You'll most likely need to deal with rust on a regular basis (maybe
annually), as parts that are dipped in lake water then stored outside year
'round are difficult to make rust-proof (particularly when they're bolted
together and subject to shock loads).

I'd avoid using the galvanized pipe if the other parts are not also
galvanized. Primers for galvanized steel usually aren't the same as for
untreated steel.

If these guide bases? are to be extended upward vertically, the threaded
pipe ends will be relatively weak. Ideally, the vertical guides should be
one piece (they may bend, but not snap off when you aren't expecting it).

Because of the complex mating surfaces and the mechanical tension of the
hardware, the assembly should probably be dipped (or thoroughly coated) in
something thick that will have good adhesion.
I haven't tried it myself, but there are a lot of positive comments about
the (aerosol or brush on) bedliner coating products. That might be something
that's capable of being applied heavily in multiple coats.
I'm not familiar with what prep work/primer coat would be suitable for those
products. I assume they are to be applied over a good quality paint job.

There are a couple of ways a protective coating works. If the steel is
completely clean and is provided with an appropriate surface treatment, the
correct primer coat will adhere properly.
When the primer coat is properly prepared, the paint provides the
protection. Many primers provide very little protection from the weather or
severe environments/conditions.

For steel that will be outdoors, I clean the metal thoroughly, then treat it
with a phosphoric etch solution applied with steel wool or scuffing pads,
with a vigorous scuffing action to get a good etch and provide a surface
that isn't slick. Primer generally won't adhere properly to a slick surface
(it may stay there for a short time though).
After about 20 minutes of being continuously wet with etch, the part is
rinsed with fresh/clean water and dried as quickly as possible. Clean
compressed air, a heat gun, radiant heat or other forced drying method that
doesn't contaminate the surface.
The primer should go on as soon as possible after the part is completely
dry, and even better if the steel is still warm. If spraying from a gun,
give the primer a final stir, and start applying it. Repeat after a waiting
period determined from the manufacturer's guidelines.
It's usually difficult to determine how much primer is applied when it comes
from a spray can because the stuff is really thin (even if it's properly
shaken). There is a lot of solvent, and only a minimal amount of solids.

After the primer is dry, an appropriate finish coat(ing) can be applied.
Some primers require scuffing before painting, for maximum adhesion of the
finish coat.
Forced drying of enamels will often improve their durability. This can be
accomplished by placing the parts in sunlight for the day, on a sunny day,
and turning them over a few times. Dark colors will absorb faster than white
or light colors.
Most paints aren't intended to be applied in excessively heavy coats, the
results will most likely be that the drying action will cause the paint
coating to fail.

Proper preparation and application through the entire process insures
maximum durability.

WB
................

"Ignoramus26696" wrote in message
.. .
I made this boat trailer guide:

http://igor.chudov.com/projects/Trailer-Guide/

I need it because we frequently go boating on a river with very strong
current, which makes keeping the boat aligned over the trailer
difficult during retrieval.

The base is made of 3/8" thick hot rolled mild steel. The bolts are
half inch bolts.

How do I paint it to prevent corrosion?

thanks

i





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I'd simpy paint the whole thing with Rustoleum every two years, but
more importantly cover it with indoor/outdoor carpet so that it doesn't
damage the hull of the boat.

Harry C.