From: Frank Condelli
It's is not any kind of Epoxy based paint. Epoxy's are two part paints,
paint and curing agent. POR-15 uses humidity to cure. The higher the humidity
the faster it cures. Once cured nothing can penetrate it's glass like
surface. It can be used anywhere on a vehicle not just undercarriage. Yes, it is
ultraviolet ray light susceptible and will turn a chalky grey in the sunlight
but that does not harm its capacity to protect the metal. On exterior
surfaces it must be top coated with primer or paint before it sets. Best method is
to apply primer as the POR-15 becomes tacky to the touch. It can be top
coated after curing by either sanding so that ALL the surface is dull and I do
mean ALL, any where it is shiny the topcoat of anything will not stick. That
said POR-15 is now selling a product called Self-Etching Primer and can be
sprayed on top of cured POR-15 which will allow a top coat of whatever primer
or paint you wish. Using POR-15 to repair seam rust is in my opinion the best
way. It stops further rusting if you clean out the seam and I mean CLEAN,
follow the prep instructions and do both sides of the seam. You do not want
to get the POR-15 too much beyond the rusted area on to fresh metal, just
enough to make a seal to fresh metal.
Top coat with high build primer, feather
edge the resulting edge into the existing good surface then prime again in a
larger area until you have a perfectly smooth surface to apply paint. Paint
and good luck trying to get a perfect match. That's the hardest part unless
it's white. I usually try to paint to a seam line or body line to hide the
new/old finish line. Epoxy and Urethane based paints are the worst for trying
to blend edges Base-Clear goes a little better but the Clear is still Epoxy
or Urethane and there will always be an edge where the new and old meet.
There are many tricks to hide that edge but that's best left to very experienced body persons who know them well.
I recently began using POR-15 to repair perforated rust areas and so far
I am very satisfied with the results. Using POR-15 paint, POR Patch and
chopped Fiberglas to fill has proven to make a like new surface that will not
rust again and the area is a strong as it was originally. I have not tried
this in very large areas and I suspect that it will not work. For large rusted
out areas the best way is still to cut and weld in new metal. Repairing
small rusted or perforated areas with the POR-15 technique will not require the
use of any body fillers. Some top coat surface putty may be necessary to get
a perfectly smooth surface on really rough spots but most time successive
coats of hi-build primer will get the surface smooth for painting.
The one trick to all this is to make sure you use the POR-15 as
directed. Read the instructions provided with the material. Do not attempt to
circumvent these instructions and complain afterwards that POR-15 does not work
for you. Clean the surface with POR-15 Marine Clean, flaky rust should be
removed prior to cleaning as much as possible but not entirely necessary. It
will give you a smother surface in the end if you remove the flaking rust. I
usually like to use a wire wheel on a rotary air tool or spot sand blaster.
Rinse the area with clear water and air dry. Apply POR-15 Metal Ready and let
set until the surface becomes etched. Rinse with clear water and air dry.
Now your ready for the POR-15 application. Do not touch the prepped surface
with your fingers or anything else. If you contaminate the surface the POR-15
will not adhere well.
Get a POR-15 catalogue and read it. You will find a wealth of rust
repair & prevention information in those pages.
And, NO, I do not sell the stuff or have any shares in the company.
Just a very happy user of over 15 years.
Almonte, Ontario, Canada
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