Escaping MEK-PAK : Is this a thing?

[JimC]

Walked into the room I keep modelling stuff this morning to be greeted with a strong smell of solvent. Seems my tin of MEK has rusted out and sprung a leak. B******d up the bookshelf too. Is this a thing I should have been aware of. Going to get grief from SWMBO if the solvent smell doesn't clear too. 

[Michael Hodgson]

You had me worried for a minute there.  Thought I've got one of those, but I've just been and checked. 

I must have used it as my mek-pak is in bottles, so they won't rust through.

 

But thanks for the warning.

[Edwin_m]

Don't put it in the wheelie bin or it will probably melt it!  

[cctransuk]

3 hours ago, JimC said:

Walked into the room I keep modelling stuff this morning to be greeted with a strong smell of solvent. Seems my tin of MEK has rusted out and sprung a leak. B******d up the bookshelf too. Is this a thing I should have been aware of. Going to get grief from SWMBO if the solvent smell doesn't clear too. 

 

I have had this happen with Xylene - I'm guessing that the contents were contaminated with water, which would settle below the less dense solvent.

 

My container was a 5 litre can, which was not easy to decant into what few glass jars I had to hand.

 

Beware of reusing domestic glass containers such as jam jars for storing solvents; the fumes can degrade the sealing ring on the lid.

 

CJI.

[JimC]

Yes, a vinegar bottle would probably be best, but at the moment I have nothing suitable so it's relegated to the yard and I'll see if any is left when I can find a jar. 

[Andy Hayter]

Well you've had that tin a long time because the label makes clear that the contents are not MEK but one of the earlier versions which they describe as "halogenated".  From what I remember most likely based on Carbon Tetrachloride.  Nasty stuff as we now know, which is why Slaters went back to MEK.

 

Ventilate the room very well indeed.

 

As for the corrosion of the tin, if the contents have somehow reacted with any water (not something that carbon tet. does easily), it will probably have created hydrochloric acid - which will happily corrode the tine from the inside.   

[Michael Hodgson]

So the rusty tin is "hazardous waste" and you're not supposed to chuck it in the bin?

[Andy Hayter]

Exactly.  I doubt it would damage the wheelie bin but it does need to be handled as hazardous waste as you say..

 

Looking again at the picture and the rust ring on the shelf, I wonder if the solder join on the can's base has been corroded - perhaps even from the outside.  

[Paul H Vigor]

5 hours ago, JimC said:

Walked into the room I keep modelling stuff this morning to be greeted with a strong smell of solvent. Seems my tin of MEK has rusted out and sprung a leak. B******d up the bookshelf too. Is this a thing I should have been aware of. Going to get grief from SWMBO if the solvent smell doesn't clear too. 

Escaping SWMBO may be your next 'thing'! 😎

 

The liquid may go xenomorph and melt through the ceiling!

Edited November 12, 2022 by Paul H Vigor
to add information

[JimC]

The rust ring is strange. I would surely have smelt the stuff if it had been leaking for any length of time. I think it must have developed quite quickly, days rather than weeks. I was once an industrial chemist, and like to think am still reasonably aware of solvent smells. 

[Wheatley]

4 hours ago, cctransuk said:

 

I have had this happen with Xylene - I'm guessing that the contents were contaminated with water, which would settle below the less dense solvent.

Had the same with aerosol cans of paint (Halfords and Humbrol), I don't know if either of those has xylene in. I both cases the bottom seams rusted out and the varnish/carrier was forced out. 

[The Johnster]

Don't worry about SWMBO, attack is the best form of defence, claim she's spilled some nail varnish remover.  We'll visit you on the casualty ward...

[DenysW]

1 minute ago, The Johnster said:

spilled some nail varnish remover

Tricky. I use nail varnish to colour-code the AC wiring driving accessories on my layout. Pot, Kettle, Black might be the response.

[Dave Hunt]

4 hours ago, Andy Hayter said:

Well you've had that tin a long time because the label makes clear that the contents are not MEK but one of the earlier versions which they describe as "halogenated".  From what I remember most likely based on Carbon Tetrachloride.  Nasty stuff as we now know, which is why Slaters went back to MEK.

 

 

Mekpak started out as MEK then changed to perchlorethylene.

 

Dave 

Edited November 12, 2022 by Dave Hunt

[Dunsignalling]

I had exactly the same thing happen with a can of Mek-Pak a few years back. Once emptied, I left it outside to vent for a week. Back then, there was only the dustbin to put it in. Nowadays, I'd only put it in the recycling if no smell remained.

 

Consequently, I  switched back to using real MEK (aka Butanone) which Mek-Pak hasn't been for decades, as my default solvent. No problem with half-litre cans bought from plumbing merchants*, but my most recent supply came via a Web source and arrived in a polypropylene* bottle.

 

* MEK has been widely used for cleaning polypropylene pipes etc., prior to bonding but doesn't attack the material itself. 

 

John

Edited November 12, 2022 by Dunsignalling

[Andy Hayter]

1 hour ago, Dave Hunt said:

 

Mekpak started out as MEK then changed to perchlorethylene.

 

Dave 

 

 

I agree that it started as MEK.  It may have changed to perchloroethylene (PCE) although I am not sure about that.  PCE has quite a high boiling point compared with carbon tet.  (121C versus 77C) and so would be much slower to evaporate away from the point of use and therefore more likely to mark the visible surfaces.  

 

I am all but certain  (but I never did a chemical analysis) that what I bought (probably late 80s) was Carbon Tetrachloride.  Dry cleaning fluid ( PCE) had a different smell.  

 

The tin description could describe either.

 

Either way both are unpleasant in their long term exposure to humans and the environment in general.  

 

Slaters have gone through various solvents that "do the job" and may well have used both chlorinated solvents before reverting back to MEK.  The problem is that they never divulge the exact composition and more than likely use mixtures that are not pure - deliberately or through contaminants in the materials they purchase.  

 

EDIT

Just to add:  MEK boiling point is 80C so a close match to Carbon tet.

Edited November 12, 2022 by Andy Hayter

[Dave Hunt]

As an ex-director of Slaters I can assure you that Mekpak was not carbon tetrachloride.

 

Dave

[Andy Hayter]

OK I accept that I was wrong.

[BWsTrains]

6 hours ago, Andy Hayter said:

Well you've had that tin a long time because the label makes clear that the contents are not MEK but one of the earlier versions which they describe as "halogenated".  From what I remember most likely based on Carbon Tetrachloride.  Nasty stuff as we now know, which is why Slaters went back to MEK.

 

Ventilate the room very well indeed.

 

As for the corrosion of the tin, if the contents have somehow reacted with any water (not something that carbon tet. does easily), it will probably have created hydrochloric acid - which will happily corrode the tine from the inside.   

 

I'm pretty sure that Carbon tetra-chloride (tet for short) had been removed from most applications including laboratory chemistry (my background) by the early to mid 70s. Most polychlorinated saturated hydrocarbons were by then recognised for their toxicity / environmental persistence so unlikely to have been used in this modelling application.

 

Perchlor was rather different; it is unsaturated which gives it a handle to break down / be broken down and while less common in laboratory use, was widely used in dry cleaning etc. for long after the saturated produces were removed

 

The saturated hydrocarbons are very stable.

In contrast, perclor could release hydrogen chloride from reaction with minute amounts of water such as condensation or moisture in the air, perhaps catalysed by metal ions. Normally it would not be held in a metal container that long. The HCl will corrode the seam leading to eventual failure

 

Go back 40 years and metal tins were the best option to store perclor. Glass has breakage risk, and perclor would migrate thru any bottle plastic. It was only later that commercial fluorination of plastics made them able to resist solvent migration.  

 

PS. The solvent of those days in MEK-PAK might even have been a mix of perclor and trichloroethylene, the later being a more powerful solvent

 

 

 

Edited November 12, 2022 by BWsTrains
add'n

[DenysW]

22 hours ago, Dunsignalling said:

real MEK (aka Butanone)

Despite @Dunsignalling being absolutely correct, no-one has yet pointed out that MEK stands for MethylEthylKetone, more correctly nowadays called Butanone (this IUPAC nomenclative stuff was new-ish when I was learning chemistry in the late1960s. Doesn't time fly.) It's a higher boiling-point version of acetone (DimethylKetone, Propanone). Most of the other solvents, such as TCE (trichloroethylene)  actually had stabilisers in them, so were not 'pure' chemicals.

[BWsTrains]

13 minutes ago, DenysW said:

........................MEK stands for MethylEthylKetone, more correctly nowadays called Butanone (this IUPAC nomenclative stuff was new-ish when I was learning chemistry in the late1960s. Doesn't time fly.) It's a higher boiling-point version of acetone (DimethylKetone, Propanone). Most of the other solvents, such as TCE (trichloroethylene)  actually had stabilisers in them, so were not 'pure' chemicals.

The issue of 'pure' is a difficult one to categorise in such black and white terms. In once sense the above comment is correct but in another sense not at all relevant to the issue the OP raised.

 

Ketones such as MEK and acetone are relatively stable compounds which might not need stabilisation.

 

Other solvents often require some degree of stabilisation so might have a tiny amount of antioxidant or radical inhibitor included OR they'd not be pure by the time they reached the customer. So a laboratory chemist would expect to open a bottle of 100% diethyl ether ("ether") confident he would not get his head blown off precisely because that ether had been prevented from forming deadly peroxides while on the shelf because of preservatives. That chemist would consider the purchased stabilised 100% ether to be 'pure'.

 

On the other hand unstabilised ether which started out at some earlier point at 100% would no longer be so. #  He might need to distill ethers before use but would never then keep any excess hanging around. Since I spent my PhD days distilling various ethers to make them ultra pure / oxygen free I'm speaking from extended experience.

 

Perclor might well have a small amount of stabilisers included when first sold, to help keep them as purchased but that benefit can only hold for so long.

 

# anyone interested how deadly good old simple dentist's ether can become should read the Wikipedia entries for diethyl ether and its peroxide!

 

 

[Dunsignalling]

11 hours ago, DenysW said:

Despite @Dunsignalling being absolutely correct, no-one has yet pointed out that MEK stands for MethylEthylKetone, more correctly nowadays called Butanone (this IUPAC nomenclative stuff was new-ish when I was learning chemistry in the late1960s. Doesn't time fly.) It's a higher boiling-point version of acetone (DimethylKetone, Propanone). Most of the other solvents, such as TCE (trichloroethylene)  actually had stabilisers in them, so were not 'pure' chemicals.

 

Interestingly (or perhaps confusingly) the last can of "MEK" that I acquired through a plumbing merchant was labelled as EthylMethylKetone. It smelled the same but seemed somewhat less "aggressive" in use.  

 

Not being a chemist, I don't know the difference, or even if there is any!

 

John

[BWsTrains]

They are the same thing, a ketone comprising 1 ethyl group and 1 methyl group

 

CH3CH2-CO-CH3

 

Depends which end you start the naming which is non-systematic. I think EMK was the favoured older way to name it, MEK came along later.

[JimC]

On 12/11/2022 at 22:34, BWsTrains said:

 The HCl will corrode the seam leading to eventual failure

Yep, makes sense. Now I only have to deal with a book shelf that will be emitting chlorinated hydrocarbons for some considerable time...  I should have known it was a chlorinated hydrocarbon, but carbon tetrachloride and methylene chloride were the ones I've had most to do with, and it was neither of those. Nearly all evaporated from the tin now before I could find a suitable container, so it must have been a very fresh leak.
 

Nail varnish not a feature of my house, so that strategy would be doomed to failure!

 

Thanks all for contributions.

Edited November 14, 2022 by JimC

[Not Jeremy]

Apologies if I missed it in the maelstrom of chemistry and chest beating that followed this intriguing post, but what caused the problem and how can one avoid same if one is in possession of one of those big tins of Mek Pak?

 

Please, no theories or lectures, just a credible explanation.

 

If you don't know then there is no need to tell us, really, please.....

 

Simon