Underseal or Paint?

[Boomlander]

Hi all,
I can't decide whether to protect the underside of the car with standard brush on underseal or to paint it with Hammerite or to have it professionally coated bearing in mind that funds are a bit limited.
Any suggestions? [frame][/frame]

[bmcecosse]

It looks grand under there at the moment - to apply 'paint' you may have to strip off what's there already. Hammerite is horrible stuff.... There are many who will say don't use 'underseal' - but that's what I have on my own car. You should certainly make sure all the closed cavities are well treated with Waxoyl or similar - and you could consider spraying the underside with that - but it will need regular re-treatment.

[Tapitha]

Underseal mixed 50/50 with white spirit gives a lovely underneath finish.
Mike

[customjob]

Hi,

We used Smoothrite on the underside of our 54, spent a full weekend on my back with a powered wire brush cleaning off the underside wheel arches and wings, spent the following weekend again on my back and knees along with with my 70 year father painting it grand total of 4 lts two coats lovely smooth finish and all you have to do to clean it off is jack it up and give it a blast with a pressure washer job done. Can't do that underseal can you awful stuff, as it dries out it cracks and traps water which leeds to rust which leeds to well we all know what it leeds too. Waxoyl as somebody has said yeah great for cavities and hard to get places, but the underside it says sticky so all the muck and salts and detritous will stick to it, also the spray from the tyres when it rains will eventually wash some of it off, plus when you come to re do it you've got to clean it off anyway otherwise your just sealing the muck salts and detritous in. At least with painting you can see where it's chipped scratched just a quck rub down and slpap of paint over the top done. When moggie's were built they didn't use underseal it was a form of rust prevention paint.

[stag36587]

I have used spray on body schutz on another car - hard, gritty, slightly rubbery texture and has given excellent protection for some 12 years already

[dave.c]

Hi I have been removing the underseal on my car and replacing it with 2 coats of bilt-hamber zinc primer, followed by 2 coats of white rustseal.

[chickenjohn]

The trouble with underseal is it is very different from the original micacious bitumen coating used on Minors which was much higher quality.

The underseal you can buy in the shop is cheap stuff, it dries out and cracks after a few years, allowing water and mud to get in and cause rust. It is then very good at hiding the rust as it spreads.

Smoothrite/ hammerite are also not very good as these paints are designed for garden gate and decorative ironwork use and are too brittle for car underbody use.

I prefer to remove all rust, then zinc prime, use a good seam sealer in any seams or welds, then a few coats of anti stone chip paint and finally paint with chassis black paint- which unlike hammerite IS designed to be used on the underside of a road vehicle. Stone chip on its own is porous and needs a top coat.

This is all then topped off with underbody wax and cavity wax. Topped up yearly, depending on the use the vehicle has had. Of course mud and salt washed off the underside as soon as possible.

My system is based on how the best protected cars on the road are done. - Porsche start with galvanised bodywork (i.e. Zinc), then use loads of seam sealer, anti stone chip coat, finally a top coat of paint on top of the anti stone chip and finally wax.

as for underbody wax trapping dirt, this may be true with the cheaper varieties, but I have found Dinitrol actually repels water and keeps mud off the underside. It is actually cleaner than just using paint or underseal. With paint alone, one stone and rust will start.

[customjob]

I'll grant you that Chicken John, but the chap at the begining was asking in relation to cost I'm sure your systems works but at what cost to the back pocket, one thing thing i didn't disclose was that before the smoothrite went on we zinc primmed before granted any paint will chip but if you regularly look round your top and bottom side when greasing if you see some chips or rust spots it a quick easy cheaper repair.

[chickenjohn]

Compared to welding, or panels and loads of time, proper protection of the underside of your car is great value!!! Will save money and time in the long run.

[aupickup]

i have used dinitrol on the outer sills on my car
the orginal zeibart is on the rest and has kept the floor panels in ex condition

[Boomlander]

Many thanks for all the advice folks

[spannerdave]

I use Agricultural paints. If they're good enough for tractors and farming implements in a farming environment, then on a car they should be just fine. Vapourmatic is the brand I use, hard as nails, and available on line or at your local farm store and not expensive you'll find a good colour choice too. Stone chip is alright for the wheel arches and inner wings and the outer edge areas of the underside of the body. Personal preference I guess, but I wouldn't do the entire underside in it. A nice shiny painted floor is a treat along with nicely painted axle/suspension etc, and polished copper brake pipes and I love the mot testers faces when they get the car up on their ramp "its comical".

[fasthamster]

i have used dinitrol on the outer sills on my car
the orginal zeibart is on the rest and has kept the floor panels in ex condition

Hi,

Did you buy Dinitrol and Zeibart from a UK supplier ?

Thanks in advance,
Robert

[RobThomas]

Crikey. 6 years ago...I can't remember stuff from 6 DAYS ago.



PS Dinitrol on Ebay.

[67-2door]

Dinitrol is excellent stuff, it can be bought in the UK from Rejel automotive.