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Rustoleum Hammered Paint - To prime or not to prime?
Posted: Mon Mar 02, 2009 5:04 pm
by mickyd
What's the users recommendation for whether or not to use primer when painting the sheet metal and cast aluminum SS parts using the spray cans? The front of the can says no primer needed yet instructions on back says primer recommended on bare metal.
I saw a difference in texture when painting a side by side sample of primed vs. unprimed sheet metal. You can see it
here.
Posted: Mon Mar 02, 2009 6:46 pm
by bucksaw
I always prime just about everything I paint, especially metal.
Posted: Fri May 08, 2009 12:22 pm
by mickyd
I wanted to update this thread with some info I got off the Rustoleum website regarding priming. The
technical data sheet recommends not to use primer (in the surface preparation section) whereas as mentioned in my first post, the actual
spray can label indicates primer recommended on the back of the can but also says no primer needed on the front of the can!!! I guess this means flip a coin???
I tried both methods when I did
my Greenie. The sheet metal
belt cover and
motor pan were unprimed and
all the other painted parts were primed with
self etching primer. I should have tried no primer on one of the cast aluminum parts just to see if there would be a longevity issue but.....didn't think of it. Next time for sure.
At this point, I can only say that
my experience on sheet metal test sprays with
spray speed constant, the texture of the paint varies when applying to primed or unprimed surfaces as shown in
this other post. You'll notice the primed left side of the panel has very little texture and the right side has a heavier texture. In order to get the unprimed sheet metal to match the primed, the application had to be heavier (slower speed). Unprimed has to use MORE PAINT to get good texture. Hopefully, this wasn't the motive of Rustoleum's marketing / engineering group for increasing paint sales.
I guess the bottom line to this thread at this point is.....don't know the longevity effects of priming vs. not BUT I do know the effects on texture. Only time will answer the question regarding longevity. My comparison will ultimately be the sheet metal base legs (primed) as compared to the Belt cover and motor pan (unprimed). To get the texture right, you need to make sure to do test sprays on an similar base substrate (primer or not).
p.s. To get your hands on cheap sheet metal, keep your eye on Craigslist. In populated areas, people are giving away file cabinets / desks all the time.
Posted: Fri May 08, 2009 2:07 pm
by JPG
mickyd wrote:I wanted to update this thread with some info I got off the Rustoleum website regarding priming. The
technical data sheet recommends not to use primer (in the surface preparation section) whereas as mentioned in my first post, the actual
spray can label indicates primer recommended on the back of the can but also says no primer needed on the front of the can!!! I guess this means flip a coin???
I tried both methods when I did
my Greenie. The sheet metal
belt cover and
motor pan were unprimed and
all the other painted parts were primed with
self etching primer. I should have tried no primer on one of the cast aluminum parts just to see if there would be a longevity issue but.....didn't think of it. Next time for sure.
At this point, I can only say that
my experience on sheet metal test sprays with
spray speed constant, the texture of the paint varies when applying to primed or unprimed surfaces as show in
this other post. You'll notice the primed left side of the panel has very little texture and the right side has a heavier texture. In order to get the unprimed sheet metal to match the primed, the application had to be heavier (slower speed). Unprimed has to use MORE PAINT to get good texture. Hopefully, this wasn't the motive of Rustoleum's marketing / engineering group for increasing paint sales.
I guess the bottom line to this thread at this point is.....don't know the longevity effects of priming vs. not BUT I do know the effects on texture. Only time will answer the question regarding longevity. My comparison will ultimately be the sheet metal base legs (primed) as compared to the Belt cover and motor pan (unprimed). To get the texture right, you need to make sure to do test sprays on an similar base substrate (primer or not).
p.s. To get your hands on cheap sheet metal, keep your eye on Craigslist. In populated areas, people are giving away file cabinets / desks all the time.
How's THIS for an explanation of the label/tech info "CONTRADICTION" regarding use of 'PRIMER".
1) The Tech Info is written/created by folks who KNOW of what they speak(they know what they are talking about).
2) The label is created by Marketing by folks who know a LITTLE about what they are talking about(Not what is, but what isn't).
The label refers to BARE wood or metal. The tech info seems to be referring to previously painted objects. Yes the label info jumps around(must have been written by a female).
OOps! I wrote this like a PM! Others would not understand some of the jabs. I am letting it post as is. Let the chips fall where they may.
Posted: Fri May 08, 2009 3:08 pm
by mickyd
JPG40504 wrote:................Yes the label info jumps around(must have been written by a female).
OOps! I wrote this like a PM! Others would not understand some of the jabs. I am letting it post as is. Let the chips fall where they may.
Eyyyy..... and a brave man you are!!!
Posted: Fri May 08, 2009 3:39 pm
by etc92guy
imho.....prime if it's wood so the surface doesn't swell from the moisture of the paint. prime if the metal is so smooth that the paint won't grip. no priming necessary if you have a metal surface that the paint will grip.
The hammered line was formulated to cover damaged metal surfaces. The textured surface is supposed to hide surface defects.
Posted: Fri May 08, 2009 5:44 pm
by judaspre1982
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Posted: Fri May 08, 2009 5:57 pm
by mickyd
Excellent overview jp. I'm glad you mentioned about your aluminum tailstock not having primer and not being as chip resistant. Also glad you mentioned that the steel parts held up well as compared to aluminum since that is what I did on the headstock.....no primer.
It's very possible that Rustoleum recommendation for not primer applies to steel and not aluminum.
I has a more warm and fuzzy priming also BUT....I will test it out for myself.....just the way I am.......gotta know first hand!!!
Posted: Fri May 08, 2009 6:00 pm
by judaspre1982
=========================
Posted: Sat May 09, 2009 3:58 am
by mickyd
judaspre1982 wrote:Micky D , On your test piece of sheet metal, how many top coats were applied?................................. ------Dave
Dave,
There was one coat on the test piece shown