McElroy Discussion Forums

Soak Times
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Author:  aisha [ November 5th, 2010, 4:50 pm ]
Post subject:  Soak Times

I am curious if anyone out there has a good rule of thumb regarding soak times for welding. I have spoken with quite a few people on the subject and have gotten many different answers. For the past two and half years I have not had any welds break so i figure I am doing something right. I have just heard about 11 seconds per millimeter soak time but I am not sure if that is based off of pipe wall or OD. Would love to hear from some folks on this.


Author:  chrisweight [ December 7th, 2010, 9:56 am ]
Post subject:  Re: Soak Times

As far as I know there is no set time on soak times it goes by the size of the bead on the pipe and that bead size is set by the manufacturer. If you just run off of soak times when it is 110 degrees outside you might have a bead of 3/4 of and in and when it is 30 degrees outside you might have a bead of 1/4 of and inch. The way I was taught was to go by the bead size. If you go to my company web site in the upper right hand corner there is a like that says Information Center and in that link is a Butt Fusion Joining Procedure. If I can be of any help don't hesitate to email me.

Author:  tulsamurph [ December 8th, 2010, 9:07 am ]
Post subject:  Re: Soak Times

Thank you for your post!

The reference to 11 seconds per millimeter refers to an ISO standard. The visual melt bead size is the method used when fusing to ASTM standards; F2620 to be precise. The reason for the visual indication is to accommodate the wide range of ambient temperatures you might be working in. The 11 seconds per mil is a reasonable expectation, but two things are important: if you are fusing to ASTM standards, the only current acceptable method is the visual indication of melt, and if you are simply trying to see if an operator is following the standard pretty close without leaning over his shoulder, colder weather will make soak times a little longer, and hot weather may shorten soak times a bit.

As the industry matures and standards are constantly being revised, some changes may occur, and it is important to check in with the standards organizations from time to time. This information is current today, but keep an eye on your resources, like this forum, ASTM, Plastics Pipe Institute ( see Technical Report 33), and be sure to take advantage of McElroy fusion training courses.


**Edit** 11 seconds per millimeter of wall thickness, not pipe diameter.

Author:  PhilSask [ December 13th, 2010, 4:21 pm ]
Post subject:  Re: Soak Times


The only failure I have had was on a 6" coiled line used for irrigation purposes in -10c conditions, no wind, but in a middle of a field.

Attempt 1:
After 3 hours getting it the 28 machine ( coiled memory - no line tamer ), waited till the bead size, cooldown etc. Snapped when coiling back on the drum.

Attemps 2:
Heated the pipe up a meter from the fusing joints, once we got it in the machine ( 3 hours later using a backhow and botcat , waited beyond the bead size, 2 x cooling time. then preheated ( and then some )the pipe before it went back on the roller, then it was ok.
Had to do another one on a different drum and that orriginal one was still ok.

So if you fuse in cold whether, then a shelter and heat is necessary or propane tourch and forced air if not ( no wind or falling snow etc).

Thanks Phil

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Author:  Joshua [ December 13th, 2010, 5:11 pm ]
Post subject:  Re: Soak Times

ASTM does forbid the use of open flames, but a warmer and shelter are definitely useful.

Author:  PhilSask [ December 14th, 2010, 9:39 am ]
Post subject:  Re: Soak Times

Joshua wrote:
ASTM does forbid the use of open flames, but a warmer and shelter are definitely useful.

Woops :oops: , I will remember that from now on, we were kinda stuck on how to do this and they did not have a heater out there in the middile of nowhere.

Guess we are going to have to invest in a industrial hair dryer or something that can fit in my truck with all the rest of the equipment.

Thanks Phil

Author:  Joshua [ December 14th, 2010, 10:32 am ]
Post subject:  Re: Soak Times

Lol. I have been there. Sometimes you have to make do. :lol:

Author:  chrisweight [ December 14th, 2010, 5:58 pm ]
Post subject:  Re: Soak Times

Just a little bit of information for you Phil I sell what they call a power blanket that normally in about 30 minutes could have your pipe heated up to around 90 degrees farenheit. If you have any questions or want more information on these blankets don't hesitate to e-mail me at or call me at 1-307-299-6676

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