PVC 101

I had produced an Instructable recently on making a PVC Toddler Bed Guard; however there were some concerns over home-made kid safety items and teaching others’ to make it, so, out of empathy, I took it down (it's now back up, check the link below). I did have a lot of great information in that Instructable that people asked me about in relation to methods of cutting, joining PVC and some great PVC resources.

NOTE:  The PVC Toddler Bed Guard has returned to Instructables in all of its glory.  Check it out here.

There have been some other Instructables out there that have identified some basics, such as cutting and painting PVC, but I thought it best that I try to aggregate some of the ideas into one big, ultimate Instructable:  PVC 101.

I work as a Design Engineer for an architecture/product design firm and I use PVC repeatedly to create prototypes and mock-ups, some of them even to ¼” scale, so one could say that I have a lot of practice with PVC.  And since PVC is the ultimate make-anything-toy-set for adults, I only thought it wise to share my experience and knowledge of it on Instructables.

Let face it.  PVC is awesome.  It’s easy to obtain, cheap, easy to manipulate and you just push it together (and cement if you like) and presto.  You can pretty much make anything you can think of by just using some fittings and pipe, and I’ll augment that basic idea along with some tips, and other information for PVC in this Instructable.

There are tons of PVC-based step-by-steps available out on Instructables. Search for one and I bet there is something you will want to make.  Last I checked, there were over 1140 Instructables involving PVC.

So if you are new to PVC, or if you are a constant user like me, please peruse.  If you have other tips that I have not mentioned in this Instructable, please feel free to add your comments, as I’m always looking for more ideas.
 

Step 1: Pipe Sizes

First up are pipe sizes.  Pipe size can do a number of things to your project, depending upon your needs.  The smaller you go, the more flexible your pipe will be.  So if you need curved surfaces for a frame, need hoops or loops, go small.  If you want stiffness and strength to the max, go big.  As the pipes increase in size, so does their inner wall, making them stronger and more inflexible.

I’m only covering basic, white PVC available in most home stores, as ABS is too brittle (and weak) and PEX is just not as friendly.

I’ve broken down the sizes into categories below:

1/2”:  Super-uber flexible, but not very strong. It can actually kink when bent.  This works well for kites and other light structures, but not so much for something you want to mount anything to.   Plus, it’s so small you would need tiny screws to attach anything to it.

3/4”:  Very bendable, ideal for just about any project that requires flexibility, specifically hoop houses, green houses, pet agility hoops and other curved frames.  This is also good if you need elasticity in your project, as it will spring back perfectly (be careful though!).

1”:  Only slightly flexible, but still fairly rigid.  This is if you want a bit of sway to your project, but still need a strong framework, 1” is good.  Marshmallows fit in them nice and snug.

1-1/4”:  This is probably the most ideal size for very rigid, lightweight project.  This is perfect for framing, structure, and anything else you might need to build a strong sturdy platform, shelf, table or wall with.  It still has SOME flexibility, but not much.

1-1/2”:  Pretty much rigid as it gets, except for 2” (below).  It’s heavy though.

2”:  Probably as strong as you could ever need, will hold tons of weight.  It is very heavy and very expensive in relation to other just as strong sizes.  However if your project is requiring a good foundation, 2” is perfect.  It also works well for canister-style projects (in conjunction with end caps), like garbage bag holders, etc.

Summary:  For most projects, either 3/4” or 1-1/4” are ideal.  If you need flexibility, go 3/4”, for rigidity, go 1-1/4”.
 

Comments

[MichelMoermans]

An extra step for your instructable.

I remember discussing this somewhere else on instructables but can't really remember so I'm just gonna give you the link to the site that promotes it.

www.thepipeviper.com/

It's a site that sells a tool with which you can cold bend a pvc pipe.

I live in Belgium (Europe) and followed industrial science in highschool. We had electricity there which involved alot of pvc bending. I however never heard off hot bending pvc before I came to this site.

We always bended our pvc cold using the same tool that that company sells. It doesn't damage the pipe and keeps the hole inside open as much as it would if you didn't bend it. It's really handy, easy and there is no danger at all of hurting yourself. And it doesn't take more then a 15 year old boys strength to do it :)

So check it out I'm sure you'll find it interesting :)

Michel

[DanYHKim]

I looked at the site you linked. Very interesting tool. They don't have a FAQ page, so I thought I'd ask you, since you have experience:

Is this suitable only for conduit applications, or can it be used for household water systems? I'd think that even though the pipe is 'not damaged' by cold bending, it may be weakened enough that it would not reliably carry pressurized water for household cold and hot water. So, is this used for water, or only for conduit?

[MichelMoermans]

I remember the plumbing classes in my highschool using the same cold bending method I described above for your usual kitched plumbing. You are right that the structure is weakend but the same goes for hot bending (in both cases you are stretching out the material over a longer length)

So yes you can use it to run hot and cold water unless you plan to do some crazy bending with it (over 270 degrees) but for normal 90 degree bends it should do fine :)

[DanYHKim]

Wow. Thanks for the quick reply and information. I may stick with solvent-welding to molded fittings for plumbing, but I have some ideas for running conduit for which this might be just the ticket.

I will have to see if a regular length of flexible spring will work almost as well.

[tomtortoise]

Using a wood saw is just silly? ive tried using both hacksaws and wood saws and the wood saws work great, they cut so much faster and give you a straighter cut.

[kabira]

I am always confused about the quantity of cement to apply.

Should it be:
1. A thin layer, or
2. Very generous?

Can I use Acetone as PVC pipe cleaner as well?

Thanks.

[trevormates]

I would recommend a thin layer. Once the cement hits the plastic it begins to melt, so you really don't need too much.

And yes, you can use acetone as pipe cleaner as well, but I recently found out that those sandpaper foam pads you get in the hardware store work just as good to prep the connection points, as well as remove the ink and marking.

[Galonii]

you can also paint plastic with Killz or Benz paints, they're alot cheaper but you have to brush it on, and home depot will tint your Killz for you.

[jayb1]

In Australia there are 2 types of PVC. Non-Pressure or Down Pipe Grade, or Pressure Grade which is used to transport liquids.
The larger pipes 90 mm, 100mm up to 230mm & beyond. are great for buildings. Pot plants, Hydroponics even a wind tunnel with the 230mm.
The PVC off cuts can be picked up for free in the "Poor Mans Bunnings" or the rubbish point on a building site, along with timber scraps, bits of copper pipe, insulation, etc . For the larger pipes go to a New Estate site & ask if you can have the left over water & drainage off cuts (230mm). They'll give them to you, mostly. It saves you having to get rid of them. I ended up with enough house bricks to build a house once. They said, " you pick them all up you can have them." All different colours, but, Hey! If you don't ask you don't get.

[DannytheGreat]

it says on the can "no sanding required"

[trevormates]

I know, but the manufacturers sometimes have embossments on the pipes and fittings and if there is anything more filthy, it is PVC from Home Depot.

Plus I come from the old school of 'sand, paint and sand again'. Its just a recommendation...

[foosefoose]

This is an instructable that doesn't teach you how to build a dang thing! This is also one of the most helpful instructables I have ever seen, complete and straightforward!

Great job.

[joen]

Great instructable! I especially liked that you design in Sketchup. I down loaded the fittings you showed and have been trying to design something from them. I seem to have a problem with lining up the pvc pipe and the fittings. No matter how hard I try I can't seem to get them straight. I am obviously doing it all wrong, and I do mean ALL WRONG! The sketchup tutorials were no help. Neither was Google Warehouse. Any suggestions on how to start getting things straignt? (An Instructable perhaps)

Any suggestions would be appreciated.

Thanks

[bobjacksonjr]

I am building a boat out of 1.5 inch PVC and had the same problem with making the 90 degree angles exactly 90 degrees. Build a gig out of 2x4 or 2x6 and not only will your joints be parrell but you can also make a press into it so the pipe will seat completly into the fittings. Also you can make a simple gig (two demental) using a sheeet of plywood and pieces of square 2x4 blocks. I can send you a picture and dementions if you like. ([e-mail]). Bob

[joen]

Thanks for the reply bobjacksonjr.
Some people think that building a jig to get something you're building built right is a waste of time and trouble but it really isn't especially if you really need to get it right. So you are right

To get real pipe to make real 90 degree angles is not a problem for me. What I was talking about was how to get real 90s in Sketch up. The 3 dimensional manipulation that you have to do can be a little tricky. I have gotten somewhat better at it since I wrote the post last year but there is still a lot of hear pulling to get it right. Maybe it is a good thing I keep my hear short::) If I am building something with PVC I will use the fittings in the design process to get the angles I need. Getting it to look right in Google Sketchup is the challenge.

Wish you success in your boat;

Joen

[TheGreatS]

I hear filling the PVC pipe with hot sand also is a method for bending the pipe.

[sysop]

On my last project I considered buying a PVC cutter, but after looking at one in the store I borrowed my wifes ratcheting action pruning shears instead. Sharpened the blade a bit and It worked like a champ!

[tolson411]

What's wrong with nitrile? It can withstand more acid and chemicals than latex and is 3x more puncture resistant...

[Capt. Kidd]

i use warm sand to bend. just fill the pipe, and bend. you can also bend it cold with a pipe viper.

[DBMods]

 you can just get pvc primer and then paint over that

[thewetturd]

I thought this instructable was very informative thanks for posting it.
 
I use a modified technique to cut with a ratcheting cutter.  I mark my cut line and I put moderate pressure with the cutter and instead of preceding to cut the pipe through, I roll the pipe in the cutter.  With each turn that I twist the pipe with one hand, I add more pressure on the cutter with the other hand.    If you do it right, after with some practice, you will end up with perfect cuts every time.  
It is very important to make sure that if you are using a power miter saw that you get the saw to full revs before you make the cut.  (I know you mentioned it, but wanted to make sure others undersood why it is so important)   Otherwise, the pipe can catch on the teeth of the saw and become sharp, jagged, projectile sharpnel. 
Awesome instructable!
Oh, btw, that pipe bending coil tool.  WOW!  If I were to start doing more project with PVC, it may pay for itself after a while. 

[dolabil66]

a easy way to bend the pipe is use a heat gun , a few minutes waving back and forth will do it ( depending on the size) and with a little practice you can bend it with out kinking , the trick is slow bending with pressure , and then a cool wet rag to help set the bend

[kminer49er]

One of the problems that you may encounter when using PVC in unsupported lengths of over 4 or 5 feet, is sagging.  This can be easily remedied by running a piece of thin-wall electrical conduit (EMT) inside the PVC.  For 3/4" pipe, use 1/2" EMT; for 1" PVC, use 3/4" EMT and it should run the entire unsupported length.  This will give extra rigidity to both vertical or horizontal runs (of up to 10')  It is reasonably cheap and only adds a small amount of weight.

[sssssbooom]

The strength of the pipe really depends on its schedule not the outside diameter. In most cases what you said is true, but you might find a piece of sch 5 2" and that would be a lot weaker that a piece of sch 40 1". The schedule plays a big roll in its strength.
Also a metal pipe cutter works perfect on pvc if its sch is around 40 and up. With the thinner pipes it puts too much pressure on it and kind of turns it oval resulting in a really bad cut, but on sch 40 and up it makes a perfectly straight cut you may need to ream it (in model/furniture making making reaming usually isn't necessary) I use one all the time.
And if you are painting something that you will be touching often then an epoxy finish over your paint will work great. it is tough and will last a really long time.

Just though I would add what I know about pvc. I make potato guns and I work with my father on plumbing jobs so I got some experience with pvc (along with copper, pex, iron, etc lol) Anyways amazing instructable!

[trevormates]

Completely agree.  I'm going to have to update the instructable with these remarks.  I'm getting alot of word from folks that a metal pipe cutter will work just fine.  I think I've been overrule on this one.  Look for some forthcoming changes!

[Whatnot]

I really don't think there's much issue with painting PVC at all, however drainage pipes for the sink and such are often made not from PVC but from PP, and they look virtually  the same but PP is such that almost nothing sticks to it, in fact you normally use connectors that clamp for them since you can't glue it like PVC.
It will say on the pipes what the material is though so you can easily tell, also PP is just slightly shinier, but you only notice that when you see them together.

[xd12c]

Do you mean PolyPro when you say PP?
If that's the case, PolyPro can be welded to itself with a plastic welder.
PP is also a bit more brittle & has more of a tendency to shatter.

[Whatnot]

I'm not sure where yo get that it's more brittle than PVC, I'd say from experience it's more the opposite, but yeah I mean PP as in Polypropylene (http://en.wikipedia.org/wiki/Polypropylene).
And sure you might be able to weld it but that's not so easy for the average person as glue, you need a precisely controlled temperature for welding plastics, and apply that locally, and my point wasn't that you can't find ways to connect it, but that it's more resistant to being painted and the resistance to gluing just underscored how hard it is to make stuff stick to the stuff you see.

Thanks for reading my comment though :)

[xd12c]

Used to work with Polypro in the Orthotics field. I had pieces shatter when they were removed from the mold. When thermoforming, PP is considered brittle compared to PE, etc...
There are also specialty welders made for just plastics that are on the market.
And I'd always wondered about painting PP. We always used transfer images when thermoforming the plastic.

NP, you pick up other stuff when you take the time to read the comments :)

[xd12c]

Couldn't you also stop at the local supermarket & get a pair of rubber kitchen gloves?

[trevormates]

Yup.  Excellent point.  They are probably best!

[casvandegoor]

Thanks for the reference to 3D PVC components!

[trevormates]

No problem.  They make life sooo much easier.

[Grimmster]

An even easier way to bend PVC is sticking it in boiling water.  If you cut it in half down the length of the pipe first, you can easily make strips to cover your PVC chairs, tables, etc.

[XGundam05]

For Band Saws, I have found that the ones I have access to work rather well. For one, they were both designed to cut steel rather quickly, and two, they both have adjustable drop rates. (Both are horizontal band saws)

And for Pipe cutters, they will work, you just have to be careful with them. I've used them in the past to get really square and even cuts when I didn't have access to a band, chop, or miter saw. Although you do have to really crank the blade in after getting a nice initial groove started.

[snowfreak]

yes thank you for saying that XGundam05 i have found that my metal pipe cutter works almost as well as anything else I have used including a dremel with a metal bit in it.

[Tommyhzy]

 This Instructable is so well written that I just HAD to give a 5 star rating.

[trevormates]

Awesome!  Thanks!

[BeDub]

I agree with the other commenters that this is a very helpful and informative instructable.  I'd like to use PVC (or CPVC) to make an underground irrigation system to which a garden hose can be attached.  What diameter pipe would you recommend for this purpose, and where can I get the garden-hose-compatible fittings?  Thanks!

[trevormates]

PVC is fine.  You can use 1/2", but I think 3/4" is best.  As for garden hose compatible fittings, there is an assortment of them at HD or Lowes, if you have one in your area.