Underseal and Corrosion removal/Protection

[griffsplace]

After being somewhat disappointed about the state of the underneath of my Supra and wanting to make it last another few years, last winter i set off to clean it up and treat it, rear end first. Having read that nearly every product is rubbish or completely brilliant depending on who you listened to.

 

I though it would be good to have a thread where like-minded people who have done this can report back on any pros and cons, and update on any degradation over time.

 

I opted for:

 

Body

Strip back to bare metal where possible

POR-15 3 stage (degrease, metal prep, 2 coats of clear)

Hammerite Stonechip

ABRO rubberized undercoat for the inside of the wheel arches.

 

Small clips fittings etc just had black smooth hammerite spray, or silver hammer finish over the POR-15

 

Cavities injected with Dinitrol 3125

 

So far its still on axle stands in the garage, but i have noticed, as i begin reassembling that there seems to be very poor adhesion between the por15 and the undercoat which is very disappointing, but i am just going to live with it.

[Annabella]

[rider]

I only completed my Supra rear end underside project 18 months ago so it might be a little soon to comment on durability but the parts treated and coated in POR paint then top coated in acrylic are all good. I still have some bits to tackle like the bit in the middle running between the sills and the tunnel which is where undersealed has been applied in the past and as that is lifting little by little then surface rust is usually exposed. I'm just sanding these little imperfections, treating, applying zinc primer and top coat black acrylic painting the imperfections as they show themselves. I have the car on my ramp a couple of times a year so as things become evident they get tackled. The good thing about having spent well over 100 hours on the underside is that now the inspection leads more to a wash down with a damp cloth to get the surface dirt and dust off those nice new parts than it does tackling rust.

 

With the POR adhesion a lot may come down to the prep work, I've seen videos were people complain they have applied POR straight onto rust and its lifted a few years later. I did a lot of sanding and chemical treatment before applying the POR and only time will tell whether that helps with the POR adhesion over time. You mention poor adhesion to the undercoat of the POR paint. Is that correct as the POR is designed to be applied directly to the metal surface or treated surface? The POR dries to an aerated plastic film which is impervious to air and moisture from what I've seen and dissected from the dried drip runs I removed, so the POR paint probably prefers a rough surface to adhere to over a smooth surface.

[Scooter]

I think the OP is talking about adhesion between the 'undercoat' ABRO stuff which has been applied 'over' the POR15 which I 'think' has adhered well?

[griffsplace]

I think the OP is talking about adhesion between the 'undercoat' ABRO stuff which has been applied 'over' the POR15 which I 'think' has adhered well?

 

I am totally happy with the POR15, i did meticulously follow the instructions for prepping prior to application so i am hoping that at least the base layer is fine. It is the hammerite stonechip that i sprayed over the top seems to come off too easily where I am bolting things back together on top of it.

[Burna]

Two years on and mine is perfect

 

http://www.mkivsupra.net/vbb/showthread.php?343109-Burna-s-UK-Spec-Restoration

[rider]

I am totally happy with the POR15, i did meticulously follow the instructions for prepping prior to application so i am hoping that at least the base layer is fine. It is the hammerite stonechip that i sprayed over the top seems to come off too easily where I am bolting things back together on top of it.

 

I sprayed black matt and black gloss acrylic over the silver POR15 and that adheres fine. So you can buy a can of Simonize spray paint to cover over any parts where the Hammerite flakes off.