# Bulkheads, Tubing, Drill Bit sizing, Tubing



## Howiedoit (Oct 29, 2009)

This subject is probably covered somewhere but I had a hard time finding the exact answers w/the search. I wanted to drill two holes at the top for 2-10 gallon verticals and a 20 gallon high. This is to run my ultrasonic humidifier through it. (I'm wondering if this one humidifier will be strong enough to do th job but assuming I can always just have it set to run longer) I was on Glass-holes.com and see that they have 1 1/8" drill bits but says it is for 1/2 inch bulk heads? Just wanted to confirm that is correct before I go off buying. Also if anyone knows which bulkhead will work best since it comes with different options ie. slip x thread, tread x thread, thread x slip, Slip x slip. Now tubing, assuming 1/2" tubing will be the fit I need for 1/2" bulk heads? Feel free to suggest different sizing that may work better. Thank you in advance.


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## Phyllobates (Dec 12, 2008)

I won't be much help with the humidifier because I haven't used one but I can help with the bulkheads:

1/2 bulkheads take a 1 and 1/8 inch bit because the fitting itself is larger than 1/2 inch.

I prefer to used thread x thread because I can reuse them for other projects later if I need to and because many of the strainers and barbs that are used are male threaded.

I'm not sure on the hoses either. There is a really good thread out there about the DIY ultrasonic humidifier but I can't remember who posted it...

Chris


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## davecalk (Dec 17, 2008)

Personally I think having to drill a 1 1/8 inch hole to fit a 1 /2 inch bulkhead is kind of nuts. I make my own bulkheads much cheaper and don't need to drill such large holes. 

Go to your local big box home improvements store like Home Depot and look around in one of three areas for fittings to make bulkheads. They can be found in the plumbing section, (White PVC), the electrical section (Gray PVC), and in the lawn sprinkler / irrigation section (Black Polypropylene). 

The gray PVC pipe and fittings in the electrical section is used to run conduit through which electrical wires are passed through. You can purchase thin nuts that will tread onto the PVC fitting, which is normally used to lock the conduit onto the electrical boxes. They work fine to thread and lock the PVC fitting onto glass. I don't normally go this route, but I use two threaded fittings to make my bulkhead, one a male thread and one a female thread. 

A 1/2 inch PVC pipe has a nominal inside diameter of 1/2" and an outside diameter of 7/8".

I only have a 3/4 inch diamond bit and the fitting is a bit too large to go through the hole without buggering up to threads so I flare or ream the hole a little bit larger by rotating the bit in the hole while holding the drill at an angle. If I had a 7/8 inch bit I wouldn't need to flare the hole, but it only takes a minute or so to widen the hole enough so that the fitting will thread easily into the hole. 

These are some of the fittings that work well.























A bit of teflon tape and a ring of silicone around the inside and outside glass makes everything waterproof.

The other advantage is that the completed home made bulkhead costs about $1 - $3 per fitting compared to $4 - $8 for a "real" bulkhead.


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