Why is oil Based Paint so poisonous?

[drgj]

I just sprayed a bit of Railmatch yellow oil based paint with "Contains lead chromate" written on it along with a skull and crossbones. I was wearing a good mask but why does it have to be so poisonous? Their own acrylic paint of the same colour is non toxic. Why can't they use the same pigments in oil based paint or is it some kind of tradition to use the old stuff?

 

I would rather use acrylic but sometimes goes into little blobs and pools on the surface when airbrushed. Does that mean it is too thin?

 

Dave

[Mick Bonwick]

16 minutes ago, drgj said:

 

 

I would rather use acrylic but sometimes goes into little blobs and pools on the surface when airbrushed. Does that mean it is too thin?

 

 

 

 

Either it's too thin or the pressure is too high. Or both, of course.

[Andy Hayter]

Why don't they use the same pigments?

 

Pigments can and do react with the carrier that is used to disperse it,  A pigment that is stable in the acrylic medium may perhaps react or be oxidised ( changes in contact with the air) if put into an oil based medium - and vice versa.  Some pigments will remain as finely dispersed particles in one medium and will coagulate and form lumps over time in another.  Getting these to redisperse can be difficult to impossible.

 

There is a further point.  The manufacturer is obliged to itemise risks of using their products and to make these publicly obvious to all purchasers.  This is done (within the EU at least*) with standardised symbols and warning messages.  It is entirely right that this is done.  A potential purchaser should be aware of the risks of using a product.  

 

*The US has a different but it seems equally overt system of warnings.  I have a tube of Squadron white putty filler for models and among the information given it states, " This product contains a chemical known to the State of California to cause birth defects or other reproductive harm".  It does not however carry a skull and crossbones pictogram that might be required under European laws.

 

It is however easy to over-react.  Lead Chromate is a potential problem on two fronts - lead and high valency Chromium, both of which are a problem if brought into the body in quantity.    There are two obvious ways this could occur:

1.  During the application phase by breathing in the vapour from the air brush.  This should never happen if you have a properly set up spray booth or spraying centre and use a spray mask if appropriate.  

2.  Once applied the pigment could cause problems if the item sprayed is then put into the mouth and sucked.  I hope you don't suck your models!  But without the warning someone could inadvertently for example spray a Brio train with the yellow and a child could then put the item in its mouth.  More than anything this is why the warning is there.  

 

My advice therefore is be aware of the warning and treat the paint with the respect it deserves, but don't over-react to the warning. 

Don't breath in the vapours while spraying without the use of a mask suitable for handling aerosols (hard to get just now)

Wash hands after spraying to remove any paint residues

But

Used sensibly the paint will not harm you.

[F-UnitMad]

11 hours ago, Andy Hayter said:

" This product contains a chemical known to the State of California to cause birth defects or other reproductive harm".

I think it's the law that every product made in the USA has to have this warning printed on it  

Only kidding, although certain chemicals in the Floquil range of paints led to the withdrawal of that make from the market. A pity as I managed to get some of this American paint range here in the UK, & they blew away the likes of Humbrol & Railmatch for quality.

 

But the simple answer to the OP's question is there in the title - 'chemical' oil itself (as opposed to oils in food) in it's myriads of available forms is poisonous to us, if ingested in any way, so no wonder oil-based paints will have some health warnings about it somewhere. Just look at a tin of household solvent-based gloss paint, for example.

[Wheatley]

These might or might not be of interest:

 

https://www.artistsnetwork.com/art-mediums/oil-painting/yellow-pigments-and-their-stories/

 

https://www.chemistryworld.com/news/why-use-lead-in-paint/3004319.article

 

The pigment used has to not only not react adversely with the carrier, it has to cover reasonaly well. Lead chromate is very opaque and therefore you only need a small amount.  It is also insoluble in water so is tough and hardwearing once dry. I suspect the pigment used in the acrylic paint is either incompatible with the carrier in the oil paint (e.g. is insoluble in it) or is more expensive, or less opaque.  

 

And be careful where you buy your tumeric !

[drgj]

Thanks for the answers.  I am careful with paint when spraying.

 

I am going to have another crack at using acrylics. I have a Badger double action airbrush with a glass jar underneath so this needs a certain amount of pressure to work. The instructions say 30 psi. I set the gauge to this when the airbrush is not going  but the actual working pressure is lower than this.

[johndon]

On 16/04/2020 at 13:42, drgj said:

I am going to have another crack at using acrylics. I have a Badger double action airbrush with a glass jar underneath so this needs a certain amount of pressure to work. The instructions say 30 psi. I set the gauge to this when the airbrush is not going  but the actual working pressure is lower than this.

 

I use a very similar airbrush and never set the PSI to anywhere near 30, I always use acrylics and can spray quite happily right down to 5 PSI...

[F-UnitMad]

On 16/04/2020 at 13:42, drgj said:

The instructions say 30 psi. I set the gauge to this when the airbrush is not going  but the actual working pressure is lower than this.

What sort of air compressor are you using? If it's one with a tank & auto shut-off, you have to let it keep running until it fills the tank, when the motor shuts off. Then adjust the regulator to the spraying pressure you want. Air will then be fed at that pressure, and the sensor restarts the motor to top the tank up as required.

If your compressor doesn't have a tank then I'm not sure how the regulator works.

 

[drgj]

Thanks for the new answers. 

 

F-unit- When I mentioned the working pressure I meant that if I set the compressor to 30 and let the tank fill the gauge drops when I start spraying.

 

Johndon- I will give it another try at a lower pressure. Come to think of it before I had a compressor I used a car tyre and adapter and the brush did spray when the tyre was quite low on pressure towards the end of a session.