The Seagull Part VI: Painting

Why paint an engine?

Painting helps prevent rust and makes an engine look brand new.

Above:  The 1958 Johnson Seahorse.

After sandblasting the next step in restoring the Seagull was to paint it. Before sandblasting the metal surface was smooth, but without any paint it was now a little more coarse, like emery paper. Dirt could easily stick to the metal, and if this happened I would have to sandblast it all over again to get the dirt off. Paint won’t bond to metal if there is any dirt in the way. I had to handle the parts with clean grease free hands to ensure that dirt wouldn’t get into the tiny grooves on the metal.

Painting can be tricky. If too much is applied it will run or drip and the finished result will not look very professional. When I painted the Viking (a past outboard project), I gave it one coat, and when I saw that some places didn’t have enough paint I sprayed it again before the paint had dried. This resulted in large globs of paint in various places and didn’t look very good at all. I had to resand it and repaint it which was very time consuming and quite frustrating. The proper way is to give the object several light coats instead of one thick coating.

Before painting, remove all the old paint. With a small engine, the best tool for the job is a sandblaster. Once the old paint is gone, prime the metal before painting or use rust paint (no primer necessary). Primer helps the paint stick to the metal. It is best to paint on a warm dry day; this will help the paint dry and bond to the metal. If there is too much humidity in the air you run the risk of the paint looking “sticky” or taking ages to dry. I like to use cans of spray paint because you avoid brush marks with spray paint. Make sure you have a large drop sheet or piece of plywood under your project before painting.

Above: Painting the float bowl.

Here’s website that offers some useful advice:
<http://www.oldengine.org/members/murphy/painting.htm&gt;

After painting it’s best to leave the paint to dry for at least a week. Once I left a motor to dry only for one day and the next day I tried to reassemble it. The paint scratched off almost immediately; when I tightened the nuts and bolts, the underside of the bolt would scrape paint off the surface. It was incredibly frustrating. If I had left it to dry for longer it wouldn’t have done this. The paint eventually dried but the finished result was (sadly) amateur looking.

Painting bolts and nuts can look nice, but I find that when they are being removed the ratchet bit can scrape paint off the nut or bolt. One solution is to buy new bolts and bypass painting them altogether. This also avoids the issue of having old nuts crack during reassembly.

Above: Don’t forget to clean the cap off when you’re done painting! Old paint will dry up and block the small opening on the nozzle.

To clear the cap of paint you turn the can downside and spray for a few seconds, until the paint no longer sprays out.

After painting I used PlastiKote engine enamel to seal the surface. This adds gloss and prevents dirt from sticking to the paint. It looks especially nice on gas tanks and flywheels. It also handy if you’re replacing engine decals as it will keep the gasoline from dissolving the decal.

 

The Seagull Part III: Sandblasting

This year I used a tool that I have never used before with any of my projects: a sandblasting cabinet, or glass beading machine. These sorts of machines come in handy for removing rust and paint off metal objects in a short space of time. Sandblasting leaves you with a nice smooth piece of metal, ideal for painting. If old paint is not removed, new paint may flake off and you can see old paint under the new. I don’t own one of these items but I was able to use one that belonged to the grandfather of a friend of mine.

Above: The sandblaster (0r glass beading machine).

Above: Inside – the red plastic piece is the sandblaster (the gun).

Above: The crankcase before sandblasting.

Above: Lower half of crankcase after sandblasting.

How it works:

There are several components to the machine that I used: the sand/glass mixture, the cabinet itself, the sandblaster and the compressor. The cabinet is the big metal box which holds the sand/glass mixture. Connected to the gun is the compressor. It takes in air and then pumps it through a hose to the gun at extremely high pressure (above 80 psi). The magazine on the gun contains a generous amount of sand. As the air flows through the gun it carries the glass/sand mixture with it and blasts from the barrel of the gun at an incredible speed. The operator has to be able to hold the gun while sandblasting, so there are two black gloves which are fastened onto the metal box and won’t come out. They protect the operator’s hands from the tiny sand particles racing around inside the cabinet. There is a little window at the top of the box so you can see where to aim the gun.

Operating Procedures:

  1. Fill the sandblaster with sand
  2. Turn on the compressor
  3. Place the soon-to-be-blasted piece
  4. Close the lid
  5. Start blasting!

Sandblasting is very effective when you have a rusted old motor like the Seagull. Old rust is gone is a matter of minutes, depending on the size of the piece you are sandblasting. Sandblasting it also very fun!