Bolt refinishing

[TezzerTel]

So I'm (slowly) starting to rebuild my 550F1. The long bolts that go through the frame and engine/gearbox casings are corroded on the heads and have been poorly painted over in the past. What do people do with these? I was thinking of taking them back to bare metal and then maybe painting them with Cerakote in silver or something similar?

Thoughts?

[DomP]

I bought a Gateros zinc nickel plating kit, well worth it for what you're doing.  Many weekends ast year I had it set up on the kitchen table while was rebuilding my F1.

[Johnny4428]

+ 1 for the Gateros plating kits. Not expensive and very satisfying.

[McCabe-Thiele (Ted)]

On my 400 I had all the engine bolts with a few other items  re-plated cost about £40 locally.

[SteveW]

I’m replacing mine with stainless where possible and polishing the head to remove any numbers.

[Orcade-Ian]

Steve,
You may already be aware but if you do go down the stainless route, then a good barrier paste is essential to prevent galvanic corrosion between those dissimilar metals.  In the Aircraft industry we had to use Duralac.  This is still available as Duralac green.  DON'T use copaslip!  I think Lear do one in their ACF 50 range, called 'Corrosion block'.
Ian

[McCabe-Thiele (Ted)]

Interesting information Ian - made me wonder just how much greater the galvanic effect is for  SS compared the original steel bolts.

[Orcade-Ian]

Ted,
The possibility (probability) of galvanic corrosion depends on the 'nobility' of the the two dissimilar  metals - Stainless and aluminium alloys are quite far apart in nobility, so when dampness (water, esp containing salt) is present, you have set up a simple cell and Mr Galvani has his wicked way!  I dare say that one of our 'chemical brothers' with a better explanation with 'anions and cations' will chime in.  Zinc is closer to aluminium but it's still good practice to use something like 'Corrosion block' grease where possible - it makes future dismantling easier.  I always remember a chap I served my time with saying 'Always make it easy for the next person who might have to work on this job - it might be you yourself!'  Great advice that I have tried to follow.

Ian

[Deano400]

Ian, I don't know anything from a scientific view but found this. Supports your comments I think.

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[Orcade-Ian]

That's a great graphical way of showing the problem Deano, many thanks for sharing that!
Ian

[nairb]

For the larger bolts, if they are zinc plated, I remove the old zinc and polish the bolts and take them to the local zinc plater for BZP.  The smaller items I do myself with my zinc platinig kit.

Zinc plating is much cheaper than chrome and usually much quicker.

[TezzerTel]

Thanks for the information guys. Looks like I'll need to find a local platers for the long bolts that go through the cases that are not standard bolts.

I'm replacing the 'standard' bolts with stainless as I go as most of the ones I've removed are either non standard or broken.

Interesting about stainless reacting with the alloy. We use this at work didn't know it is so expensive!!!!

 https://www.powertoolsdirect.com/rocol-anti-seize-stainless-500g?msclkid=a8acec05c0361fe723648b1638071edf&utm_source=bing&utm_medium=cpc&utm_campaign=PMax%3A%20Google%20Shopping%20Smart&utm_term=2334744222502650&utm_content=Ad%20group

[DomP]

I've also done as SteveW suggests on any 'non engine' casing fasteners