Dedications what you need

[Joloke]

If you wanna be a record breaker!

[SiC]

I'm interested in this topic too, as I need to do some protection and rust management on my MGB. 

[gordonbennet]

Have a good look round BiltHambers (Essex) website, they have everything you need once you've wire brushed that rust off, from rust converters to two pack paint hard as bloody nails to their mainstay, the two types of underbody wax, one for exposed areas another type for cavities.

 

Where they win over others is that the probes for the large aerosols are the dogs bollocks, so coverage inside cavities and around corners is good, no blockages at all.

 

I've done 3 cars with their stuff now, the Outback i did getting on for 4 years ago and its still bloody good considering the rear subframe was very rusty pre treatment.

 

Reckon on needing about £200 in products altogether, it cost me getting on for £300 in product to do the present Landcruiser, but remember thats a bloody heavy ladder chassis so lots of area to treat and if i do a rustproofing job i go to town on it.

 

Went and looked at a Landcruiser the dodgy trader seller of which said had been waxoyled...yeah right he'd leant under the front bumper and emptied a poxy aerosol of the shit across the front of the cross member and wishbones that was it, when i dived under the back i poked me hand straight through a body box section, two minutes later i'm on me way home, 300 miles of utter waste of my time.

[derskine]

It's been covered a lot on here. Waxoyl is quite shit though actually.

You're better with Bilthammer Dynax if you want to go the waxy route. A good coating with some strong epoxy paint IMO is better though.

[twosmoke300]

I use and rate dinitrol ML and the black one that goes over it

[derskine]

If you're planning on selling it then personally I would just slap some hammerite on it.

[jonny69]

This stuff works quite well and sprays on nice and easily: https://www.screwfix.com/p/hammerite-vehicle-underbody-aerosol-seal-black-600ml/6221h

 

Stays nice and bituminous and sticky. Jack the car up and stick a dust sheet underneath. You'll need 3-4 cans for a car. Doubt it's particularly easy to get it back off, but I'll worry about that later. 

 

Note: you can also get it in Halfords but it's much more expensive.

[mercrocker]

My method (which has kept my Morris on the road for 12 winters) 

 

Get that back to bare metal.   To prep, you can use Bilt-Hamber Deox but its messy.   Vactan is better if there is still rust showing particularly on inaccessible areas.   Once the Vactan has done its stuff and gone black (24 hours) go over with Bilt-Hamber Zinc Primer.   Obviously you want to keep the car dry whilst the Vactan goes off and you still have bare metal areas.   

 

After another 24 hours -  2 coats of chassis black.  I am not particularly fussed on brand as long as it doesn't react with either the Vactan or the primer.   I ran out of BH primer this month so I got paired aerosol cans of zinc primer and satin black chassis from my motor factors for the areas that required re-treating (either through me missing them or  road abrasion etc.) 

 

Give the 2 x topcoats another 24 hours and then paint over with Bilt-Hamber UB brushable - don't use the Waxoyl equivalent for this its got the clinging ability of a greased banana skin.   Finally, you can spray over the area with Bilt-Hamber UB or UC spray (UC is clear, UB is black). 

 

 

Overkill?  Possibly.

 

Also,  I go back under the car every September before the forthcoming winter.   I personally slate Waxoyl from experience both of useage and effectiveness and only use BH equivalents now.    

 

Sorry this is not entirely relevant to your situation, Joloke - but I had started writing it before your last post!   

 

Quick and dirty - wirebrush, vactan and straight to the brush on UB!

[The_Equalizer]

I've become a Dinitrol convert. It's not cheap, but does a good job. Check the 'bay of delights for kits. You'll need to wire brush the lose bits, use the RC800 rust converter and then the 4941 underbody wax. Waxoly, as mentioned, isn't that good although I did find that it had - over a long period - managed to make rusty bolts on my Land Rover dead easy to undo. Any rust proofing needs 'topping up' from time-to-time.

[DodgeRover]

Your plan seems sound to me wire brush as much as possible, vactan, some chassis black, then cover with underseal.

 

I've had mixed results with Vactan on minor rust but lots of rust on thick stuff it seems ideal.

[sierraman]

A tin of Finnegans Underseal with added Waxoyl. Goes on nice and remains tacky. Swat some Waxoyl over the top.

[RayMK]

Having bought one or two cars which had been freshly undersealed and looked sound,  I would walk away from any car so treated unless the seller could show me recent photos of the prepared, pre-undersealed areas.  The black bitumen type underseal is too often used to hide rust and can turn buyers away.

[steveo3002]

underseal and stuff just covers it imo....maybe a great move on a brand new car but not a well used one

 

i would jack that up and put it on stands with the wheels off , old clothes on and roll about under with a jet washer 

 

then once its fully dry get a tin of marine grease and a paint brush and cake it on, maybe a dab of old engine oil any bolt threads first  , each spring jack it up again and repeat , costs like £5 and wont ever peel up or flake off

[mercrocker]

Having bought one or two cars which had been freshly undersealed and looked sound,  I would walk away from any car so treated unless the seller could show me recent photos of the prepared, pre-undersealed areas.  The black bitumen type underseal is too often used to hide rust and can turn buyers away.

 

Yes, I should add that I never intend to sell the Minor.   The Cowley, which may have conceivably to be parted with in my no doubt reduced retirement circumstances, has been treated with Lizard Skin - an American underseal paint.    So far, so good - it only seems to have had trouble in a hot spot where the exhaust arches up under the axle and has been seared.   I have knocked this bit back to metal and proceeded as per my usual.   Trying to keep it looking neat underneath rather than black and greasy!    Its also a very light grey colour which is very helpful in spotting any abrasions.

[sierraman]

A few thoughts...

 

90% of any applications success is based around the preparation, if you apply it over rust it won't last 2 minutes. That's obvious. I wire brush it back and on areas which are heavily pitted, use the grinder. Treat any areas with some rust converter then a coat of the thick gloopy underseal like I suggested, then using a mix of Waxoyl and spirits, spray it on or on heavy impact areas paste it on thick as you like with a brush. Any areas I've done this I've then never had a problem with corrosion. In areas that's recessed like trailing arm mounts I've sprayed it until it's reached saturation point and it's dripping off. Needless to say the areas got to be completely dry.

 

You will need to go over this and maintain it each year. You want the thick waxy underseal though not the old shit you find in the shed, the Finnegans stuff never completely goes off so it can cure if there's any chips.

[Vince70]

I've just used a knockoff waxoyl made by Tetroseal and its £20 for a big 5 litre can of the stuff and it can be thinned down with white spirit to make it easier to spray and I used an old garden sprayer rather than a compressor and it seemed to spray ok.

 

With that amount I managed to spray up the underside of a Z3 a KA and a E36 so it goes a long way and for added protection I had a can of hammerite brush on underseal which contains waxoyl anyway.

 

If your painting the underseal its worth brushing it on first before spraying the waxoyl as it remains sticky and with a coating of waxoyl over the top it seems to seal it so it stops you getting covered with the stuff at a later date.

 

But then saying that the cars were rust free anyway (even the Ka) so it was only put on for protection rather than rust treatment.

 

I find that mainly on surface rust I just cover the area with grease and all my cars I've done that to seem to have never got any worse but that's only because I'm tight and I got loads of tubes of the stuff for free from work.

 

On areas that hold water such as the plastic jacking point rubbers on BMWs I just fill the things with grease and it seems to have kept them as good as new which is a rarity.

 

Also white vinegar is good for treating rust on the cheap as I put my rusty car tool kit in some overnight and it brought it up as good as new.

[Bobthebeard]

Bilt Hamber Dynax UB . Wire brush/knock off/scrape the loose rust off and apply. Dries to a dark brown coating and does the job very well IMHO. Never had an issue using the stuff. It does what it says really.

[MikeR]

having just bought a 14 year old ford focus that had a underside in quite good nick , I decided to just repaint any tired subframe paint with poundshops best spray gloss ,  some of that brush on waxoil stuff to more worn areas , and oil spray into any box sections , I was working on the premise if it had lasted 14 years already with minimal input  , it was going to last a bit longer with some TLC ,

 

 

whenever I jack the thing up , I have a cleaning rag and a can of oil and paint spray to hand , 

[steveo3002]

hah thought i recognised that car , was doing just that on ours yesterday but with a pot of grease , take a look at the inner sills where the suspension bolts on , they can get frilly there too  

[MikeR]

those bits are fine , just got to finish off the polishing during the next break !!!!

 

funny how the back metal work suffers the most !

 

 

 

 

[steveo3002]

yeah another £1 worth of paint when they made those subframes would have kept them tidy , expect they had the lightest misting of black when new

[mercrocker]

Just finished the Morris today - last job was coating each inner wheel arch and inner face of the wings with Dynax UB.   One can per side.   Just the van to do now and the Cowley when it comes back from the welders.   I don't do this thorough a job every year but I do go over everything again each September/October with the UB spray.    

 

You would think the bastard wouldn't rust but it still does!  

 

Inner surface condensation is the killer and you can only slow it down but even that's worth the effort.     

 

I didn't tread any into the house carpet this year either - Result.

[sierraman]

Biggest issue with the Focus is the recess where the trailing arms sit, a thorough wire brush down then absolutely pump it full of Waxoyl. Should see off any corrosion. Serious rust there then it's goodnight Vienna.

 

Interestingly saw some Normfest Bottom Coat in ECP yesterday, looked fairly hefty stuff, you can overpaint it as well.