Minature sprayer

For my sins, I have a 1963 Citroen 2CV Van. The rear body panel has a small leaky box section about 1cm x 1cm running transverse across the vehicle. Water has got inside this and its rusting from the inside out. I need to spray phosphoric acid into the section, then protect the inside with Waxoil or similar. I could pass a plastic pipe through a 6mm hole with some sort of spray head on it. Any ideas how to mix air / acid , pass it along the pipe and finally spray out of the end.
I guess that the "volume of the section is about 1/4 Litre.
BobH

Waxoyl used to make a sprayer with a long plastic tube and a spreader at the end, exactly for this sort of thing, might be woth giving them a call.

Have a look on the Machine Mart Website. Product code 000512105. Its an underbody sealing gun but it has a hose that can go on the end of the gun for spraying inside things. Used one for my Land Rover chassis. From memory I extended the hose to get well down the chassis rails.

Martin C

2CV van -lucky you, I've got a field full of dissolving ones. A cheap and cheerful way is to put a self tapper in the end of a plastic pipe , you will need to do a bit of testing to set up .

Choose your pipe, make a bung to fit in the end, drill the bung with a small hole, cut a groove across the front of the hole. Fit bung into end of pipe and spray. The spray pattern will depend on the flow rate, pressure, size of hole and shape of groove. A little experimenting should give you what you want.

I use a paraffin gun for this kind of job hooked up to the compressor. Great for spraying thinned and warmed waxoil on the Land Rover.

I had one. It was a piece of clear pvc tube with a wood screw in the end, and a few pin holes. The spray pattern was unlike any other spray nozzle I've come across, but it sort of worked for Waxoyl provided it was warmed up or diluted with white spirit.

As I recall the 'spreader' was little more than a flat-headed nail, not sure how it was kept in the tube without blocking it?

Neil

Thanks for the ideas there, just a bit more, how do I mix the air and the phosphoric acid as I assume that is how things should work.

I think I have found my expert. Thanks for the info and its into the workshop tomorrow morning.
BobH

1cm x 1cm box section is way too small for any off the shelf wax sprayer to deliver a suitable thickness coating The typical recommended coating thickness for cavity wax is around 0.1mm 'wet' which reduces to about 30% of that when all the solvents have flashed off. Underbody waxes are applied at about 0.75mm flashing off to about 0.4mm.

By off the shelf wax sprayers I include the waxoyl pump-up tin of old, the aerosols with extensions, a Schutz Gun and the professional compresser fed cavity wax gun with multiple interchageable nozzles and spray patterns as used by many body shops.

All you will be able to do with any of those methods and that size cavity is to massively overtreat and partly fill the cavity and that can stop it draining. This could be a very bad thing to do, actually promoting more rust and making any subsequent weld repair 'interesting'

It's the wrong time of year to be considering treatment, pick a very hot day and get the wax as hot as you can. Let any excess drain, maybe drilling additional holes Even then you'd be far better off fabricating a new piece of steel, possibly a bigger section if you can, properly removing the rot and getting it properly welded.

Dinitrol do an aerosol phosphoric acid RC900 which can (although not specified as such) use an extension nozzle used for their range of waxes but it will only give you a couple of feet of extension.

rejelrustproofing on ebay is a good mail order source for Dinitrol phosphoric acid, cavity and underbody wax and application kit (no connection)

While it is British I'd not use Waxoyl, it's still iirc a one mix formula does all and cavities have totally different requirements to exposed underbodies, and old cavities have different requirements to new ones. The waxes that vehicle manufacturers use have been way ahead of Waxoyl for decades.

Congratulations on your van. We have a Charleston in our garage which I need to restore to good working order and an approximation to watertightness. It is in working order (not MOT'd) though it needs to be driven in the wet while wearing Wellington boots.

Regards,

Richard.

It sounds as if you access the ends of the box section?

If so, Waxoyl, warmed, and sprayed from a paraffin sprayer with a long spout, powered by an air compressor set to deliver at least 80 psi, should be finely atomised, and will coat the inside of the box section pretty thoroughly, especially if the nozzle can be inserted fully from both ends.

I used this when we had a Renault 6 and 16. The only sections that rusted, as you might guess, were the ones that I could access to spray. Their successor Renault 5s, treated similarly, had not rusted after 17 years, and one lived outside!

Do warm the Waxoyl can in a bucket, or sink of really hot water, before filling the sprayer, that way you should get a real mist that penetrates well.

Howard