Electrox vs por 15

[Skilli]

There are so many products out there that I am struggling to decide what to paint the unerside of my Mk1 golf with.

I was originaly planning on going back to metal and then painting Built hamber electrox zinc rich primer followed by some unerbody dinatrol waxy stuff.

Now Im not sure. everyone is raving about por 15. kills rust, is easy to apply, looks good, is really tough etc etc.

I must admit that the electrox dosen't seem to adhere very well and chips and flakes.

Any tips?

 

[steveo3002]

por15 needs perfect prep or it peels off

in my experiance it doesnt kill rust , maybe slows up well cleaned up stuff fairly well, but dont go thinking you can paint it over a rusty bit and forget about it

over sandblasted minty stuff its fairly good , hard as nails you cant chip it off

id look for something else that isnt so fussy , epoxy mastic seems popular , i like it so far but havent used it long enough to say if it lasts well

 

[MG David]

I have found POR15 to be very sensitive to the surface finish of the metal being painted. The metal needs to have lots of tooth such as when freshly sand balasted or heavily sanded with P60. If you do not get that correct it will peel off. It also tends to shrink back a little from sharp edges when painted. So you need to run a file along panel edges giving them a radius. If you get all of that correct it does a good job if not it is a waste of money.

Recently I have used epoxy mastic from Rustbuster. It seems to be more tollerent of surface quality. In 10 years time I will be able to give a better answer about how well it lasts.

 

[grim_d]

Do you have a good key and are you using panel wipe before paint with the electrox? I certainly have had no issues with it flaking or peeling, I will admit however it is not a tough product, but it is a primer and should really be overcoated, despite what the datasheet says.

Also would not use it over anything but clean metal, any underlying rust will break through it.

I am going for electrox overcoated with epoxy mastic from rustbuster although I cant comment on the epoxy mastic yet as I have not used it.

Also have not used POR-15 but from what I have read on it (a lot) I am inclined to stay away from it as its a bit hit-or-miss.

Remember to also stonechip the underside for that extra layer of protection.

 

[Ginger]

Thanks for your input. I think I will give up on the por 15. dont know anything about epoxymastic and will look it up.

I suppose I was being a bit negative about the electrox. Its just that I spent what seemed like ages taking off the black primer that came on the repair panels and coating them with electrox just to see it chip off when I was trial fitting and trimming. Its not tough but I gather it has excelent anti-corrosion properties.

I stripped the panels, treated them with jenolite and then cleaned them with white spirits. Waiteed about half an hour then paint with electox. Could anyone advise on whether this is an appropriate method?

 

[steveo3002]

the black e coating is often very good (some cheapo panels have poor stuff) its best keyed up and painted over next time

so you cleaned new panels with jenolite? no need there , epoxy over bare metal would have been the best way forward , its also pretty tough although not as tough as por when its gone right

 

[jaykay]

ginger whitespirir is not the best way to clean.use panelwipe or good old celly thinners

 

[grim_d]

Can only really echo the above, electrox or epoxy mastic should only really be applied to bare metal, I'm overcoating the electrox with epoxy mastic more for it's toughness rather than its rust inhibiting properties.

If you feel the metal has enough rust left on it to warrant using a rust treatment like jenolite then it is simply not ready to be topcoated. The only place I am going to be using a rust treatment (hydrate 80) is to inject into seams I cant get anything else into, may do nothing but every little helps.

Clean panels using proper panel wipe, its about £12 for 5 litres.

 

[Ginger]

This has all given me much more to think about.

I use the hadrian panels. Does anyone know the quality of the e coat on these?

steveo3002, you mention epoxy over bare metal. What is this? Is it only availabe as a 2k product?

The only reaon that i am strippint the panels is because previous outer arch repairs have aleady rusted throught the paint. They were done perhaps arounnd six years ago before i owned the car. I just want my repairs to last lonnger. Is this notpossibel to the home restorer?

I thought welding was a hard to get my head around but rust treatmnet and prevention is a nightmare.

 

[grim_d]

you mention epoxy over bare metal. What is this? Is it only availabe as a 2k product?

http://www.rust.co.uk/epoxy-mastic.cfm, it is 2k but it is iso free and brushable, it's intended for undersides and chassis etc so a brushed finish is usually acceptable (to me anyway), if spraying you still need an air fed mask.

I thought welding was a hard to get my head around but rust treatmnet and prevention is a nightmare.

It's actually fairly simple, the only real method of treating rust is complete removal, rust "converters" don't work, ever ,complete waste of time on accessible areas.

What is the car by the way?

 

[Skilli]

83 mk1 golf gti.

I'm working on the car weekends here and there and I know primers and fillers are porpous and I am a long way from getting the car painted.

I also know that just cleaning metal with a whire wheel is not good enough and you got to get rid of all trace of surface rust. I first use built hamber deox gel which seem to be good stuff but messy. Went over to jenolite as no water is needed but is less effective on pitted surfaces. I used to use bulit hamber etch primer as a temp coating but disovered that this too is purous. I know use frost zinc rich primer as a temp coating/ Doesn't adhere as well as the etch but was hopign that the zinc will provide extra protection.

Like I said in an earlier meassage my arches (not at the weld joint this was fine) had already rusted out form a previous repair and i assumed it was because there was traces of rust on the metal before they painted them. I'm just anxous that all my hard work will rust away just after I get the car back on the rod.

Forums like these really are a valuable resource and I appreciate all your comments.

 

[grim_d]

According to bilt hamber electrox is non-porous.

Maybe the previous repair on the arch was not painted/sealed on the inside too, this would cause it to rust through again.

I'm restoring a Pulsar Gti-r and the rear arches rust from the inside out, maybe the golf is similar?