I'm going to mix up a batch of MEK and acetone to determine how well they work as a weld/glue for plastic styrene. I'm very familure
with all the health warnings and toxicity of the chemicals. My question is: Has anyone tried this and what mix worked
the best. 50% MEK/50% acetone or some other combination. At $5.00
to $7.00 for a small bottle of Tamiya, Plastistruc, or Tenax.....it
makes no sense if they are putting the same stuff in the bottles.
I have a full quart of each which costs a total of $15.00. Don't worry... I do realize this stuff can make you sick.
Would appreciate comments and feedback about my project.
Thanks,
Tony Pots

I think both are a trifle volatile for my taste, Acetone more so; I'm not sure it would remain liquid long enough on the workpiece to actually cement. I have used it in the past as a brush cleaner, but with very bad results for that reason.

Nothing to say about ratios, I'm afraid, but I would suggest that you store your final mix in a container with a good seal and try surrounding said container with ice to keep its temperature down. Perhaps in a mini ice bucket, or with the cooler blocks marketed to place in cool bags - less potential mess. I don't know how much difference that might make, but it may increase your working time and decrease evaporation fom the container.

No need for the acetone and it is mostly useless for getting good bonds for styrene anyway.
MEK is unnecessaruíly harmful so I would STRONGLY recommend that you get some ethyl acetate.
I bought a 5 litre (1.32 US Gallons) can for approximately 100 US$ at a painting supply store.
https://en.wikipedia.org/wiki/Ethyl_acetate

This works excellently for styrene and it is a major compound in acetone free nail polish remover so SWMBO can't really complain since she uses it for her fingernails.
The cheap remover I used to buy for styrene cementing has changed the mixture and replaced much of the ethyl acetate with other solvents which made it useless for my purposes.
The content of ethyl acetate needs to be around 80% and upwards.

/ Robin

I have used a mix of MEK/acetone to create an ABS slurry when doing some motorcycle fairing repairs, because it's what I had on hand in large enough quantities, and I had to work fast as it dried quickly.

It would not be my first choice for models, as even less volatile than acetone, MEK is still pretty volatile, and extremely aggressive on styrene. My experiments with pure MEK for model building failed when I either struggled to get it to the model before it evaporated off the brush, or I applied too much. A needle style applicator might work better, but seems more trouble than it's worth imo.

I second the recommendation for ethyl acetate.

Interesting.

Don't dispose of your Acetone; I personally would never use CA without a bottle handy - it frees glued fingers and cleans spills well. It will also, when left immersed, free white metal joins with Epoxy which have gone awry.

I would like to know if Ethyl Acetate (fond memories of actually making that stuff) does that? If so, I might source some.

Have you looked into thermal plastic welding? I've repaired any number of fairing components this way.

Would have preferred that, but plastic welders weren't easily available locally at the time, so went with what I could get that was cheap.

I use pure MEK and have no complaints. Also, I have grown a third arm which has become very helpful in the hobby!

That's probably from inhaling the MEK fumes.