I figured I would post this as I'm sure there are others who would prefer to optimize flow, alleviate using some fittings, and save a few dollars too. Shaping PVC is sometimes done by plumbers but it is quite easy to DIY and only took me about 10-15min per bend and that was with thick Sch80 pipe. I'm sure it would be much quicker on Sch40. This idea came from DANFEIG's build "A reef tank in the desert 1400g+-" where his system builders did this in his build.
This was appealing to me as 2" sch80 fittings are hard to come b and each one is about $6. However my main reason was to improve flow as much as possible. In that build they discussed sweeping 90's well those are hard to get in sch40 and I doubt exist in sch80. I needed two of these to alleviate using 45's or 90's. I had to go up from my return pump -->over the top of the fish closet in the rafter bays --> and back down to the top of the tank. Using this method I was able to do this in 1 piece!! I put a union up along the ceiling where the pump is and now I can remove the entire section if I ever need to.
----Heres how-----
1) build the jig as shown in the photo below. It is a simple piece of scrap plywood, two scraps of 2x4, and an 1qt old paint can to use as the form for the bend. You'll need a pair of leather gloves (pipe gets pretty warm), and I used a portable torch with MAP gas bottle - available at ACES, HD, Lowes, etc. After building the jig it helps to screw it to the floor or secure it somehow.
2) mark the pipe where you want the pipe to be straight again. In other words where the bend stops. The sweep will be about 1-2 long depending upon the size of the pipe. Mine was 2" and thick sch80 pipe so it took about 2'.
3) heat the pipe with the torch. The trick is to CONSTANTLY keep moving the flame and never stay on a single spot. It will char the pipe if you do. I ket the flame so that the tip was almost touching the pipe. I heated the area from the line back about 2'. It took about 10 min to heat the pipe. During this time keep rolling the pipe so that you heat all sides. As you roll it try to bend it with one hand. You'll know it for sure when you can it'll flex as easy as somewhat stiff rubber hose.
4) place the pipe into the jig with the line at the edge of the jig. shown in the photo as the right side at the right edge of the 2x4.
5) bend the pipe along the paint can until it is it the angle you need. Its helpful to have a sample 45, square, etc to help you.
6) if the pipe kinks work it it a little by squeezing out the kink, relaxing the bend, make the sweep longer, etc.
7) You'll need to slightly over bend the the angle needed as the returns a bit when cooled. You'll also need to keep your hands on it and hold the shape for a minute or two until the pipe cools a bit to hold the shape.
8) two angles from a single piece are difficult to measure but very possible. There are calculations you can do to figure this out - but I'll leave that for someone else. I simply figured out the inside measurement between my 2 90s' and made the 2nd sweep to that spec. It took a bit more work than the other due to the precise measurement. If making to angles be careful to watch aixs of the bend so that you don't have one up in the air and the other off somewhere else like a lope-sided Z or U. It helps to do this on a flat floor to prevent this.
You can make almost any shape
Hope this helps others. I was amazed at how easily it turned out to be. On a scale of 1-10 this is a 3. Be careful with the torch. Probably best to do this in the garage or outside.
The Jig
First Bend
The whole piece
This was appealing to me as 2" sch80 fittings are hard to come b and each one is about $6. However my main reason was to improve flow as much as possible. In that build they discussed sweeping 90's well those are hard to get in sch40 and I doubt exist in sch80. I needed two of these to alleviate using 45's or 90's. I had to go up from my return pump -->over the top of the fish closet in the rafter bays --> and back down to the top of the tank. Using this method I was able to do this in 1 piece!! I put a union up along the ceiling where the pump is and now I can remove the entire section if I ever need to.
----Heres how-----
1) build the jig as shown in the photo below. It is a simple piece of scrap plywood, two scraps of 2x4, and an 1qt old paint can to use as the form for the bend. You'll need a pair of leather gloves (pipe gets pretty warm), and I used a portable torch with MAP gas bottle - available at ACES, HD, Lowes, etc. After building the jig it helps to screw it to the floor or secure it somehow.
2) mark the pipe where you want the pipe to be straight again. In other words where the bend stops. The sweep will be about 1-2 long depending upon the size of the pipe. Mine was 2" and thick sch80 pipe so it took about 2'.
3) heat the pipe with the torch. The trick is to CONSTANTLY keep moving the flame and never stay on a single spot. It will char the pipe if you do. I ket the flame so that the tip was almost touching the pipe. I heated the area from the line back about 2'. It took about 10 min to heat the pipe. During this time keep rolling the pipe so that you heat all sides. As you roll it try to bend it with one hand. You'll know it for sure when you can it'll flex as easy as somewhat stiff rubber hose.
4) place the pipe into the jig with the line at the edge of the jig. shown in the photo as the right side at the right edge of the 2x4.
5) bend the pipe along the paint can until it is it the angle you need. Its helpful to have a sample 45, square, etc to help you.
6) if the pipe kinks work it it a little by squeezing out the kink, relaxing the bend, make the sweep longer, etc.
7) You'll need to slightly over bend the the angle needed as the returns a bit when cooled. You'll also need to keep your hands on it and hold the shape for a minute or two until the pipe cools a bit to hold the shape.
8) two angles from a single piece are difficult to measure but very possible. There are calculations you can do to figure this out - but I'll leave that for someone else. I simply figured out the inside measurement between my 2 90s' and made the 2nd sweep to that spec. It took a bit more work than the other due to the precise measurement. If making to angles be careful to watch aixs of the bend so that you don't have one up in the air and the other off somewhere else like a lope-sided Z or U. It helps to do this on a flat floor to prevent this.
You can make almost any shape
Hope this helps others. I was amazed at how easily it turned out to be. On a scale of 1-10 this is a 3. Be careful with the torch. Probably best to do this in the garage or outside.
The Jig
First Bend
The whole piece
