DIY Extra Thin Quick Drying Cement

Firstly, a huge warning, this HAS to be done in a well-ventilated room, and you need to wear a mask and eye protection. The fumes Will have an effect on you, if you don't, so please be careful. If you spill any on yourself or in your eye's please seek medical advice - You have been warned, so please read all warning labels as I cannot be held responsible for your actions.
Now the Figures:
I’ve seen prices ranging from £5 - £12, this includes postage. So to be fair, I’ll take the lowest price there is £5.
My Purchases:
1 Litre of Butyl Acetate: £15 (Including Postage) from eBay
1 Litre of Acetone: £10 (Including Postage) from eBay
Total: £25
So, I can make 2 Litres of Extra Thin, Quick Drying Cement for £25. The glass jar is 40ml, which means I can make 40ml of the cement for £0.50 or 50 pence!!!
To buy 2litres of Cement at £5 per 40ml (40ml goes into 2Litres 50 times) would cost me at least £250 (£5 x 50)…Doing it this way I’m saving £225 that I can now spend on models, decent tools, airbrushes, brushes and paints.
Yes I realise there are other factors to take into consideration, R&D (Now more than paid for), the glass jars and the ingredients, so let’s be generous and say 50p for ingredients, 50p for R&D and 50p for each glass jar, so that’s a total of £1.50 that it’s costing them, per bottle,. They probably sell it on at £3. They’re doubling their money! We get to pay at least £5 (including postage). It’s fair, it’s business, but I’m afraid I’ll not be ripped off into paying stupid amounts when I can make it cheaper.

COSSH Sheets:
Acetone:
https://www.nhsggc.org.uk/media/236208/msds-acetone.pdf
Butyl Acetate:
https://www.fishersci.com/shop/msdsproxy?productName=B3961