinges...no problem. DO NOT ever plate springs with electroplating. The problem is that the electrolyte required for zinc electroplating (and many other metals)....is acidic and along with the current it WILL 100% cause surface hydrogen embrittlement. This will de-tension springs and cause them to snap very easily.

Yes...you can do a treatment bake in an oven but you have to know what you are doing. The springs ...and any tension steel ....must be IMMEDIATELY...within 2 minute or less....neutralized, rinsed in distilled or de-ionized water .....dried....and put into an oven for a period of time of about 10X their plating time.
The oven is not that hot but it needs to be stable.

Painting the springs is not a problem. Use an enamel.

You find springs and high tension bolts from factories that are plated...because the plating companies have this down to an automated art. Ray

Sat Jul 25, 2020 9:00 pm

raygreenwood wrote: Yabbadubbadoo wrote: As the title says I'm thinking of plating my front bonnet hinges and torsion spring in silver zinc plating. I don't much like the idea of painting them and trying to keep the paint without chips or scratches during installation. Im also unsure of the 2k paint's ability on the torsion spring to twist without cracking.
What's your thoughts on this idea?
Does anyone have pics of what I'm suggesting? Plated hinges, do they look OK? I can't recall seeing any done like that but I'm sure its probably been done before.
Cheers, Paolo.

NO....NO....NO!

The hinges...no problem. DO NOT ever plate springs with electroplating. The problem is that the electrolyte required for zinc electroplating (and many other metals)....is acidic and along with the current it WILL 100% cause surface hydrogen embrittlement. This will de-tension springs and cause them to snap very easily.

Yes...you can do a treatment bake in an oven but you have to know what you are doing. The springs ...and any tension steel ....must be IMMEDIATELY...within 2 minute or less....neutralized, rinsed in distilled or de-ionized water .....dried....and put into an oven for a period of time of about 10X their plating time.
The oven is not that hot but it needs to be stable.

Painting the springs is not a problem. Use an enamel.

You find springs and high tension bolts from factories that are plated...because the plating companies have this down to an automated art. Ray

That's a bit of a bummer. The spring was the main piece I didn't like the idea of painting.

Sun Jul 26, 2020 9:03 am

Yabbadubbadoo wrote: raygreenwood wrote: Yabbadubbadoo wrote: As the title says I'm thinking of plating my front bonnet hinges and torsion spring in silver zinc plating. I don't much like the idea of painting them and trying to keep the paint without chips or scratches during installation. Im also unsure of the 2k paint's ability on the torsion spring to twist without cracking.
What's your thoughts on this idea?
Does anyone have pics of what I'm suggesting? Plated hinges, do they look OK? I can't recall seeing any done like that but I'm sure its probably been done before.
Cheers, Paolo.

NO....NO....NO!

The hinges...no problem. DO NOT ever plate springs with electroplating. The problem is that the electrolyte required for zinc electroplating (and many other metals)....is acidic and along with the current it WILL 100% cause surface hydrogen embrittlement. This will de-tension springs and cause them to snap very easily.

Yes...you can do a treatment bake in an oven but you have to know what you are doing. The springs ...and any tension steel ....must be IMMEDIATELY...within 2 minute or less....neutralized, rinsed in distilled or de-ionized water .....dried....and put into an oven for a period of time of about 10X their plating time.
The oven is not that hot but it needs to be stable.

Painting the springs is not a problem. Use an enamel.

You find springs and high tension bolts from factories that are plated...because the plating companies have this down to an automated art. Ray

That's a bit of a bummer. The spring was the main piece I didn't like the idea of painting.

All of that said.....if you have any "serious" plating houses in your area.....and by serious I mean they are not just a dude with a warehouse full of vats and piles of bumpers.....but serious plating houses with a tank or barrel plating line that does mountains of bolts and parts.....they will usually have the ovens and know how.

The gist is that big plating lines that run piles of parts througb a high circulation system with monitering of fluids.....also have ovens. The last few stages are the barrels of parts are neutralized, rinsed and just go in as pile into a batch oven.

So you can get this safely done....but you just may not be able to do it in a home set up.

The problem is also this.......people get away with plating springs and bolts without heat annealing for hydrogen embrittlement..........when the parts are low tension or limited use.

Examples are......grade 3 and 5 bolts.....small ones.....in low torque, low stress usage....may never exhibit fracturing if they are not in a high stress usage. For example....an 8mm class 8.8....functionally equal to grade 5 SAE.......being used at 18 fot lbs to hold on a fender.....not a problem.

However......a class 10.9 or 12.9.....which are higher alloys and recieve more damage tha n the 8.8....AND are used in higher stress areas......say the same 8mm size in 12.9.....may be being used for a CV bolt......that one will be very prone to fracture.

With springs.....if its not a highly stressed spring.....and does not get used a lot.....and is large and oversized for its use.....you may have few if any issues even if it does have damage.

An example of one that will break quick would be a valve spring or a master cylinder spring.

You will notice that master cylinder springs are either not plated....or are black phosphate coated. I have seen very few that are plated. One assumes that when they are plated.....they have been baked/stress relieved.
25 years ago there was a rash of Vanagon clutch master cylinder springs that had the oddity of snapping in the 10-15k miles range. They were all shiney zinc plated. It took me two decades to learn what I know....which is limited.....and cycle back to those in my mind.....and figure out what was happening.

So.....call a plating house....tell them what you need.....which is bright zinc.....and ask them about a post bake to prevent hydrogen embrittlement. If they say.....we dont do that.....or we never have any issues so we dont bother......walk away.
Ray

Sun Jul 26, 2020 10:07 am

The place I had my playing done at asked me specifically about baking them. They did that to all of my silver car hardware. That being said I never send springs for the reasons that Ray stated.

Mon Jul 27, 2020 4:26 am

Raygreenwood many thanks for the lesson in plating. Taking all that very detailed information into consideration I'll probably just paint it all and move on to one of the many hundreds of restoration tasks in front of me. The couple of plating shops in my vicinity are not very high tech and very painful to deal with.

Mon Jul 27, 2020 7:54 pm

Yabbadubbadoo wrote: Raygreenwood many thanks for the lesson in plating. Taking all that very detailed information into consideration I'll probably just paint it all and move on to one of the many hundreds of restoration tasks in front of me. The couple of plating shops in my vicinity are not very high tech and very painful to deal with.

If you decide to paint the spring, don't use too much high build primer on it. I'd probably just go with an epoxy based primer, and just seal it off, then paint it.

Mon Jul 27, 2020 11:50 pm

Bobnotch wrote: Yabbadubbadoo wrote: Raygreenwood many thanks for the lesson in plating. Taking all that very detailed information into consideration I'll probably just paint it all and move on to one of the many hundreds of restoration tasks in front of me. The couple of plating shops in my vicinity are not very high tech and very painful to deal with.

If you decide to paint the spring, don't use too much high build primer on it. I'd probably just go with an epoxy based primer, and just seal it off, then paint it.

Thanks Bobnotch for the tip. I guess that's the reason I got started on the idea of plating. I also thought the paint might need a flex additive on the spring.