The Mitsubishi Pajero Owners Club®

[destroyityourself]

I had to do some chassis repairs,  I was considering washing underside of the pajero, clean surface rust,  red oxide,then waxoil or drinitol.  Question is , am I wasting my time at this time of year.. wanted to get it done outside in the summer,  I couldn't find the time.

[Google]

[hutchy]

unless you can get it really dry,you could make it worse by trapping water or moisture between the steel and the wax,and as it will be covered you won,t see the rust until it,s to late

[peteinchad]

As Hutchy said - you won't get it dry enough so you will just make it worse.
Wait until next summer.

[assassin]

Forget Waxoyl and Dinitrol as this is now old fashioned and times have moved on, I only use Bilt Hamber products now and the products you would need are!

Deox Gel - this is a rust remover and boy does it work, you simply paint it on after removing surface rust and leave for a while, then put another thick coat over the top to build it up to around 3-4mm thick and cover with cling film to keep the active ingredients moist and working, can be left for around 3 hours uncovered, or left for up to 3 days covered, depending upon the severity of the rust; remove the cling film and scrub with a scrubbing brush and soapy water and the rust just runs off and leaves clean, rust free metal. It isn't hydrochloric acid based either and is water soluble and biodegradable and you can wash your brushes out in water.

Dynax S 50 - this is a cavity spray and comes in 750ml cans pressurised to 70 PSI and can be used in any position, leave them in the house overnight before use and if you have 1 spray can then buy the extended atomising lance, if you have 2 or more spray cans then you get an atomising extension lance free for every 2 spray cans you buy, this can be used on damp metals but not wet metals as it is very thin and penetrates everything much better than Dinitrol, fit your lance to your can and do a test run using a piece of box section or similar as this really does atomise and people travel too slowly with it, then insert the lance inside your chassis and inject it, it will penetrate any joints and arrest any rust and its self healing.

Dynax UB - this is an underbody wax for the outside of the chassis and can be painted, rollered, or thinned and sprayed on with a Schutz gun if you have a compressor and you stand this in the house overnight to warm it and open the tin and stir it as it begins to thicken at the top and simply paint or roller on or thin with white spirits and spray with a Schutz gun, this can go straight onto bare metal or you can use another Bilt Hamber product, Hydrate 80 which is a rust convertor and etch primer and there is a knack to applying this and this is to apply it very thinly and work it in all directions to ensure coverage, leave for 30 minutes and apply UB straight over it.
Dynax UB cannot be used on wet metal and is not moisture displacing so if this is an issue simply apply two coats of Dynax S 50 at 24 hour intervals to the outside of your chassis and leave this until summer and go over it with Dynax UB when the weather is better, and if you have any S 50 remaining you can inject the sills or other vulnerable areas by swapping the extension atomising lance and putting the ordinary spray button on and using like an ordinary spray can.

When you have finished using your extension lance then simply put the working end into a jar of white spirit to clean it again for future use.

[hutchy]

i don,t even use bilt hamber anymore,it,s all watered down,if you want a really nice chassis clean it well and get yourself a corroless chassis paint kit from arc-rite paints,this has a rust inhibitor which you apply 2 coats then a top glass flake reinforced coat,if it,s good enough for ships and oil rigs it,s good enough for cars,i painted a manhole cover in the middle of my drive last year,and it still looks new,which is not bad considering my paj drivers wheel sits on top of the damn thing

[destroyityourself]

Good helpful replies, mixed opinions on what to use everywhere I search. What about these rust neutralizer products , do they really work. Read a few posts against drinitol, saying it doesn't penetrate rust fully,  just the surface  , can read some on this company's website https://before-n-after.co.uk

[NDZ]

I've been using phosphoric acid at various strengths and textures for vehicle rust control and it definitely works leaving a clean iron oxide behind (PPE required) but my comment here isn't about which product to use its about the effort it takes to prepare the multiple surfaces, nooks and crannies you want to eventually underseal. My 96 2.8 had been waxoyled on import and about 50% is still holding up with the rest doing exactly what the critics claim i.e. trapping moisture in the bubbles and now accelerating the rust. I went through a dozen different tools and found the needle scaler to be most effective and to answer your comment "it doesn't penetrate rust fully,  just the surface" if you still have any surface rust visible then at most it should only be tiny pits on an otherwise clean area, anything more and its nowhere near prepared for the job.

In summer 2018 I spent about three days removing what rust I could from the underside then I jetwashed the chassis rails with a lance and a mountain of debris came out. I could feel there was plenty more left in so made a whip out of steel wire and drill to clear out the rest, this is a really dangerous tool but its effective it blew a 50p sized hole in one section but got that welded up and glad I found it when I did. The airline then blasted everything clear and I applied the acid, gave that a day or two to work and then began to apply Ankor Wax. As mentioned I still have 50% original waxoyl in good condition but its a complete patchwork mess and I didn't want to use another matt black underseal in case I ever revisit the job. The Ankor Wax needs a bit of warming up but will spray into the rails with a lance and for the rest it was far easier and more economical to use a brush. You can no doubt find better products than what I've used here but its held up so far and I needed a custom fix, once again it was the prep that took up 90% of the time and effort.

[assassin]

Some interesting posts.

NDZ, Ankor wax was one of the first polymer additive products and was really the first phase of the newer products and is a vast inprovement over Waxoyl and Dinitrol and is a good product in many respects, but other companies such as Bilt Hamber and Axalta (who make Corroless) took the basic formula and refined it much more for automotive applications and ease of application by professionals and DIY users alike and Axalta focused more on paints using two pack paints initially, then single pack paints.

Hutchy - Its all watered down as during manufacture it is made in solid form and has to be dissolved by using solvents to make it into a wax, Bilt Hamber use a different recipe to others when they thin it down it is for specific requirements and their thinnest stuff is the S 50 which is designed solely for penetration and much better vapour phase performance and self healing capabilities, this is where older products such as Waxoyl and Dinitrol fall down as they have fallen behind and their products claim excellent penetration capabilities, but cannot compete against the newer rivals using newer technologies. In may respects it using the correct product for the correct application which is crucial, something many people forget.

Axalta and Bilt Hamber paints are both good and virtually identical, but Axalta have aa slight performance edge due to them adding slightly better calcium based corrosion inhibitors in their primers than Bilt Hamber do, but Axalta fall down slightly on chip resistance as their top coats tend to be slightly harder and slightly easier to chip, so basically its 6 or two threes, but you cannot paint the inside of a chassis and this does not prevent rust forming inside it.  

Rust convertors, phosphoric acid or calcium based? this is actually a complex subject as it all comes down EU legislation believe it or not and this is too complex a subject to go into here, suffice to say, phosphoric slipped through the environmental net and calcium based products didn't and this is why the market is littered with such products, only recently was calcium based products technologies advanced enough to let them pass the legislation and it is now coming onto the EU markets.
Phosphoric acid products do only cover the top layer and convert it and this traps rust and moisture underneath it whereas calcium based products actually create a slight vacuum as it reacts with the rust and draws the rust convertor in and much deeper than acid based products and if you remove all the loose rust it draws it deep enough to cure rust from the steel layer to the very outside and if used correctly, eats acid based products for dinner. Acid based products dry from the outside in and often trap pockets if wet acid below the surface and over time this eats through metal and forms new holes or weak patches.

Chassis cleaning? using grinders, needle scalers, and abrasives all have their own problems and the only cure is chemical rust removers, needle scalers remove visible rust, as do wire berushes, but needle scalers hammer microscopic particles into the steel and high speed wire brushes wipe rust particles into the steel grain and both leave clean looking steel but they leave behind embeded rust invisible to the naked eye, this is exactly the same reason they "pickle" steelwork prior to galvanising it as chemical strippers remove all the rust without leaving rsidue behind.

There is another good product and this (if memory serves) is Krown and this is a Canadian product which is also one of the new generation products and uses similar technologies.

[hutchy]

got to agree,but any ladder chassis is a nightmare to clean and tidy up,unless you have the means to lift the body off to get at the chassis,your always going to struggle with certain areas,i stripped all my rear end out shot blasted the bulk of it,did some welding where required before painting it and cavity waxing it,fast forward to present day it has held pretty well just a few small ares of rust coming through,nothing major,but the council up here are torture,a slight sniff of cold air and out comes the salt,i don,t know what other councils are like,but ours are stupid with the damn horrible stuff

[assassin]

Nail and head spring to mind there Hutchy along with hammer.

In point of fact salt is applied everywhere in the UK and it is actually being seriously considered as deliberate so cars become corroded and their lives are shortened so they can be scrapped sooner which opens up the possibilities of more car sales and it is always commerce.

Is salt needed? actually no as many other countries use various non toxic and non corrosive alternatives and the Uk don't and this is again down to up front costs and UK commerce and short sightedness of council planners; synthetic salt costs around twice the price of ordinary salt but lasts at least five times longer and its operation is very simple, it is spread once and as vehicles run over it the granules are compressed into the grain of the tarmac and remain there, it is temperature activated and most types are produced to activate at +3 degrees C and constantly working, it lasts for around a week. If the weather goes above 3 degrees C it simply stops working and lasts longer, so economically its more beneficial to pay twice the up front price and save over the rest of the gritting cycle, basically you put synthetic grit down during the working day and leave it for a week and not have to have several teams gritting the same road every few hours as they do now, no overtime for working nights for drivers, huge savings on diesel and support teams to fill the trucks, and as you may be aware, these bodies and spreading mechanisms get hammered by the corrosive nature of salt, so no corrosion of lorry bodies, particularly on the multi function gritters which are ordinary lorries with demountable bodies, they bolt on an Econ gritter body amd it is only used for a few weeks and then stands for the rest of the year.

Its downside is storage as moisture degrades it so it has to have heated storage facilities if you buy it months in front as they currently do with salt, and for an entire country you need lots of storage facilities and a source of heat to keep it warm and the moisture out, I built two of these plants in 2016 for evaluation and they were large insulated bunkers large enough for lorries to drive under, they were built next to two factories using a lot of heat in their processes and the heat was simply ducted through them and onto its end user which a large hothouse grower, so apart from the initial costs of the bunker and installing ductwork there are virtually no overheads, the heat is recycled and free and the lorries can be loaded by the driver.

[hutchy]

well i have found standard of driving overall in this country is *beep*,when i was learning to drive i was taught to drive,now they are taught not to drive but to pass a test..when i drove the concrete wagons we had to be assessed every year ,not to say you cannot drive it was an insurance based thing,i ended up leaving the assessor on a building site,after he told me,why are you using your gears to slow down,thats what the brakes are for,so i said to him thats fine in summer and dry weather,can you tell me what happens when there is a heavy frost or ice and maybe snow on the road if i only use the brakes,he said well you would still stop,i said yeah but not where i want it to stop,it will go where it wants to go which means i am not in control of the vehicle properly..to which he said well ive been doing this job for 7 years..and i told him i had been driving for 22 years and in some of the harshest conditions on the planet,from frozen roads in norway and switzerland to deserts jungles and some right damn nasty roads with shear drops of 200ft plus..flipping idiot