underbody & suspension treatments

[wibble_puppy]

hi everyone,

an old chestnut but brought back to the top of my mind both by the need to finish sorting out the undercarriage of my van and by this month's Practical Classics product test of "underbody coatings"

everyone who has had a classic for any length of time has their own favourite tried-n-trusted method of protecting the underside and I wondered what a little poll would reveal

if you haven't seen this latest Prat Class feature then I recommend it, it's a bit of an eye-opener - and a bit controversial

wibble

[alex_holden]

I wanted to select both paint and wax.

[dunketh]

I use Waxoyl underbody treatment which isnt quite the same stuff as waxoyl spray. Its like tar in a tin.
I'd recommend it wholeheartedly. Its been fully tested over time. I've actually seen panels rust that weren't treated on the same car as panels that are solid that were.

I've used it on all my cars, Minis, countless mk1 & 2 Fiestas (and they rust more than anything!) and the Morris.

Only gripe is its not that tough, it seems to need recoating every 12 months, or at least touching up in places.
One good thing though, you can simply wipe it off 'good' bodywork with a rag soaked in spirit or WD40.

(btw, I have tried 'stone chip' shield, normal clear waxoyl, hammerite and jenolite metal paints and none have been as good)

[Willie]

In the old days you would buy a new car and within a few years it would not be unusual for the sills etc to start rusting through from the inside.
The only reason that this does not apply nowadays is that cars have their sill and box members sprayed internally with a wax based compound from new. Wax is the answer but it needs to be tougher for exposed underbody areas which are subject to being sprayed or blasted
by the muck thrown up by the wheels.

[gairlochrosie]

I selected Paint...but I do wax the underbody...so wax/paint for me.

[Innovator]

Sand blast, de dust, chemical etch prime then stonechip and paint on top.

Wax in the cavities.

[chickenjohn]

Zinc prime, chassis black, then underbody wax- I use either waxoyl or the dinitrol as used in the test.

Having read the article (I don;t usually buy practical classics these days as the magazine is not as good as it was) I might also use epoxy mastic or stone chip coating between zinc primer and chassis black.

The main worry with "schultz's /schutz" is that you cannot see whats going on underneath- we've all seen thick underbody coatings hiding spreading rust.

[RogerRust]

How about a catagory for

"I don't take it out in the rain"

[minor_hickup]

I usually go for getting it clean with an angle grinder and knotted brush, then 2 coats of red oxide, two coats of black, then undercoat.

[picky]

Ive started using "electrox" paint, it is recommended for offshore piers and underwater structures etc so i reckon it should cope well underneath a car. It also has the advantage that if the paint is scratched then the metal along the scratch wont rust, clever stuff

[wibble_puppy]

picky is that the Bilt-Hamber stuff? very new? It was included in the PC tests, and I think I'll be trying it out meself

[picky]

yes that is correct wibble, I read about it in practical classics. you cant get it online you can only buy it over the phone the number is 01277 658899. They said that a 1 litre can (the only size you can buy) will cover 8 to 10 square metres. £25 including postage. If it works how it says it does then it should be very good but ive only had it on my car for two days...

[wibble_puppy]

was it fiddly to apply? there seem to be a couple (at least) of different tins you have to mix together and you have to apply it in a certain way... fiddly?

[picky]

it is only a single tin of paint, although they do stress it needs to be mixed before using it and during use to stop it seperating. no mixing together or different tins, u must be thinking of something else

also u applied it with a paint brush, it can be sprayed on if you want, but u will need a spray gun as you cant buy it in pressurized can.

[wibble_puppy]

oooh yes you're right, I was thinking about Rustbuster's Epoxy 121 - I liked the sound of that one in terms of rustproofing (unbeaten in two PC tests) but the two-tin thingy sounds a bit of a hassle.

Brush is fine..... I have no compressor so it's either brush or spray can for me and spray cans are naughty aren't they

[picky]

you can get quite a smooth finish with a brush if you sand it afterwards. I am painting the entire engine bay area so i need a smooth finish. if you are doing sills or whatever a brush may be better so you can get into all the gaps etc.

[wibble_puppy]

yeah I'll be doing wheel arches, underneath, stuff like that. invisible and highly cherished

[picky]

the only issue i can think of when using electrox as oppose to other paints is that it protects the metal electrically. This is a huge advantage for small scratches/areas of developing rust, as the rust will not develop any firther.But if you have two seperate areas of rust and you only treat one of them with electrox, I think the paint will attempt to protect both areas, and will rapidly corrode and then no longer protect at all.

[chickenjohn]

Whats in eletrox?? It can't be magic, so its probably just a 90% zinc primer as zinc sets up an electrolytic cell that protects the steel.

You can get a 90% zinc primer much cheaper than £25 a litre.

[chickenjohn]

"Electrox

Electrox is a unique zinc-rich coating that protects steel from corrosion by both barrier and electrical functionality.  Coating steel with Electrox produces a surface film containing over 90% metallic zinc, "

try your local paint factor or ESM for the unidox primer as thats also 90% zinc rich. and about £13 per litre from local paint factors.