I'm sure there's significant sections of both Harry's and Flinty's posts that are correct, but it's a case of picking and choosing the right bits, which as someone with vastly less experience than either of them does present a bit of a challenge! I do understand that take off with glycol on the lift surfaces is acceptable in certain situations though, but I'm equally prepared to accept there are situations and combinations which make it a total no-go.
As some of you know, I bowl about in a FIKI SEP and haven't fallen out of the sky yet with this one - that has included launching in sub-zero into the murk, and for which I've followed the PoH AFMS
instructions, which are pretty much "on and active before takeoff". I can't say I've looked at what is flowing over the wings during the take off roll (I've got other priorities), but I know in the cruise the TKS fluid can be observed rippling its way over the top surface of the wings, and TKS fluid is 85% glycol
. My pre-take off departure check will include that it is visibly running over the wing roots from the prop blast, that the screen is getting a right mess due to the prop slinger, which also means a certain amount is going over the engine, as well as down the air induction over the air filter, and even into the heater muff. The last of those does create a bit of a pong, but isn't visible nor sets off a CO alarm, but clears quickly once airborne.
Back to the original nest I stirred up with the suggestion of glycol as a ground deicing agent, I still believe you're ok with neat
glycol added to IPA (particularly if squeegeed off before flight), as it is the bigjet holdover fluids include a thickening agent
...Type II and IV fluids add thickening agents to increase viscosity ...Type III fluids also contain thickening agents ...
which costs extra.
If however your source of glycol is from jet "surplus", you'll have to do your own research and risk assessment