Spray painting
Mikko Peltoniemi
I'll try it for the fun of it. (Ok, so I was painting a computer case ;)
Anyway, I sanded the case down well, all smooth, applied primer and
all. But when I got to the painting part I ran into trouble.
Every once in a while, sometimes more often, sometimes never, there's
a big glob of paint that lands on the painted surface. Sometimes
there's a bunch a small drops. How the hell do I avoid these? Is
it in the technique? Or in the brand of paint?
The problem is not that paint collects into big pools, since I do
thin coats. But the globs start from the nozzle itself. Sometimes the
spray isn't fine mist, but it looks like someone took a paint brush
and just flicked it to get the paint out.
Without these, I'd say the paint job would look pretty good... :(
And yes, I did shake the can for a long, long time...
--
Mikko Peltoniemi
Film & Video Editor, Avid Technician at large.
http://www.discountcadavers.com
Russell Stewart
> I was trying spray painting for the first time in my life. I figured
> I'll try it for the fun of it. (Ok, so I was painting a computer case ;)
>
> Anyway, I sanded the case down well, all smooth, applied primer and
> all. But when I got to the painting part I ran into trouble.
>
> Every once in a while, sometimes more often, sometimes never, there's
> a big glob of paint that lands on the painted surface. Sometimes
> there's a bunch a small drops. How the hell do I avoid these? Is
> it in the technique? Or in the brand of paint?
>
> The problem is not that paint collects into big pools, since I do
> thin coats. But the globs start from the nozzle itself. Sometimes the
> spray isn't fine mist, but it looks like someone took a paint brush
> and just flicked it to get the paint out.
>
> Without these, I'd say the paint job would look pretty good... :(
>
> And yes, I did shake the can for a long, long time...
I'm not sure, but I'd guess that this is inherent in the spray-
painting process. When you think about it, spray paint is basically
a cheap version of airbrushing. And cheap == lower quality, so you'd
naturally expect things of this nature. If you want a really good-
quality, even coating, you'll probably have to go with an airbrush.
--
Russell Stewart | E-Mail: dia...@swcp.com
UNM CS Department | WWW: http://www.swcp.com/~diamond
The first obstacle to solving an interesting problem is the
belief that you're not smart enough to do it.
Tony Myers (now with flavor crystals!)
Mikko Peltoniemi
> try holding th can further away
Thanks, but no... The globs of paint reach just as far as the fine mist
itself. Possibly even further.
Mikko Peltoniemi
> a cheap version of airbrushing. And cheap == lower quality, so you'd
> naturally expect things of this nature. If you want a really good-
> quality, even coating, you'll probably have to go with an airbrush.
Well, I could live with that, I mean a few specs are fine, since no-one
is even going to look at it but me. But I was wondering if there's a
fault in my technique in painting, that caused them.
And I knew to expect problems with spray anyway, such as the orange
peel surface and stuff like that. But nowhere did I see any mention of
the paint globs.
Eddie G
the can.
"Mikko Peltoniemi" <mikk...@hotmail.com> wrote in message
news:3cfpvfF...@individual.net...
Bob E.
>
> I was trying spray painting for the first time in my life. I figured
> I'll try it for the fun of it. (Ok, so I was painting a computer case ;)
>
> Anyway, I sanded the case down well, all smooth, applied primer and
> all. But when I got to the painting part I ran into trouble.
>
> Every once in a while, sometimes more often, sometimes never, there's
> a big glob of paint that lands on the painted surface. Sometimes
> there's a bunch a small drops. How the hell do I avoid these? Is
> it in the technique? Or in the brand of paint?
Three ideas come to mind:
1. The valve on the spray can was defective. Did you try another
can?
2. It's your technique. Are you pressing the valve down fully? Only
pressing it part of the way does not allow the correct volumes of
propellant and paint to mix in the valve, and you can get globbers.
Also, you need to develop a sweeping pattern where you press down on
the valve before you hit the edge of your object being painted, and
carry on past the other edge before letting up on the valve. Starting
and stopping the spray can result in globs, and you don't want to be
pointing at your target when they fly off the nozzle.
3. Some paints go bad on the shelf, and no amount of shaking will
rejuvenate. You may have no way to tell if the paint had been
sitting on the shelf for a long time, try another can from a different
store. Flecto Varathane is known to have this problem.
--Bob
=======================================================================
Bob Ellingson bo...@halted.com
Halted Specialties Co., Inc. http://www.halted.com
3500 Ryder St. (408) 732-1573
Santa Clara, Calif. 95051 USA (408) 732-6428 (FAX)
Les Albert
Mikko Peltoniemi wrote:
> Tony Myers (now with flavor crystals!) wrote:
>
> > try holding th can further away
>
> Thanks, but no... The globs of paint reach just as far as the fine
mist
> itself. Possibly even further.
Try holding the can closer.
Les
Stephen Fels
> Russell Stewart wrote:
>
>> a cheap version of airbrushing. And cheap == lower quality, so you'd
>> naturally expect things of this nature. If you want a really good-
>> quality, even coating, you'll probably have to go with an airbrush.
>
> Well, I could live with that, I mean a few specs are fine, since no-one
> is even going to look at it but me. But I was wondering if there's a
> fault in my technique in painting, that caused them.
>
> And I knew to expect problems with spray anyway, such as the orange
> peel surface and stuff like that. But nowhere did I see any mention of
> the paint globs.
It may not be possible to /avoid/ paint gobs, but there are techniques that
can minimize them. Spray for short periods and wipe the nozzle frequently.
Keep a largish scrap of paper, or card, nearby and begin each spray with a
quick blast at the scrap, to clear the nozzle.
--
Stephen
Home Page: stephmon.com
Satellite Hunting: sathunt.com
Hactar
Mikko Peltoniemi <mikk...@hotmail.com> wrote:
> I was trying spray painting for the first time in my life. I figured
> I'll try it for the fun of it. (Ok, so I was painting a computer case ;)
>
> Anyway, I sanded the case down well, all smooth, applied primer and
> all. But when I got to the painting part I ran into trouble.
>
> Every once in a while, sometimes more often, sometimes never, there's
> a big glob of paint that lands on the painted surface. Sometimes
> there's a bunch a small drops. How the hell do I avoid these? Is
> it in the technique? Or in the brand of paint?
IIRC the pros have some setup where the nozzle is electrically charged one
way, and the target is charged the other way. Net result, more of the
paint hits the target (less drifts away on the breeze) and my WAG is that
the droplets would repel each other and be less likely to combine. Maybe
you can rig something similar up?
Failing that, probably the humidity affects the paint's behavior.
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
A. A Top Poster \ http://www.fscked.co.uk/
B. Who's there? \ writing/
A. Knock-knock -- from bob...@xxx.com \ top-posting-cuss.html
mdginzo
2. prime
3. paint
4. let dry
5 spray again
6 sand
"Mikko Peltoniemi" <mikk...@hotmail.com> wrote in message
news:3cfpvfF...@individual.net...
mdginzo
"mdginzo" <mdg...@bellsouth.net> wrote in message
news:1QE8e.80611$vL3....@bignews4.bellsouth.net...
> 1. sand
> 2. prime
> 3. paint
> 4. let dry
> 5 SAND
> 6 SPRAY AGAIN
7. SAND
SAND BETWEEN COATS WITH ULTRA FINE SANDPAPER MADE FOR SPRAY PAINT.
SoCalMike
> IIRC the pros have some setup where the nozzle is electrically charged one
> way, and the target is charged the other way. Net result, more of the
> paint hits the target (less drifts away on the breeze) and my WAG is that
> the droplets would repel each other and be less likely to combine. Maybe
> you can rig something similar up?
sounds like youre describing "powder coating"
Dave T
> I was trying spray painting for the first time in my life. I figured
> I'll try it for the fun of it. (Ok, so I was painting a computer case ;)
>
> Anyway, I sanded the case down well, all smooth, applied primer and
> all. But when I got to the painting part I ran into trouble.
>
> Every once in a while, sometimes more often, sometimes never, there's
> a big glob of paint that lands on the painted surface. Sometimes
> there's a bunch a small drops. How the hell do I avoid these? Is
> it in the technique? Or in the brand of paint?
>
> The problem is not that paint collects into big pools, since I do
> thin coats. But the globs start from the nozzle itself. Sometimes the
> spray isn't fine mist, but it looks like someone took a paint brush
> and just flicked it to get the paint out.
>
> Without these, I'd say the paint job would look pretty good... :(
>
> And yes, I did shake the can for a long, long time...
>
Try several light coats instead of trying to cover it in one go. (it
sounds like you're doing this) Sand with fine sandpaper between coats.
Warm the can of paint before you use it by partially submerging it in
warm water. Or, for more excitement, in the microwave oven. (kidding!).
This makes the paint flow better.
--
Dave T.
Remove "slu" to reply
Hactar
Could be. Would a similar setup work wrt spray paint?
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
Drive nail here > < for new monitor.
Mikko Peltoniemi
> Try several light coats instead of trying to cover it in one go. (it
Yes, I am doing that already. The trouble is that ever time you get a
glob of paint, it's much more than any light coat I'm applying, so
no wonder it's noticable.
> Warm the can of paint before you use it by partially submerging it in
> warm water. Or, for more excitement, in the microwave oven. (kidding!).
This seemed to help a lot. I put some hot tap water in a container, and
put the paint can in there, before painting. At first I got a lot less
globs, and whatever I did get were so fluid that they evened themselves
out.
But unfortunately, towards the end of the can I got a few. Even though
I did submerge the can for a while in between. But I'll probably settle
with that.
Hactar
Mikko Peltoniemi <mikk...@hotmail.com> wrote:
> Dave T wrote:
>
> > Warm the can of paint before you use it by partially submerging it in
> > warm water. Or, for more excitement, in the microwave oven. (kidding!).
>
> This seemed to help a lot. I put some hot tap water in a container, and
> put the paint can in there, before painting. At first I got a lot less
> globs, and whatever I did get were so fluid that they evened themselves
> out.
>
> But unfortunately, towards the end of the can I got a few. Even though
> I did submerge the can for a while in between.
Maybe the can's cooling off as you use it, in which case a drink can
sleeve would help (if it fits). I guess a towel wrapped around it would
work if it doesn't.
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
Answer: two spoonfuls in my cup, please.
Question: how much should I use? (why top-posting is bad)
http://www.fscked.co.uk/writing/top-posting-cuss.html
Tim Wright
> In article <3clgddF...@individual.net>,
> Mikko Peltoniemi <mikk...@hotmail.com> wrote:
>
>>Dave T wrote:
>>
>>
>>>Warm the can of paint before you use it by partially submerging it in
>>>warm water. Or, for more excitement, in the microwave oven. (kidding!).
>>
>>This seemed to help a lot. I put some hot tap water in a container, and
>>put the paint can in there, before painting. At first I got a lot less
>>globs, and whatever I did get were so fluid that they evened themselves
>>out.
>>
>>But unfortunately, towards the end of the can I got a few. Even though
>>I did submerge the can for a while in between.
>
>
> Maybe the can's cooling off as you use it, in which case a drink can
> sleeve would help (if it fits). I guess a towel wrapped around it would
> work if it doesn't.
>
from a liquid to a gas.
Mikko Peltoniemi
> The propellant will cool the can as the propellant transitions from a
> liquid to a gas.
Yep, anyone who's ever used a liquid air can has experienced this. They
get mighty cold.
Ok, after curing the paint for four hours, the results are amazing. But
I can't believe just warming the can could've caused it. I used the
same brand and type of paint as before. But the results are much better.
Except for one thing.
On top of the case, the paint cracked in an area of a few square
centimeters. It didn't look like that at first, but after letting
it cure for a few hours, they had appeared. Damn, if it wasn't for that
it would look great.
What could've caused the paint to crack? Too much paint? Not enough
sanding? Contamination?
Also, should I paint just the top part again, or the whole case?
Do I risk a big difference in shade, if I just paint the top part? Sure
there's a little bit more work involved, if I paint the whole case once
more. But what I'm worried is if something else goes wrong, again, and
ruins the otherwise good paint elsewhere.
Hactar
Robert Crowe <robc...@iglou.com> wrote:
> On Tue, 19 Apr 2005 23:40:05 GMT, the alleged Hactar, may have posted
> the following, to alt.fan.cecil-adams:
>
> >Maybe the can's cooling off as you use it,
>
>
> >in which case a drink can sleeve would help (if it fits). I guess a
> >towel wrapped around it would work if it doesn't.
>
> small amount of environmental warming.
OK, a towel with a big honkin' hand warmer. And paint in short stretches.
It probably would be more effective to warm the gas while painting,
considering that the gas is cooler than the liquid (in the short term).
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
LIBRA: A big promotion is just around the corner for someone
much more talented than you. Laughter is the very best medicine,
remember that when your appendix bursts next week. -- Weird Al
Dave T
I dunno. One of the reasons I stopped building plastic models was the
frustration of never getting a good finish with spray paint (or an
airbrush for that matter). The cracking is probably due to too much
paint. But it also could be that the layer of paint underneath was not
quite dry when you added the next coat.
ra...@westnet.poe.com
<snip>
> I dunno. One of the reasons I stopped building plastic models was the
> frustration of never getting a good finish with spray paint (or an
> airbrush for that matter). The cracking is probably due to too much
> paint. But it also could be that the layer of paint underneath was not
> quite dry when you added the next coat.
Huh, with plastic models, I'd say that your surface prep wasn't up there:
The articles I've read in _Fine Scale Modler_ show that with reasonable
care you can get amazing finishes: things like prewashing the parts to
remove traces of mold-releaase compounds.
John
--
Remove the dead poet to e-mail, tho CC'd posts are unwelcome.
Mean People Suck - It takes two devitations to get cool.
Ask me about joining the NRA.
Reunite Gondwanaland (Mary Shafer)
wrote:
> On Tue, 19 Apr 2005 23:40:05 GMT, the alleged Hactar, may have posted
> the following, to alt.fan.cecil-adams:
> >Maybe the can's cooling off as you use it,
>
> Yep, it sure is.
>
> >in which case a drink can sleeve would help (if it fits). I guess a
> >towel wrapped around it would work if it doesn't.
>
> That's very doubtful. I'm thinking that Boyle's Law will trump any
> small amount of environmental warming.
I don't think it can. Boyle's Law says that the propellant that
you're spraying will cool, but only after it leaves the can and really
expands. The remaining propellant will cool very slightly as its
volume increases to fill the can as you spray, but that's not very
much.
You'll get more heat transferring from your hand clutching the can
than you'll get from the propellant expanding inside the can.
Mary "paint isn't a gas"
--
Mary Shafer Retired aerospace research engineer
reunite....@gmail.com or mil...@qnet.com
Charles Bishop
While using an airbrush, the propellant can got noticably colder as the
propellant was used up. There was even a bit of frost on the lower portion
of the can. Haven't noticed this with spary paint cans though.
--
charles
Hactar
Charles Bishop <ctbi...@earthlink.netttt> wrote:
> In article <nqvh61dq95nnbna3r...@4ax.com>, "Reunite
> Gondwanaland (Mary Shafer)" <reunite....@gmail.com> wrote:
>
> >On Wed, 20 Apr 2005 04:54:15 +0000, Robert Crowe <ebop...@tznvy.pbz>
> >wrote:
> >
> >> On Tue, 19 Apr 2005 23:40:05 GMT, the alleged Hactar, may have posted
> >> the following, to alt.fan.cecil-adams:
> >
> >> >Maybe the can's cooling off as you use it,
> >>
> >> Yep, it sure is.
> >>
> >> >in which case a drink can sleeve would help (if it fits). I guess a
> >> >towel wrapped around it would work if it doesn't.
> >>
> >> That's very doubtful. I'm thinking that Boyle's Law will trump any
> >> small amount of environmental warming.
> >
> >I don't think it can. Boyle's Law says that the propellant that
> >you're spraying will cool, but only after it leaves the can and really
> >expands. The remaining propellant will cool very slightly as its
> >volume increases to fill the can as you spray, but that's not very
> >much.
Not only does the volume of the propellant increase in the can, part of it
goes away with the paint.
> >You'll get more heat transferring from your hand clutching the can
> >than you'll get from the propellant expanding inside the can.
>
> While using an airbrush, the propellant can got noticably colder as the
> propellant was used up. There was even a bit of frost on the lower portion
> of the can. Haven't noticed this with spary paint cans though.
WAG #1: A significant heat contribution is made by your hand. Had you
been holding the can the whole time you were painting, you
would've warmed it to non-frosty temperatures.
WAG #2: The propellant in airbrushing is used faster than the propellant
in spraypainting; thus its container cools off more.
Greg Goss
wrote:
>> >in which case a drink can sleeve would help (if it fits). I guess a
>> >towel wrapped around it would work if it doesn't.
>>
>> That's very doubtful. I'm thinking that Boyle's Law will trump any
>> small amount of environmental warming.
>
>I don't think it can. Boyle's Law says that the propellant that
>you're spraying will cool, but only after it leaves the can and really
>expands. The remaining propellant will cool very slightly as its
>volume increases to fill the can as you spray, but that's not very
>much.
>
>You'll get more heat transferring from your hand clutching the can
>than you'll get from the propellant expanding inside the can.
One of the temp labour jobs I worked at in the early nineties involved
changing the propane tanks on "tiger torches". (The condo was vastly
behind schedule, during and partly because of a deep cold snap -- cold
from the viewpoint of the "wet coast" of course. The fire inspector
had a date booked to look at the sprinkler system before the next step
could start, so the water went into all those pipes. So now they had
to keep the windowless condominiums from freezing.)
When I walked into each room, I could immediately see the level of
propane from where the frost sat on the bottle.
The cold "appeared" at the point where the liquid turned to a gas,
rather than at the point where the gas expanded.
Does the propellant in a spray can turn to gas in the can, or in the
valve?
--
Tomorrow is today already.
Greg Goss, 1989-01-27
Clint Mason
ebe...@tampabay.ARE-ARE.com.unmunge (Hactar) wrote:
> Not only does the volume of the propellant increase in the can,
What? Why? Are you talking about an explosion? I can see the size of the
can increasing under abnormal circumstances.
> part of it goes away with the paint.
I can only hope that you mean the propellant and not the volume.
Have fun,
Clint
Jordan Abel
of course - the extra volume for the first part of his statement comes
from the paint going away.
Peter Ward
posted....
>"Reunite Gondwanaland (Mary Shafer)" <reunite....@gmail.com>
>wrote:
>
>>> >in which case a drink can sleeve would help (if it fits). I guess a
>>> >towel wrapped around it would work if it doesn't.
>>>
>>> That's very doubtful. I'm thinking that Boyle's Law will trump any
>>> small amount of environmental warming.
>>
>>I don't think it can. Boyle's Law says that the propellant that
>>you're spraying will cool, but only after it leaves the can and really
>>expands. The remaining propellant will cool very slightly as its
>>volume increases to fill the can as you spray, but that's not very
>>much.
That seems reasonable. Certainly any cooling effect will not be
prevented by insulating the can. In fact it will be exacerbated as
heat transfer from the environment will be much reduced.
>One of the temp labour jobs I worked at in the early nineties involved
>changing the propane tanks on "tiger torches".
[snip]
>When I walked into each room, I could immediately see the level of
>propane from where the frost sat on the bottle.
>
>The cold "appeared" at the point where the liquid turned to a gas,
>rather than at the point where the gas expanded.
>
I suspect that, in the propane bottles, the cooling effect is due to
latent heat of vapourisation, rather than the expansion of the gas.
Thus, the liquid is the cold bit (as observed).
I believe paint propellants are already gaseous, in which case there
should be no latent heat cooling effect.
--
Peter
I'm an Alien
Alistair Gale
Somebody wrote:
[snip]
>>
>>I don't think it can. Boyle's Law says that the propellant that
>>you're spraying will cool, but only after it leaves the can and really
>>expands. The remaining propellant will cool very slightly as its
>>volume increases to fill the can as you spray, but that's not very
>>much.
>>
[snip]
>When I walked into each room, I could immediately see the level of
>propane from where the frost sat on the bottle.
>
>The cold "appeared" at the point where the liquid turned to a gas,
>rather than at the point where the gas expanded.
>
>Does the propellant in a spray can turn to gas in the can, or in the
>valve?
So what is going on in the spray-can may be a case of "latent heat of
vaporization" instead of Boyle's law?
--
alistair
Hactar
Greg Goss <go...@gossg.org> wrote:
>
> One of the temp labour jobs I worked at in the early nineties involved
> changing the propane tanks on "tiger torches". (The condo was vastly
> behind schedule, during and partly because of a deep cold snap -- cold
> from the viewpoint of the "wet coast" of course.
> The cold "appeared" at the point where the liquid turned to a gas,
> rather than at the point where the gas expanded.
Propane can be liquefied by pressure alone at human temperatures. Also
see those stick-on gauges for propane barbeque tanks that work when you
splash water on them, relying on the different thermal properties of
liquid and gaseous propane.
What is the propellant in most spray cans? Is there some warning about
"will not work below X degrees"?
> Does the propellant in a spray can turn to gas in the can, or in the
> valve?
Or is it always gas?
Even if it's a lousy propellant with a low vapor pressure, if it
works at all it has to boil _some_ in the can, so the vapor takes up the
space vacated by the paint.
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
TAURUS: You will never find true happiness - what you gonna
do, cry about it? The stars predict tomorrow you'll wake up,
do a bunch of stuff and then go back to sleep. -- Weird Al
Blinky the Shark
> Propane can be liquefied by pressure alone at human temperatures. Also
> see those stick-on gauges for propane barbeque tanks that work when you
> splash water on them, relying on the different thermal properties of
> liquid and gaseous propane.
I've never used a propane BBQ tank. Unless it says "Hey! You just
splashed water on me!", what is this warning?
--
Blinky Linux Registered User 297263
Killing all Usenet posts from Google Groups
Info: http://blinkynet.net/comp/uip5.html
Hactar
Blinky the Shark <no....@box.invalid> wrote:
> Hactar wrote:
>
> > Propane can be liquefied by pressure alone at human temperatures. Also
> > see those stick-on gauges for propane barbeque tanks that work when you
> > splash water on them, relying on the different thermal properties of
> > liquid and gaseous propane.
>
> I've never used a propane BBQ tank. Unless it says "Hey! You just
> splashed water on me!", what is this warning?
What, where I asked "Is there some warning about 'will not work below X
degrees'?"? I don't have any spray paint to check, but it seems all
consumer products include some ass-covering and legalese somewhere. Such
a warning, if it exists, may indicate the liquefaction temperature of the
propellant, if the propellant isn't otherwise known.
If you're speaking of the stick-on gauges, they just indicate the fluid
level via color difference. There's no warning on them TTBOMK, and some
concerning the usual hazards of a compressed, flammable gas on the tank.
I have used a propane BBQ, but never one of those -- I always judged the
amount in the tank by sloshing the contents. Here's one:
http://harrietcarter.com/Detail.cfm?prod=5864&UDC=Y
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
PISCES: Try to avoid any Virgos or Leos with the Ebola virus.
You are the Lord of the Dance, no matter what those idiots at
work say. -- Weird Al, _Your Horoscope for Today_
Blinky the Shark
> In article <slrnd6lb78....@thurston.blinkynet.net>,
> Blinky the Shark <no....@box.invalid> wrote:
>> Hactar wrote:
>> > Propane can be liquefied by pressure alone at human temperatures. Also
>> > see those stick-on gauges for propane barbeque tanks that work when you
>> > splash water on them, relying on the different thermal properties of
>> > liquid and gaseous propane.
>> I've never used a propane BBQ tank. Unless it says "Hey! You just
>> splashed water on me!", what is this warning?
> What, where I asked "Is there some warning about 'will not work below X
> degrees'?"? I don't have any spray paint to check, but it seems all
Only if that's the one that's moisture sensitive, as described in the
paragraph to which I responded and quoted.
> If you're speaking of the stick-on gauges, they just indicate the fluid
That's what's mentioned in the paragraph to which I responded and
quoted.
> level via color difference. There's no warning on them TTBOMK, and some
Fluid level indicator, then. Thanks.
Greg Goss
The volume is a measurement of the propellant. After the volume
increases, some of the propellant is in the can and some of the
propellant is not in the can. The can, generally, retains the same
volume. Indeed, since this thread started with a discussion of
refrigerant effects, the can is probably getting SMALLER.
Jordan Abel
>>What? Why? Are you talking about an explosion? I can see the size of the
>>can increasing under abnormal circumstances.
>>
>>> part of it goes away with the paint.
>>
>>I can only hope that you mean the propellant and not the volume.
>
> The volume is a measurement of the propellant. After the volume
> increases, some of the propellant is in the can and some of the
> propellant is not in the can. The can, generally, retains the same
> volume. Indeed, since this thread started with a discussion of
> refrigerant effects, the can is probably getting SMALLER.
except, that as paint leaves the can, the volume available for the
propellant to take up increases. you know, as there's less volume of
paint. if one assumes [i was assuming - it sounds reasonable] that the
paint is a liquid and the propellant is a gas
Greg Goss
I was assuming (it sounds reasonable) that the propellant was a
hydrocarbon and a liquid mixed with the liquid paint.
I'm surprised that no authoritative (or authoritative sounding) source
has jumped in yet to tell us which is correct.
Hactar
Here you go. There's a sidebar on
http://science.howstuffworks.com/aerosol-can3.htm :
,--
| Up until the 1980s, a lot of liquefied-gas aerosol cans used
| chlorofluorocarbons (CFCs) as a propellant. After scientists concluded
| that CFCs were harmful to the ozone layer, 70 nations signed the
| Montreal Protocol, an agreement to phase out CFC use over the next
| decade.
|
| Today, almost all aerosol cans contain alternative propellants, such as
| liquefied petroleum gas, which do not pose as serious a threat to the
| environment.
'--
--
-eben ebQ...@EtaRmpTabYayU.rIr.OcoPm home.tampabay.rr.com/hactar
SAGITTARIUS: All your friends are laughing behind your back... kill
them. Take down all those naked pictures of Ernest Borgnine you've got
hanging in your den. -- Weird Al, _Your Horoscope for Today_