Mordant then etch or standard primer & what about filler?

[julianf]

As per the other thread, i now need to paint this -

I have a bottle of mordant solution, but the directions label has been lost.

From reading, it seems that i just apply it, and then wash off when its gone black?

Can i spray it on, or is it likely to rot my cheap and cheerful gun?


What is the best plan from there?
Should i use an etch primer too?


I have a tin of standard upol filler (the stuff in the red and black tin)

Im aware that they also make one for galvanised metal, which, i assume, has an etching agent in it, to key it.

Once ive used the mordant, is this still required, or can i smooth over with the standard filler, and use standard flexible seam filler?

...and should i do this before or after the primer? I noticed on the factory finish, the seam filler was certainly applied after the primer, but it seems odd putting body filler over primer?

 

[penfold]

Epoxy primer straight on I'd have thought; Lechler's instructions say it doesn't need any prep other than being clean.

 

[lexi]

I often wondered why go to bother of galv, then kill the surface a bit with Phosphoric Acid (mordaunt) so you can paint. I know you are converting the surface, but you must eat a little of the zinc thickness.
I did etch then primer on galv but would go Epoxy now I think.

 

[julianf]

From what ive read, you can paint onto brand new galv, but, as soon as it starts to oxidise, the paint wont adhere.

...and then, after a whole load of time, a different type of oxide forms (or somthing?) and then it will stick again.


This is only what ive read though.

I dont know how long the window is between gavanising, and just using etch primer, without t-wash. My other half has our only working car at the moment (and she is away) else id have gone and purchased some etch primer today, and tried.

 

[lexi]

Loads of guys have used the T Wash with success. You have it so maybe as well use it? I think it is just a preference and there is no ultimate or best way.

 

[ajlelectronics]

Modern thinking is epoxy primer.

 

[julianf]

2k will cost me a fair bit in someone else's labor though - unless i misunderstand, and there are good products that do not require air fed masks?

 

[julianf]

Loads of guys have used the T Wash with success. You have it so maybe as well use it? I think it is just a preference and there is no ultimate or best way.

I think the amount of zinc it takes off is so minimal that its not of concern. I dont know what the copper in it does, but the phosphoric - well its not as if it will eat through the whole job if you get distracted by the phone...

(i got a load of phosphoric from a chem supplier once - it wasnt as fierce as i was hoping by any means, but i know it comes in different percentages)

 

[ajlelectronics]

2k will cost me a fair bit in someone else's labor though - unless i misunderstand, and there are good products that do not require air fed masks?

Who said anything about 2K? Epoxy primer does not contain isocyanates.

 

[julianf]

Can you give me a product name?

I read through this thread last night -

http://www.mig-welding.co.uk/forum/threads/epoxy-primer.20533/

which certainly gave the impression I'd be looking at 2k.

 

[marlinspike]

I am pretty sure there was a thread a long time ago where a member emailed Lechler in Italy and received a reply that their epoxy was non iso. The Lechler 29107 is very popular on here, I know Langy uses it a lot and rates it. I haven't used it myself as my project is moving pretty slowly atm, but this was the cheapest I could find when looking. You need to ask for it to be tinted I believe :

http://www.express-paints.co.uk/epoxy-primer-29107/

Apart from being non iso, as I understand it the big advantage of epoxy primer is that it does not absorb moisture. You can roller it on too apparently.

Edit: the info sheet says it's two pack but that refers to it being a two component product, ie. product and activator, not that it is necessarily dangerous.

I would recommend getting one of the Gerson masks that are good for limited spraying of 2k though as they are only about £15 and are very good at keeping out fumes.