Rust Treatment

Lyons

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I spent a load of time treating a few small areas of rust on the Passat a few months ago, and have noticed the paint is bubbling again slightly on the sill just outside the door seal.

What is the best primer to use on such areas after they are sanded down? I did use a rust etch primer of some sort, but it obviously wasn’t up to the task.

Devastated at the prospect of having to do it all again!
 

Burt2000

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I’ve used this in the past and found it excellent. It can be top coated aswell. It’s used mainly in marine applications. I think it needs clean steel though as it’s a protection coating similar to galvanising

www.rawlinspaints.com

Zinga | Metal Paints | Anti-Corrosive Coatings

Buy Zinga at Rawlins Paints today, a straight-to-metal anti-corrosive coating system for the protection of steel.
www.rawlinspaints.com www.rawlinspaints.com
 

Coog

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Just be sure it’s not coming from the inside because no matter what you do externally, short of cutting / welding, it’ll always bubble through.
 

Lyons

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I genuinely don’t believe it’s coming from inside. There’s always been a lot of moisture sitting on the sill (not sure why) so it might just be because it’s constantly subjected to a damp environment?
 

Woodcutter

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Needs stripped right back to bare metal and then treated.

But as @Coog says, if it’s coming from behind, you’re beat without cutting out and replacing the metal.
 

Lyons

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I had it back to bare-ish metal.

What would you recommend?
 

Woodcutter

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Strip it back completely, remove all paint and primer to expose the metal. Then Dinitrol RC900 or Bilt Hamber Hydrate 80, maybe a coat of Bonda Primer or Zinc 182 primer, then paint it.
 

Coog

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If it’s always moist it’s more than likely coming from the inside. Do the bubbles pop and are they filled with water?
 

Jbridges522

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The impossible job lol everyone has a different favorite product but the key is always getting the area as clean as possible and follow the instructions of whatever coating you use to the letter.
 

KevM

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Reece Kirk

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Is there any sort of Rust preventative you could apply to the bottom of a car, would Bilt Hamber Atom-mac be effective?
 

BobSpounge

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2k epoxy primer is the absolute best you'll get as a barrier to stop moisture getting back in. You could sand a car down to bare metal, spray it with epoxy and leave it out in the rain and it will be fine.

Prep is key with anything though. You have to get ALL the rust gone beforehand and if it's pitted it's hard to get it all, wire wheels are best for DIY jobs though. For the bits you can't get treat with hydrate 80 however rust treatments are not an alternative to getting rid of the rust mechanically, only use them as a last resort.

2k epoxy shouldn't contain iscocyanate (i use mipa and it hasn't) so no need for an air fed mask. I have a spray gun but there are epoxy primers available in aerosol but once they're activated you have a limited time to use it up.

For underneath the car I use EM121 epoxy mastic over the clean or treated metal, it's really good stuff but expensive. I then cover that with a good thick coat of tigerseal.
 
Last edited:

BobSpounge

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Reece Kirk said:
Is there any sort of Rust preventative you could apply to the bottom of a car, would Bilt Hamber Atom-mac be effective?
Click to expand...

I'd only use atom mac for something that I've rubbed down to bare metal that im not going to get to paint straight away. It prevents flash rusting but doesn't have any mechanical resistance so would be no good under a car. Use Bilt Hamber Dynax UC or Dynax UB for that.
 

ger16v

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BobSpounge said:
2k epoxy primer is the absolute best you'll get as a barrier to stop moisture getting back in. You could sand a car down to bare metal, spray it with epoxy and leave it out in the rain and it will be fine.

Prep is key with anything though. You have to get ALL the rust gone beforehand and if it's pitted it's hard to get it all, wire wheels are best for DIY jobs though. For the bits you can't get treat with hydrate 80 however rust treatments are not an alternative to getting rid of the rust mechanically, only use them as a last resort.

2k epoxy shouldn't contain iscocyanate (i use mipa and it hasn't) so no need for an air fed mask. I have a spray gun but there are epoxy primers available in aerosol but once they're activated you have a limited time to use it up.

For underneath the car I use EM121 epoxy mastic over the clean or treated metal, it's really good stuff but expensive. I then cover that with a good thick coat of tigerseal.
Click to expand...


I am glad this has come up as i was going to ask for recommendations for a mk2 golf that iam restoring
The amount of stuff out there claiming to be the best is confusing to say the least

Can i ask who stocks em121 epoxy mastic locally.
 

Woodcutter

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Cookies

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Ive just bought a bottle of Neutrarust 661 to try after watching a YouTube video of a guy sorting out the underside of his Range Rover. Worth a try I thought, and it's self priming.

 

Lyons

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Just put a timing belt etc in it so it’s here for a while yet!
 
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