©By: John T. Blair (WA4OHZ)
1133 Chatmoss Dr., Va. Beach, Va. 23464; (757) 495-8229
Last updated: Jan. 21, 2000
1. What is POR-15 paint?
POR-15 is a polyurethane paint that contains a rust inhibitor. It
can be painted over light rust and will stop the rust for spreading.
It dries pretty much rock hard and is very scratch resistant.
It seals the metal and is used as a primer which can be lightly
sanded and painted over with another primer or a color coat. It
will fill in small (pin) holes. The stuff is great any place that
you'd expect to get rust.
It is moisture cured. The higher the humidity the faster it drys.
2. How is it applied?
It can be brushed or sprayed. However, for most areas, I suggest
brushing. It will gum up a spray gun. I purchased an undercoating
gun from JC Whitney
for $35 that I use to spray the POR-15 in places
(like the quarter panels from inside the trunk) that I can't reach
with a paint brush. It flows pretty well. (Note: 2009 I don't see the
undercoating gun at JCWhitney's.)
If you plan on spraying it, do so only if you are wearing a
It contains Polyisocynates and is
nothing to fool around with, but the results are worth the precautions.
3. Can it be used as a top coat?
No! While POR-15 does flow out nicely and dries to a nice high
gloss, it has a tendency to generate tiny bumps as though the
paint were out gassing which is noticeable on smooth metal.
However on items like chassis or rusty metal that are rough any
way the bumps aren't very noticeable.
The only disadvantage is it is Gloss Black, but the color will flush
out if exposed to UV (sunlight). Consequently, any POR-15 that will
be exposed to Sun light should have a top coat of some other paint
applied. It makes a great "chassis" paint as the chassis is not
exposed to sunlight.
4. Is this like a asphalt based paint or undercoating?
- No, it isn't.
5. How should metal be prepared before painting?
It is best to sand blast the metal. This is especially true
for "new" metal. POR-15 needs something to bite into. Old
rusty metal can be cleaned by using a wire brush. By this
I mean a knotted wire wheel on a 4" 10,000 rpm grinder.
6. How do you store it?
I save all my cherry and olive jars and tops. You want
relatively small jars about 2" in dia. and maybe 3" tall.
When the quart of POR-15 is first opened, pour it into
several of these small jars and place a piece of plastic
or wax paper over the top of the jar then put the top
back on. If you don't put the plastic on, the top will
stick to the jar and you can't get it open. I've
also found that if you store the jar upside down it helps.
Especially any that are not totally full. The POR-15 is
activated by humidity and the air that is trapped in the
jar will cause the top surface to harden. You can cut
down through it to get to good paint. But by storing the
jars upside down, the film will be at the bottom so when
you open the jar, you have paint! [Just check that the
tops and plastic are on tightly. I've had one jar leak
all over my bench. I don't recommend using jars with
plastic tops if you plan on storing them upside down.]
I've also found that it has a much longer shelf life if you
store it in the refrigerator. [Hint: Not you your wife's
refrig in the kitchen. And don't store it upside down in
7. How do you use POR-15?
When you want to use POR-15, open a storage jar and pour
a little into a plastic cup, (I salvaged small butter tubs
from the kitchen). Then immediately reseal the storage jar.
A little POR-15 goes a long ways. It's easier to go back
for more than to have a lot of it go bad. It will "flash",
start to harden, and not be spreadable much like body putty
fiberglass resin, or epoxy.
Depending on the humidity, the life of the paint in an open
container, (butter tub) is about 1/2 hour (at least here in
Southern VA. when the humidity is between 95 and 106%).
Do not return any unused portions to the storage jar after
you have had it out. This will contaminate the paint in
the jar and cause it to harden. So take the leftovers and
paint your ramps, inside your bumpers, rusty steel wheels.
Since you aren't opening 1 big jar all the time, the POR-15
lasts a lot longer. At worst I only through a little away
when I get to the bottom of the jar. Before I started doing
this, I have had to through about 1/2 a quart away - $20 down
8. How do you stay clean?
I purchase the loose fitting plastic gloves from a warehouse
buying club (Price Club/CostCo). I get 3 packs of 100 gloves for
about $5. I where these when ever I'm using the POR-15 or a
acid metal etchant. While I don't stay completely clean, it's
a lot better than not wearing the gloves.
While the paint is still wet, you can wipe it off using a rag
and lacquer thinner.
9. What type of bristle brush do you use?
I buy the cheapest 1" brushes I can get, about 75 cents each, from Kmart.
When I finish painting, I pour any remaining money (I mean POR-15)
into the garbage can on top of old paper. Then I clean the butter
tub and paint brush with lacquer thinner or acetone. I get
indefinite use from the butter tubs (10 or more uses) and at least
3 uses from 1 brush.
But then again, I'm cheap.
BTW if you aren't aware of it, you can purchase a 5 gal. of
**cleaning** grade lacquer thinner for $18-$25. That is quite a
savings since I just paid $18/gal for lacquer thinner to paint
10. Is there an acceptable way to thin POR-15?
Yes. POR sells a solvent that you can used to cut the POR-15
with. However, you can only cut it about 20%. I've found that
if I am brushing it on, I don't need to cut the POR-15. So
you can save you money.
11. Where can I get POR-15?
The POR company. They advertise in Hemmings all the time.
Their address is:
P.O. Box 1235
Morristown, NJ. 07962-1235
To email POR-15 Company with comments or questions.
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