Re: (ET) Rust and Paint

[ThompsonG DFO-MPO GC CA]

Hi
I can't stay silent anymore I am currently just finishing up a
Auto/Restoration painting class at my local Community college. As such we
dealt with the issue of rust and rust repairs at length. 
First, there is no magic bullet, the only way to repair rust is to remove 
it
completely and replace the missing metal if required. The only way to do
this is by sand blasting (or soda, or glass) But, you get the drift and it
is highly unlikely that this can be done in a small shop, although some
restorers (eg, Don Barry) can do it quite well. It is usually best done in 
a
dedicated sandblasting shop. So if you really want it done right send it
out.
Second, Freshly sand blasted metal start the process of rusting as soon as
the blasting stops. So really good shop will coat blasted parts with a two
part Epoxy primer, these are usually almost black and are meant to seal the
metal for moisture and they work. This is not the "grey build" primer most
folks see in body shops. In dryer climates (ie Southern California some may
use etching primer as the sealer coat. (like in American Hotrod). But, it
stinks and is pretty toxic.
Third, repairs made after sand blasting ie (body filler, welding, patching
etc. need to be re-sealed with that either etching or epoxy primer again
moisture is the problem.
 
Careful attention to this process can produce a repair that will last
indefinably. But it costly in time and money. Not much of an issue for one
or two cars or a tractor. 
However. Most if not all body shops are in it for the money and the more
cars through the better, that why they  figure a repair is only good for 3
years or at least that the kind of repair the customer is prepared to pay
for. Hey Business is business. 

Fourth, only when these 1 thru 3 are done can you move on to "Preping"  the
surface for paint. This as all cosmetic and the better you do it the better
it will look. It involves body putty and layers of high build primer (the
grey stuff) and Block sanding. 

In terms of longevity (longer than 5 years)  you don't need to anything 
more
than put one coat of grey primer on then a top colour coat to effect a long
lasting repair. You could even do this with a brush and roller if you 
wanted
Like I said prepping is cosmetic. Personally, I am going for as close to
perfect as possible but that just my thing.

Finally, once the paint has cured that's in the order of 30 days. A coast 
of
high quality car wax will give it the UV and Acid rain protection it need
this is really important on horizontal surface. 

I am using "equipment" paint or commonly called tractor paint as opposed to
High end auto paints like Dupont Imron. I think they are very close to what
was originally on the tractor. They are cheaper and while not really
important more resistant to Gasoline and fluid spills.  It just seems right
to put tractor paint on tractors.


It all really depends on how long you want the fix to last and how good you
want the tractor to look. But, there is no magic trick.

Cheers