Zagato wrote:

Yes Corroheat will go straight on, no etch primer needed. Agree also about putting a coating over the galv. Galvanising is just putting on a sacrificial zinc layer (and not that thick in some cases), trapped mud can rot through the thin zinc layer in no time. By putting a barrier on top of the galv, it makes the structure pretty rot proof. It's why you should do the same with a new galv chassis. Damp mud sitting inside your box sections or on top of your chassis rails can rot through surprisingly quickly.

Similar to supposed red oxide paint, galvanising has had its day for many applications. With all the rock hard, impenetrable paints now on offer (not good on old rusty metal, fine on brand new metal) galvanising is an expensive process that is not the most environmentally friendly way of priming and protecting metal. It takes time for these old industrial processes to change... simply spraying paint is so much quicker. These rock hard paints came from the development of similar paint used years ago to go directly onto flat beds so you didn,t need to cut boards to put in the back of your truck for protection.

WarPig wrote:

Thats interesting to read Zag, thanks.
I'll order some Dinitrol, it seems to be about £25 (posted) per 500ml can.

P.S I assume it's worth also applying to the load/floor area prior to fitting a sheet of rubber or ply?

Thanks.

Zagato wrote:

Swings and roundabouts isn,t it. Galvanising can chip especially on edges or where you have to put in a fastener, where as these rock hard paints can be hit with a hammer without causing any damage. They don,t peel and certainly don,t flake... get it on your skin and it's there for weeks, get it on the paint lid edge and you won,t get the lid off again. Instructions are to decant it into your paint pot it Is incredibly strong stuff, think bonding cement rather than paint. Mud sitting in a box section will rot through galv... mud sitting on top of this paint in a box section will never do anything to compromise the impenetrable barrier. I have seen new galv chassis rust in mud trap areas after 5 years. If they had been painted on top of the galv they would have been pretty bomb proof.

Zagato wrote:

Swings and roundabouts isn,t it. Galvanising can chip especially on edges or where you have to put in a fastener,

Zagato wrote:

How do you mean, "building a spare chassis up". Is this a new chassis? Is it already galvanised or ungalvanised. There are many suitable products on the market, even rubber based stuff you paint farm building metal superstructures with. I like the POR-15 range but there are many on the market, choose also by which will go onto galv if it is already galvanised and if you need it to be UV resistant I.e. Rear crossmember. The picture below is one I have just taken as an example for one of the previous posts, it may not be an example for your question.

So think bonding cement not paint. This particular POR-15 comes in two parts like an epoxy, it can be hand painted or sprayed. It takes 3 days to fully go off etc etc... bloody hard stuff and yes you cAn belt it with a hammer and nothing happens.

If you are building up an old chassis then I would use the Dinitrol range. You don,t want to put this stuff anywhere near old metal where there is a risk of rust. You are just trapping the rust in, as said soooo many times. They don,t stop rust as they claim, they just stop it showing through.... have fun

Mossberg wrote:

Zagato wrote:

Swings and roundabouts isn,t it. Galvanising can chip especially on edges or where you have to put in a fastener,

Galv should not chip off as it should bond with the metal. If it chips or peals then it has not been done correctly. If you drill a hole the only galv that comes off should be taken off with the drill bit. The only time it should come off with a hammer is when the metal deforms.

.

The reality is I have worked on many Marsland and Richards Chassis, two of my own from new that had the galv chipped in places on arrival, the same with Ifor Williams trailers and my boat trailers which easily chip, especially on the edges. Agree with the thoroughness of dipping if there are enough holes to ensure the galv gets in all the nooks and crannies, so it doesn,t explode in the process where these air holes are you can spray inside even the smallest of box sections with a 360 dregree spray. Quick, easy and with an impenetrable coating, not a sacrificial one. Job done. I see little point in going to the cost and expense of galvanising something that will rot away in time when you can do a permanent job from the outset at little cost with one of these newer products on offer. The saving cost to the industry alone would be massive.

Zagato wrote:

How do you mean, "building a spare chassis up". Is this a new chassis? Is it already galvanised or ungalvanised. There are many suitable products on the market, even rubber based stuff you paint farm building metal superstructures with. I like the POR-15 range but there are many on the market, choose also by which will go onto galv if it is already galvanised and if you need it to be UV resistant I.e. Rear crossmember. The picture below is one I have just taken as an example for one of the previous posts, it may not be an example for your question.


Click image to enlarge

So think bonding cement not paint. This particular POR-15 comes in two parts like an epoxy, it can be hand painted or sprayed. It takes 3 days to fully go off etc etc... bloody hard stuff and yes you cAn belt it with a hammer and nothing happens.

If you are building up an old chassis then I would use the Dinitrol range. You don,t want to put this stuff anywhere near old metal where there is a risk of rust. You are just trapping the rust in, as said soooo many times. They don,t stop rust as they claim, they just stop it showing through.... have fun

liking the Saab, Zagato  Clayton.

1996 Golf Blue 300Tdi 110 Pick up.
Keeper.