Just thought I'd throw some pics on here, as you all know the underneath of my car is very white, but my lovely RCM system was looking abit tatty and shabby comopared to the rest, which in no way of course detracted from the fact it's beautifully made.
A lad on the P1woc who knows a thing or two about metals ... he is basically a freak in the metal department offered to gove it a spruse up.
This consists of shot blast and then acid etch it , which would leave it a nice bright matt silver finish and would stop surface rust and attack from road salt as I would finish it with a coat of phosphoric acid which will leave a passive film of protection on the surface.
Before pics:
After pics: These items are not finished yet but you get the idea, James over on the P1woc has worked hard on these and given up his own time aswel. It's a great community spirit within these Subaru forums
, something of which I have yet to experience on any other forum.
The way James has treated this means that it will now build up its own passive layer and will not rust, even though it is a stainless system the welding destroys the original passive film layer and then it's a downwards spiral.
The silencers meant he could not immersion dip the sections for fear of damaging the baffle plates. Decided against shot blasting and went with a more aggressive blend of acids. After meticulous prep work (pieces have to be spotlessly clean, no oil or grease allowed) the acid solution is hand painted onto the pipework which etches the damaged surface of the steel away leaving the clean material beneath. This is left to cure, rinsed off, and then bathed in deionised water before being left to dry naturally for 24 hours or so. This allows the material to form a passive (chromium oxide) layer over itself which will act as a very effective barrier against the elements.
As I've said to Kris, even RCM systems will rust unless treated properly. The passive layer is damaged by welding, iron particles and other contaminants are then trapped in weld pools which will turn into iron oxide and rust - stainless or not. Given time, this would blow through. This photo shows that quite well: