Basic products/paints for starting rust repairs

[240ZBUILTBYME]

Hey Guys

Going to be starting rust repairs shortly and doing research on what products I will need. Any help or past experiences with products you enjoyed using would be appreciated. 

Based on my research to start I will need:

-A rust converter/acid etch: I’m not sure what I’m going to use on this front, options include rust blast, vht spray on rust converter, basic phosphoric acid converters, Eastwood’s rust encapsulator 

-A pre paint prep: prepsol should do the trick right? 

-A rust encapsulator/protective coating: was looking at KBS rustseal as a lot of people on the forum have used it. My issue is their 3 step process, step 1 aquaclean which I assume is a wax and grease remover, then step 2 rustblast which is a rust converter, problem is both these steps 1&2 stipulate rinsing the surface with water, this seems mind boggling to me, why would I want to soak my newly rust free internal body cavities with water!? Can anyone elaborate on using the kbs rust products?  

my other option I was interested in was Eastwood’s rust encapsulator, wire wheel as much rust as you can away, prepsol, apply a few coats and done! Is it too good to be true? I’ve seen independent YouTube tests where they use it on rusted surfaces and leave the metal in the elements for a year and it holds up well, so should hold up fine on the internals of a car that’s never going to see wet weather ever again! 

- A weld through primer: was going for Upols copper weld through primer

- A Epoxy primer- again not sure what I’ll be using, preferably something rattle can/temporary as the car still needs blasting. So just to protect the metal till the full blast and epoxy prime is done

- Internal frame coating: was going to use Eastwood’s internal frame coating with the fancy little tube

If I need something extra let me know or if there are products I’m not considering that I should be. 

 

[AndBir]

13 hours ago, 240ZBUILTBYME said:

my other option I was interested in was Eastwood’s rust encapsulator, wire wheel as much rust as you can away, prepsol, apply a few coats and done! Is it too good to be true? I’ve seen independent YouTube tests where they use it on rusted surfaces and leave the metal in the elements for a year and it holds up well, so should hold up fine on the internals of a car that’s never going to see wet weather ever again! 

I would consider the use of Cold Gal for the parts of the car body you are not going to expose to the elements.

13 hours ago, 240ZBUILTBYME said:

why would I want to soak my newly rust free internal body cavities with water!?

I would refer to a medical specialist for advice 

[gilltech]

Quote

I would consider the use of Cold Gal for the parts of the car body you are not going to expose to the elements.

As long as it doesn't also need to be decorative painted, as painting over anything zinc coated is likely to be problematic with respect to paint coating longevity.

Edited July 3, 2021 by gilltech

[240ZBUILTBYME]

Cold gal isn’t something I’ve seen used a lot online, doesn’t mean it doesn’t get used.

im more focusing on preparing a rusted surface for rust conversion and then protection against further rust. 

specific job I’m doing is removing the lower rear valance, cleaning and coating the internal section thats behind the lower rear valance panel, that it spot welds onto. That whole boxed section is pitted and rusty. 

[NickF]

Depends where rust is if in cavities use rust converter (don't worry about water use air or heat and it will dry) then you can paint with anything then use fish oil 

I've used fish oil only, just sprayed into cavities it forms a skin its messy but lasts for ages

Weld through primer good 

If you can always remove rust mechanically 

You can use etch primer rather than epoxy that will keep rust at bay till you are ready to paint

[240ZBUILTBYME]

5 minutes ago, NickF said:

Depends where rust is if in cavities use rust converter (don't worry about water use air or heat and it will dry) then you can paint with anything then use fish oil 

Ahh ok, so nick you’re saying use water to rinse them immediately dry with air/heat? That makes more sense and now seems obvious lol

[NickF]

Behind the valance is an open box section so no problem drying 

pitting can appear solid till you wire wheel then holes magically appear

good luck

[gilltech]

When using a rust converter one must follow the instructions for that particular product. Brands I've used over the years have all required washing off with water once the chemical has done its work. I then dry the metal and get an etch primer on ASAP, and preferably top coats soon follow. I believe there are other types that don't require a full clean off prior to painting but they're not for me, not for panel steel anyway.

Not wishing to handle industrial strength chemicals I just use a very mild rust converter from a general hardware store. I patiently brush it in then rinse and scrub it off several times or more as required to actually dissolve away the iron oxide as much as possible so that only a very minimal amount of converted rust - by then an inert black - if any, remains.

I've just done that to my brake booster which had surface rust on its underside thanks to a leaky master cylinder. A rigorous wire brushing followed by several rust converter and rinse applications and the rust had gone albeit leaving some light metal scarring which was ameliorated with a generous coating of etch primer before the repainting process.

Well that's my method anyway.

[AndBir]

5 hours ago, gilltech said:

as painting over anything zinc coated is likely to be problematic

AFAIK, all of the rust treatments produce a zinc phosphate coating.

Maybe you are thinking of galvanised steel that does require some type of etching/priming to get paints to adhere properly.

I would only use it on areas that are to be subsequently treated / coated with a rust preventative such as a wax / fish oil etc. such as the sills, chassis box section, bottom of doors etc.

Edited July 3, 2021 by AndBir
added txt re usage areas

[RestoZ]

OK, in for a penny in for a pound. 

I'm not going to say if this is right or wrong, but I had the need to get all my body work coated with something after having stripped my entire car using paint stripper prior to winter arriving (this year). Firstly, with paint stripper it is important to clean all exposed parts with water once stripped. That done, it was dried with compressed air. Once stripped, all exposed rusted bits were treated with a product called Exit Rust - produced by a company in Malaga WA, sold by S&S Industries in Midvale and costs about $35 for 750ml. Does what it is supposed to do and converts any rust into a black inert substance, the residue being easily cleaned off. 

Now the right or wrong bit and I'm sure there are any number of opinions which are probably both right and/or wrong. To keep my panels (surface) rust free while I get around to putting a full primer on, I've sprayed them with an etch primer (Concept Paints 103 Etch Primer). I've taken this approach because: 1. I'm doing the stripping myself and therefore that takes time; 2. I can spray panels, etc. as and when I need to; 3. On bare metal, etch primer, I am told and have no reason to doubt, provides an equal or better level of adhesion than epoxy primer; and finally, provided you have the time (which fortunately, I do - yea, I'm one of those ROF's) the cost is next to nothing compared to blasting and epoxy coating. All up it's cost me a lot of hours (which is probably a killer for a lot of people), about $200 for paint stripper, $115 for etch primer and thinners and $35 for rust treatment. Significantly less than the $2k I was quoted to have the body blasted and epoxy coated. 

Now, I'm not an expert in any of these matters, but I have sought advice from a number of people who work in the industry and got totally confused going through the many (conflicting) bits of information on the 'net, and it seems opinions vary and most agree to disagree. One of the key areas seems to be with drying times. I am once again reliably informed that provided etch primer is given time to dry (like days, not hours) then problems with laying high build primers and base and clear over the top are minimal. 

Which leads to the next step - filling. Can fill be applied over an etch primer? Well, advice I have been given is "yes" or "no" - your choice. You can sand the primer off in those places where you need to fill, or you can apply fill over the top. Once again, lots of conflicting advice, but at the end of the day seems it's a personal choice.

If you apply etch primer, you shouldn't apply an epoxy primer over the top and you shouldn't apply etch primer over the top of any fill repairs you may have done. Advice provided to me is to use a 2k acrylic urethane primer over the etch and any fill repairs and then sand and flat after that. This is based on my choice of wanting to later apply a clear over base finish.

I'm keen to hear if my proposed approach is flawed and/or if there are potential problems that I haven't been advised of that people have experienced. Better to find out now than after I've applied the final clear coat. 

Sorry Ryan, I guess the short answer to your original question is hit it with an etch primer.  

I'll wait for the tsunami. 

Cheers

Paul

 

Edited July 3, 2021 by RestoZ

[NickF]

Pretty much my approach only I would go back to bare metal for any filler

Think your scheme is a solid way for a home job

[C.A.R.]

[gilltech]

Quote

AFAIK, all of the rust treatments produce a zinc phosphate coating.

There are numerous products on the market. I don't use 'treatments' unless they are converters that will act as rust removers. To dissolve away rust and leave me with clean bare steel, ready for etch primer. There's no zinc, any residue is iron phosphate. In fact they will react with and begin to dissolve any zinc they encounter.

Painting over zinc is always problematic. If I must do, then I make sure the zinc is fresh, or if old zinc then any oxidation has been removed first, as it's not a good idea to paint over oxidised zinc. Ask any paint manufacturer. Then I will quickly follow up with a very good quality etch primer.

My 2c worth anyway.

Edited July 4, 2021 by gilltech

[AndBir]

I am sure we all would like our cars to have the rust protection that is present on todays vehicles, so maybe an understanding of todays car manufacturer paint process would help. Of course this is just based on Google searches and not first hand industry experience.

History of Protecting the Automotive Body (https://www.paint.org/coatingstech-magazine/articles/brief-history-automotive-coatings-technology/)
Topcoat technology was steadily improving for automotive coatings systems, but cars still had a major issue—rusting of the automotive body. A major coatings advance in the 1970s resolved this issue: electrodeposition primers, commonly known as “e-coat.” The first automotive electrocoat was an anodic product developed by Dr. George Brewer at Ford around 1957. However, there were drawbacks in the technology and PPG Industries introduced the first cathodic e-coat system for automotive bodies in 1973. Because these coatings essentially stop the automotive body from rusting, this new primer technology one was of the biggest breakthroughs in automotive coatings technology.

Modern electrocoat automotive primers are applied by totally submerging the assembled car body in a large tank that contains the waterborne e-coat, and the coating is applied through cathodic eletrodeposition. This assures nearly 100% coverage of all metal surfaces by the primer. The coating chemistry is waterborne enamel based on epoxy, an aminoalcohol adduct, and blocked isocyanate, which all crosslink on baking to form an epoxy-urethane resin system. This resin technology, combined with the excellent coverage provided by electrodeposition, delivers one of the most effective coatings for corrosion protection known. Virtually all cars use e-coat technology as the foundation of their coating system today.

Process Overview    :   (http://www.ppgecoat.com/Process.aspx)
The electrocoat process can be divided into four distinct sections:
Pretreatment: Parts are cleaned and pretreated with a conversion coating to prepare the part for electrocoating.
Electrocoat Tank: Direct current is applied between the parts and a "counter" electrode. Paint is attracted by the electric field to the part where it is deposited.
Post Rinses: Parts are rinsed to reclaim undeposited paint solids.
Bake Oven: Paint is thermally cross-linked or cured.

Pretreatment Process for Electrocoat Paint Application     :    (http://www.ppgecoat.com/Process/Pretreatment.aspx)
In the pretreatment process, metal surfaces are cleaned and prepared for electrocoat paint application. Oils and other contaminants are removed from the part. Existing rust spots may be removed and a phosphate or conversion coating is applied. The pretreatment process is necessary to improve electrocoat performance, ensure a high quality electrocoat finish and to keep the paint bath clean of unwanted contaminants. The number and type of pretreatment stages depends greatly on the type and condition of metal being introduced to the system. It also depends on the part configuration and the overall performance requirements of the phosphate or conversion coating.
 
Zinc and iron phosphates are the most widely used conversion coatings in the electrocoat industry. Zinc phosphate is the preferred pretreatment choice in the electrocoat industry because it provides the best corrosion resistance and paint adhesion..

So, if this theory is still valid for manual (spray/brush) application of primer then repairs/repainting should involve:

1) Manual removal of coatings (rust/paint) down to freshest possible bare metal

2) Clean all surfaces with your preferred degreaser 

3) Apply your preferred surface treatment to produce a zinc phosphate coating on the metal

4) Apply your preferred sealer coat (for non exposed area KBS Rust Seal seems to be a good option with atmospheric cured resins).

 

Edited July 4, 2021 by AndBir
changed top coat to sealer coat

[gilltech]

Agreed that metal treatment and automotive repair products are improving all the time and becoming more environmentally friendly. Most important is to ensure that all selected products - be they metal treatments, body fillers, sealers and all coatings - are compatible. This I know, having seen issues belatedly arise with older and not so old restorations.

You must do your own research on the products you think to use.

I've often seen difficulties with product adhesion on steelwork so for my purposes I prefer completely clean steel and have the zinc in the protective etch primer as part of the overall selected paint system. To each his own. Agreed though, need the zinc.

But whatever systems car restorers choose to use these days they will undoubtedly be a vast improvement over factory practices of the past and old restorations and probably preserve the cars well past their own lifetimes.

 

Edited July 4, 2021 by gilltech
typo, improved grammar

[AndBir]

1 hour ago, gilltech said:

You must do your own research on the products you think to use.

100% agree, there is so much conflicting or more accurately confusing information for people who have not done this sort of thing before and probably never will again :-)

[RestoZ]

1 hour ago, gilltech said:

Most important is to ensure that all selected products - be they metal treatments, body fillers, sealers and all coatings - are compatible. This I know, having seen issues belatedly arise with older and not so old restorations.

 

Totally agree. Again, based on my research/questioning/confusion it seems compatibility is a key issue and the advice I've received has been to use, wherever possible, one supplier for all levels of filler, primer, base and clear and top coats.

[AndBir]

Just to add to the mix of info : https://www.whichcar.com.au/features/car-paint-preparation

 

[kamarchi]

"I don't use 'treatments' unless they are converters that will act as rust removers. To dissolve away rust and leave me with clean bare steel, ready for etch primer."

What do you use?

Edited July 6, 2021 by kamarchi

[240ZBUILTBYME]

13 hours ago, AndBir said:

Just to add to the mix of info : https://www.whichcar.com.au/features/car-paint-preparation

 

Well I think there’s some great discussion going on in this thread. And in accordance with what I’ve researched on the inter webs, a lot of different opinions with no one clear and defining truth lol

Andy this is a great article by a guy who has and does amazing paintwork. To be honest is in line with what I’ve been told and learnt in my dads paint shop. 

so I did a year or so of full time work in my dads panel and paint shop when I was 17 out of high school. Unfortunately there was not a great deal of education that went on from my dad, I think because my dad didn’t want me to be a panel beater/spray painter, so he didn’t want to fan any flames of interest. So suffice to say I learnt how to sand things, I mainly did guide coat sanding on primers, they couldn’t afford to let a 17 year old do any painting or finish work on color coats. We only used epoxy primers. 

I’ve spoken to my dad about this subject and he has his own opinions, reason I don’t take his knowledge as gospel is the fact that technology changes and he may not have the up to date knowledge, he’s been out of the auto paint game for 10 years now.

what I’ve never understood is why anyone would use etch primers anymore? Due to the extra work that comes with filling panels etc. epoxy primers go on bare metal, accept body filler, can go over body filler. No compatibility issues. And Epoxy is more resistant to absorbing moisture. So why go etch? Can someone shed some light on this?

all professional restoration shops I’ve talked to recommend epoxy primer. 

[NickF]

"all professional restoration shops I’ve talked to recommend epoxy primer." 

I think professional is what's important, if you are doing the work yourself and don't have full respiratory equipment and a booth then epoxy most probably is not 

the best option .

Ready to be corrected 

[NickF]

Over the years I've  done  8 bare metal resprays all using grey primer and top coat, they mostly look great just from the gun and even better when cut back and polished the finish lasted as long as I owned them.

The last, my daily driver 1962 EK ute was painted the same way 20 years ago, grey primer and top coat and the finish is great still.

So I guess any of the prep coats and finishes should give even better results

[240ZBUILTBYME]

4 minutes ago, NickF said:

Over the years I've  done  8 bare metal resprays all using grey primer and top coat, they mostly look great just from the gun and even better when cut back and polished the finish lasted as long as I owned them.

The last, my daily driver 1962 EK ute was painted the same way 20 years ago, grey primer and top coat and the finish is great still.

So I guess any of the prep coats and finishes should give even better results

Specifically what type of primer? Etch or epoxy? I assume you mean etch? 

[240ZBUILTBYME]

42 minutes ago, NickF said:

"all professional restoration shops I’ve talked to recommend epoxy primer." 

I think professional is what's important, if you are doing the work yourself and don't have full respiratory equipment and a booth then epoxy most probably is not 

the best option .

Ready to be corrected 

For what reason is it only a professional product? I’m assuming you mean for health risks of breathing in 2k products? 

so if you had the correct respiratory equipment and a make shift booth it would be an acceptable option? 

[NickF]

I don't know if it was either maybe acrylic primer, just went in and asked for 4lt primer dint seem to be a choice !