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MG MGA - new member with mk 2 mga roadster

Hi I'm now the proud owner of a mk2 1600 mga partially restored.
restored: the engine + gearbox + interior + engine bay

needs : paint job.

Looks quite sound underneath.

What treatment would you recommend underneath as I don't want to seal any moisture in.

should I wire brush , underseal , waxoil, chemical rust treatment
or simply spray with oil.

any advice would be much appreciated
DJ Joy

Heres a picture

DJ Joy

I would recommend coating with a cavity wax, Waxoyl is much maligned, but very good. I use Dinitrol and Rejel products because they are available in the 1 litre disposable (Shultz) cans. DIN3125M is my current favourite as it gets absolutely everywhere, but runs off so there is no thick build up left on nuts/bolts and other fasteners. I would recommend masking off the body before applying as overspray mist takes more time to clean off than masking takes to put on!

You will need to wire brush all the loose paint and rust and that is a time consuming and fiddly job. It is also beneficial to paint some phosphoric acid onto the exposed rust before coating with wax.

I would not recommend using paint or underseal that dries out as it will trap rust underneath and then flake. Even (especially) the so called paint on rust products. If parts are removed and shot-blasted then that is a totally different matter.

if you want a "nice" cosmetic finish or better wear resistance to any exposed parts, you can overcoat the cavity wax with a black underbody wax, again Dinitrol or Rejel.

unfortunately most of the corrosion on MGAs is hidden from view, even from underneath, but that's another question!

Just seen the picture - nice car!
N McGurk

Thanks for the advice, (it doesn't look so good close up)
I was thinking of phosphoric acid to treat the rust. Maybe I could spray it into the less accessible places. I believe It forms a coating .
ontop of the metal by converting the rust.

is waxol only of use on metal not rust ?

ps I used to live in Cumbria, purchased an MGB mk2 in 1981 and kept it for 20 years (Ulverston)
DJ Joy

Hi DJ, do you ever get to the Portsmouth area, we could meet up sometime to compare notes. MGA mk2 coupe
John
J H Cole


"I was thinking of phosphoric acid to treat the rust. Maybe I could spray it into the less accessible places. I believe It forms a coating on top of the metal by converting the rust."

Yes, but the surface must be clean with no flaking rust as it will just convert the outer layer which will then flake off.

"is waxol only of use on metal not rust?"

Yes, the only thing to put un rust is phosphoric acid and only then on after removing any loose. Sheet steel that just has a surface coating of rust is fine, but once the rust has penetrated through the steel will flake and any coating will only work on the outer "flake".

The biggest killer is salty roads and humidity/condensation if the car is left outside overnight. If garaged and used mainly in summer you should be able to preserve the car in its current state without problem.

If you are going to get it repainted then any rusty areas will bubble through again unless it is done properly. That means removing all (16 not including dashboard) bolt on panels to make sure all rust is cut out. If it has not had a recent body off restoration then you will certainly find corrosion in the inner sill and outer chassis rail.

In fact, just unbolting a front and rear wing will tell you pretty much everything you need to know about the condition of the body.
N McGurk

To do a pucka job, the best thing to do would be to take the body off, strip the chassis and have it powder coated - not sure what you have to do to restore your car. The powder coating for a bare chassis costs around £3-400. If you not keen on this I wouldn't use underseal as I think it is awful stuff. Hard to remove and to most people I know people are wary of underseal as it used to cover a multitude of sins. Try looking at the RustBuster website. They have really effective chassis paints that have acid in them so they will bond to the surface.
A Stojanovic

Thanks again, for the advice sounds like a big job taking the body off, might be worth it though, how long would it take ?
rear
In the meantime I might take a panel off to see what I'm dealing with. Is it best to take the front or rear off.

Get to Portsmouth when my wife wants to go shopping, I don't ushally take the car.
DJ Joy

DJ, see answer to thread "separating body from chassis.
Art Pearse

Hi DJ - welcome to the ranks of MGA ownership . Your car looks good from the photo. Removing the body is only necessary of you want to do a full restoration - if the chassis needs welding or the body sills are rotten. If it looks ok from underneath ( the floor support rails need to be in good condition and the inner sill panels should be intact) then just clean the exposed areas of the chassis of surface rust and apply rust curing application ( your choice is large and down to personal preference).Most of the rust on mine was around the battery cradles with hardly any on the fuel tank or chassis rails. With my car - now owned for 9 years - I removed the splash panels from behind the front wheels - checked that there was no major rust as you can see right back to the A post from here, - and then sprayed in copious amounts of waxoyl - then I repainted the panels and replaced them . I did the same with the panels in front of the rear wheels. It will be easy to see with these removed of rust has taken a hold on the B posts. Mine were OK and I did the same treatment as at the front. You should also check the seams of the body inside the boot - again mine had been welded at a previous restoration so all I had to do was add loads more waxoyl.
Cheers - good luck with the work and keep us updated - Cam
Cam Cunningham

This thread was discussed between 17/10/2012 and 20/10/2012

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