Storing spray paint

[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…