tractor_37260 Posted June 18, 2017 Share Posted June 18, 2017 Having recently opened a new bottle of Salter's Mek Pak I've discovered it does not appear to work as well as the older bottle, it also smells totally different ? Perhaps the formulation has been changed, I've resorted to using an old bottle of Butanone in the meantime........... Anyone else have issues ? TIA Link to post Share on other sites More sharing options...
RMweb Premium Andy Hayter Posted June 18, 2017 RMweb Premium Share Posted June 18, 2017 In my experience the formulations have almost constantly changed - possibly not just Mekpak but also look alike versions. The "problems" probably relate to environmental issues and perceived risks to the users should he decided to douse himself rather than his models with the product or to spend his leisure time inhaling said solvents rather than sticking things together. ( and while it may not seem so, I do not belittle the safety issues in handing these and similar solvents.) Over time I have seen Mekpak and similar solvent based glues contain (MEK - Methyl Ethyl Ketone - hence the MEK bit), Methylene Dichloride and Carbon Tetrachloride (both now under a bit of a cloud due to potential carcinogenic effects ( as was MEK at one stage), Ethyl Acetate or similar (the time when solvents smelled of pear drops and back to MEK, which has a better bill of health than many other options. In all cases I doubt if the solvents used were pure (as in +95% of the above compounds.) I have detected whiffs of Toluene and Xylene in some compositions. Today competitors offer what might be called "light" solvents whose grip is light and may take time to take full effect, through to aggressive where an over enthusiastic use may melt the mouldings. So has the composition changed? Quite probably. depending when and from whom you purchased your Mekpak (or similar) Link to post Share on other sites More sharing options...
peter220950 Posted June 18, 2017 Share Posted June 18, 2017 I've long since given up with Mekpak, a litre of Butanone is only about £8.50 delivered, I found it cheaper and more effective, it just needs decanting into old Mek bottles to make it easier to handle. Peter 1 Link to post Share on other sites More sharing options...
Pete the Elaner Posted June 19, 2017 Share Posted June 19, 2017 In my experience the formulations have almost constantly changed - possibly not just Mekpak but also look alike versions. The "problems" probably relate to environmental issues and perceived risks to the users should he decided to douse himself rather than his models with the product or to spend his leisure time inhaling said solvents rather than sticking things together. ( and while it may not seem so, I do not belittle the safety issues in handing these and similar solvents.) Over time I have seen Mekpak and similar solvent based glues contain (MEK - Methyl Ethyl Ketone - hence the MEK bit), Methylene Dichloride and Carbon Tetrachloride (both now under a bit of a cloud due to potential carcinogenic effects ( as was MEK at one stage), Ethyl Acetate or similar (the time when solvents smelled of pear drops and back to MEK, which has a better bill of health than many other options. In all cases I doubt if the solvents used were pure (as in +95% of the above compounds.) I have detected whiffs of Toluene and Xylene in some compositions. Today competitors offer what might be called "light" solvents whose grip is light and may take time to take full effect, through to aggressive where an over enthusiastic use may melt the mouldings. So has the composition changed? Quite probably. depending when and from whom you purchased your Mekpak (or similar) I mentioned Evo's Pipe weld to my local model shop (which I had only recently seen for sale). I was a little surprised when the assistant replied that it was useful because MEK had changed, no longer using MEK as you described. He went in to further detail which I cannot remember. Pipe weld is thicker & more suitable for larger areas. It seems to be more of a glue than a solvent than MEK but it does melt the plastic just a little & holds plasticard together very nicely though. Link to post Share on other sites More sharing options...
Phil Traxson Posted June 19, 2017 Share Posted June 19, 2017 I mentioned Evo's Pipe weld to my local model shop (which I had only recently seen for sale). I was a little surprised when the assistant replied that it was useful because MEK had changed, no longer using MEK as you described. He went in to further detail which I cannot remember. Pipe weld is thicker & more suitable for larger areas. It seems to be more of a glue than a solvent than MEK but it does melt the plastic just a little & holds plasticard together very nicely though. For a thinner solvent try plumbers pipe cleaner rather than the pipe weld, it's mostly MEK and is available over the counter at your local plumbers supplies at about the same price. I've been using it for over 20 years now and it's never failed me. Phil T. Link to post Share on other sites More sharing options...
rynd2it Posted September 12, 2018 Share Posted September 12, 2018 I've long since given up with Mekpak, a litre of Butanone is only about £8.50 delivered, I found it cheaper and more effective, it just needs decanting into old Mek bottles to make it easier to handle. Peter Hi, I just found this when searching for MEK etc and according to various science-based places Butanone is MEK, just another name for it. So I am confused, any clarification would be appreciated. Thanks David Link to post Share on other sites More sharing options...
pete_mcfarlane Posted September 12, 2018 Share Posted September 12, 2018 There's more info here: https://en.wikipedia.org/wiki/Butanone. Wikipedia says that it's soluble in water, so I'm wondering if the differences between different brands are due to dilution. Link to post Share on other sites More sharing options...
Guest Posted September 12, 2018 Share Posted September 12, 2018 I recently got a new bottle from Eileen's emporium,must of been old stock because it's fine,no issues with it. Link to post Share on other sites More sharing options...
rynd2it Posted September 12, 2018 Share Posted September 12, 2018 I searched some more and finally bought the MEK 500 ml from Amazon, which if you search for butanone, is what Amazon finds. £10 delivered is very reasonable Cheers David Link to post Share on other sites More sharing options...
Junctionmad Posted September 12, 2018 Share Posted September 12, 2018 Having recently opened a new bottle of Salter's Mek Pak I've discovered it does not appear to work as well as the older bottle, it also smells totally different ? Perhaps the formulation has been changed, I've resorted to using an old bottle of Butanone in the meantime........... Anyone else have issues ? TIA Slater’s changed the formula many years ago and openly admit so. It’s no longer MEK Dave Link to post Share on other sites More sharing options...
sharris Posted September 12, 2018 Share Posted September 12, 2018 Having recently opened a new bottle of Salter's Mek Pak I've discovered it does not appear to work as well as the older bottle, As Dave mentioned it has changed. My workbench now has MekPak, Butanone, d-Limonene and Plasweld (I think I got the latter when I was shopping and couldn't get MekPak). d-Limonene is gentler and doesn't have such a detrimental effect on thin plasticard. Butanone is methyl-ethyl-ketone (it has the classic ketone aroma) which is what I think MekPak used to be in the old days, and works better than modern MekPak on ABS. MekPak has a different aroma - not sure what its chemistry is these days. Generally my usage is: MekPak - thick styrene (>10thou) - structural work d-Limonene - thin styrene (<=10thou) - overlays Butanone - C&L plastic sleepers, and I'll give it a try on plastics that MekPak doesn't like. Plasweld - when I run out of MekPak. Link to post Share on other sites More sharing options...
Captain Cuttle Posted September 22, 2018 Share Posted September 22, 2018 I searched some more and finally bought the MEK 500 ml from Amazon, which if you search for butanone, is what Amazon finds. £10 delivered is very reasonable Cheers David Just bought similar on Ebay for £7.99 post free. Regards Alan Link to post Share on other sites More sharing options...
dasatcopthorne Posted September 23, 2018 Share Posted September 23, 2018 Get together with other Club memebers or friends and buy 5lt on eBay for about £23.00 Then share it out. Just make sure the others have well sealing glass bottles to put it in. Dave Link to post Share on other sites More sharing options...
Derek Russan Posted October 1, 2018 Share Posted October 1, 2018 I recently got a new bottle from Eileen's emporium,must of been old stock because it's fine,no issues with it. Not old stock, we turn over enough to never be more than a few months old. Link to post Share on other sites More sharing options...
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