Painting suspension components - 2K Acrylic over Epoxy?

I asked this exact question a year or two ago, also as a complete novice, and as you might expect got a range of similar but different answers. There's no right way and everyone has their own opinion.

I was also going to start with zinc rich primer, BondaRust in my case, and this was confirmed a good idea. It's also delightfully easy to apply.

I was also going epoxy prime (not sure if you were meaning epoxy primer or epoxy mastic) due to the non-porous characteristics but was told this wasn't necessary if the top coat was right.

As you want it to be safe for home spraying I assume you're discounting typical automotive acrylic 2 pack top coat, so not sure what 2k acrylic you're referring to as I'm no paint expert. I was advised against 2 pack epoxy mastics, Jotun/POR15 etc, due to their sensitivity to prep and undercoat, and iirc they can chip and let water underneath similar to a powder coat. In the end I went with Frost Chassis Paint to overcoat and the results have been pretty good. It's a bit more a pain to use through the gun than acrylic 2k, I thinned to 15% with white spirit and use a 1.7 or 2.0 tip and as its single pack air dry I found it takes a good few days/week to fully cure even in the height of summer.

Best of luck with whatever you decide.

Interesting reading, thank you both for such comprehensive replies! Much appreciated

I may have gotten my wires crossed on the appropriate application. I had thought that Epoxy 'primer' and Epoxy 'mastic' were largely the same thing, the latter being a marketing phrase. However, on further reading, it seems the mastic may be a little thicker and tougher?

In an ideal world, I'd zinc prime (Bilt Hamber Electrox is normally my go-to) and then epoxy prime over the top. Job jobbed. However, the UV stability of the finish concerns me slightly hence why I thought I may need a 2k topcoat to finish?

I thought that 'Acrylic' versions of 2k meant no isocyanates (as opposed to solvent-based isocyanates) so safer to spray? Trade-off of being a longer drying time. I may well be mistaken!

Brushing would be ideal, just not sure my ham-fisted painting skills would look good enough so would need have some element of self-leveling . The above looks great though!

Got to be honest for chassis parts I don't think it matters. We use 2k on bodywork because you can cut it but single part synthetics are decent enough paints for suspension unless you plan to buff it up 😂.

Never used a non icocyanate 2k so cant comment but those paints are all acrylics so most people will just refer to them as 'icocyanate free' to differentiate.

Primer sounds fine to me. Zinc will give some galvanic protection. Epoxy is almost just like an extra top coat. Makes sure theres plenty of resistance to moisture ingress.

Paint is always a bit of a trade off. 2k is stronger but brittler. Synthetics are more rubbery but damage easier. You cant really win.

My understanding is the majority of 2 pack paints contain isocyanates as it is contained in the hardener rather than the paint itself. There are some non-iso hardeners around, I think generally referred to as converters or similar, which convert the acrylic from chemical dry via hardener mix to air dry. Here the trade off is the drying/curing time but take it from me, don't bother. They never seem to fully cure and don't have the hard wearing, resistant qualities of true 2 pack paint, you'd be better off with a single pack paint /enamel.

If you did want to go down the 2 pack route they are far safer to apply by brush with care than by gun as you don't have the atomised paint being able to enter via lungs/eyes/skin etc.

As you've read up epoxy primer and epoxy mastic are very different products. Epoxy primer is still very much a primer but as far as primers go has a reasonably thick build, good adhesion and best of all is non-porous. Epoxy mastic is I think designed to be a hard setting, high adhesion top coating but needs good quality prep to work well.

Don't forget to use a converter/primer (like dinitrol rc900) and cavity wax inside any boxed/reinforced sections of your components after painting. From my experience the shot blaster will be able to get more reach in these areas than your paint.

Thanks so much for all of the advice and recommendations! Love this forum!

Perhaps I need to stay away from 2K stuff. Especially if I spray it. I'm not a health and safety nutter but you only get one set of lungs and all that.

The arc-rite stuff above looks very good and interesting he mentions it's what Buzzweld is based on. I've actually used their CIO paint before, wonder if I still have the tin in the garage.

Great shout on coating the insides, I'll be sure to do that.

I think I best do a little more reading up