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Garage => Interiors & Exteriors => Topic started by: SteveDuNord on 15 August 2022, 05:06 AM

Title: Dinitrol rust treatment?
Post by: SteveDuNord on 15 August 2022, 05:06 AM
I've found a local business that offers dinitrol ML treatment, starting with a wire brushing. They keep the car for a few days and it's their sole business, so I would expect a proper job.

Has anybody used this product on their 116?
Title: Re: Dinitrol rust treatment?
Post by: rumb on 15 August 2022, 08:18 AM
It looks like it is a cavity wax. I wonder what the effect would be of spraying wax over existing rust. I suppose a good layer could keep oxygen away, but would it also stll allow rust to grow underneath at all?

On w116 the majority of the original shultz is usually sound, but its the edges that have broken down and then allow water to go to work. Also most of the rust is inside something, not on an outside surface , like wheel arches and rockers and it is loose rust not just surface.

The rockers have plugs front, rear and all along the top edge. I would be more inclined to spray a rust converter in all those plug holes after first blowing air in the holes to remove as much crap as is surely in there.

The wheel well, esp rear remove tire and find any loose edges with a screwdriver and peel or grind back to expose all rust. Then convert it and then the wax could go over that, or just use some new schultz.

Warning though what may look like surface rust can easily become a hole when you start picking at it.
Title: Re: Dinitrol rust treatment?
Post by: gurrier on 16 August 2022, 03:09 PM
Hi SteveDuNord,

It may be FMK Vapour Blasting who have a YouTube Video showing their process that you refer to.  I presume they have the Irish Franchise for what is no doubt a world wide product provided by the parent company.
Seems a fairly extensive job that they do.
In my opinion it is a case of closing the door after the horse has bolted to rustproof unless it is a case of rustproofing after doing repair work. Unless a car has been kept in a climate-controlled garage all its life and not used in rain there will be rust.  Postproduction rustproofing will not resolve the water drainage design fault which lead to rust behind the fuse box - or in the bonnet/hood release cable area.
More generally as with many vehicles it is from about bumper level down that most corrosion happens. 


Poor design in the jacking points - continued by Mercedes through W124 and W201 production - could have benefited from better rustproofing.  (Incidentially this is a 1977 280 that is on sale in Ireland for Euro 6500, the four corners appear more or less the same)

In short rustproofing done early in a vehicles life and topped up periodically was the way to go.  40-50 years down the line will it make much difference. 
I was a bit surprised to see the internals of box sections being extensively vapour pressure blasted in the Youtube Video.  Does this not introduce moisture?
Title: Re: Dinitrol rust treatment?
Post by: rumb on 16 August 2022, 06:57 PM

looks like water and glass beads.
in the US is a big supplier of these "dustless" systems.

Both systems use a rust inhibitor in their process and are used to strip paint and everything else, whereas Dry Ice blasting will remove all the crud/grease/dirt under a car but leave the paint and schultz there in very clean almost like new condition.

I agree that wax treating an old car probably isnt going to help, and may actually hurt it in the long run.
Title: Re: Dinitrol rust treatment?
Post by: SteveDuNord on 19 August 2022, 05:21 AM
Cheers, chaps. I should add that the company uses a wire brush and then etch primer to remove rust before the treatment.

I read that Dinitrol is grease based, whereas waxoil is wax based.

I think my car is already waxoiled because it's starting to peel under the arches and I can see rust. Hopefully not perforated...
Title: Re: Dinitrol rust treatment?
Post by: rumb on 19 August 2022, 08:08 AM

States that it is wax/oil and primarily for cavities. The peeling you are seeing is the original shultz and if you scrape it back you will see rust under it no doubt. The loose areas trap moisture and accelerate rusting. I found that an angle grinder with a 4" hard wheel grinds shultz the easiest. A wire brush works poorly to remove shultz.
I would much prefer a rust convertor than etching primer as it will creat a hard surface that resists further rusting. It turns red rust into a black material. You want to remove the loose rust but leave some for the convertor to work with.

Etching primer only promotes adhesion of the primer, but primer also absorbs water and needs top coated.

Por15 is also a good rust encapsulater.

My opinion your most efficient course is to grind loose edges and then paint all rust with por15. The inside of the rockers wax will probaly help. You can buy cans of wax that come with a long wand. The areas that rust the most are the bottom of the inner rocker and the jack points.

Csn you post some photos of the worst areas?
Title: Re: Dinitrol rust treatment?
Post by: daantjie on 19 August 2022, 12:05 PM
Is this stuff the same as Cosmoline?