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Hi all,

The rattle cans I have just bought state they should be used between 15-21 degrees C.

Is that the temp of the can or the temp of the environment I’m in? I.e do I need to wait to spring to use it or can I just put it in some warm water?

Thanks

Are they just paint? If there's nothing special about them, you can just warm the can, you'd probably warm it to more than 21°C to keep the pressure up while you use it.

There are some special rattle can based coatings we use at work that I won't use outside of the recommended temperature range because it can cause issues, but for regular paint I'll spray it anywhere from 0 to about 25°C. Too hot and it'll tend to grain, so in hot weather I try and do my spraying in the morning when it's coolest, and avoid humid days. In winter it only ever gets down to about 0°C out here at worst and I've never had issues.

EDIT: Also, matte varnish is one I try and only spray it in good weather because you can end up with very different results on a hot day to a cold day or a humid day to a dry day, there'll be months at a time where I won't even attempt to matte varnish stuff. Gloss varnish is a lot less picky though.

It’s always humid in the UK ha

It’s a gloss black primer and colourshift paint from green stuff world. I tested it out on an old mini and there was a bit of saturation which I assume is becuase the can was operating below the expectated temperature

mrFickle wrote:
It’s always humid in the UK ha

It’s a gloss black primer and colourshift paint from green stuff world. I tested it out on an old mini and there was a bit of saturation which I assume is becuase the can was operating below the expectated temperature

I've found cold and humid to be less of an issue than warm and humid. Out here we'll get a hot day in the 30+°C range, then it'll cool down to 20-25°C which puts it in the right temperature range but the humidity will kill it.

On cold damp days in winter I've had less issues, often I've sprayed stuff while it's been raining, just going outside under the verandah to do it.

When it comes to speciality paints, often the effect is dependent on the drying time and getting a consistent surface finish, so I could believe they'd be harder to use outside of the specified operating temperature range, but yeah, maybe try and warm it up a bit and try it again on another test model.

Rule of thumb is avoid intense direct sunlight and extremely dry climate. They both cause the medium to evaporate during spraying before the paint particles reach the intended surface.

Always remember to shake vigorously as this affects the quality more so than ambient temp/humidity.

Are you sure its a gloss primer?

 skchsan wrote:
Rule of thumb is avoid intense direct sunlight and extremely dry climate. They both cause the medium to evaporate during spraying before the paint particles reach the intended surface.

You can somewhat compensate by holding the can closer to the model than is recommended in those sorts of conditions, and likewise if it's too cold hold it further away. There is a limit to how much you can compensate for it though.

I've always found high humidity to be a bigger problem because it's hard to impossible to compensate for it.

It probably somewhat depends where you live in the world what as to what the most adverse conditions will be and when is the best time and conditions to spray.

 Rybrook wrote:
Are you sure its a gloss primer?

Yes specifically made for the special effect paint

AllSeeingSkink wrote:

 skchsan wrote:
Rule of thumb is avoid intense direct sunlight and extremely dry climate. They both cause the medium to evaporate during spraying before the paint particles reach the intended surface.

You can somewhat compensate by holding the can closer to the model than is recommended in those sorts of conditions, and likewise if it's too cold hold it further away. There is a limit to how much you can compensate for it though.

I've always found high humidity to be a bigger problem because it's hard to impossible to compensate for it.

It probably somewhat depends where you live in the world what as to what the most adverse conditions will be and when is the best time and conditions to spray.

Yes, but holding the can too close will likely cause overspraying, thus clogging up the fine details. Conditions where it allows greater spraying distance is not an issue, but being forced to spray closer is.
Spray paint that dries mid air yields the grainy look.

High humidity is an issue for large scale painting, but for our purposes all it means it increases drying time between coats. You just have to make sure you give it enough time to fully dry. It does become an issue however, towards the later end of a spray session (where the spray can has cooled due to decrease in pressure in the can over the course of its usage) in hot & humid climate where it can potentially start to condense mid air.

Ultimately, low internal temperature, particularly so if it was stored for quite a bit, makes it more difficult for the paint particles and spray medium to mix well together - think how it's more difficult to dissolve salt in cold water than it is in warm water. Spray can that is not mixed properly will cause sputters and spits.

What you don't want to do however, is to heat up the can above room temperature. Too high of increase in internal temperature drives the pressure up, causing the propellant to expel at greater rates than needed, thus shortening the life of your can where you still have paint left over inside the can but no propellant to spray it out.

Unless the can is absolutely cold, the heat conducted from your hand while shaking the can is usually sufficient enough to heat up the internal temperature to proper levels. Just remember the recommended two minutes of shaking is usually not enough to properly mix the contents - try about 4-6 minutes if you continuously run into issues spraying.

Be careful. Rattlecans receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated that deters predators or serves as a warning to passers-by.

Rattlecans are the leading contributor to paint injuries in North America, but rarely bite unless provoked or threatened; if treated promptly, the bites are seldom fatal. Just keep them standing straight during storage.

General rule of thumb you want the can itself to be room temp when you spray it.

If its hot outside, make sure you spray in the shade or somewhere like a garage. where its cooler so its not doing to dry before it hits the model, very few times that a dusty application of primers is a good thing.

If the paint is to cold when spraying it can dry in really weird ways, and does not cover good at all.

What i like to do, as i live where it can get pretty cold during the morning hours, i just kinda keep the can between my thighs when im outside and arranging stuff before i spray, or ill just do a little bit at a time and let the can warm up and stay room temp.

 Niiai wrote:
Be careful. Rattlecans receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated that deters predators or serves as a warning to passers-by.

Rattlecans are the leading contributor to paint injuries in North America, but rarely bite unless provoked or threatened; if treated promptly, the bites are seldom fatal. Just keep them standing straight during storage.

Very good!

 skchsan wrote:

AllSeeingSkink wrote:

 skchsan wrote:
Rule of thumb is avoid intense direct sunlight and extremely dry climate. They both cause the medium to evaporate during spraying before the paint particles reach the intended surface.

You can somewhat compensate by holding the can closer to the model than is recommended in those sorts of conditions, and likewise if it's too cold hold it further away. There is a limit to how much you can compensate for it though.

I've always found high humidity to be a bigger problem because it's hard to impossible to compensate for it.

It probably somewhat depends where you live in the world what as to what the most adverse conditions will be and when is the best time and conditions to spray.

Yes, but holding the can too close will likely cause overspraying, thus clogging up the fine details. Conditions where it allows greater spraying distance is not an issue, but being forced to spray closer is.

You just move your hand faster so you spend less time spraying at the model. The usual advised method for spraying models is to not start or stop spraying while point at the model, you start spraying while point one side of the model, whip across it, then finish spraying on the other side of the model. So just whip your hand faster to lay down less paint.

There's a limit obviously, I'm certainly not saying go out and try and spray stuff in 35°C temperatures, at some point you can't get closer without getting a poor spray pattern and at some point it's so warm that the paint doesn't have time to self level on the model even if it didn't dry in the air. But yeah, I'm just saying if it's a few degrees warmer than usual try spraying a bit closer.

What you don't want to do however, is to heat up the can above room temperature. Too high of increase in internal temperature drives the pressure up, causing the propellant to expel at greater rates than needed, thus shortening the life of your can where you still have paint left over inside the can but no propellant to spray it out.

That probably somewhat depends on what your room temperature is. I've never bothered to measure the temperature, but I generally warm it until it's warm to the touch which must be somewhat above room temperature and I can't say I've ever noticed a problem with paint running out significantly before propellant. But then I also don't bother inverting the can and spraying until the nozzle is clear after a session and I've also never had issues with blocked nozzles, I guess I just like living my life on the edge.

Also remember that part of the reason to warm the can is to get the pressure higher, the other part of the reason is because the propellant undergoes a phase change from liquid to gas which makes the can cool down rapidly while you spray, so warming it up is to somewhat compensate for that cooling effect.