Epoxy aerosol on top of Bilt Hamber Electrox?

[OtherAlex]

Advice please - I need to attempt some driveway DIY on underbody corrosion, so no workshop, no air tools and limited to cordless, and aerosols.

This is how I plan to tackle it:

- thoroughly degreased and cleaned
- loose rust removed, down to bare metal where possible
- degreased + cleaned
- DIY rust remover paste: citric acid+baking soda+water+washing up liquid+cornstarch+clingfilm - a few applications+agitations, left overnight then rinsed off with bicarb of soda solution
- then applications of Dinitrol RC900
- then x2/3 coats of aerosol Bilt Hamber Electrox.

- then an epoxy primer.

Are epoxy primers generally OK to go over BH Electrox?

Anything in the above process that is a bad idea given the limitations of driveway DIY, please?

 

[LewisT]

- then applications of Dinitrol RC900
- then x2/3 coats of aerosol Bilt Hamber Electrox.

Think most will recommend you skip these and straight to epoxy. As for the epoxy would just recommend jotun or something similar and hand brush/roller it.

 

[richie00boy]

The RC900 will probably be an issue if the rust has been removed with citric, also it will render the Electrox ineffective.
Aerosol epoxy primers, most I've seen are not an activated product (button on can to release hardener which then means contents must be used within a few hours) therefore poor.

For rust scab removal look into polycarbide wheels rather than wire brushes as they are more effective and leave a paintable rather than burnished surface.

 

[OtherAlex]

I'll think about the straight-to-epoxy but I've got the toucans sitting here on the shelf and I'm thinking about how much I spent on them ('sunk cost' fallacy, I know).

I'm happy to have a reason to skip the DIY paste stage, tbh.

Bought a cordless angle grinder+M14>type R adapter and some 50mm polycarbide wheels in advance, got a few extra 80 discs. Might treat myself to one of these 115mm Blaze ceramic wheels as a back up if the PCs wear out quick.

Thanks for the advice re DIY remover vs zinc.

 

[richie00boy]

People aren't saying skip the citric paste, just to skip those two steps of Dinitrol and Electrox.

That paste recipe looks like a bit of a youtube special, not sure you will have great success with it. Try soaking sheets of kitchen roll in just citric and water and sticking them on, you will need to keep spraying fresh citric liquid on every couple of hours or so. Citric works a lot better when its hot.

 

[marlinspike]

Electrox has to be in contact with the metal to be effective at preventing rust. I would just get it back to bare metal and brush 2k epoxy over it. I like Electrox but I don't think it would be any better than 2k epoxy for your purposes, especially as you have epoxy already.

 

[Smallfry]

I love Bilt Hamber products, BUT, Electrox only works on bare clean steel. If there is any rust at all it does not work. Hydrate 80 and the Dinitrol equivalent, are merely encapsulators IMO, after 18 months or sooner, the "converted" rust will be back. The only rust treatment I rate, is Fertan, but even that needs serious preparation, and a couple of treatments.

If you are after a "painted" underside finish, then Epoxy Mastic , Jotun, or any TWO PART epoxy really, again, after serious preparation.

Single pack "epoxy" is just paint.

Lanolin products are a waste of money and time.

Failing that, its down to one of the greasy products, if you can put up with them.

 

[charlysays]

I love Bilt Hamber products, BUT, Electrox only works on bare clean steel. If there is any rust at all it does not work. Hydrate 80 and the Dinitrol equivalent, are merely encapsulators IMO, after 18 months or sooner, the "converted" rust will be back. The only rust treatment I rate, is Fertan, but even that needs serious preparation, and a couple of treatments.

If you are after a "painted" underside finish, then Epoxy Mastic , Jotun, or any TWO PART epoxy really, again, after serious preparation.

Single pack "epoxy" is just paint.

Lanolin products are a waste of money and time.

Failing that, its down to one of the greasy products, if you can put up with them.

Electrox works best on bright clean steel but according to BH it can be used on prepped corroded metal to protect it. The surface does need to be metallic and conductive (e.g st3) so thorough needle gunning, wire wheels, sander etc to rough it up and remove all loose deposits. If you've gone as far as needle gun, wire wheels and sanding you might as well give it 24 hrs with a citric paste under clingfilm IMO. What makes electrox good over other paints including 2k epoxy is that it is incredibly conductive so it can protect much like galvanising but still accept all types of top coat. Personally I think it's one of the best coatings to use when there are lots of edges, seams and risk of damage as it doesn't seem to suffer as much from cathodic debonding as less conductive 2k top coats.

 

[charlysays]

Advice please - I need to attempt some driveway DIY on underbody corrosion, so no workshop, no air tools and limited to cordless, and aerosols.

This is how I plan to tackle it:

- thoroughly degreased and cleaned
- loose rust removed, down to bare metal where possible
- degreased + cleaned
- DIY rust remover paste: citric acid+baking soda+water+washing up liquid+cornstarch+clingfilm - a few applications+agitations, left overnight then rinsed off with bicarb of soda solution
- then applications of Dinitrol RC900
- then x2/3 coats of aerosol Bilt Hamber Electrox.

- then an epoxy primer.

Are epoxy primers generally OK to go over BH Electrox?

Anything in the above process that is a bad idea given the limitations of driveway DIY, please?

I'd be wary about applying anything which leaves a film and then using primer over it. Most data sheets warn against this. If your acid paste has done the job you won't need a rust converter of any kind so just go ahead with your primer after the acid paste has been thoroughly rinsed and wire brushed off.
What you do once you have a rust free albeit cratered surface is still under some controversy.
Many will say go with epoxy.
I've done both and after consideration I'd say that for outer panels I'd use 2k epoxy but underneath, where damage is more inevitable and hard to spot, I prefer something like bilt hamber electrox or woco unidox which will continue protecting even when damaged and will be more resistant to cathodic debonding (rust getting under the coating and pushing it off the substrate). The downside is they don't adhere as well as epoxy and aren't as resistant to chipping but then chipping is inevitable so it can become as important to have something which still protects even when damaged. As such a flexible spray sealer or other solvent based flexible coating over the electrox would give the best of both worlds.