Which primer for 2K spray paint on steel and/or aluminium frame

[EddieV]

I've got a few components including a modified frame that I'm busy painting after stripping to bare metal.

I've used Rust-oleum etch primer on the bare metal/steel, and started with a thin coat of 2K base coat just to detect the flaws in order to fill and sand.

Should I have used a 2K epoxy/other primer on top of the etch primer as filler before the base coat. This frame was in good nick and luckily did not have many dents.

What is the difference in 2K primers - what type do I use in whichever situation?

Also, and maybe a question for my next spray attempt and other components - is there a 2K "etch" primer available in SA, or is that overkill?

Current process is:

1. Rus-oleum etch primer

(1.b  Should I rather use a epoxy 2K epoxy primer after/instead of the etch primer here?)    

2. 2K base coat (red) on specific areas - then some minor masking (light sanding)

3. 2k base coat (black) - major masking (light sanding)

4. 2k base coat (grey) - remove masking (light sanding)

5. 2k Clear coat

 

All criticism is welcome ....  

 

[stefmeister]

I'm not an expert at all, but I'd probably have gone for the etch primer first too.

Depending on how much filling/sealing the job require would determine what primer you go for next. Epoxy primer is probably not necessary for a frame.

As for spraying itself, a conventional/basic gun with 2k will probably not get you the best results. Spraying 2k isn't for amateurs, which I assume you are. A touch up gun will yield better result with a small piece like a frame. 

Lay down your primers until you have a perfect finish. Sand between coats if you have to. Then do your base colours, but be prepared for orange peel with 2k. Not sure how you'll be able to flat sand between different colours/layers, if you do end up with it.

You can get 2k in cans as well, made up in any colour/finish, that might be easier, and the less expensive route, as you'll need to account for 2k hardener and thinners, and cleaning your gun. For a small job like a frame, 2k will be quite expensive, especially with multiple colours. Think Paint Chemistry in CT can help you with 2k cans.

[EddieV]

16 minutes ago, stefmeister said:

I'm not an expert at all, but I'd probably have gone for the etch primer first too.

Depending on how much filling/sealing the job require would determine what primer you go for next. Epoxy primer is probably not necessary for a frame.

As for spraying itself, a conventional/basic gun with 2k will probably not get you the best results. Spraying 2k isn't for amateurs, which I assume you are. A touch up gun will yield better result with a small piece like a frame. 

Lay down your primers until you have a perfect finish. Sand between coats if you have to. Then do your base colours, but be prepared for orange peel with 2k. Not sure how you'll be able to flat sand between different colours/layers, if you do end up with it.

You can get 2k in cans as well, made up in any colour/finish, that might be easier, and the less expensive route, as you'll need to account for 2k hardener and thinners, and cleaning your gun. For a small job like a frame, 2k will be quite expensive, especially with multiple colours. Think Paint Chemistry in CT can help you with 2k cans.

I have done a few projects in 2K including some classic cars, but it's been a while - more than a decade ago.

I did purchase a quality lvlp gun, and touch-up gun for this project. Had to do a bit of testing before I got the right gun setup, but my last coat seemed pretty uniform.

Did the can thing on a few frames in the last couple of years but wanted a durable 2K finish and a proper setup for future projects. Happy to clean equipment, and like the idea of mixing my own colours.

 

What is the difference in primers? I can't seem to find a 2K etch primer in SA?

Will the non 2K etch primer not compromise the project by having a soft binding layer?

 

 

[stefmeister]

5 minutes ago, EddieV said:

I have done a few projects in 2K including some classic cars, but it's been a while - more than a decade ago.

I did purchase a quality lvlp gun, and touch-up gun for this project. Had to do a bit of testing before I got the right gun setup, but my last coat seemed pretty uniform.

Did the can thing on a few frames in the last couple of years but wanted a durable 2K finish and a proper setup for future projects. Happy to clean equipment, and like the idea of mixing my own colours.

 

What is the difference in primers? I can't seem to find a 2K etch primer in SA?

Will the non 2K etch primer not compromise the project by having a soft binding layer?

 

 

Best would be to go to an autobody shops and speak to them. I don't think it's the soft binding you have to worry about, it's more to do with the acid itself in the etch primer that can mess with the other layers/filler.

Etch primers do well on bare metal, and adheres well. Epoxy primers do seal better and offer better protection. You'd have to get the spec sheets and advice from the supplier to know for sure about compatibility etc.

[BogusOne]

1k etch primers are k a k.  Especially the crap you get in rattle cans. Its so thinned out and the chances of messing up your job is almost 99%. Get yourself something decent like Corrocoat 1 from Dulux. For spraying you need to thin with etch primer thinners otherwise it will just come out as cobwebs. Years ago when i used to spray aluminium trailers we used Corrocoat 2 which was a right pain in the ass to spray.... You couldnt spray it without a proper mask as the stench/chemicals was so bad you wanted to die... Imagine something close to mustard gas probably hahaha (Really good stuff but unfortunately or rather fortunately its not around anymore)

Anyway after the etch primer 1 or 2 layers of a good quality 2k filler primer, dont spray this wet or shiny. Mix 4:1 for best results. Once dry, sand this primer smooth as you can get it without going through to metal again. Normally around 600grit wet.

That should give you a good base to start the rest of your paintwork. 

[EddieV]

25 minutes ago, BogusOne said:

1k etch primers are k a k.  Especially the crap you get in rattle cans. Its so thinned out and the chances of messing up your job is almost 99%. Get yourself something decent like Corrocoat 1 from Dulux. For spraying you need to thin with etch primer thinners otherwise it will just come out as cobwebs. Years ago when i used to spray aluminium trailers we used Corrocoat 2 which was a right pain in the ass to spray.... You couldnt spray it without a proper mask as the stench/chemicals was so bad you wanted to die... Imagine something close to mustard gas probably hahaha (Really good stuff but unfortunately or rather fortunately its not around anymore)

Anyway after the etch primer 1 or 2 layers of a good quality 2k filler primer, dont spray this wet or shiny. Mix 4:1 for best results. Once dry, sand this primer smooth as you can get it without going through to metal again. Normally around 600grit wet.

That should give you a good base to start the rest of your paintwork. 

Thank you for the advise 

I saw the Corrocote 1 Metal Etch Primer when I ordered these 2 etch primers: Glaker and Supreme, but at the time they only had the 5L units for the Corrocote. I do have some etch primer thinners as well. Have you any experience with these manufacturers above? I will order the Corrocote 1 in any case.

It's early enough in the job to strip the frame again, the etch primer on there is pretty soft and came off easily when I tried to smooth out the flaws. I'd rather start from scratch. I aim to use this frame as my future road-bike, thus want to do it properly. And everything rusts to sh!t in Cape town if not done properly.

How many layers of initial etch primer should I use, or should it be very thin - just enough to make sure I cover the steel, before applying the 2K primer filler? 

 

 

[BogusOne]

4 minutes ago, EddieV said:

Thank you for the advise 

I saw the Corrocote 1 Metal Etch Primer when I ordered these 2 etch primers: Glaker and Supreme, but at the time they only had the 5L units for the Corrocote. I do have some etch primer thinners as well. Have you any experience with these manufacturers above? I will order the Corrocote 1 in any case.

It's early enough in the job to strip the frame again, the etch primer on there is pretty soft and came off easily when I tried to smooth out the flaws. I'd rather start from scratch. I aim to use this frame as my future road-bike, thus want to do it properly. And everything rusts to sh!t in Cape town if not done properly.

How many layers of initial etch primer should I use, or should it be very thin - just enough to make sure I cover the steel, before applying the 2K primer filler? 

 

 

Have seen the Supreme brand but have not used it. Dont know the other one at all. The etch primer when thinned and sprayed properly will appear almost transparent on the frame. In otherwords you shouldnt spray it like a normal primer to cover up the metal. It should basicically just do what the name says and that is to etch the metal. So 1 to 2 light fume coats on the job should be sufficient. Touch dry in about an hour and you can recoat in around 4hours.

2K Primers i use Glasurit 801-72 epoxy primer filler or another good one is PPG D8505 grey primer. Both these use hardener and should be mixed as previously mentioned 4:1 ratio.

Enjoy

[EddieV]

1 minute ago, BogusOne said:

Have seen the Supreme brand but have not used it. Dont know the other one at all. The etch primer when thinned and sprayed properly will appear almost transparent on the frame. In otherwords you shouldnt spray it like a normal primer to cover up the metal. It should basicically just do what the name says and that is to etch the metal. So 1 to 2 light fume coats on the job should be sufficient. Touch dry in about an hour and you can recoat in around 4hours.

2K Primers i use Glasurit 801-72 epoxy primer filler or another good one is PPG D8505 grey primer. Both these use hardener and should be mixed as previously mentioned 4:1 ratio.

Enjoy

Thank you so much for sharing your knowledge 

I feel much better about the project now! ????

 

[BogusOne]

7 minutes ago, EddieV said:

Thank you so much for sharing your knowledge 

I feel much better about the project now! ????

 

Anytime. Enjoy and if you need any advice feel free to ask. Always willing to assist where i can ????