Under body protection

Just a quick question regarding under body protection, the plan is to use red oxide initialy followed by stone chip, but do I need to remove all of the existing (original) paint to bare metal before priming or can I prime over it as long as its solid. At the moment the under side is covered in under seal which is very thin and be wire brushed off leaving the orignal paint. Thanks in advance.

 

If you go back to bare metal you need to etch prime first dude

Modern red oxide is rubbish and doesent bond well to bare steel

 

as long as you have a clean greese free surface that has been keyed to premote adhesion you will be ok but i would want to top coat over any primer as its porous and will soak up water

 

Thanks for the swift replies. What would you recomend, I don't want to bare metal it as there are only a few small areas requiring attention and I've heard alot of bad things about underseal, it drying out a cracking then causing more trouble.
Cheers

 

if you can get away with just removing the bad bits of underseal repaing the paint underneath then resealing over that you would be best as removing the lot is a nightmare ive done it on both my split and bay and both were a nightmare even with the van on its side

 

A lot of people slate it without good experiance of using it but im a big fan of waxoyl underbody seal

If it used over good solid steel not rot it lasts years before it dries out and needs reapplying

Its bodgers that have give it a bad name

Stay away from tetrashutz underbody seal it hides faults well but goes hard in three years

 

Just don't slap it over any rust.

 

I'm a big fan of Epoxy mastic 121 from Rustbuster

..........its expensive but good

 

don t remove original paint but treat any exposed bare metal red lead zinc primer or eitch and plenty of stone chip them when dry a couple of coats of clear wax owen nw

 

Cheers everyone.

 

...and then move away from Hull before your van rots like a whores knickers

 

heres the webpage for the mastic stuff http://www.rust.co.uk/
how much would i need to the underside of a bus with a brush probably

 

If you're brushing it, you'll probably need the 5l for £89

 

I've used about 8.5ltr so far brushing it on

......but that has covered all the inside panels, inside of sills before they were welded on and everything has had 2 coats

so as Paul said about 5ltrs is probably about right.

I think you would get a good finish spraying but it wouldnt get into all the seams and gaps over the tiop of the top hats etc ......depends on if your keeping them really

I think it makes a bloody good job of protecting seams and you can push it right in using a brush

 

thats the problem one of em has got to go and i don’t know which one i am keeping yet
my uk bus is desperate to get a good coating before it goes to far and my use bus has never been done