Storing spray paint

[tom_tom_go]

I had a go at painting some tins my wife wants to use in the kitchen, however, I have had various issues with the paint along the way so wanted to see what you all think.

1) U-POL etch primer sprayed clumpy despite being brought up to room temperature and shaken well. It is at least a few years old and stored in a garage that is not heated but insulated so has it gone off? The nozzle was clean and I spray cans upside down after use to clear the jet.

2) Halfords clear matt lacquer produced white bits on the paintwork when sprayed so has it expired as well as it is also a few years old and stored in the same garage.

[Big Jim]

I understand that etch primer can go off.
I don't know what this consists of, it may just loose the etching properties.

As for the lacquer, it may have separated in the can beyond what a good shake can do.

How long did you leave them inside for before using?

[Peter Butler]

I don't know about the paint Tom, but I think the lacquer might improve with temperature increase...... possibly?

[TonyW]

A lot of paints and their constituents absorb water over time. One I use has a usable life of about six months, and after that it starts mucking up the paint finish and so goes in the bin. Time then for a new tin of new stuff from my supplier ... and not one that I have kept on a shelf for many months.

[tom_tom_go]

Interesting Tony, I would of not considered a pressurised spray can to absorb water?

[IanC]

I've never stored rattle cans for long but it is worth bearing in mind they may deteriorate with time.

[TonyW]

Interesting Tony, I would of not considered a pressurised spray can to absorb water?

Ah yes, a good point. I'm using proper tins. Condensation maybe, but that requires the existence of water vapour in the first place. Hmmm...

[tom_tom_go]

I've never stored rattle cans for long but it is worth bearing in mind they may deteriorate with time.

But why, they are pressurised?

[Paul_A_C]

I have found that if aerosol cans are stored for a long period of time, the propellant can leak away, rendering the can useless. I store my cans in the back of the airing cupboard (my wife is a crafts person and understands why ). That keeps the paint comparatively warm and stops the cans going rusty.

[FWLR]

I have never had a problem with rattle cans leaking, losing pressure or paint deteriorating in all my years of using them, nearly 50 years. They have been in cold garages and hot sheds. The halyards grey primer I use a lot was in the hot shed last summer and the garage this summer as well now in the cold garage and I have used it last on Sunday to prime a Modeltown water tower tank with, (I am not to happy with the tower as a whole). It did the job brilliantly.

So pressurised cans in my opinion and experience don’t go off………..

Unless of course you put them near a fire or something else extreme………..

[BorisSpencer]

I was taught many years ago to turn the can upside down and give a short squirt before storing for a long time.
This blows propellant up the tube and clears the tube and nozzle of paint which could dry and clog things up.

I don't know if it has any effect, but I still do it out of habit.

[IanC]

I've never stored rattle cans for long but it is worth bearing in mind they may deteriorate with time.

But why, they are pressurised?

I tend to use them up! To get the best out of them I spray in batches so I end up using them to exhaustion in one session. I only use primer in rattle cans. For all my other spraying work I have a compressor and selection of airbrushes which I prefer for control.

[tom_tom_go]

I was taught many years ago to turn the can upside down and give a short squirt before storing for a long time.
This blows propellant up the tube and clears the tube and nozzle of paint which could dry and clog things up.

I don't know if it has any effect, but I still do it out of habit.

I also do this.

[FWLR]

I've never stored rattle cans for long but it is worth bearing in mind they may deteriorate with time.

But why, they are pressurised?

I tend to use them up! To get the best out of them I spray in batches so I end up using them to exhaustion in one session. I only use primer in rattle cans. For all my other spraying work I have a compressor and selection of airbrushes which I prefer for control.

You really haven’t answered Tom’s question Ian, that they are pressurised….So they won’t deteriorate….

i think most of us have a compressor for don’t more intricate work, but there are those who can do very good work with just paint brushes, I am not one of them…..

[FWLR]

I was taught many years ago to turn the can upside down and give a short squirt before storing for a long time.
This blows propellant up the tube and clears the tube and nozzle of paint which could dry and clog things up.

I don't know if it has any effect, but I still do it out of habit.

I also do this.

I do as well….

[GTB]

1) U-POL etch primer sprayed clumpy despite being brought up to room temperature and shaken well.

2) Halfords clear matt lacquer produced white bits on the paintwork when sprayed so has it expired as well as it is also a few years old and stored in the same garage.

Always worth reading the tech data sheet for paints, which are usually online. The U-POL etch primer TDS states it has a 2 year shelf life. Some etch primer formulations are stable and some react with themselves after a while and form 'lumps'. It seems U-POL is one of the latter.


Matt clear finishes have a matting agent added which is a fine powder, talc is a common one. Left for a long time the fine particles clump together and settle out as a hard layer. When you shake the can the layer breaks up into little white bits which don't fully disperse again. You'd probably get RSI from shaking the can, before you could completely dispersed all the clumped particles again.


Note water vapour can get into an aerosol, although it isn't the cause of Tom's problems. The steel can may be impervious, but the valve parts are plastic and water vapour can diffuse slowly through most plastics, as can gases and some solvent vapours, for that matter.

Regards,
Graeme

.

[FWLR]

It will take a few years to go (off) though in my experience Graeme

[GTB]

It will take a few years to go (off) though in my experience Graeme

I've had etch primer go off in 6 months. I don't use that brand anymore.........

Also there's no date stamp on paint, so no way to know how long it has been sitting around in a warehouse and then the shop, before you buy it.

Graeme

[tom_tom_go]

Graeme makes a good point here, the paints I have do not have date stamps so checking the data sheets is what I should of done!

[FWLR]

It will take a few years to go (off) though in my experience Graeme

I've had etch primer go off in 6 months. I don't use that brand anymore.........

Also there's no date stamp on paint, so no way to know how long it has been sitting around in a warehouse and then the shop, before you buy it.

Graeme

You are correct Graeme, so it's a bit immaterial how long it lasts for….Like you say, it could have been in the warehouse for sometime before it gets to the shop and if it’s not a popular colour, well it’s then down to the shop to get rid if it has run out of shelf life…But invariably they don’t….That’s way I have had some paint I have bought some years back (8+) and they are still useable.

So for most of us, we use the paint we buy within a year two, for me thats more than enough time to use it up. You just buy the colour/colours you use the most if you use rattle cans. For airbrushing though, I make the paint up has and when I need it in small batches…