Instead of a sight glass....

I'm working on an idea. I've seen a lot of posts for diy sight glasses, and I'm glad that I'm not the olny tight-a$$ out there. Anyway, my idea is this. 90 degree fitting, compression fitting, SS or copper tubing, and some round boyant material (not sure what yet. Don't think balsa would be the best material). My idea is basically modeled after a tire pressure gauge. The balsa, or whatever, which is calibrated and graduated to fit your HLT, will float atop the water in the tube, and the marks will align with the top of your tubing. I'm gonna experiment, and let ya know how it turns out. Please share any ideas you might have, or just tell me I'm crazy and that it'll never work.

I'm not sure how much difference it will make, but your buoyant material will act like a hydrometer. It will read slightly lower in water than in wort. Also, balsa is about the worst choice of material for use in a wet environment. It will act like a sponge and quickly become unusable.

That's why I said that I don't think balsa would be a good idea. This design would be specifically for a HLT, and I would have to find something where the temp of the water would have little effect on the boyancy.

Keep in mind, this is just an idea, with no real high expectations; just a thought.

Your material choice will have little bearing on the effects of water temperature. It's the water density that will change the reading, not the material in the water. Give it a test run. Capped CPVC pipe will probably work well. I'm guessing that the "hydrometer" effect will be somewhat negligible.