Talk Morgan Forums Community The Malvern Arms RAIN!

the rain in Queensland is getting worse by the day. So far over 5 towns have been completely evacuated, down to the last cat and dog. The area covered is now about the size of middle Europe.
Poor folks have lost everything again.Trouble is the towns are built on the flood plains and it will happen again next year. There have been plans to build and divert the waters inland to form the largest man made lake in the world, but the politicians have historicly diverted the funds needed to suit their own agendas and nothing has ever been done to date. The event this year has already cost the federal gov over 10 billion dollars and rising by the day. I hope that this snaps them into action and the diversions begin this year. They also want to build a fast rail link the entire length of the eastern seaboard (300 kmph) but it will go no-ware if it has to stop at the Queensland border. Trains dont float as do Morgans with plimsol lines to prove it!

Just to re-assure you a bit, no the idea of galvanising isnt undermined. Galv isnt like paint intended to protect just by covering the surface. It also protects by electrolytic action when penetrated. Sure this means it will gradually erode away but if the chassis is hot dip ( which is what it looked like when I had a quick glance) then this will take a long time. That said, probably still better to waxoil it.

I don't disagree at all with what you say but two thoughts still strike me: (1) given the proensity of the chassis to flex, surely this must crack the coating and undermine it to an extent (2) in similar vein, as soon as any hole etc is drilled throgh a galv surface, doen't this, again, detract from the protection?

I may be wrong here and I'm no metallurgist but I thought this was why all the best resto jobs went for powder coating?
As I said, happy to be corrected
Cheers,
G

Powder coating Gerwyn?

Now go and wash your mouth out..............

when galvanised if the steel is exposed [ie by drilling or scratching] the surrounding zinc forms a galvanic cell and protects the steel - an example of a sacrificial coating because eventually the zinc is erroded away.

This is an area I scratched the surface of (not intended) when I got my first Morgan which was a +8 this had been fitted with stainless firewall and inner wings retrospectively. I know enough about the Cathodic table to know that alluminium wings and stainless inner wings will eat each other electrically unless there is a complete barrier between them. You see these metals are about as far apart from each other as you can go on the Cathodic scale. Add a bit of road salt and H2o and errosion begins on a grand scale !
This link will provide a little light reading for you all. http://www.corrosionist.com/Galvanic_Corrosion.htm
It won't stop me enjoying mine though just as HFS and his descendents intended. Pictures of the early "properly" Lands End trials makes you realise this is what they had in mind when they built them - not polishing - sorry Dave with your concours bonnet on !

MMC insulate the inner wings from the outer using a leather gasket - this is my sport in build last september

Yes I saw my gasket when I greased up my sliding pillars - liking your photograph. A bit like corking on boats really, that's why we love them there is still something primitive in there !

On the +8 it was some black gunk akin to roofing felt.

I find that amazing that leather, which is porous is used as a separating gasket. Surly high tec neoprene would be better, even old malthoid roofing salvaged from the chicken shed would do.
BTW that is an amazing picture, the gauge looks like it would fit the underground rail system at a pinch?

Galvanising by hot dip gives a thick coating of zinc. Provided air pockets are avoided and cavities done properly it will give the best long term protection. It acts has a double function by making a durable coating and also provides an electrolytic protection method. However, drilling - even widening existing holes - will remove the zinc layer leaving potential for localised corrosion. Any coating removed in this way will also leave a "gap" as they all rely on creating a barrier as the first line of defense. If drilling then its worth trying to replace the removed zinc with something, either the special paints etc. also, after completion of the job, apply another layer of protection - waxoyl/underseal etc.
That takes me back to my metallurgy days!
Even stainless steel can corrode, especially at welds when incorrect filler metal is used as this can create an electrolytic cell which causes corosion on a microscopic level, weakening the weld. If welding s/s then use a filler "stabilized" to remove the effect and a very low carbon content. Its the combination of chrome and carbon that causes the effect known as "weld decay"
sospan