Plastic Welding





Introduction: Plastic Welding

I went cruising in the car, to see if there was anything worth having out of someone's skip. My eyes were peeled for any container I could use for potato growing. Down one alleyway I spied just what I was looking for, in shocking pink.

Unfortunately, the container had a 6 inch split, which might have still held soil but I wanted to make sure. The previous owner of the container regarded a broken plastic container as finished, threw it outside his house and probably bought another.

All too often, plastic items are thrown away just because they have a split in them. This is common amongst containers that are meant to carry water; buckets and watering cans.

When recycled these items will be shredded into pellets and melted into new plastic items, a waste of energy.

A far better way of recycling split plastic items is to renew them through plastic welding.

Instructable by

Step 1:

All you need to plastic weld is a piece of metal with a handle that doesn't conduct heat. You are going to heat the metal in a flame to get it hot so your hand needs protection from the heat. I use a bradawl.

After 10 seconds or so in a flame the metal will be hot enough to weld with.

(Sorry for the paucity of photographs in this instructable but I only got the idea for the instrucatable just after I completed the task.)

Step 2:

Hold the two edges of the plastic tightly together and make a few "tack welds" to keep the two sides of the split together. Draw the hot metal from one side of the split to the other. When the hot blade touches the plastic it will melt and can be drawn across the split. Don't dig deeply into the metal, just melt the surface of the plastic. After a few seconds the metal will have cooled so you will have to put it back into the flame for another 10 seconds.

After you have performed your tack welds you can then seal up the split with broader strokes up and down the split. Imagine buttering a piece of bread and move the plastic from both sides of the split, over and along. Don't let the metal sink into the plastic otherwise you will thin and weaken the plastic. You just want to get the surfaces of both sides to fuse together.

Step 3:

When you have completed one side, do the other side to strengthen the weld. On completing both sides you will have something that is usable once again.

Step 4:

And here is the completed container with a few drainage holes drilled in the bottom, some soil and eight seed potatoes buried inside. I could have bought one in a garden centre earlier in the day for 5 pounds. Admittedly, it would have been a nice deep green colour but still, that was 5 pounds too much for me to spend.

Reduce, Reuse, Recycle.

Have a Green Day!

James @



  • Sew Warm Contest 2018

    Sew Warm Contest 2018
  • Gluten Free Challenge

    Gluten Free Challenge
  • Minecraft Challenge 2018

    Minecraft Challenge 2018

We have a be nice policy.
Please be positive and constructive.




Yoshhash asked if various types of plastics behave differently?  Yep!  Different melting temps and decomposition characteristics.  Thermoplastics love to stick to the skin and not let go until cooled!  Which probably is the main reason the art of plastic repair will forever be a "lost art".  Throw in the fact that Little Billy doesn't see a woodburning kit under the Christmas tree anymore due to liability,protectionism, and ignorance from the parents.  Well if I get a chance I'll do a little show & tell using a proper plastic welding iron which does have a variac and a feed assist thingamajig built into the "shoe" of the iron.  My welder has saved many hundreds of dollars for me and paid for itself with the first fix on my '72 El Camino.  

Very useful information; thank you for posting.  And good comments.  I like the soldering iron idea.

Is that what it is?

I hope people throw out some more, I have uses for them"

The link refuses to load, but why have you added it to every step?


I can't read it because it won't load for me, but why have you posted it in every step?


It makes the thing look spammy. You still haven't answered the original question - 7 times (now) on one page is excessive. (still won't load for me) L