Has anyone used Flex Seal to coat the inside of a hull? I keep seeing the commercials and it has me wondering if a coat on the upper and lower hulls would greatly reduce noise from getting out and grime from getting in.

Never used it but it looks like it might just work!

I read a theory on here that the turrets and such are much louder on these modern tanks because the cavernous interiors act as a speaker box, amplifying everything inside. This makes a lot of sense and I have been thinking of putting something to dampen the sound, but being reminded of Flex Seal makes me think this is the perfect way to seal up the switch holes, lessen the axle gap and dampen all vibrations inside the hull. I'm just wondering the mess involved and how many coats would be required since it takes 24-48hrs to dry. Masking might be a challenge too.

I'd stick a spare set of axles in the holes in hopes it would create a sort of built in gasket.

Plastidip may work better you can brush it on?

The turret is really loud on the Leo I think a little fluffy pink insulation in the back of the turret would absorb a lot of sound.

This would be the best way to dampen any unwanted acoustic noise you may have. i would not use any product like above mentioned inside because the vapors from the products can be volatile and may not be safe for plastics. Plus there is the mess of application and the problem of removal if it is not successful. Just use some foam or fiberglass insulation.
That is what is used in speaker cabinets to dampen unwanted acoustics.

Rumor has it that this stuff is very similar if not the same as Plasti-dip except with an inflated price tag.

I found some tissue paper in the closet and moderately stuffed the lower hull as a test. Wow. Cut the noise in half. Now to find something more permanent for the lower hull and move the tissue up into the turret. I'm thinking some floral foam board that I can carve into any shape I want and easily lift it out in one or two pieces. Also no worries about it getting caught in the fan or the gears.

Thanks guys.

This ripoff stuff is the same as plastidip and ten times the cost! You can brush it on in multiple coats, depending on how thick you want it. It will waterproof anything and is non-conductive. If you want powerful sound proofing, brush it on then apply 3/8-1/2" foam of any kind. I like the "memory" foam and it's cheap! You can use this for your car or hot rod if the rattle trap makes too much racket for ya! Especially in those doors that sound like a tin box when you close them!! Try it, you'll like it!!

I used a bit of old polystyrene in my KT to try and dampen the sound.

Warren I would say this is more than a bit. I race RC boats and sound is a concern as we have rules on max sound. One thin we have found that quiets the hull noise a good bit is lining it with the camping mat foam. Its about a 1/2" thick and also acts as floatation. One other thing that may be worth a try is the gray egg crate foam that a lot of stuff comes packed in. The shape is a lot like the professional acoustical foam they sell. Should keep the sound waves from bouncing around.
Jimmy

Yea it looks the same as plastidip. You might be lucky and get some cheap liquid electrical tape too, it is almost the same yet not quite as durable but sometimes I find a big bottle for less than the cost of plastidip at my local Harbor Freight. Most of the time the plastidip is cheaper though. I use liquid tape for lots of stuff, it is great to make backings for PCB boards if you are in a tight fit and cant use a case and worrying about shorts.

You can buy some of that dynomat but a cheaper brand of it and all you need to do is cut some thin strips and line them inside and it will stop all resonating.