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Decanting Small Amounts from Rattlecans


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I've read that when decanting paint from rattlecans, it's necessary to let the paint sit open for a few hours to "gas out" or it can explode. This is usually about decanting whole cans at a time. I've sprayed small amounts of rattlecan paint into the can's cap, let it sit for a few minutes to thicken up a bit, and used it for brushed touchups, no problem. But what if I want to decant, say, 1/8 to 1/4 ounce of paint for airbrushing? Can I just go ahead and thin that (with lacquer thinner) and airbrush it, or would I need to let it sit before thinning it? If so, how long? 

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I have sprayed it through a large straw into the airbrush bottle and re-sprayed it right away. I’ve never had an issue with bubbles. I’ve also added lacquer thinner right away (Tamiya TS paints mostly). I figure it’s not getting gassed out any further if you’re spraying it directly from the can onto the model. The paint is very cold at this point, but  I don’t believe that makes too much difference? My paint jobs are not stellar, but that has more to do with my prep, and the fact that I usually lay it on in two or three heavy coats instead of misting layers on like I should.😳

Edited by NOBLNG
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I'll decant small amounts right into my airbrush cup. Usually wait 10-20 minutes before spraying. I will give the paint a good stir before I start shooting. If I notice the paint bubbling, I'll give it a few more minutes. Some paints take longer to degauss and other paints you can shoot almost right away. 

Danger

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If you decant into a plastic bottle with a screw top, it may not be strong enough to hold the propellant. Resulting in a new spot on your shop apron or worst yet, a tongue lashing from your better half. Decanting also adds air bubbles to the paint. Think of it as creating turbulence like scrambling eggs or making whipped cream. So I suggest to be a little patient and let it gas out a bit.

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2 hours ago, Rick L said:

If you decant into a plastic bottle with a screw top, it may not be strong enough to hold the propellant. Resulting in a new spot on your shop apron or worst yet, a tongue lashing from your better half. Decanting also adds air bubbles to the paint. Think of it as creating turbulence like scrambling eggs or making whipped cream. So I suggest to be a little patient and let it gas out a bit.

I leave my decanted paint in the airbrush bottle. It has a vent hole in it that will relieve any residual pressure. I don’t think the air bubbles are an issue since the airbrush uses air pressure to atomize the paint and blow it onto the model. Maybe enamels are different? That’s just my opinion though, no algebra involved.😈
Edit: I couldn’t find part two of the video, but I don’t like the attached straw idea. Seems like a disaster waiting to happen?

Edit: Found part two.

https://youtu.be/c2NjMD3AW2A

 

Edited by NOBLNG
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When painting with my Badger 200 suction feed, if I didn’t let the paint gas out it would always make a bubbly mess at the tip, causing spitting and dripping. It took me awhile to work it out, but I figure the paint was off-gassing when it incurred a pressure drop in the mixing chamber. I started giving the paint 30-40 minutes to gas out, giving a little stir occasionally until bubbles stopped rising. Problem went away. It may not be such a problem with a gravity feed brush. 
 

I remember the first time I decanted paint, I filled an airbrush bottle 3/4 full. Seemed benign enough. I set the bottle down on the bench a little too sharply, which released a rush of gas and the paint instantly bubbled up and overflowed the bottle heavily. Crazy stuff the way the gas remains trapped in the paint until enticed to leave. 

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4 minutes ago, Bainford said:

When painting with my Badger 200 suction feed, if I didn’t let the paint gas out it would always make a bubbly mess at the tip, causing spitting and dripping. It took me awhile to work it out, but I figure the paint was off-gassing when it incurred a pressure drop in the mixing chamber. I started giving the paint 30-40 minutes to gas out, giving a little stir occasionally until bubbles stopped rising. Problem went away. It may not be such a problem with a gravity feed brush. 
 

I remember the first time I decanted paint, I filled an airbrush bottle 3/4 full. Seemed benign enough. I set the bottle down on the bench a little too sharply, which released a rush of gas and the paint instantly bubbled up and overflowed the bottle heavily. Crazy stuff the way the gas remains trapped in the paint until enticed to leave. 

Very useful information, thanks so much! B)

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2 hours ago, Bainford said:

When painting with my Badger 200 suction feed, if I didn’t let the paint gas out it would always make a bubbly mess at the tip, causing spitting and dripping. It took me awhile to work it out, but I figure the paint was off-gassing when it incurred a pressure drop in the mixing chamber. I started giving the paint 30-40 minutes to gas out, giving a little stir occasionally until bubbles stopped rising. Problem went away. It may not be such a problem with a gravity feed brush. 
 

I remember the first time I decanted paint, I filled an airbrush bottle 3/4 full. Seemed benign enough. I set the bottle down on the bench a little too sharply, which released a rush of gas and the paint instantly bubbled up and overflowed the bottle heavily. Crazy stuff the way the gas remains trapped in the paint until enticed to leave. 

I never had that problem with my Paasche H, but it is an external mix. There’s certainly no harm in letting it gas out for a while. Was that enamel or lacquer paint?

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2 hours ago, Bainford said:

Crazy stuff the way the gas remains trapped in the paint until enticed to leave. 

Not much different from the CO2 gas in a carbonated beverage (like a Coke can or bottle).  If you shake it, you'll see it bubble up.

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2 hours ago, Rick L said:

I actually tried to watch that video but fell asleep waiting for him to, just do it already! What do these u tubers do, get paid by how many minutes they can bore us?😆

You can always just move the video timeline slider forward past the boring parts.

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For small amounts of decanted paint I recycle Tamiya acrylic jars.

Bit of tape over the top.

jarprep.jpg

I found some plastic straws that are a good press fit over the Tamiya nozzle, I super glue around the straw to seal and lock in place.

supergluetonozzle.jpg

Also helps to add a few vent holes to let the excess gas escape.

jarprepf.jpg

 

readytodecant.jpg

 

After decanting into the jar, I pretty much do the same as Trevor.

Wait 30 mins, then occasionally stir gently until paint bubble's to near top of jar, stop and then let it settle back down. Repeat until its fully gassed out before pouring into airbrush paint cup. 

 

 

 

 

 

 

Edited by Cool Hand
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9 hours ago, peteski said:

You can always just move the video timeline slider forward past the boring parts.

Sure, but I think a two part video of decanting paint is quite unnecessary. I assumed that I was going to see a newfound technique. If I knew ahead that this presentation was going to be drawn out I would have slid forward. And thank you for that additional useless information. 😆 

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If you're decanting not too sure why would you need to thin it.  It's ready to go from the can so it should be ready to go after you decant or am I missing something?

I've decanted.

1.  I let it sit 24 hours to off gas.

2.  Make sure that your straw to nozzle connection is well sealed - putty worked for me.

3.  Decant only what you'll be using in say the next week or so.  I decanted a full can of Tamiya primer and a year later the pigment had solidified at the bottom of the jar - rock hard it was.  ☹️

4.  I strongly suggest doing this outside so that if there are any "accidents" the damage is minimized.

5.  Don't leave your decanted paint in the hot sun.

Edited by showrods
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12 hours ago, Rick L said:

I actually tried to watch that video but fell asleep waiting for him to, just do it already! What do these u tubers do, get paid by how many minutes they can bore us?😆

You don't get out of the basement often, do you? Brett Green isn't a "u tuber". He's the editor of HyperScale, an online model magazine established in 1998, and a highly respected aviation modeller. You must have the attention span of a goldfish if you get antsy watching a six minute video.

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I decant 2x enamel and Rustoleum lacquers outdoors, just what I need at a time. All I do is use a rubber glove in the left hand, paper towel over the mixing bottle or Paasche H bottle/ bottles, put the nozzle under the paper towel and over the edge of the bottle and press gently letting up now and then to see the level of paint in the bottle. I usually fill about 2/3 full then nothing gets blown out.

Ok so now I have the paint and just set the cap on the bottle not screwed down for about 30 minutes. However after that 30 minutes I have added a bit of thinner and screwed the cap down tight. Later in the day upon loosing the cap have heard a slight pressure release. Whatever was left has never been enough to effect the paint job.

I can't speak for model paints but the Rustoleum 2X and regular Painters Touch paints you can spray more and thinner coats by a slight thinning with a bit of LT. And you get a nice flow out on the model, the results are every bit as nice as having shot the old MM enamels.

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18 minutes ago, SfanGoch said:

You don't get out of the basement often, do you? Brett Green isn't a "u tuber". He's the editor of HyperScale, an online model magazine established in 1998, and a highly respected aviation modeller. You must have the attention span of a goldfish if you get antsy watching a six minute video.

Sorry you were offended. 

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58 minutes ago, Rick L said:

Sure, but I think a two part video of decanting paint is quite unnecessary. I assumed that I was going to see a newfound technique. If I knew ahead that this presentation was going to be drawn out I would have slid forward. And thank you for that additional useless information. 😆 

Well Rick, you seemed to be unhappy being stuck watch the boring parts.  It seemed that you were not aware you could easily skip to any part of the video.  It is silly to kvetch about something if you know what to do to remedy what you kvetchign about.  Useless info?  Well, you are welcome anyway.  BTW, I didn't watch those videos - just offering very unhelpful hints. That's me, silly Peteski ;)

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4 hours ago, SfanGoch said:

Brett Green...[is]...the editor of HyperScale, an online model magazine established in 1998, and a highly respected aviation modeller. 

And his armor models are at least as nice and as well-respected as his airplanes. I have no idea how he builds as many models as he does, as quick as he does them, and still write/photograph them up and publish something new on HS five times a week. He really is a super-modeler. 

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Thanks for all the replies. I'll be decanting Krylon and/or Rustoleum paints, at least to start, maybe some Duplicolor. Not gonna screw around with straws or any of that, just gonna spray direct into small plastic cups until it looks like I have enough for my immediate need. Pour it into a Floquil 1/2 bottle, let sit 30 to 60 minutes and see what it looks like, then thin as necessary. 

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