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SDR-21

Posted: Sun Sep 14, 2008 5:54 am
by SpudFarm
hey i just found a Norwegian that sells PVC with three different SDR values, SDR 34,4 - 21- 13,6.

the smallest SDR pipe i can get is 63mm, that is what this topic is about. i need metric ID and OD of your SDR-21 pipe that fits golfballs

you get your SDR rating by dividating diameter of pipe on wall thickness.

the pipes up to 110mm has a safety factor of 2.5 and SDR-21 has a rating of PN10 (10 bar) and a wall thickness of 3mm (i think)

well look at the stuff i got from the web site..


SDR 21 - 63mm - 3,0 (PN10)

thats all

Posted: Sun Sep 14, 2008 3:16 pm
by psycix
I believe most pressure rated PVC (SCH40 thickness) has about 4mm wall thickness. SDR may be an exception to that, which is why it may be reinforced with SCH80.
The point to SDR is, that the wall thickness increases along with the pipe diameter in order to have the same pressure rating for all diameters pipe.
I do not have any SDR, sorry.

Posted: Sun Sep 14, 2008 3:37 pm
by frankrede
Sdr-21 pipe is thinwalled.
The OD is the the same as any other piece of 1.5" pipe.

Posted: Tue Sep 16, 2008 10:50 pm
by dat7203
check out harvel.com they give dimensions of all types of pvc including sdr 21. this will give a very good and tight fit on gold balls they have a diameter of about 1.693 inches; 1.5 inch OD sdr 21 has an ID of 1.7 inches. golf balls need a little help from ram rod to fit in 1.5 inch sdr 21. Make sure to sleeve 1.5 inch sdr 21 with 2 inch sch 80 pvc for safety reasons. standard to metric conversions can be googled.

Posted: Tue Sep 16, 2008 11:40 pm
by frankrede
dat7203 wrote:check out harvel.com they give dimensions of all types of pvc including sdr 21. this will give a very good and tight fit on gold balls they have a diameter of about 1.693 inches; 1.5 inch OD sdr 21 has an ID of 1.7 inches. golf balls need a little help from ram rod to fit in 1.5 inch sdr 21. Make sure to sleeve 1.5 inch sdr 21 with 2 inch sch 80 pvc for safety reasons. standard to metric conversions can be googled.
I have never had to use a ramrod to push a golf ball down a piece of sdr-21.

Posted: Wed Sep 24, 2008 3:18 pm
by CS
Standard Dimension Ratio (SDR) - The Engineering ToolBox
[Just explains what SDR is, just incase anyone is interested.]

Frankrede, I think for the simple fact that we are using it for tight tolerance chacteristics, but it isn't necessarily made to such high tolerances is why this happens. When I was selling the SDR-21 there for a while I learned my fair bit about it. Even though it is sold by several manufactures under the same name, the dimensions vary.

Dat, what you may try is cleaning your barrel. I know just from the potato juices, and whatever else I cleaned my barrel with a shop rag and a broom stick every once in a while. Or it could simply just be the pipe you have. I've bought SDR-21 that doesn't even fit golf balls. As well exposure to weathering would probably make it a bit harder to get down as well.