Alternative zinc rich primer to Bilt Hamber Electrox?

[charlysays]

I've run out and they're out of stock of the 1l tins indefinitely. The aerosols are expensive, no good for getting into tight spots and block easily.

For those that don't know Electrox has 90%+ zinc in the dried film, is a modified alkyd paint which uses xylene as thinners, is electrically conductive once dry (I checked this with a multi meter once lol). It is also tough and sticks well for a 1k paint. Unlike a lot of galv type paints you can overcoat it with pretty much anything, e.g 2k paint, enamels or acrylics- it doesn't seem to react with anything.

I suspect Bilt Hamber buy it in from someone else but I'm struggling to find an equivalent. Anyone got any ideas?

 

[Tigman]

I use Dacralyte Rapidac HP. Lovely drop of paint !

 

[OJCar]

Soham Oil and Paint Zinc Rich Primer

Now called Woco Zinc Rich Primer 90%
https://www.withamgroup.co.uk/zinc-rich-primer-90

You can buy it via Ernest Does
https://www.ernestdoeshop.com/product/woco-unidox-zinc-rich-primer-500ml/
https://www.ernestdoeshop.com/product/woco-unidox-zinc-rich-primer-1l/

 

[Ross365]

Those kind of paints must be pretty expensive; what application warrants their use?

 

[steveo3002]

zinga is another brand to look at

 

[marlinspike]

It's a good product but I totally agree about how easily the aerosols block.

 

[barracuda816]

Is there any application this would actually be better over an epoxy mastic? Is it just about convenience? Genuine question.

 

[charlysays]

Those kind of paints must be pretty expensive; what application warrants their use?

I use it for spot repairs mostly both underbody and external panels especially where I feel there could be prep issues or weaknesses at edges or seams etc. Also use it on stone chip repairs. In my experience these very high zinc alkyd paints protect the metal better than epoxy mastics when there's coating damage or questionable film thickness/ consistency. I suspect the rust struggles to get underneath them due to the strong anodic protection, unfortunately epoxy primers lack decent anodic properties due to the resin isolating any anodic pigments.

 

[charlysays]

Is there any application this would actually be better over an epoxy mastic? Is it just about convenience? Genuine question.

Under cars where perfect prep is very difficult I think these high zinc 1k primers can be better than Epoxy. Epoxy is great onto blasted metal where there is no end to the coating (entire item or car is encapsulated in epoxy) however even after meticulous mechanical prep and degreasing I've found the adhesion of epoxy mastics to be a bit disappointing, almost hit and miss is a description I might use, rust can certainly find it's way under it and what looks like a thick coating can develop random specks of rust.
Electrox plus a good chassis enamel is not quite as tough but in my opinion it fares better once inevitable damage occurs.

I did read an article written by a company who maintains steel bridges in America and they still much prefer these 1k primers to epoxies.

I still think both have their place though, just depends on the quality of prep!
Sadly I rarely have the time or resources to blast prep my cars. They get repaired but I'm usually in a rush so a quick tickle and a wipe is all the prep they get and in this scenario I've found the high zinc 1k alkyd paint to be best.

 

[Ross365]

I'm getting on in life, have been "messing with cars" since 1975 and tend to stick with some of the old products that I know and think are good. I'm willing to concede that I may be missing out by not exploring newer products,

I've been using little else but alkyd zinc phosphate primer for the last ~15 years. I stumbled upon this (attached) article by a Chinese paint company a few days ago. I wonder what people think about what it have to say?

 

[barracuda816]

Thanks for the reply @charlysays.

I have never really used a proper high Zinc primer, and I really rate BH products so I might have to do some comparison testing when I get some time.

I always found epoxy (esp mastic) to stick like the proverbial to a blanket even when my prep has been somewhat lacking, unlike urethane paints.

 

[barracuda816]

I'm getting on in life, have been "messing with cars" since 1975 and tend to stick with some of the old products that I know and think are good. I'm willing to concede that I may be missing out by not exploring newer products,

I've been using little else but alkyd zinc phosphate primer for the last ~15 years. I stumbled upon this (attached) article by a Chinese paint company a few days ago. I wonder what people think about what it have to say?

Interesting, and may explain why I have never had adhesion problems. I have been using Zinc phosphate epoxy not Zinc rich.

 

[Dcal]

Is there any application this would actually be better over an epoxy mastic? Is it just about convenience? Genuine question.

You can get zinc rich epoxy primers, Jotun Barrier 90 for example. With the correct prep they are very good, however zinc rich paints don't have great adhesion so require better prep.
There isn't much room for binders after the zinc has been added so that seems unavoidable.
Over a blasted surface they can out preform a straight epoxy mastic but don't look or sand as well.

For less than ideal prep and the long intervals between coats that is common with DIY usage, I think an epoxy mastic is better and I use far more Jotamastic than anything else but that's just down to personal preference and what I can get locally for a reasonable cost.

Some epoxy mastics, for Jotamastic 90A for example, have added aluminium which gives some galvanic protection while still maintaining the main advantages of epoxy mastics, which I think are - the ability to stick over mechanical prep, they can be overcoated with minimal sanding and still have many years or service life.

There are many excellent products out there, so stick with the one that works for you.
The problem is even an average product if property applied should last years, so it should take many years to confirm results.
Faulty prep on the other hand usually shows up in a few months.

 

[bricol]

I'll second the problem with epoxy over less then ideal prep, compared to the zinc rich primers. I used both under my daily driver, outside in all weathers, Lancia around 20 years ago. After ten years of use and a slight interface between bonnet and the spare wheel on the back door of a 4x4, I parked it for a short while, then commenced work on it.

Where metal had been blasted, especially with commercial gear, the epoxy was pretty much perfect - the rear subframe, rear inner arches - both blasted by a guy I paid 75 quid for a few minutes work - best 75 quid ever. They are are still good now 20 odd years after it was done.

Where I blasted it, it was still pretty good - odd bits of damaged but pretty good. Took some physical abuse to shift it - flap wheels, blasting etc.

When I used epoxy on sound, smooth metal, or wire brushed metal - it looked good until poked around a bit - when large flakes/sheets simply came away - the bond to the metal wasn't there - water got underneath and rust ensued. Fingernails were good enough to pry it away.

Where I used the bilt hamber stuff on smooth metal, it was pretty much still intact - a lot better adhesion. Not as tough as the epoxy, but it was still there, still protecting.

All paint covered with different colour machine enamel and then 3M or Waxoyl underseal - the colours meant I could see damaged underseal and sort it.

The above is why I comment a lot when I see the epoxy applied on metal that simply doesn't have enough of a key to promote good adhesion - it looks fantastic . . . but I worry what will be happening behind it in a few years time.

 

[charlysays]

Soham Oil and Paint Zinc Rich Primer

Now called Woco Zinc Rich Primer 90%
https://www.withamgroup.co.uk/zinc-rich-primer-90

You can buy it via Ernest Does
https://www.ernestdoeshop.com/product/woco-unidox-zinc-rich-primer-500ml/
https://www.ernestdoeshop.com/product/woco-unidox-zinc-rich-primer-1l/

I bought a litre of this in the end. Looks basically identical to Electrox after comparing the MSDS. Thanks for the tip