Amazon: Under car rust proofing

[Sonobeno]

Hi,

Looking to drive the 66 Amazon through the winter and looks like its the time to get a proper under car rust proofing. As far I can tell from its history, this has never been done before, but the under car is solid.
Do you guys have any experience/recommendations for this?

-Dinitrol versus Waxoyl?

-Recommendable shop around London, but OK for general UK?

-Price expectations?

Thanks!

[Triple-S]

This was in the 240 section a few months back.


An interesting comparison of anti-corrosion treatments.

However - there's a few aspects to this test which raise questions:
* The winner of the test was Bilt Hamber Dynax S50 - BUT - although the test was performed by Dr Phil Green at the University of Hertfordshire, the test was done FOR Bilt Hamber Ltd, and these results are published on their website. Might this influence the results?
* And the Dinitrol product used was 3125HS - this is a product for old metal, with 'high levels of corrosion inhibitors'. Because the test used fresh pieces of unrusted metal, why didn't they use Dinitrol 3650, designed for this task?
* This test doesn't explore the penetrative ability of any of the products (eg to get into seams etc.)

Like any car of the vintage of a Volvo 240, arguably the most important features needed here - other than longevity - are penetrative properties, as well as the ability to slow existing rust. (And the test proves neither).

Looking on ebay...
Here's a price comparison (in order of the test results):

Dynax S50
5ltr £49.68 incl p&p (in plastic bottle)
750ml aerosol £17.90 incl p&p

Auson Noxudol 700
1ltr £19.99 incl p&p (needs sprayer)

Rustbuster
Couldn't find anything on ebay

Dinitrol 3125
2 x 500ml aerosol £25.95
4 x 1ltr £48.96 (needs sprayer)

Hammerite Waxoyl
5ltr £26.50 incl p&p (needs decanting into sprayer unit)

Conclusion? The Dynax S50 is good value - so if it's the best product as well then brilliant it's the one to go for. But if the Dinitrol 3125 is known to be a good product on older cars, and people here vouch for it, then, maybe it's the best choice. Auson Noxudol 700 clearly performs very well, but is twice the price.

Has anyone used Dynax S50 on an older car?

For me, although I have this Waxoyl, I have decided to do the sills and chassis rails with either Dinitrol 3125 or Dynax S50.

Any further opinions?
John


P

[Billy Smalls]

I believe there is a school of thought that says - why cover it up? leave it painted and don't worry about what's going on under the underseal....

....awaits a barrage of abuse!

[Triple-S]

Certainly no abuse from me, Billy. When I was refitting a rear wheel onto my 144 this morning after drilling mudflap bracket attachment holes I debated with myself exactly what I should do with the huge amounts of underseal larupped under my car by the previous owner. When digging for a surface to bolt bracket in place I picked huge hunks off - and the metal was going rusty underneath in places. I foresee a large bill to remove it all, attack the trapped rust then refinish with one of the above I listed earlier.
However, unless your car is a show-car being readied for an appearance at the hugely glitzy NEC (where shine is the rule) I wouldn't leave ones underside just wearing paint - it won't last any time being pummeled with road grit. That's why I'm putting mudflaps back on mine - they probably came with them so why remove them?

P

[Faust]

I refuse to have waxoyl anywhere near my cars… many years ago I used the stuff on a Capri. Then I got a massive welding bill! The waxoyl had 'lifted' and let water underneath where it rotted the metal out behind the so-called 'protection' of the coating.

I was NOT pleased.

I've used Dynax S50 in the box sections, door bottoms, inner sills etc. on my Amazon, and Bilt Hamber UB (underseal) for the floor pans, wheel arches and anywhere else subject to attack from road debris. They also do a clear version of UB so you can have nice painted floors AND keep an eye on the metal at the same time… clever stuff. The long lance (about 2 foot in length) the aerosol cans comes with really makes sure you can get wax into all those nooks and crannies that you can't normally reach.

I like the way that Dynax creeps into welded joins and that it is self-healing… tried this myself on a test piece of metal: if you scratch it, it 'heals' itself within a few hours and the scratch is gone! I was most impressed.

I've heard very good things about Ditrinol also, and I would certainly give it a go, but I went for the BH stuff for my car…

As far as application goes, I wouldn't want a company to treat my car. As it's such an important job I'd rather do it myself. The local restoration company I've just got my car back from let me use their ramps to underseal my car. Filthy job but very satisfying to do. Always worth asking a local garage if you can 'borrow' one of their ramps during a quiet period (offer to make a donation to the mechanics beer fund). Jet wash the underside of the car first and make sure it's properly dry before you start. If you can't find a ramp, get your car in the air, wheels off, cover your drive/the road (and brakes!) and get working.

I use my Amazon all year 'round… just spent a fair bit on the restoration so I wanted to make damn sure the rust protection was properly done.

[Derek UK]

Fancy a trip? http://www.jrclassics.co.uk/index.html

Apparently the London Black Cabs are Dinitrol treated from new and should have it topped up every few years. Owner drivers who are keen enough to do this might be able to tell you where they get the rewaxing done. Ask around maybe.

[Burdekin]

Dinitrol underbody wax for outside areas etc and Dinitrol cavity wax for inside chassis rails, make sure you cover all areas when sprayed inside chassis rails.

[paul staines]

Originally Posted by Billy Smalls

I believe there is a school of thought that says - why cover it up? leave it painted and don't worry about what's going on under the underseal....

....awaits a barrage of abuse!

No abuse from me. My 66 P1800S spent all it`s life on the isle of wight. The chassis was rock solid having had many coats of various underseals applied over the years. After much prodding and poking we decided to inject wax oil into the chassis and coat everything with stonechip. The inside wings also rust free so coated with wax oil and fitted Locari aluminium wheel arch liners.
The only rust we could find on the car was the bar under the radiator. this had been replaced with a new one at some point but it looked a bit feeble so we replaced it with much heavier steel section. Also rust on the door bottoms. 2new door skins fitted and wax oiled. regards Paul

[grantbennett2]

I used Dinitrol underbody wax and cavity wax and ten years on all is good. I would never paint on an underbody sealant (hard type). My rear doors were in very bad condition and after repair I sprayed so much dinitrol into them that even now on a hot day the smell of the wax is strong.

[Palmer 221]

Glad to here you want to run through the winter.
I think the preparation is almost as or more important then the product.
When i had the gearbox, prop and exhaust off, I found a few places that needed re-coated of zinc primer then over it all with Dinitrol.