2 weeks with the MX5 Restorers booked in March 2022. Rear subframe coming out for a sandblast and repaint.
Originally thinking of powder coating, but POR 15 has been suggested.
Any opinions/experience?
I have used POR15 on some of my Kit Car parts in the past, my experience is that it’s brilliant stuff, mega tough, mega expensive, a pain to paint on but does what it says on the tin.
If you do use POR15 … READ THE INSTRUCTIONS CAREFULLY and follow what they say!
Also I suggest you wear 2 lots of rubber gloves! … if you get it on your skin and it goes off it wears off over about 3 weeks, you cannot remove it from your hands!
Roy
I’ve always had my underside parts powder coated
My current plan is to get front and rear subframe a and all arms then just throw the whole pile at a powder coater and hope for a good deal (after giving them all a dunk in the acid bath at work to hopefully save a few pennies)
I’ve never used por15 but it sounds messy, I like seeing bits of colour when you look in behind wheels and grills and stuff so I’ll probably just get it all done gold as per usual
Powder coating was my “go-to” thought, however does it have a weakness that it’s brittle and will crack if stones are thrown up at it…then flake off once water, salt, mud etc gets underneath?
That’s the reason i always went powder coating over paint, not had any problems like that with well coated parts
Simple choice in my view …
Tough or Pretty?
If I want already surface rusted parts rust proofed and long lasting then the best I’ve used is Por15 rust proofing paint with their top coat on top. A bit of graft to do properly but done once to last.
Powder Coat is very good with better finish.
Why not try and test in severe salty weather both options on some small parts then choose.
Your call.
Roy
I think you’ve hit the nail on the head, Roy. …tough or pretty.
Some like to show you that you can eat your dinner off the underside of their car, some are happy with strong and practical. Each to their own objectives of MX5 ownership.
Tizzy will never be pretty, but I expect her to be tough and fast.
Lewigie,
If you are going to MX5 Restorer I would lean on their advice, they undersealed and cavity waxed my car, or have they recommended POR15?
Also you will find it very tricky to get POR15 inside the box areas of the subframe.
I have used Bilt Hamber Cavity Wax in the past for treating inside box sections whilst using POR15 on the outside, cars typically rot from inside out.
If you use POR15, buy several cheap brushes rather than try to clean, although I have had some success cleaning brushes with Cellulose Thinners but if the POR15 starts to cure nothing will touch it.
Roy
Roy
Hi Roy,
They recommended the the standard strip back, seal and wax treatment (with a little more attention around some of the seams and replacement of my bracing) and in addition, I wanted the rear subframe dropped, blasted and powder coated (and a few other jobs) for which Garath gave me a suitable quote for. When chatting to them to make the booking, it was suggested that powder coating might be brittle, whereas POR 15 would do a solid job. I’m realising it will probably = “more expensive” but as I have no previous experience of POR 15 I thought I’d ask for opinions here. I think I’ve made my mind up already, unless it costs considerably more than powder coating.
I did my rear subframe and arms with POR15 but used Bilt Hamber products to remove all the crud first.
Have a skim down my photos here https://photos.app.goo.gl/sBbFiB7U5fUYha9D7
I’m on my phone but will upload proper pictures later.
I finished by cavity waxing inside the subframe with bilt hamber dynax.
Proper job but no cheaper than just handing the whole lot to my local powder coater. I nearly bit off more than I could chew and ended up with the car in bits for 4 years!
Some embedded pics:
Subframe wire brushed - quite the mess for a 41k mile garage queen!
After a couple of days in the BIlt Hamber solution - you can see that we’ve part failed paint. It wasnt good enough to paint over and needed stripped right back:
So… gel paint stripper… and lots MORE time…
Bare metal at last and NO pitting or damage. I got it all in time
Now I did the 3 stage POR15 - Marine Clean, etch, paint.
The problem then is… where do you stop! Its pulled apart, so I did bushes, new bolts all over, new coil overs… chassis rails… etc etc… cost me a clean fortune but was worth it.
I was reminded of something mentioned elsewhere a few weeks ago. …
I follow a Youtube channel called HubNut, aka Ian Seabrook. In this specific video, he was referring to UPOL Raptor on his 2CV. As I read your original post, I mis-remembered UPOL as POR 15. Personally, I wouldn’t powdercoat, it doesn’t self heal in the event of stones thrown up. I don’t have any experience of POR15.
Nevertheless, you might be interested to watch the video.
I use wax.
As others have said it’s pretty or tough 
powder coat or stove enamel looks lovely and does last but usually you want to overcoat it with a sacrificial wax or something.
I’ve had mixed results with POR15 and the requirements of the prep made it tricky on all but blasted metal. I’ve used it on beetle floor pans.
I found epoxy mastic to be excellent all round, very protective tough and resistant and can be used on wire brushed clean metal. It’s abit more tolerant as to prep conditions. Gives a satin black finish which ideal underneath. You can overcoat with body paint or stonechip like raptor
Looks tidy the job youve done, money well spent!
Interesting Montana, did you use POR15 Rust Preventative Paint or the POR15 topcoat?
My experience has been with POR15 Rust Preventative Paint. The main issue I found with the POR15 Rust Preventative Paint is that UV light turns it a tad grey, I don’t think this matters other than appearence though, alternatively it can be over painted with POR15 Top Coat which I chose to do sometimes but I understand it is not a requirement if the UV light effect does not matter.
The Rust preventative Paint can be used on rusty surfaces or old paint etc. I just wire brused and sometimes sanded, the toughest results I had was on rusty surfaces just wire brushed.
Roy
Hi Roy,
It was a while ago I used it but I used the full system including their degreaser and prep solution. It was on a full restoration so used their top coat too.
A lot of the underbody paints seem to suffer with UV degradation as they don’t have the same pigments as top coat but often restorers will use 2k gloss or base coat and clear coat over the top if the visuals of the under side are important.
Retro power have a system in which they zinc spray, epoxy prime, seam seal and overcoat with raptor and then body colour if necessary. They say this resists over 3000 hours of salt spray testing.
I don’t like por15 as it encapsulates the metal but offers no protection beyond that. I don’t like power coat as I can’t see what the blaster has done before coating. I may be fine if I trust the blaster. There may again be little protection. I used the Bilt Hamber system which is blast, de grease, hydrate 80 to kill off anything left on the surface or in seams, electrox zinc rich primer, 2x 2k chassis paint and satin top coat.
