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manifold electrolysis
JamesyCottony - 17/8/15 at 10:39 AM

Hi there,

I have an Austin Metro 1.0L engine and the exhaust/inlet manifold has rusted slightly on the outside, so I wanted to get rid of the rust and then paint with very high temp paint. Is electrolysis safe to do on the manifold? or is it hardened steel? so would there be a chance of making it brittle?

Thanks

blakep82 - 17/8/15 at 10:46 AM

More likely to be cast iron I'd have thought

JamesyCottony - 17/8/15 at 10:48 AM

So you would says its ok to use this method to de-rust it?

blakep82 - 17/8/15 at 10:57 AM

I don't know, I'm just pointing out its not steel, and its certainly not hardened
If its only rusted outside, and all easy access, wire brush or preferably wire brush in a grinder will give quicker results

JamesyCottony - 17/8/15 at 11:05 AM

Ok thanks, I just thought this would get deeper into the small crevices

MikeRJ - 17/8/15 at 11:22 AM

The joined inlet/exhaust manifolds on the A series are good to prevent carb icing and to minimise the use of the choke, but they are a bit of a disaster from a performance perspective due to the heating of the intake air and relatively poor flow characteristics.

This is why the so-called "stage 1" tuning kit for a mini (or metro) that replaces the combined cast iron manifold with separate performance inlet and exhaust manifolds makes such a noticeable improvement to performance.

Benzine - 17/8/15 at 11:34 AM

Personally I think electrolysis is overrated! I'd take it to the local shot blasters with some universal credit vouchers (the ones with queen liz on) and get the best possible surface to paint on to

loggyboy - 17/8/15 at 11:55 AM

You'll have no issues with electrolysis on a cast manifold.

[Edited on 17-8-15 by loggyboy]

Irony - 17/8/15 at 12:14 PM

quote:
Originally posted by Benzine
Personally I think electrolysis is overrated! I'd take it to the local shot blasters with some universal credit vouchers (the ones with queen liz on) and get the best possible surface to paint on to


This is locostbuilders. Paying money when it can be done for free is frowned upon!

I have had great results with electrolysis. There are some rumours of hydrogen embrittlement but as a manifold isn't a stressed part in terms of safety I wouldn't worry. Plenty of discussion on here if you search. Oh and don't use a Stainless Steel sacrificial part. Noxious gases are produced if you do!

JamesyCottony - 17/8/15 at 12:56 PM

Thanks for all the help people

Benzine - 17/8/15 at 01:08 PM

quote:
Originally posted by Irony
This is locostbuilders. Paying money when it can be done for free is frowned upon!


I've had good results too with electrolysis but I prefer the wire brush attachment in the grinder or the blasters. The only time I'd ever use electrolysis is if I was doing a restoration where I wanted to keep a rare original part. Nothing will give a better key for the paint than blasting. £5 for the blasters vs £5 plastic tub, £15 charger, £1 for soda crystals, £35 for the osteopath after lifting a large tub of water (just me? :p )

I still think with electrolysis that there's a large element of "something is doing the work for me while I'm having my dinner. Also it's fizzing which is pretty, so it's better"


I'm Spartacus!*

*One of the most locost forum users

Irony - 17/8/15 at 01:35 PM

I never had much luck with Soda Blasting. I took a part into work where we have big compressors and made a DIY soda blaster using a bit of pipe etc. I think I made more mess than anything else. i was glad I did it at work. Soda everywhere!

Angel Acevedo - 17/8/15 at 04:45 PM

Unless you go ceramic, no paint will withstand the high heat of the manifold.
With this in mind, the cheapest option would be no bother.
The next cheapest, electrolysis, and, while this may cause hydrogen embrittlement, cure for this is normally baking the parts in an oven, but, being this a part exposed to hig heat in normal use, this would be redundant.
HTH.
AA

britishtrident - 17/8/15 at 06:23 PM

The method of choice for cleaning it would be getting bead blasted.

Interestingly single carb Metro manifold flowed better than twin SUs.

dilley - 17/8/15 at 09:20 PM

quote:
Originally posted by blakep82
I don't know, I'm just pointing out its not steel, and its certainly not hardened
If its only rusted outside, and all easy access, wire brush or preferably wire brush in a grinder will give quicker results


100% agree.

JamesyCottony - 17/8/15 at 10:51 PM

Thanks for everyone's help, but I'm going for electrolysis as its best for me I think. Is it just sodium carbonate I need?

JamesyCottony - 18/8/15 at 08:55 AM

Are DP soda crystals ok to use? Also I can use mild steel in it can't I?

micksalt - 18/8/15 at 12:18 PM

quote:
Originally posted by JamesyCottony
Are DP soda crystals ok to use? Also I can use mild steel in it can't I?


I wasn't aware of any problems with mild steel. Stainless steel is a no-no though due to its chromium content.

JamesyCottony - 18/8/15 at 01:06 PM

Started and it's looking good!! Going to do it again tomorrow as off to work soon