Bodywork and Glass - Rust

From VW T25(T3)-Tech
Jump to navigationJump to search


What do peeps suggest would be the best way to stop the rot moving elsewhere? 

Dry everything out thoroughly - i.e. truck on blocks, wheels off and pull out all the plugs, scrape out muck where you can using fencing wire (round off ends with file). Vacuum, brush or blast out thoroughly and after a good few days dry weather, inject Waxoyl into closed sections. Must be dry (hot air gun?) and sections/crevices must not be full of debris/dust/damp crud - be thorough if you intend to keep the van/truck/camper.

But first read on... Anything you can see is a bit rusty or on the way but not yet critical, give a good heavy wire brush to remove dirt, rust and old paint or underseal. Paint: Use a Rust Encapsulator or similar product* - try starting with the straight paint, its quite thick, decant some into smaller tin to avoid contaminating original... throw £ shop small cheap brushes away (a few long handled ones useful) - keep well ventilated in enclosed areas - if the smell is too much, get the hell out of it for 5 minutes, the fumes are not good! Can use spray can into enclosed or difficult sections. A degrease spray and wipe is recommended (Eastwoods Pre or Brake cleaner on a rag); can be top-coated for toughness or appearance with Eastwood's Chassis Black or almost any hard finish paint; Read instructions on all tins and cans first

Paints, oils, waxes and treatments

Generally, paints/stonechips/shutzes goes on outside (chassis), oils and waxes internal to sections, panels etc. but Waxoyl is an exception, used inside and outside sections

Waxoyl is, er, the famous Waxoyl. Deserves an article in itself... but today there are better products around

RustEncapsulator is 100% water, UV light and oxygen barrier. £25/US quart or spray can (£16). Eastwoods products (US) from sole UK supplier Frosts Can be thinned with lacquer thinners or Hammerite thinners (£4-50/250ml); can be bought in black, silver or red

POR15 System and Vactan is getting rave reviews on the forum these days (much cheaper)

Jenolite also make a rust stabiliser paint, like red lead paint that brushes similarly, your choice.

Dinitrol products are highly rated. ML Cavity wax, 3350 or RC900 Coverrust (see Frosts website)

RC900 spray can is particularly easy to use. Combining with rust, penetrates and seals to a hard black surface which acts as a primer for paint if required. Very good for unseen areas like the rear tail-light boxes and a lot quicker than using Waxoyl in smaller cavities. To some extent the nozzle can be used to spray into cavities through a reasonable sized (22mm) bunged hole, but when whole sections/cavities are to be treated after cleaning out, then one of the other bulk (1 litre) Dinitrol products requiring a compressor and gun fitting should be used... Sees to be slightly higher tech range of products than Waxoyl. The spray adapter, when used with a compressor, achieves easier results than the usual Waxoyl pump (which requires heating the Waxoyl)

Dinitrol RC900 spraycan... Remove loose rust as far as possible, spray twice 6 hours apart. RC900 acts as a good paint primer (e.g. Eastwoods epoxy Chassis Black is a good tough topcoat)

Corrosion X Corrosion X, a high technology polar-bonding product

Vactan - Widely adopted by 80/90 members as you don't need to paint the treated area immediately so great for touching stone chips before they become a bigger problem and/or during prep for a repaint. Flows well into recesses such as seams. It is an acrylic based on tannin. Shelf-life one year. Very similar to Dinitrol RC800 Converust liquid.

Bilt-Hamber Laboratories Billericay based British firm that produces some world-class rust removal, rust prevention and other clever chemicals. Not over-priced and easy to order on-line directly

Bilt-Hamber Labs homepage

Hydrate 80 (BH equivalent to Vactan and RC800 rust convertors)

B-H Dynax S50 wax A top quality cavity wax, notable for being supplied also in aerosol format with 360 degree 2 ft wand.

If it's structural cut it all out back to good metal (a good twistknot wire brush (£10) on a 110mm/4.5" angle grinder (an essential tool, £15~£35) is wicked for this, exposes anything that isn't solid, and to cutout straight sided shapes, those thin, 1mm, metalcutting discs for same grinder are excellent) - then get a similar thickness steel repair plate welded in (0.7~ 0.8mm for body panels or 1.2mm, 1.7mm and up to 5mm for thicker structural parts) - butting up is best rather than overlapping on surface body panels. Finish treat it really well, repairs often rust again quickly, so degrease and prime and paint well in good dry conditions and you'll be OK for a good few years!

If there are signs of rust bubbles along the seams, then wire brush to clean initially and then rip out the seam sealer and clean back to where the pitting stops on the panels (maybe 1" away or more) - use specially ground hacksaw blade or screwdriver to chip paint off (3m pad on a drill or shot blaster is better! dremmel can be used with the mini grinder wheel to remove sealant) until you find the extent of surface rust - then RustEncap deep into the seam and surrounds; others prime and use Tigerseal or a good polyurethane seam sealer - it'll come again though, sometime, unless you also attack from behind seams, really cleaning the joins out (twisted knot brush/scraper, remove underseal) and then dry thoroughly (hot air paint stripper on medium) and again, load the whole area up with RustEncap, forcing into gaps in seams.

Cavity waxes and treatments

Waxoyl Deserves an article in itself... but today there are maybe better products around!

Bilthamber Dynax wax

Dynax PR blurb

  • Class-leading long-term protection for cavities, voids, chassis, doors, mud traps machinery, boats etc.
  • Resistant to changing conditions found in cavities, others are not
  • Self-healing, protects even if film is cut
  • Clings to vertical surfaces
  • Displaces moisture
  • Kills existing corrosion
  • Deeply penetrates flanges and folded seams
  • Easy to use - atomises superbly
  • Low odour
  • See-through coating with brown tint
  • Provides Lubrication
  • Available in ready to use modular injection system

So there is closed section wax and treatments, like Dynax, Dinitrol ML etc., that aren't really suitable for under arches, or open chassis where stone-chip type products tend to be the final layer (after good prep and paint).

Bilt-Hamber Labs: B-H Dynax S50 wax Bilt-Hamber Labs (Billericay) Dynax S-50 cavity wax

B-HL products come out top notch in tests. Their Dynax cavity wax is notable for being supplied in a useful DIY format, large aerosol with a 360 degree 2ft long wand. This is supposed to pentetrate into and behind rust, water and dirt that cannot be removed, and stay there, self-healing, like some of the Dinitrol waxes. Of course, make as good an effort as possible to rattle & blast or vacuum out as much as possible.

£12-95 for a large (750ml) aerosol seem pretty reasonable value, as with this system it gets to the places others might not?

DIY Approach

This one suggested by sarran1955 for de-rusting wheels

You will need:

A plastic bucket.

A plastic watering can, with sprinkler

A pack of wallpaper paste.

2 or 3 sachets of kettle descaler powder, (the sort you find free with coffee filters) (Sulphamic acid for the chemists)

I sachet of epsom salts, bath salts will do, and you get lovely smelling wheels. :rofl :rofl

What you do:

Mix up the wallpaper paste with cold water, double strength.

leave 2 mins.

Stir in sachets of descaler, wait 5 mins.

brush rusty bits liberally, (it might be a good idea to have a responsible adult nearby) :rofl

Leave 1/2 hour.

Wash off with water.

If all the rust is gone , make up the epsom salts, one handful to 2 litres water, (responsible adults have larger hands.) :roll: , Water liberally. (this stops the reaction and passivates the metal)

Blow dry with compressor.

Paint straight away.


Also, note what has rusted and why - nearly always it'll be closed sections that can't breathe or water getting in that can't get out, I always like to create a drain hole just in case, but that has to be rustproofed too, so think it through - i.e. stop underbody splashes getting in, but let it drain out.

Certain areas can be protected from splash/grit/stones abrasion and rust using corrugated plastic (those Estate Agent signs) stuck loosely with RTV or similar - they are easy to fabricate (big scissors/stanley knife), jam in and fix, to stop a vulnerable area being hammered by stones/water etc. Always allow a draining vent in case water gets behind - a good area to protect is behind the rear wheel, the snorkel boxes either side, they always seem to go on the front bottom corners, maybe all along the engine flitch panel/chassis rail join, clean and fill that area with sealant to stop water sitting there. Drill the centre of the snorkel boxes to drain (1/4" min) and protect from below with a small plate... if you've got a DJ with electrics in there, vital it's dry and well aired. Ditto plastic above the wheels under the seat, under the front door step treads etc. Angle them a bit so any water ingress can drain, check and clean out occasionally.

... you did say you wanted a project for the winter?

  • NB. Never use a grinder or twist knot brush without heavy leather gloves, and for all rust removal under van, you must wear goggles or a full face mask, the latter is essential when grinding metal anyway (acrylic full face masks used for strimming are good, and can be had for about £12) You can trust me on this, 'cos I'm NOT a doctor - you don't want even a mild eye injury, let alone a nasty one, it will destroy your enjoyment of driving, if not much more than that - the eye does not like dirty rusty metal even if it just plops into it gently, which it will under your van - if it hits with force, you've had it!

Bad Light stops play...

The problem with goggles or masks of any kind, is that they serioualy impede your vision in bad light under the van.

The answer is to use a bright light in daytime under van, or a head-torch (a must-have, cheap £3 ones from Aldi, are indispensible for underbody work)

A bright light is also very handy when MIG welding in bad light, even with a modern auto-darkening welding helmet. Or a small torch can be held alongside the welding torch, a cheap small shaker torch is good, just be aware that its plastic lens will eventually get burnt and frosted from heat and spatter (but your weld will be much better).


Grumps on rust

Grumpy Midget

First, your never going to be able to eradicate rust, but you can delay its appearance. Mask out the seams your going to prepare with 2" masking tape,to prevent damage to surrounding painted area, keep it local sand blast seam with fine nozzle grit gun (very fine graphite) or a course sanding paper grade 120 wet/dry dust out with a brush, strip off masking tape that will have been damaged with preperation. Re-apply fresh masking tape to seams, apply your rust inhibiting gel, and refer to the instructions that apply to the use of the gel (myself I would use an automotive rust inhibiting acid, it penetrates better into the metal, on contact with rust it turns black in colour Leave for 30mins and wash off with cold water, some specs on acid say use hot water, therefore always read the label)

Blow dry wet area with either compressed air or heat gun (Hair dryer will suffice). Do not sand or abrade after rust treatment there is a sealed film on the metal substrate after treatment, apply a build up of primer paint, when dry apply an automotive seam sealant down the seam joint, smooth with finger, before sealant dries remove masking tape and gently re/smooth edges of sealant to body panel, leave to cure (dry) Re-mask area to seams again then paint with your likle brush in your desired colour or spray with aerosol, flatten back painted edge with a cutting compound. as I said you cannot cure but can delay its appearance if any Mods wana put this in the wiki then you have my permission, Ex Co Employee Member of the SAAB 100 Club for paint spraying & refinishing

Put rust on-hold (temporary treatment)

If you can't do a permanent repair (cutting it back & welding in new steel)
then it's a good idea to stop it getting worse by a temporary treatment.

A can of Dinitrol RC900 Rust-off , Rust Encapsulator, POR15, Rustoleum or your own fav. rust paint and a few wire brushes. The thin curved plastic handled ones are good, as are single & double row tradtional wooden ones, the pointy ends can be filed off for better access.

WireBrush Axm 01.jpg

will keep rust at bay for a year or so. Spray or force it into gaps between seams and where you can't see, once they've been raked out, that's where the rust will be, and as the link says, gently ease overlapped layers apart and get wire bristles between, leave to air or use hot air gun, then spray or paint, wait and fold seam back down.

Example: Jacking Points rust problem - temp repair

If the areas around the jacking points look grim but you can't get them done properly for a year or so, attack fiercely, chipping heavy flakes off with a hammer and scraper, then heavy wire brush. Dry it out again once the area is opened up and can breathe, then after airing, use anti-rust treatment (e.g. RC900 or anti-Rust paint, if so stippling it in thickly everywhere you can). Don't hesitate to go right through with rotary wire brush where tame looking surface paint bubbles indicate rust underneath - if it's damp and can't breathe it will rust from inside out - don't kid yourself it won't get worse... it will

Finish off with a spray of Dinitrol or Waxoyl inside member

See also: Behind peeling/bubbling underseal (very similar to above, illustrated topic on removing u/seal and a temporary repair)

RTV Silicone and Seam-Sealers

If you need to seal something up to prevent further water ingress (e.g. rear ends of sill sections, from thrown water) then there's not much better or quicker than proper RTV silicone (about £6/tube at your local Motofax, clear or black usually)... If gap between two sections/seams is too big for paint to seal it, wipe a bit of RTV along it. Can also be used to stick corrugated plastic pieces in-place to block large holes from continual water spray (cut-up old Estate Agent signs are the sort of thing, often left lying about)..

But always check that if mud/water can get behind something, it can also get out again, or air (e.g. plastic can be clipped, self-tappered, RTV'd or even jammed into wheel-arches, under front cab-step etc. temporarily so they can be quickly removed for a clean and brush-up.

Seam-sealers skin up and dry much quicker, and for sticking panels in-place, attaching temporary plates for blocking holes etc, soem prefer to use these mainly polyurethane sealers.


Internal panels

I removed the backs off the units to expose the horrors behind, depends on the conversion but the backs weren't very well attatched on mine, also the trim panels could be unscrewed and bent back to get access. Initialy wire brushed the worst of it off, then possibly dremmel with mini angle grinder, then hoover out the rust dust. (I then used clear waxoyl; I used the aerosol and hand pumped versions depending on the difficulty of access, but I'm sure a compressor would be better. Check behind your fridge esp the vents, the voids below the rear vents in the engine bay, and remove the breather tanks in the front wheel arches and check behind, as these are notorious rot points (you may wish you'd never looked!)


Using malt vinegar to remove rust

Bodywork and Glass - Rust - Elecrolytic de-rusting

A good prep disk

Ghost123uk :

melmelody : in a post at ( ) recommends stripping disc similar to these:

He says they are plastic coated wire pads that will rip paint and sealer out but don't remove large quantities of the metal panel like a grinder or dremel does You can get them to fit a drill or a 4 12 in. grinder

The manufacturer (Dronco) says DRONCO Coarse Cleaning Fleece, or "Clean & Strip Discs", are outstanding for removal of paint from car panels.

Manufactured from synthetic coated nylon they will not score the surface of the work-piece and are an ideal surface preparation tool.

Useful for removal of old paint, rust, welding spatter, gasket materials, and also removal of thermal bluing after welding stainless steel. Good on wood & plastics too!