The job the OP is offering is manual hot air/plastic filler work. As they said, it is different from other welding. There are plastic fab shops, much like a steel fab shop but working with plastic. one of My friends is VP of the one in Our town, it is an interesting shop.
Some years back My cousin was fabricating custom thermoplastic water & waste tanks for boats, that is the only time I have done any of this type of welding. He wanted Me to take over for Him in Annapolis, but having just been diagnosed with cancer, I could not.
No, Steve. Heavy wall plastic pipe welding is carried out in automatic machines according to the method called "hot plate plastic welding".
The pipe ends are square and no filler is used.
The pipe ends are put into contact one on each side of a hot plate until a few millimeters of the end is molten. Then the pipes are taken away from the plate, the plate is removed and the pipes ends are pushed one against the other until they solidify, thus making up a welded joint. All the operation is automatic.
The whole natural gas distribution piping net of Sao Paulo city (18 million inhabitants) was constructed in this way.
Enter www.omicronitaly.com and select the English language.
Once in there, click on Products.
Once in there, click on Butt fusion technologies.
Once in there, click on Butt fusion machines.
More than once I've suggested on this Forum that AWS should have a Committee on plastic welding, but I wasn't never heard.
Giovanni S. Crisi
Sao Paulo - Brazil
It was so long ago that I do not remember the details. Sorry I did not mean to mislead.
Thank you for posting up the current methods.
Steve
Hello;
I have done this kind of welding in the U.S. using a manual machine. We used the hot plate as you mentioned and a manual buggy with clamps to hold the pipe. After heating the ends and removing the hot plate, we used a lever to slide one to pipe the other stationary pipe and applied pressure. As the pressure was applied, the hot material, in my case poly, would roll out forming a bead of material. It looked similar to a weld bead on steel pipe. We ran about 5,000' of 4" this way without leaks. Was an interesting job. Wish there was an automated rig on that job.
Have a good day;
Matt
Just as a side note on the subject of welding plastic, I started welding plastic when I was a youngster many years ago.
I discovered I could use my wood burning tool (soldering iron) to fuse my models together instead of using glue. Of course this didn't work very well with small parts, but it did work for long seams like joining the deck to the hull of the ship and it work very nicely with the tank hulls. I used the styrene runners as welding "rod". The major advantage was that the model didn't fall apart in water as did the "glued" models. It was imparative that the model ships stayed intact on their last voyage across the pond, decks set ablaze and firecracks waiting to be lit. Such a glorious end to many a model ship.
Best regards - Al
The hot air welder is only slightly more sophisticated. Heat is controlled so that the parent material and filler are not quite melted, but soft enough to flow. With the speed tips, the filler is squezed ino place as You move along the seam, really pretty simple once You get the heat and speed figured out.
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