Red Oxide Primer. The Big Questions.

Turboman said:

Yes, my mate lives in Blackpool, Pompey on the forum, and it is pretty salty. Not so bad as here, they get the protection of Ireland.

Not painted any bridges myself, but another friend has a contract painting company, and they paint all manner of interesting stuff.

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Youll have to tell him the story of the painter who won a multimillionpound
contract by giving the decision makers two nails in a plastic cup of water. One he said has been sand blasted with our secret additive and one hasnt. Two days later one of the nails had started rusting.

The other had been sprayed with his wifes hair lacquer.

farmershort said:

Which is already being done to my new chassis..... But I want morrrre!

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Build a wheel wash at the end of your lane.





And fill it with diesel.

Hmmm. Think the end of my lane is the a330 just off the m3.... There might be complaints!

farmershort said:

Hmmm. Think the end of my lane is the a330 just off the m3.... There might be complaints!

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Round Micheldever kind of way? Nice area, used to work around there a lot twenty five years ago!

Apologies, but there is no underside pic in Members Vehicles, I checked, I will look out a pic of the chassis and post it.

People often paint galv chassis prior to install, not done it myself, but I don't think it is that easy, chassis needs to be treated with mordant, and then painted with special primer before painting.

I understood that it needs mordant solution, then just your choice of primer... I may be wrong though... I'm not into painting really.... I want to a) hide the galv chassis and b) give the galv a few years head start before it sees the outside world. I'll fill the box section with something oily of course.

farmershort said:

I understood that it needs mordant solution, then just your choice of primer... I may be wrong though... I'm not into painting really.... I want to a) hide the galv chassis and b) give the galv a few years head start before it sees the outside world. I'll fill the box section with something oily of course.

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New galv you need mordant, calcium plumbate primer, undercoat, topcoat!

And even then it doesn't always take very well.

Much better plan is to leave it to weather a few years, then paint, but of course that is a pain cos it is then fitted to the vehicle

Unpainted is pretty good, I know a few people have that, no real issues. The one thing that galv doesn't like much is road salt, turns the galv brown and crusty sometimes.

I'm more and more convinced by mordant and this dinitrol system..... Cavity wax (3125) followed by 4941.

farmershort said:

I'm more and more convinced by mordant and this dinitrol system..... Cavity wax (3125) followed by 4941.

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3125 is really good stuff, been using it for years, never used the other, I always paint where I can.

TBH, mate, I really wouldn't waste money spraying a galv chassis inside, it will outlast you anyway, pour some old gear oil or something in if you are really worried.

If you want to paint outside for salt protection and appearance is fine, best of luck with it staying on!

Turboman said:

The site of these steels is very wet, and it is a very salty environment, West facing coast. So the metal needs good protection. Shed upcountry a couple of any primer is fine. Unprotected mild steel here just dissolves!

Also, time is critical, I need to shore up the sheds to use them, before they come down

So I was hoping to get some good stuff, two coats and drying time, and get them up! Going to the teamac place tomorrow.

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If they're coming down, why bother with the expensive stuff?

We tend to use a fair bit of red oxide at work, it gets slapped on anything we've made in the hope we can chance to paint it properly! ( Our rather expensive bulb planter has a bodged on red oxide painted safety guard that i made, it looks awful but i'm all out of john deere green! )

Big Mat said:

If they're coming down, why bother with the expensive stuff?

We tend to use a fair bit of red oxide at work, it gets slapped on anything we've made in the hope we can chance to paint it properly! ( Our rather expensive bulb planter has a bodged on red oxide painted safety guard that i made, it looks awful but i'm all out of john deere green! )

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Hopefully the shed wont come down once the steels have been installed. Hoping it will last for the rest of my life once repaired!

i emailed the dinitrol guys and they think it's fine to go straight onto galv.

question
"Can you tell me if Dinitrol 4941 can go directly on galvanised metal.
Specifically a land rover defender with a new galvanised chassis?

Or does it need t-wash, primed and top coated as usual?"

answer
"You can put it straight on to chassis as long as it is clean and free from dust"

who know's if they are totally correct. could always do a test area

now, just to ease my latent worries... dinitrol 4941 isn't the stuff that people used to say dries out and allows water to creep underneath it (between it and the metal) forming a horrible rust mess that you can't see?? I know that people say that about underseal.... or is it stone-chip??? but is it fundamentally the same here?

Which still leaves the question: If you have a Disco (for example) which is good and sound but has been round the block a few times i.e. green lanes, p&p etc. and the chassis is full of residual mud, silt, gravel, twigs and leaves and possibly the odd dead rodent, how can you possibly get it clean enough inside the cavities to apply any sort of rust inhibitor/killer?

trax said:

i emailed the dinitrol guys and they think it's fine to go straight onto galv.

question
"Can you tell me if Dinitrol 4941 can go directly on galvanised metal.
Specifically a land rover defender with a new galvanised chassis?

Or does it need t-wash, primed and top coated as usual?"

answer
"You can put it straight on to chassis as long as it is clean and free from dust"

who know's if they are totally correct. could always do a test area

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I didn't think it would cause a problem, just that it is a waste of money, I cant see the inside of a galved box section rusting for fifty years anyway. Doesn't get much weather exposure.

farmershort said:

now, just to ease my latent worries... dinitrol 4914 isn't the stuff that people used to say dries out and allows water to creep underneath it (between it and the metal) forming a horrible rust mess that you can't see?? I know that people say that about underseal.... or is it stone-chip??? but is it fundamentally the same here?

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No, no and no! 3125 is nothing like waxoyl, or underseal. It is a thin fluid that runs like water and can easily be sprayed through a Schutz sprayer. When I did my (unglavanised) chassis I blocked all the drain holes with epoxy putty, and drove around with the stuff sloshing about after spraying it! I took the plugs out before winter. When you spray a door pillar, you can see the dinitrol running out of the bottom,stained brown with dissolved rust!

Yoyodyne said:

Which still leaves the question: If you have a Disco (for example) which is good and sound but has been round the block a few times i.e. green lanes, p&p etc. and the chassis is full of residual mud, silt, gravel, twigs and leaves and possibly the odd dead rodent, how can you possibly get it clean enough inside the cavities to apply any sort of rust inhibitor/killer?

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You cant, effective rustproofing of any make really needs to be applied when the vehicle is new. You can wash it out with lots of water and dry thoroughly, but it wont get everything out.
For this reason, I never buy a Landrover that I think may have been driven through water or deep mud, especially anything where salt water might be involved! I always look for the one that rich folk owned to occasionally use in bad weather, or light business use, one like that!

As promised, chassis pics, not very detailed I am afraid, as it is sound I have never photographed it much!

25 years old, completely original apart from rear chassis legs!

Turboman said:

I didn't think it would cause a problem, just that it is a waste of money, I cant see the inside of a galved box section rusting for fifty years anyway. Doesn't get much weather exposure.

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it's the outside dinitrol, underseal. protects against salt/grit an all that

if it does stick on fresh galv, then it could be an ideal/cheap way of hiding/protecting a galv chassis

trax said:

it's the outside dinitrol, underseal. protects against salt/grit an all that

if it does stick on fresh galv, then it could be an ideal/cheap way of hiding/protecting a galv chassis

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Yes, yu are quite right, senior moment! :crazy: I meant 3125!

Right... So this is underseal then.... The stuff that has pretty much got a terrible name now for allowing water to seep underneath?

farmershort said:

Right... So this is underseal then.... The stuff that has pretty much got a terrible name now for allowing water to seep underneath?

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Never used the outside one, as you can see, I paint the outside,

The one I use is 3125, but it is too thin too be very effective as an outside coating, strictly for inside!

Common sense would suggest underseal may be better when applied to a new, corrosion free chassis, than to an old one with surface rust already present.