[AMRadio] More Painting Tips

[Donald Chester]

W5SUM wrote:
 
I had a BC348 with the small removeable panel just under the dimmer control,
and that panel was totally devoid of paint.  I put that panel in a 150
degree oven ( please.. do NOT rat me out to my wife as she swings a mean
skillet ), for about ten minutes. I removed the panel and turned off the
oven.
Took the panel outside, let it cool for maybe 2 minutes then sprayed ONE
heavy coat on it. AFTER it had finally begun to wrinkle I put it back in the
turned off but still warm oven, for about ten minutes.   Man. it produced a
BEAUTIFUL deep black wrinkle. 

I'm very pleased
------------------------------

Here are a couple more paint tips I gleaned off other websites in the past.
Didn't save the names of the sources, but here is the text I  saved, and an
anonymous thanks to whoever posted them. The first one was obviously from a
gun collectors' site, not a radio site, but paint should work pretty much
the same on any kind of metal, regardless of what it is used for. I recall a
similar presentation at the AM Forum at Dayton one year, regarding R-390(A)
knobs, but unfortunately lost the notes I took to the black hole that hovers
in my shack. The presenter brought along a main tuning knob;  the glossy
black paint was glazed on tight as porcelain and couldn't be scratched with
a fingernail the way most paint-on-metal jobs seem to turn out.

These instructions may be a little confusing on temperature and when to bake
at 150 degrees and at 300 degrees. From what I read, he does two coats,
pre-heating each one to 150 degrees, then sprays on the paint from the warm
can, then bakes at 300 degrees,  lets it cool back down to 150 and repeats
the whole procedure a second time.  Perhaps someone has successfully tried
this and can verify that my reading comprehension is functioning properly.
Otherwise, trial-and-error experimentation with a piece of scrap metal might
be in order before applying the technique to an actual project.  BTW, these
instructions were for smooth finish paint, NOT for wrinkle finish; I  would
stick with Ron's suggestions for the latter.

A recent experience in the kitchen convinces me even more that the bake-on
technique should work. We cooked something in a  stainless steel pot and let
it get a little too hot and scorch on the bottom. That black  stuff wouldn't
budge after repeated soaking in strong detergent solution. I ended up
manually scraping it off with a blade, and even that was painstaking and not
easy. I thought to myself how I wished I could find paint that would adhere
that well to metal - particularly since this was stainless steel, which
normally doesn't hold paint very well.


(1) BAKE RUSTOLEUM

Makes it rock hard in an hour or so after it cools...

Usually < 200 deg. lower for lighter colors is a good idea. If I recall,
about 140-160F is optimal for Rustoleum.


(Didn't save steps 1-7. Probably irrelevant)

8. Preheat the clean, not handled with bare hands rifle in the oven to 150
degrees or so. You don't want to preheat it more than 200 degrees. To
achieve 150 degrees, you will want to leave the rifle in the oven for 15
minutes or so after it is already up to 150. Some ovens are quick to heat,
some are slow.

9. Hang the rifle and the parts up somewhere and spray them with a light
first coat. Plug the chamber with something, but spray everything else,
inside the receiver and out. I moved the gas tube lever to the locked
position for this coat, if you want you can move it to spray underneath on
the second coat. Be sure to remember the front of the FSB, the front and
underneath of the gas block, etc.

Hold the warm can of Rustoleum (don't spray out of a cold can) back at least
14" to get a good textured finish. You might feel like you're wasting paint.
Get good coverage on this coat, but don't worry about laying it down thick.

10. After allowing the paint to dry a couple minutes until it's at least a
little tacky, put it in the oven and bake it at 300 degrees for an hour.

11. Repeat step 9. Be sure to let the rifle cool down to approximately 150
degrees before you spray again.

12. Repeat step 10.

Let the rifle cool enough to handle with latex gloves and check out the
finish. If you're happy with it, stop here; if you don't like the
consistency of the finish, repeat 9 and 10.

Enjoy your finish! After the rifle has cooled after curing at 300 degrees
for an hour, the finish will be tough and ready to handle.


(2) RUST-O-LEUM NOT THE BEST

"In my opinion Rust-o-leum is probably the worst quality spray paint out
there. It doesn't flow out well. It runs and sags easily, takes forever to
cure and isn't all that durable.

I use an engine enamel that's sold by NAPA Auto Parts stores. The brand is
Martin-Senour. I flows and builds well, seems more durable and just plain
looks nicer than most spray paints. The can even sprays in a fan pattern
like a real spray gun. (no connection with NAPA... yadda yadda yadda) For
my lathe I picked the #7883 grey universal engine enamel. It didn't have
the slight blue tint that the original paint showed but was about the right
shade of grey. This stuff is a bit more expensive at almost $6 a can but
it's worth it.

I've got a couple of spray guns that I use for cars and finishing furniture
but the convenience of a can and the result I can get with this brand keeps
the spray rigs in the cabinet.

I strip everything to bare metal and put on 2 coats of paint. No primer
necessary. After drying for a few hours everything that fits gets baked in
the oven at 200 degrees for 2 hours. This gives a really hard durable
finish. I've used this technique on many engines and machine tools with
great success."

Don k4kyv