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 Post subject: AQUATHERM BUTT FUSION
PostPosted: June 13th, 2016, 3:10 pm 
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Joined: September 29th, 2009, 2:45 pm
Posts: 172
I currently have a HF 412 machine and I am wondering if it is possible to butt fuse 6"-12" PP Aquatherm pipe with it. I know a low force machine is made and recommended but I was curious to know if its possible by turning the valves down? If not can you please explain the differences and why a low force machine is needed?

Thank you!


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PostPosted: June 24th, 2016, 5:04 pm 
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Joined: December 18th, 2013, 3:56 pm
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Per the ASTM-F2620 butt fusion of HDPE requires an interfacial pressure (IFP) of 60lbs - 90lbs, we use typically use 75 lbs as to never go above or below the allowable range. IFP is the amount of force applied per square inch of material being fused and is part of the fusion pressure calculation. Per the DVS 2207 the IFP for butt fusion of PPR is only 14.5 lbs which is a little less than 1/5th of what is typically used when butt fusing HDPE. So lets do a comparison of the pressures that would be used for similar sized HDPE and PPR pipe on your machine.

Machine: 412 High Force
Pipe: 10" IPS DR 11 HDPE
IFP 75lbs psi
Drag: 30lbs (default)
Theretical Fusion Pressure: 191psi
Calculated Fusion Pressure: 221psi (gauge pressure)

Machine: 412 High Force
Pipe: 10" (250mm) DR 11 Aquatherm
IFP: 14.5lbs psi
Drag: 30lbs (default)
Theoretical Fusion Pressure: 31psi
Calculated Fusion Pressure: 61psi (gauge pressure)

Machine: 412 Low Force
Pipe: 10" IPS DR 11 HDPE
IFP 75lbs psi
Drag: 30lbs (default)
Theretical Fusion Pressure: 714psi
Calculated Fusion Pressure: 747psi (gauge pressure)

Machine: 412 Low Force
Pipe: 10" (250mm) DR 11 Aquatherm
IFP: 14.5lbs psi
Drag: 30lbs (default)
Theoretical Fusion Pressure: 116psi
Calculated Fusion Pressure: 146psi (gauge pressure)

Notice the pressure required to fuse the same pipe is much higher on a low force machine.

The issue is that any time your fusion pressure calculates to less than 100 psi it is recommended to use a lower force machine due to the fact that the speed of travel of the carriage is greatly reduced to a point where it is not possible to accomplish the open/close time (heater removal window) within the time that is allowed. Also because of the 20 psi increments of your gauge it will be impossible to set your pressure accurately with out using a datalogger. The trade off between high ans low force machines is speed vs power, low force machines move much faster on lower pressure settings than the high force machines but do not have the excess power in reserve to overcome large drag factors.

I just ran the numbers for 12" DR7.4 aquatherm on your machine and the fusion pressure with 30 lbs of drag calculates to exactly 100psi which will still provide a very slow rate of travel. This is just to show that the 412HF is overpowered for all sizes of PPR pipe currently in production in your machines pipe size range.

Option 1, purchase or rent a low force machine
option 2, purchase or rent a low force carriage to mount to your rolling vehicle.
option 3, purchase the necessary components to change your cylinders and gauge to what you would find on a low force machine. (cheapest but most labor)

Also you will need a 28 low force machine for any PPR sizes smaller than 8" DR 11 (8" DR11 is the smallest pipe the 412LF can fuse) and if you are planning on fusing any 6" DR 17 PPR you will want a 26 pitbull to fuse it manually as the fusion pressure for this pipe size calculates to just 90psi on a 28LF.

I hope this clears up your questions and please feel free to let us know if any more questions have been risen.

Anyone who reads this please let me know if there are any errors in the advice i have provided or if you have any other comment or recommendations.

Dan Rouse
Arctic Insulation and MFG
Big Lake, AK


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