Megapulse??

[NigelA]

The BMW CC UK magazine had a short bit in it about Megapulse (www.megapulse.uk.net) and the writer felt this was a cure-all for rust problems.

Has anyone any experience of this and, if so, what comments do you have please?

[Templ8e30]

Really does sound like a load of bollox to me, similar to the old 'snake oil' that claims to restore you're engine.

I certainly won't be buying it.

Cheers,

Iain T

[Brianmoooore]

Just been to the website and had a good laugh. Anyone who falls for this kind of pseudo science really does deserve to be parted from their money!
There are ways of protecting against rust that involve electricity (galvanising - coating with zinc, is one) but this definitely isn't one of them!

[stuartgallafant]

what a load of sh!t!!!

[benjy]

They use on ships. Its called cathodic protection.

[Brianmoooore]

There are ways of protecting against rust that involve electricity but this definitely isn't one of them!

[E30Mark]

They use on ships. Its called cathodic protection.

I thought that worked by having a sacraficial anode?

[Turbo-Brown]

This type of system is also used to protect underground pipework.

With galvanising, you're relying on the greater electronegativity of the zinc relative to the iron to protect the iron and ensure the zinc errodes first.

With the electrical systems, you're making the steelbodywork the negative side of a circuit which (somehow) protects it from corrosion.

Cars with a positive earth will also corrode more readily than negative earth.

I'd say there is merrit to that system (although I've not looked at their site)

EDIT> just had a look at their site and it mostly seems to ring a bell from when I did my HNC all them years ago. Think it might be a bit misleading though in the "retards the corrosion already there" bit which suggests that it'll make rusty metal repair itself, but that might just be me reading into it.

[NigelA]

Comments (thank you) from benjy and Turbo-Brown have stimulated me to do research on cathodic protection (CP) and one item I have come up with is this:
http://www.buildingconservation.com/art ... thodic.pdf

CP is used extensively in building and construction industry as a brief search for cathodic protection on Google will show. Have also sent Megapulse details to the Institute of Corrosion for their comments.

[benjy]

If memory serves me well, the system used on my current ship uses around 0.1A and between 5 and 50 mV. And yes it does use zinc anodes on the outside of the hull but there are systems that dont. I believe they use a pulsed and cycled voltage/current to provide not only corrosion protection but also to discourage the grow of barnacles etc. on the hull.

[m3-cab]

Nigel, let me know how it goes with the Institute of Corrosion, it'll be interesting to see of they agree with what Megapulse are saying....

[Turbo-Brown]

It's quite interesting seeing active corrosion prevention systems in action.

I painted the IC brackets I made for Brown using Galvafroid paint which is something like 99.9% zinc.

Not only are the bits of bracket where stone chips have completely removed the paint still shiny bare steel, but the bits of the bodywork where I bolted the brackets have also derived protection from the paint and the metal I chipped the original paint off of (with a hammer) is still uncorroded

[Morat]

What? There's an Institute of Corrosion now?
Where do I join?

[Speedtouch]

The 'Sisters of Mercy' were moved to write a song about it:

http://www.lyricsfreak.com/s/sisters+of ... 25663.html

A good song to be listening to while you're welding up those rust patches

[domross]

If its that good why don't all car manufacturers just spend £60 on this rather than galvanizing/undersealing etc. think I'll stick with the waxoyl for the time being...

[Turbo-Brown]

Would guess that manufacturers aren't keen on parasytic devices keeping the tin worm at bay when simple paint will do.

If you don't fancy having your shell dipped, treated for rust and then galv'd then that's probably not a bad solution.

[NigelA]

Nothing back from Institue of Corrosion yet. Other information suggests that whilst cathodic protection is used extensively in industry and is effective when there is water around the items being protected (as in oil rigs). There are one or two strong warnings that the system does not work (or work well) on vehicles because it is a dry environment. That is something of a simplification but it is the jist of what was said.

[Speedtouch]

The reason why car manufacturers changed from positive earth to negative earth sometime around the 1960s was because, as well as making more sense from a logical point of view as regards electrics, it helped prevent body corrosion. Electrons (being negatively charged) in a circuit actually flow from the negative side of the battery to the positive side. Notice that corrosion around the battery terminals normally collects on the positive terminal...

So there may be some benefit in having such a gadget fitted (it's not the first time similar things have been marketed).

[NigelA]

Thanks, Maurice. That is interesting.