Plastic welding and welders

[sea2summit]

My search found a lot of folks talking about them and recommending them on the forums but I'm not seeing any tips/tricks/recommendations.

I'm looking for one to repair broken seams on some fuel cans, patch an IBC tote, the odd crack on the fourwheeler/SxS/dirt bike. I'm also pretty dedicated to buy once for the rest of my life so I need one for 30-40 years that doesn't use proprietary "rods" that some of the amazon offerings seem to have.

I saw this video a long time ago and went back to it to start my research, I'd really like one like that, seems pretty dead nuts simple and pretty bomb proof. Can't find it and the one's I've found similar are not built to the standard.

 

[WranglerX]

When it comes to fuel cans, I would replace, have yet to see any plastic repair/fix that are equal to strength of original product..... If your IBC tote is cracking its because the "plastic" has become brittle and is approaching its EOL (End Of Life) probably better to replace it also....

 

[sea2summit]

When it comes to fuel cans, I would replace, have yet to see any plastic repair/fix that are equal to strength of original product..... If your IBC tote is cracking its because the "plastic" has become brittle and is approaching its EOL (End Of Life) probably better to replace it also....

Meh, actually the tote has a hole in it because a tractor fork made one. I've got many totes, some as old as 5 years old, and I haven't seen one of them crack from age yet. But your feedback doesn't tell me anything about a plastic welder...

 

[etpm]

My search found a lot of folks talking about them and recommending them on the forums but I'm not seeing any tips/tricks/recommendations.

I'm looking for one to repair broken seams on some fuel cans, patch an IBC tote, the odd crack on the fourwheeler/SxS/dirt bike. I'm also pretty dedicated to buy once for the rest of my life so I need one for 30-40 years that doesn't use proprietary "rods" that some of the amazon offerings seem to have.

I saw this video a long time ago and went back to it to start my research, I'd really like one like that, seems pretty dead nuts simple and pretty bomb proof. Can't find it and the one's I've found similar are not built to the standard.

Fuel cans crack with age because the plastcizers slowly evaporate from the plastic. Because of this weld repairing these fuel cans is, in my opinion, a bad idea. On the other hand, plastic that has been cracked due to mechanical reasons can be often be repaired and have the repair last the life of the object. Before buying a plastic welder you should determine which types of plastics you will be repairing. Thermosetting plastics, such as epoxy, cannot be welded. They can only be bonded, this means some sort of glue. You can only weld thermoplastics. There are all sorts of thermoplastics and a particular plastic piece will often have the type of plastic it is made from identified by a number inside of a triangle. So look at your stuff and then look to see if welding rods are available for your plastics, then buy some and practice. I have had some good results welding some plastics but it really does take quite a bit of practice to make high quality welds.
MY STATEMENT ABOVE THAT PLASTIC FUEL CANS LOSE THEIR PLASTICIZERS IS WRONG. HDPE PLASTIC FUEL CANS DO NOT CONTAIN NOR DO THEY NEED PLASTICIZERS. dstig1 POINTED OUT MY ERRONEOUS POST AND I APPRECIATE THIS. MY APOLOGIES FOR POSTING INCORRECT INFORMATION.
Sincerely,
Eric

 

[WranglerX]

Meh, actually the tote has a hole in it because a tractor fork made one. I've got many totes, some as old as 5 years old, and I haven't seen one of them crack from age yet. But your feedback doesn't tell me anything about a plastic welder...

I guess what you didn't comprehend is that plastic welder may no be a solution to your failing plastics problem....

 

[Doughknob]

I have tried plastic welding and even used to sell one type of the tool in a shop i had. From experience and tool feedback, i was not impressed at all with plastic welding.

I have had better luck using a two-part epoxy formulated for plastics. And if possible covering both sides of any crack/hole/etc is the best bet.

There are even specially made epoxies for fuel tank repair. Don't know about their use on plastic cans though.

 

[dstig1]

Gas cans are made from high density polyethylene (HDPE). It does not contain plasticizers. People throw that term around a lot without understanding it. Really the only plastic you ever run into that contains plasticizers is PVC (aka vinyl). You have seen rigid PVC pipes for plumbing. You have seen portfolio folders for holding papers made of vinyl that are soft and flexible. Same basic material but the soft one has plasticizers in it to make it flexible and they do leach out over time. That is why when you put printed papers in them and leave them a long time the paper sticks to the vinyl.

Gas cans deteriorate like all plastic over time due to the same things: heat, chemical exposure, and UV exposure. UV really chews up PE so they add tons of UV stabilizers to help out, and the dark pigment helps too, but you can't fight mother nature forever. Ozone can act similar to UV, so if you are near a lot of electric arcs like from motors or welding over time that can do similar damage.

 

[rangerfredbob]

I've been using the soldering iron type from Harbor Freight for a few years, it isn't great but it gets the job done and for $16 it's cheaper than buying a lot of the stuff it can fix... I used it a couple months ago to weld the gas tank of my lawn mower, used it to sink some of the stainless screen it comes with in the crack then covered it with some extra material that it comes with... You have to be gentile with the thing though, let the heat do the work as the tip will bend and break off at the threads, but you can run a 6mm die down it a couple times... It isn't a lifetime tool but it's $16... I think part of the trick is melting the parent material before you try to add material or fill gaps which this allows

 

[etpm]

Gas cans are made from high density polyethylene (HDPE). It does not contain plasticizers. People throw that term around a lot without understanding it. Really the only plastic you ever run into that contains plasticizers is PVC (aka vinyl). You have seen rigid PVC pipes for plumbing. You have seen portfolio folders for holding papers made of vinyl that are soft and flexible. Same basic material but the soft one has plasticizers in it to make it flexible and they do leach out over time. That is why when you put printed papers in them and leave them a long time the paper sticks to the vinyl.

Gas cans deteriorate like all plastic over time due to the same things: heat, chemical exposure, and UV exposure. UV really chews up PE so they add tons of UV stabilizers to help out, and the dark pigment helps too, but you can't fight mother nature forever. Ozone can act similar to UV, so if you are near a lot of electric arcs like from motors or welding over time that can do similar damage.

You are correct of course about HDPE fuel cans not containing plasticizers. I should be awake when I post stuff. Thanks for pointing out my error. I really dislike passing on incorrect information and encourage correction of mistakes I make. I knew that HDPE didn't need plasticizers yet I engaged my typing finger without engaging my brain. Thanks again for pointing out my incorrect post, I really appreciate it.
Eric

 

[mikester]

I've plastic welded some rain barrels with frost cracks over the years using a soldering iron and strips of barrel as feed stock. It's like TIG welding. Joints are water tight but not as strong as new.

A good plastic welder uses ultrasound as well as heat. $$$$. IMHO Not worth buying the tools unless you plan to make a business out of it. Keep in mind plastic isn't infinitely recyclable and you need to use virgin stock as feed material for best results.

Trying to repair a gerry can is a recipe for disaster. Just don't do it. All plastics degrade over time. A new gerry can costs $20 and no headaches or major spills to clean up.

 

[LFP57]

I use a plastic welder often to attached segmented 3D printed parts for an automotive company and I've found that it comes in handy for other things as well.

 

[Tinhack]

I watch these guys in Egypt do paint-less dent repairs. They often do repairs to plastic parts using nothing but a steel bar heated by a torch. They heat the plastic with the bar then press in screen material. When they're done, it's hard to tell it was repaired. I've seen them repair light brackets, bumpers and radiator overflow tanks. It's not all "paint-less". They do occasionally send items out for repaint. But their skills with a hammer and dolly are amazing--Nearly as good as my own.

 

[Citydude]

I punched a hole in a plastic fuel can with my grapple and repaired it with epoxy 5 years ago. Still works to this day.

 

[John0829]

They heat the plastic with the bar then press in screen material.

I have used that screen material procedure many times to repair plastic parts, only I use my soldering iron instead of a steel bar. A little bit of a learning curve but it does work well.

 

[Tinhack]

I have used that screen material procedure many times to repair plastic parts, only I use my soldering iron instead of a steel bar. A little bit of a learning curve but it does work well.

Same result. I use a soldering iron or gun for small repairs. The bar just covers more area. It looks like an old tire tool--A turned up and rounded nose.

 

[PILOON]

A lot depends on the plastic type, some can be heat fused, none want to work with epoxies
I've had success with PVC using glue sticks and heat guns.
For a smaller pin hole even a self tapping screw and leather washer (or rubber) can suffice.

LOL, I've seen many a canoe repair that attempted repairs with fiberglass and epoxies. You could just peel those patches off no problem.
What they neglect to do is to aggressively use a grinder B4 patching.

I once repaired Cessna wing fairings with hot glue since they were but commercial PVC.

 

[rangerfredbob]

For vinyl all that's needed is some MEK, which is getting hard to find but you can still find Plastruct-bondene last I checked which is just MEK in a tiny glass bottle with a brush in the cap for model railroading...