Thoughts on Restoring a Morgan
Fighting Rust
©By: John T. Blair (WA4OHZ)
1133 Chatmoss Dr., Va. Beach, Va. 23464; (757) 495-8229
Originally written: circa 1992
Last update:
June 30, 2001 - fixed link back to index
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 competes a quick course in fighting rust.
Enjoy your Morgan
John
Return to the Index of Tech. articles
To email me with comments or
questions.
|