PVC

Ok! So you've decided to make your own filter? You also know you need some piping to accomplish this. The most common is PVC or polyvinyl/chloride. It's that white plastic pipe you see just about everywhere including in your home plumbing.

Most everyone who either builds or buys a filter uses some sort of PVC pipe in construction. It comes in many different sizes or diameters from 3/8" of an inch up to 4 inches or larger. It's also rated in strength called schedule. Schedule 40 is usually most common and is stronger than 20 and 80 is stronger than 40. Get the idea? And it even comes in colors. Generally its either white or gray (the gray usually meant of hot water lines) to a semi clear version that is available.

Note that the price of PVC goes up as you move up in schedule (strength) and color.If you have any intention of burying the pipe then I'd stay with schedule 40 pipe or higher. When you're at the store, if you look closely at the pipe, it will state what schedule and size it is. PVC pipe also usually comes in 10 foot sections. Ask if they can cut it, if needed, to make the size more manageable.

So now you've got an idea for your filter.You're going to need pipe. From personal experience I've found you're better off trying to draw a diagram of what you'll need before you go to the plumbing supply section.If you're like me when you walk into the local homedepot it can be a bit overwhelming from the choices available.Plus the sales people there can really help if you're fixing a sink but I've drawn blank stares when I mention either pond or filter.In one instance when the larger chain store didn't turn up what I needed,I went to a small hardware store nearby.We actually sat in the floor to piece together what I needed.Sure I paid a little more but you can't beat the service!

Plan your filter,draw some pictures and head off to the plumbing supply.If your pipe needs to make any turns then you'll need some elbows.These come in 45 or 90 degrees.These allow you to make a turn around,up or over an object.For example to make a square you'd need 4 pieces of pipe and 4 ,90 degree elbows.The elbows will be labeled the same size as the pipe you're using.Say you make a mistake and want to add more pipe?You look for something called a coupling.This is a short piece that allows you to join separate pieces of pipe to make a longer one.Want to branch off and go in two different directions? then what you look for is a "T" fitting.It looks as described.So now you say ok I've got one inch pipe and three quarer inch pipe meeting.What do I do?You look for a reducer for those sizes.This looks a lot like a coupling but is larger on one end than the other.Trying not to be too confusing I hope, all the above fittings come in male/female and/or threaded. types also.Generally most fittings are female which allow you to push the pipe into it.Threaded fittings allow you to screw pipe and/or other fittings together.

So now you've got an idea about your pipe and what kind of fittings you need.But you've got some sort of container this pipe needs to connect to.Now we sorta get techy here sorry.You'll need a bulkhead fitting.These can be hard to find but its not impossible.What these do is allow you to attach your pipe to the container.You drill the correct size hole you need in the container.The bulkhead fitting unscrews and is placed thru this hole and then screwed back together.It comes with the proper size seals so that it won't leak.What I did to get around this was to buy a coupling.It was female on one end(push on) and male threaded on the other.I then purchased a rubber washer called an "O" ring the correct size and a toilet tank nut.After drilling the hole in the container I placed the male threaded portion thru the hole,slid the "O" ring on and then used the toilet tank nut to tigten it all up.No leaks.Bulkhead fittings are better but it all else fails there are other alternatives.

Well lets see we have our pipe,our fittings,our container and some sort of plan by now we hope?But now you want to regulate the flow of water.Either the flow to the filter or coming out or say you added a "T" fiting and made a waterfall.You can do this with something called a ball valve,gate valve or knife valve.They all do the same thing as the water faucet on the side of your house.Except they're designed to be used with your PVC pipe/fittings.They let you limit how much water goes thru them.These also come in male/female and threaded versions.There are even some called check valves.What these do is allow the flow to go in one direction only.So depending on your type filter and say you have a power failure to your pump your filter would not empty itself.The backwards flow of water closes the valve preventing it.

So now we're home and we've got this big tinker toy set to play with.Lets start putting it together.The pipe will have to be cut.With PVC almost any type of saw will work.A plain hacksaw will do best in most cases.Measure and cut your pipe and if possible cut the pieces a little larger than needed.Its a whole lot easier to trim off that extra piece than find out the pipe is too short later.When cutting the pipe be sure to clamp it to some sturdy surface by either clamps,locking pliers or a vise.Once its cut then you should clean up the edges with sand paper or a file.Not much pressure is needed for this.If any part of your pipe needs holes drilled in it then I've found that using a brad point bit works best for me.This looks a lot like a standard drill bit but has a nice little sharp point on its end that bites into the pipe and won't wander off the spot you want drilled.Again I highly advise clamping the pipe before drilling.For your container hole I use an inexpensive holesaw like you'd use when installing a doorknob in your home.

Well everything is cut out and now we dry fit to see how its going to look. Press or screw everything together and see how it looks. If you're satisified then decide on whether it needs to be cemented or not. Pipe that pretty much is going to stay and never be moved should be cemented.Pipe thats going to be under water pressure should be also.Generally the pipe inside the filter can be left dry fitted.This way you can break the filter down for cleaning later. For the cemented portions this stuff is usually sold in two cans. One is a cleaner/prep tool for the cement. It's usually looks purple. The other is the cement and is semi clear.Both of these are flamable so be careful when using these. An added hint is that when you dry fit your project mark your fittings that will be cemented across the joint. The cement dries pretty fast and the quicker you have your fittings aligned the better. And for any portions that may be screwed together, you can avoid leaks by getting a roll of teflon tape and wrapping the threads.

So here's a basic introduction to PVC.I know there's a lot left unsaid and I know that you'll probably make some mistakes.But the thing about PVC is that it relatively inexpensive and so a couple mistakes won't hurt a thing.Good Luck.