14 replies to this topic

[Kevinmini]

Can anyone recommend best aerosol primers to use on repair areas and new body panels

Epoxy primer on bare metal / fabricated work?

zinc rich primer on between panel and seams / before welding

Thanks Kev dog

[bluedragon]

Epoxy primer is the best for bare metal IMHO. If you are set on aerosols however, forget about epoxies. Epoxies are 2 part paints and unless the aerosol can claims to be able to mix 2 separate components together when sprayed (a feature I've seen once ever) it will not be a true epoxy. 

 

By nature, epoxies use a chemical additive to initiate and power the chemical reaction that links the molecules together to give it durability and moisture resistance.

 

 

Dave

[GraemeC]

There are 1k epoxy primers available - don’t know how good hey are but they presumably use air as their final catalyst

2k aerosols are available too and work well

Edited by GraemeC, 21 December 2020 - 07:28 AM.

[Vanman20]

Epoxy primer is the best for bare metal IMHO. If you are set on aerosols however, forget about epoxies. Epoxies are 2 part paints and unless the aerosol can claims to be able to mix 2 separate components together when sprayed (a feature I've seen once ever) it will not be a true epoxy.

By nature, epoxies use a chemical additive to initiate and power the chemical reaction that links the molecules together to give it durability and moisture resistance.


Dave

There are proper 2k epoxy aerosols on sale, even Euro car parts sell them

[myredmini]

Novol Epoxy in aerosols is pretty decent stuff. I use the 2k version for big jobs, the cans for smaller areas or to protect after welding.

[bluedragon]

A "air cured" epoxy is to 2 part epoxy as 1k paint is to 2k paint. It may have the name epoxy, but it isn't close to 2 component epoxy in its properties. If it were, then most people wouldn't bother with the 2 part stuff, spray can or spray gun.

 

As I said, if the spray can has two chambers for epoxy and hardener, and mixes them when spraying, then it's the kind of epoxy that justifies the name. If it doesn't have two components, it's something considerably inferior.

 

It may be perfectly adequate for your application, but one you'd be sorely mistaken if you thought the 1 part epoxy primer has the same qualities that give epoxy primer its reputation.

 

I cannot tell if the spray can Novol epoxy is a 2 component product like the spray gun compound. I tend to believe it is not, since if it did have the elaborate 2-part mixing spray can, I'd think they would trumpet that fact.

 

 

Dave

[Kevinmini]

Can or should I just use zinc rich primer? eBay sell a lot of zinc rich primer cans

[sonikk4]

A "air cured" epoxy is to 2 part epoxy as 1k paint is to 2k paint. It may have the name epoxy, but it isn't close to 2 component epoxy in its properties. If it were, then most people wouldn't bother with the 2 part stuff, spray can or spray gun.

 

As I said, if the spray can has two chambers for epoxy and hardener, and mixes them when spraying, then it's the kind of epoxy that justifies the name. If it doesn't have two components, it's something considerably inferior.

 

It may be perfectly adequate for your application, but one you'd be sorely mistaken if you thought the 1 part epoxy primer has the same qualities that give epoxy primer its reputation.

 

I cannot tell if the spray can Novol epoxy is a 2 component product like the spray gun compound. I tend to believe it is not, since if it did have the elaborate 2-part mixing spray can, I'd think they would trumpet that fact.

 

 

Dave

 

I used this on Project Paddy while carrying out the body resto and not once did i see any rust forming even in our slightly damp workshop. So does it work, yes it does, would i use 2K Epoxy, yes i would but having to mix it every time i welded a panel in place would be time consuming to say the least.

 

So as something to protect your freshly welded panels then it works, then when you are ready to paint the car go for a 2K product. I used Octoral's surfacer (PF131) on the recommendation of Ben_O and its good stuff but not cheap.

[Vanman20]

https://www.ebay.co....tm/292756741181
Plenty of others on ebay

[gaspen]

Can or should I just use zinc rich primer? eBay sell a lot of zinc rich primer cans

 

Use it only to protect the bare metal from rust at the  welded areas. A normal paintshop will completely sand back or wipe down with thinner the zinc primer before painting. Don't trust a painter who will spray over zinc primer ! They should apply 2k epoxy - putty - filler - base coat - lacquer 

[Vanman20]

Can or should I just use zinc rich primer? eBay sell a lot of zinc rich primer cans

Use it only to protect the bare metal from rust at the welded areas. A normal paintshop will completely sand back or wipe down with thinner the zinc primer before painting. Don't trust a painter who will spray over zinc primer ! They should apply 2k epoxy - putty - filler - base coat - lacquer

Putty ?

[gaspen]

 

 

Can or should I just use zinc rich primer? eBay sell a lot of zinc rich primer cans

Use it only to protect the bare metal from rust at the welded areas. A normal paintshop will completely sand back or wipe down with thinner the zinc primer before painting. Don't trust a painter who will spray over zinc primer ! They should apply 2k epoxy - putty - filler - base coat - lacquer

Putty ?

 

 

Sorry I thought they call it putty in english.

 

I meant it is the filler to repair small dents if needed

 

How to Use Body Filler - Tips and Technique (mig-welding.co.uk)

[Vanman20]

Can or should I just use zinc rich primer? eBay sell a lot of zinc rich primer cans

Use it only to protect the bare metal from rust at the welded areas. A normal paintshop will completely sand back or wipe down with thinner the zinc primer before painting. Don't trust a painter who will spray over zinc primer ! They should apply 2k epoxy - putty - filler - base coat - lacquer

Putty ?

Sorry I thought they call it putty in english.

I meant it is the filler to repair small dents if needed

How to Use Body Filler - Tips and Technique (mig-welding.co.uk)

I wouldn't follow that guide.You should never rub filler down wet, that's really bad practice.
Putty.... usually called stopper....is really only for pinholes after you've done all your filling and normally after primiing.Stopper with a hardener,like upol dolphin glaze,is much better than air dry stuff

[gaspen]

 

 

 

 

Can or should I just use zinc rich primer? eBay sell a lot of zinc rich primer cans

Use it only to protect the bare metal from rust at the welded areas. A normal paintshop will completely sand back or wipe down with thinner the zinc primer before painting. Don't trust a painter who will spray over zinc primer ! They should apply 2k epoxy - putty - filler - base coat - lacquer

Putty ?

Sorry I thought they call it putty in english.

I meant it is the filler to repair small dents if needed

How to Use Body Filler - Tips and Technique (mig-welding.co.uk)

I wouldn't follow that guide.You should never rub filler down wet, that's really bad practice.
Putty.... usually called stopper....is really only for pinholes after you've done all your filling and normally after primiing.Stopper with a hardener,like upol dolphin glaze,is much better than air dry stuff

 

 

Ok it is just a very basic guide :)

 

Main question was the using of zinc primer, which is not recommended under ANY 2K paint system in my opinion.

[Ben_O]

I would recommend a zinc rich primer in an aerosol to go in weld seams and to flash over bare metal areas during the panel work stage.

I use no nonsense zinc galv spray from screwfix. Nice and cheap, protects well and a little goes a long way. You literally need a fine mist and that's enough.

Been using it for years without any issues.

 

As has been said, it's good practice to remove the zinc spray from the panels except obviously in the weld seams before starting the prep but it's not essential and I have never heard of any issues leaving it.

 

If you are sending the car away for paint I would recommend just leaving the zinc primer on and let the painter do what is required for their paint system.

 

I wouldn't recommend applying filler over any sort of primer. I would always recommend applying filler to bare metal only to avoid issues with mapping .

 

I think discussions about what primer is best come prep time can wait until the OP is at that stage. The zinc will be suitable for now.

 

Cheers

Ben