Fighting Rust
Last update: December 17, 2004
©By: John T. Blair (WA4OHZ)
 1133 Chatmoss Dr., Va. Beach, Va. 23464;
(757) 495-8229
Rust is the oxidation (adding oxygen to) of a piece of metal or turning iron into iron
oxide. Therefore, it should be obvious, to stop rust the metal must be prevented from
oxidizing in the first place. How? Paint it! I hate bare metal, it will rust. Every metal
part on my Morgan was stripped to bare metal then painted. On most cars, we the owners,
don't have a lot to say about what should be painted by the manufacture so we have parts
that aren't painted and they rusted.
If a piece of metal has already rusted, the first step in fighting rust during a
restoration is to get rid of the rust. There are several methods of rust removal.
- Chemical dips - Have the part dipped some where. One such company is Ready Strip. This
is probably the best and definitely the most expensive. However, there are only a handful
of companies around the country that do this.
- Sandblasting - This is a time consuming operation. For big jobs, I send them out. For
smaller parts, you can blast them yourself. For this you will need to purchase or build a
sandblast cabinet (Harbor Freight sells a nice plastic one for about $120) and a
compressor (a 4hp 20 gal. tank at a minimum - $400-700).
- Chipping or scrapping - For heavy flaky rust on heavy metal (like a chassis or
suspension parts, beating the rust with a hammer or scraping it with a screw driver will
due for starters. For thinner metal a wire brush works well. A high speed (10,000 rpm)
4" grinder ($40-100) with a knotted wire wheel ($10-20) does a great job. A wire
wheel in a 3/8" electric drill can also be used. For tight areas I use a 1" cup
brush with a 1/4" shaft chucked in a die grinder.
- Part replacement - The last resort for badly rusted pieces is to re-fabricate or
purchase a replacement part. However, this can be expensive.
After the majority of the rust has been removed, the metal and remaining rust should be
treated with an acid to change any living iron oxide into an inert iron sulfate. There are
several product that do the job, two of the most common are Ospho and DuPont's 5717S metal
conditioner. These products are available from most automotive paint supplier. These
products will also etch the metal to give the primer better adhesion to the metal. With
the rust killed, it's time to paint the metal. There are a lot of possibilities here:
- For metal that will not be exposed to direct sunlight (i.e., chassis and suspension
parts) or that is very rust prone, there is a product called POR 15. This stuff is
marvelous, but expensive ($30+ per quart)! It is impervious to petroleum products, brake
fluid, can be used as a gas tank sealer, used to seal small pin holes in the metal. This
paint dries rock hard and is chip and scratch resistant. If this paint is to be used, read
the fact sheet that should accompany the paint. Once the can is opened, it must have a
piece of plastic placed under the lid before trying to close the can. I've found it is
better to pour the contents from the can into several small (7 oz) glass jars. Again place
a piece of plastic between the lid and the jar. As the British Secret Agent 007 would says
about his martini, it should be is "stirred not shaken". If the paint gets on
the lid and dries, the lid cannot be removed for the container. Consequently the plastic
sheets between the lids and the jar. When using this paint, I pour a small amount into a
used plastic butter cup and reseal the container. This will reduce the contamination of
you paint supply and increase the shelf live of the remaining paint. I also wear loose
plastic gloves to keep the paint off my hands. Once this paint gets on you and dries, you
WILL wear it for a while. If it is still wet, it can be wiped off using lacquer thinner or
Acetone. It can be applied either with a spay gun or brush. If using a brush, use the
cheapest ones you can find. When finished, I clean the brush and butter cup with lacquer
thinner or Acetone. This way I can reuse the brush about three times. I should note that
this paint can be used as a primer and painted over.
- A less expensive rust inhibiting paint such as Rust-oleum or DeRusto work well. However,
these paints can be affected by gasoline and brake fluid and are susceptible to
scratching.
- For exterior metal (usually the body) any of the automotive grade enamel or lacquer
primers and paints can be used. However, a lacquer primer does not inhibit rust. If the
part is to remain unpainted for any length if time, the primer will absorb water and the
metal will rust under the paint. DuPont as a relatively new primer called "Vera
prime". It is supposedly a polyurethane with an etchant that when dry seals the metal
from any water.
Thus completes a quick course in fighting rust.
Enjoy your Bricklin,
John Blair
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