If the tub has a flat wall, you can use regular bulkhead fittings from the aquarium store. If the fitting won't see pressure (i.e. just a tube running through the wall) use a grommet.

You're not using a paddle-type hole saw are you? For thin stuff use an actual bit or round hole saw. Putting a piece of wood behind what you're drilling into will help keep it from deforming as you apply pressure. (Don't do this if you have to stick your hand in the way to hold the wood) This helps keep the edges from getting torn.

If you have the quick change hole saws with the pin drive mandrel, you can get cleaner holes by tightening down the saw part all the way and ignoring the pins. The pins leave too much play letting the blade wobble a little and it cuts rough egdes. I add a little anti-sieze when I do that because if you don't use the pins, the cutting torque can really tighten that blade down on the mandrel.
TestPilot Reviewed by TestPilot on . Silicone for Leaks? My friend fired up his homemade E&F system for a trial run tonight and the in-spout on one bucket has a leak. We used a fair amount of silicone around each side of the nozzle the first time and after the leak we added more to it and are going to wait for it to dry until tomorrow. Is silicone the best thing to use for leaks? Also, is the tub still usable or should we get a new tub? Rating: 5