Rebuilding subframes

[rpb203]

I am certain that this has been discussed before but cannot find the link.
What is the general consensus on rebuilding subframes, front and rear.
Blast back to bare metal and then powder coat or paint?
If paint what is the generally considered best paint?

Thanks in advance.
Cheers
Gary

[MiNiKiN]

I avoid powder coating, as I don't trust it to stay flexible over the years of environmental impact. Secondly, how would it get into all those tiny corners and cavities in particular?
Hence I prefer and use Hammerite (diluted for said cavities and corners) - and to play safe I additionaly cover everything in a layer of "Fluid Film".

I assume a dipping bath to be best but my tub isn't big enough

[Aginley]

Powder coat satin black every time for me.. with a good blasting then a anti corrosion coat on before powder coating. Not cheap though. Just had 4 done and they cost £100 each to do.

[mk1]

I have done both. The key to longevity is to wax the finished item to within an inch of it's life.

I think that generally speaking powder coat looks better & if applied correctly can last a long time. Paint although never looking as good as powder coat is generally speaking more durable in the longer term.

Once rot gets under powder coat it seems to run wild, where as this doesn't happen as badly with paint. I suspect it is something to do with moisture being held in the gap between the PC & the metal substrate, where as paint allows this moisture to evaporate off harmlessly.

In truth I suspect that there isn't a "correct" answer & it's a horses for courses job.

[GraemeC]

Powder coat looks great, but I wouldn't do it on a car that is going to get serious use - as Mark says, once moisture gets in (through the tiniest crack) it just start to lift in sheets. Powder coat never really bonds with the substrate like paint. Great for a show car or fine weather toy though.

As for which paint - any good 2 pack epoxy based one should do the job. Personally I wouldn't go near Hammerite anymore - its just not what it was and is now trading purely on its name rather than results. I've had very good results with this stuff:
https://www.rust.co.uk/product/cat/em-1 ... is-paint-7

[kit of bits]

I’m not a power coat fan, I always blast and paint PPG selemix satin black..
It looks the part and lasts really well..
D

[rpb203]

Thanks All,
Really appreciate thoughts, have been down the route of powder coat before and wasn’t super impressed and did have issues with moisture tracking under the coat.

Think that blasting and painting is likely to be the way to go for me based on the above.
Thanks again.
Regards
Gary

[Spider]

I've been having them blasted and then paint them in POR15. It doesn't look original but is extraordinarily hard wearing.

I too wouldn't Powder Coat. It looks good when done, but the smallest chip or pin hole, water gets in and the Powder Coating just holds it all in like a plastic bag compounding the rust problem.

[Gray]

I had mine blasted then hot zinc sprayed they then sat outside without anything else for about 8yrs and not a spot of rust on them I just gave them a coat of satin 2k. Gray

[mini_surfari]

I’m not a power coat fan, I always blast and paint PPG selemix satin black..
It looks the part and lasts really well..
D

Does this go straight on to bare metal like epoxy? Or does it need a primer first?

[kit of bits]

I like to each prime, people do use it directly.
D

[Fanfaniracing]

I powder coat all subframes on every build.

Never had any issue over the years.

like Mark said before, its very important that the Subframe is filled with anti corrosive fluid.

I use the Mike Sanders anti-corrosive Grease. It has to be heated up to 90°C then applied with a Gun and it goes in all possible and impossible corners.

[Craig]

My experience with powder coating is it peels off over time only to leave lots of rust underneath .
Admittedly this was on a car that I used all year long , and for many years. ....

Now I epoxy prime and top coat with epoxy.

I hear good results over here regarding POR15
Might give it a try next time .

Craig

[Bitsilly]

I have never had the chance to use POR5 on a mini, but I used it on another car and it was excellent.

[Highnumbers]

I think that powdercoating developed a bad reputation years ago for failing and trapping moisture.

But modern powdercoating systems are drastically better than they used to be, and are widely used in the automotive industry for the durable finish.

The moisture concerns could certainly depend on your location as well. Here in California, I don't worry about rust too much so no need to plan ahead for it. Powdercoat is an effective long-term finish solution, cost effective and looks great as well.

[Andrew1967]

I've powder coated my subframes for the first time, I usually use a chassis black. Time will tell how it lasts but the car wont get much use anyway. PC was £60 inc. blasting for each frame.

If painting, I would now 2k epoxy then high build (if necessary) and then 2k black.

I opted for gloss black PC for the frames and 2K gloss for the running gear. Might use satin on the next project though.

[woodypup59]

I find Hammerite - or Smoothrite - is brittle and chips off easily. Also its not petrol proof.

I prefer two pack epoxy black. Its rather shiny but hard as nails.

[DUF2 ‘65 Elf]

Powder coat satin black every time for me.. with a good blasting then a anti corrosion coat on before powder coating. Not cheap though. Just had 4 done and they cost £100 each to do.

Happy birthday Alastair.

2DCDB64D-3218-47BF-918D-2B3467E7E146.jpeg

[Daz1968]

I had mine blasted, then zinc powder coated and topped off with gloss black, also about £100 a frame but came out very good, only issue was some blast media left in a few places so blew it out with an airline, then put anti rust coating inside enclosed sections, hopefully last a while.

[Peter Laidler]

I had virtually everything black bead blasted and nylon powder coated on my S including the sub frames and....., well....., every fixture and fitting that was black plus the same to my old 750 and 850 Commando and MGB GT V8 (but plenty of colour there I hasten to add), Include silver wheels too. Done in 1986 or so and still going strong. Oven bake nylon coat as opposed to paint I say. The problem with nylon is that there's no anti corrosion coat. Just a flash over with a wishy-washy solvent called RILPRIM (rilsanisation primer?) then nylon powder. Baked on and it's as tough as old boots, adheres like shi......., er..... mud to a blanket and ain't chipped or broken away anywhere since. Steve Smith had the same done to his (now stolen) antelope Mk2S. Done by ATOChem (Aquitane Total Organico), part of ATO Chem/Total petroleum who were based at Colthrop Mills in Thatcham.

This process was used to nylon coat the fixtures, hand rails, hand holds and fittings on the trains and buses

Old thread, but just sayin'