# Cutting PVC and Plastic help please



## donnyfl (Aug 23, 2014)

Good evening everyone, I know a lot of you are well rounded with many machines and tools. I've been having a small issue yet for what I do it results in a big issue. 

I am trying to cut a pvc tube and for the life of me can't figure out why it always chip at the very end and also it is not perfectly flush.

I've tried mitre saw and cut off saw with blades that have teeth and without. Always result in the same thing. 

Here is a picture of what all of my cut off pieces look like. The part where the chip is hanging is the bottom of the tube. Notice the angle of the slope as well, going from left to right. Is there any tool out there that will enable me to get flush cuts every time? I also tried the taping method but it still chip and slopes.


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## chuckorlando (Aug 23, 2014)

horizontal bandsaw would work. Handsaw and a fence to guide the blades. If the fence goes past both sides, start the bottom cut then come from the top. Like you would trim a tree limb to keep the bottom part from ripping. pvc hand cutters would give a real nice and fast cut, but not straight.


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## darkzero (Aug 23, 2014)

Not sure what your other cutting options are but try faster speed and slower feed, also finer tooth pitch would help. But since it's plastic not too fast where it will start melting the material. I get that on my horiz bandsaw on metals when I don't have the proper speed, feed, & blade setup. Sometimes it's not worth going through the hassle unless I'm cutting a lot pieces. They would get cleaned up in the lathe or mill anyway. You could also use a belt sander to quickly clean up those cuts.


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## JimDawson (Aug 23, 2014)

When you saw miter saw, I assume you are using a power miter saw.  It is possible that the blade is dull, the teeth on the left side more so than the right.  A nice sharp reasonably fine tooth blade will help, maybe a plywood blade.  Try feeding slower, that should help the tab also.  I have cut a lot of PVC and usually wind up with a bit of a tab.  Normally a file or some emery cloth makes quick work of that.

A hand miter saw should work great, assuming it is sharp and the teeth are set correctly.

I agree with chuckorlando, a hand cutter will not normally cut straight, the exception is if you spend a lot of money on a commercial grade cutter.  The ones you normally find at the big box stores have cheap and flexible blades.


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## donnyfl (Aug 23, 2014)

I like the idea of the bandsaw. I think that'll work really well for cutting the pvc and my carbon fiber tubings.

DarkZero - I was cutting them with a kobalt 10 inch mitre saw and also tried a Harbor freight 6 inch cut off saw. Both yielded the same results. I made sure to zero both of them but i think the problem lies in the handle itself. there's left and right play as you pull the blade down and I think that's why it is not flush.


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## darkzero (Aug 23, 2014)

Sorry, I meant to say "not sure what your other cutting options are". Do you have to cut a lot of them? A saw type tool would be much better for this but try the slower feed to see if that helps.


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## chuckorlando (Aug 23, 2014)

you need multiple tooth in the material. So if thats thin wall you will want a high tpi blade. If not it's gonna snag and rip a tooth or material which ever is softer. You can turn that on your lathe though.


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## donnyfl (Aug 23, 2014)

No problem dark, I do have to cut a lot of these and I mean a lot lol! I make Carbon fiber air gun suppressors. Right now I am using aluminum tubings inside to act as spacers between baffles. They were nicely cut on the lathe. However, I would like to lower the overhead cost allowing me to lower the cost of my product. So with a little bit of turning of a 3/4 inch pvc tube, it fits perfectly inside the carbon fiber tube. Each unit will have about 6 spacers 1/2 an inch each. I did contemplate on buying a sander to speed up the process but again, that is a lot of sanding. I'd rather spent the time elsewhere. I tried to part the pvc on my lathe at 300 rpm but it just melts and changes the diameter making it useless.



darkzero said:


> Sorry, I meant to say "not sure what your other cutting options are". Do you have to cut a lot of them? A saw type tool would be much better for this but try the slower feed to see if that helps.


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## drs23 (Aug 23, 2014)

Use a fine tooth metal cutting blade. Turn it around backwards. Problem solved.


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## darkzero (Aug 23, 2014)

donnyfl said:


> No problem dark, I do have to cut a lot of these and I mean a lot lol! I make Carbon fiber air gun suppressors. Right now I am using aluminum tubings inside to act as spacers between baffles. They were nicely cut on the lathe. However, I would like to lower the overhead cost allowing me to lower the cost of my product. So with a little bit of turning of a 3/4 inch pvc tube, it fits perfectly inside the carbon fiber tube. Each unit will have about 6 spacers 1/2 an inch each. I did contemplate on buying a sander to speed up the process but again, that is a lot of sanding. I'd rather spent the time elsewhere. I tried to part the pvc on my lathe at 300 rpm but it just melts and changes the diameter making it useless.



I see. Again, as many of us have mentioned, sawing is your best bet. Since you have to cut a multiples of them off the same stock, cutting as you are now with those chipped edges & sanding might not be worthwhile as the next piece would have the area that was chipped off, not sure how critical that is. I doubt you would want to just use a hacksaw but it should take that much effort to do. Do you have an air supply? Air saw is another option, you can get one cheap from HF. 

Your cuts aren't coming out straight now & neither would be something else hand held. I assume you would want the faces square. If it were me & I didn't have a bandsaw, parting in the lathe & deburring with a scraper would be my next choice. Are you deforming them in you lathe because of the speed of because of the chuck? I have a 6 jaw so that takes care of that. Try slower rpm & less grip on the chuck (assuming it's a 3 jaw.

Perhaps investing on a horiz bandsaw might be worth it. It will cut cleaner & you can set the work stop so you can just cut, pull the stock out to the work stop & cut again, it would be the fastest way. 

Just a thought, I know nothing about guns & certainly nothing about supressors (highly illegal in CA) but would PVC even hold up to the heat in repeated use?


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## donnyfl (Aug 23, 2014)

The suppressors are for air guns which generate a lot less heat than real guns and legal in many states. It is legal in CA. Making them out of pvc is actually better in terms of legality because like you said, if you put this on a real gun, the amount of power and heat it generates will blow it right off. Air guns are not considered as a *fire arm* in many states and that's the key word. In Florida, you can shoot air guns in your backyard with no problem but if you do something wrong with a slingshot you can get in big trouble with the law. On the downside, air guns can be as loud as the real ones so a lot of guys purchase aftermarket suppressors or LDC (Lead Dust Collector) so that they can shoot their guns in their backyard without disturbing their neighbors. 

I just ran down to my garage to take a few pictures of the blades that I've tried. The bottom one is 180T designed for plastic yet it still chips and not flush. Second picture shows the aluminum spacers which will hopefully be replaced by the pvc. Third is a picture I recently showed ChuckOrlando of my first Carbon fiber suppressor. 












darkzero said:


> I see. Again, as many of us have mentioned, sawing is your best bet. Since you have to cut a multiples of them off the same stock, cutting as you are now with those chipped edges & sanding might not be worthwhile as the next piece would have the area that was chipped off, not sure how critical that is. I doubt you would want to just use a hacksaw but it should take that much effort to do. Do you have an air supply? Air saw is another option, you can get one cheap from HF.
> 
> Your cuts aren't coming out straight now & neither would be something else hand held. I assume you would want the faces square. If it were me & I didn't have a bandsaw, parting in the lathe & deburring with a scraper would be my next choice. Are you deforming them in you lathe because of the speed of because of the chuck? I have a 6 jaw so that takes care of that. Try slower rpm & less grip on the chuck (assuming it's a 3 jaw.
> 
> ...


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## darkzero (Aug 24, 2014)

Haha, I totally missed the word "air". Amazing how real they look now than when they first came out. Very nice!


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## newbydave (Aug 24, 2014)

I use a plywood blade turned backwards for cutting vinyl siding and have cut pvc pipe
with my mitre box without a problem. A steady feed rate is important. Make sure saw 
blade is up to speed before starting the cut.
Dave


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## hman (Aug 24, 2014)

When I need to make a very clean cut on a piece of PVC pipe, I use my table saw.  Unlike a miter saw, a table saw lets you keep an eye on the actual cutting area, and it's a lot easier to control the feed rate.  

Be sure the blade is pretty new, or at least known to be nice and sharp.  Carbide tipped, of course.  If you hurry the cut, you'll often have a bit of a tab on the cutoff part.  But if you slow down the feed (ie, the rate of "push") when you get to the end of the cut, there will either be no tab, or else the tab will be easy to simply snap off cleanly by hand.

If your table saw's miter gage is short, attach a piece of wood to it, so the pipe is supported all the way to the blade.


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## Ebel440 (Aug 24, 2014)

Is the pvc old it looks a little yellow in picture if so it could be brittle from age and more prone to chipping.


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## donnyfl (Aug 24, 2014)

Good morning Ebel. I've cut a bunch of pvc tubes practicing and they all resulted the same. I started to use scrap ones I have laying around for further testing. That particular one was used outside to stake something short term. I use well water to water my backyard "fruit trees, veggies". It has a lot of  iron so it gives a yellow stain. In front of my house we use  reclaimed water. We are suppose to use reclaim for whole yard but I can't water my veggies with that.  Good observation 




Ebel440 said:


> Is the pvc old it looks a little yellow in picture if so it could be brittle from age and more prone to chipping.


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## Rbeckett (Aug 24, 2014)

I'M a Air gunner also.  I have a .177 Nitro venom, a .22 Umarex Octane and a .177 Webley Raider PCP.  I  would love to get off line and talk about your suppressor design because I really need one for the Webley because it has a definite sonic crack that caries a long way.  Even though I live in the country I don't want to worry my neighbors with the sound of a rifle next door...  the Webley is really a Hatsan AT44 in disguise and has the 1/2 fine thread barrel that will accept a standard suppressor with no problem.  Drop me a PM when you have the time.  And you stole my idea of using my machine tools to make suppressors for sale too!!!! 

Bob


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## KMoffett (Aug 24, 2014)

To me it looks like you are leaving the cutoff ends unsupported/unclamped as you cut through. They will tilt if unsupported and chip like that. If they are unclamped they will try to rotate as you cut through and chip. You will see that with any band saw, table saw, or handsaw.

Ken


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## Fabrickator (Aug 24, 2014)

I've always used my chop saw and got good, clean straight cuts.  Use a finer blade ( not a rip) and go through the finish slowly and you should get a clean cut.

I built a towable boat tailer (check you tube) out of 2 & 3" std PVC, seemed like a hundred cuts before I was done.  It was more of an exercise in engineering, and it worked for off-road use.


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## donnyfl (Aug 24, 2014)

Thank you everyone for your very clever solutions. I picked up this bandsaw this morning and it has been working great. I am sure it was user error for the other machines. Not doing at right speed, blade and etc. This one was very easy to get used to.






Bob I have to run some errands but will pm you later.


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## kd4gij (Aug 24, 2014)

I use a good sharp tuping cutter when I need streight cuts in pvc works great.


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## Grumpy Gator (Aug 24, 2014)

Donny,    As you move that tube into the blade when it breaks into the inside stop going forward and rotate[ Roll in place] the tube toward the back of the saw. You will be cutting on the top and the bottom will be your guide. Should give you a square cut every time.****
*************Just Saying*********************Gator**************************


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## Bill C. (Aug 24, 2014)

donnyfl said:


> Good evening everyone, I know a lot of you are well rounded with many machines and tools. I've been having a small issue yet for what I do it results in a big issue.
> 
> I am trying to cut a pvc tube and for the life of me can't figure out why it always chip at the very end and also it is not perfectly flush.
> 
> ...



I used a power miter saw to cut 1-1/2" dia. The pipe is breaking off before the blade gets to the bottom.  Try a bandsaw or a PVC tubing cutter.  Good luck


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## reds (Aug 25, 2014)

Use a masonry blade in a miter saw or a table saw. Makes a smooth cut in PVC


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## Kevin45 (Aug 28, 2014)

A Japanese backsaw and a cheap wood mitre box will work every time and leave a very nice cut.


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