Best Plastic Welder? Weld Repair Stronger Than New? Let’s find out!

Can the welders restore plastic to it's original strength or even stronger? Let's find out! Let’s compare several plastic repair options using two types of plastic welders. Plastic welders compared for repair strength on HDPE, ABS, and Polycarbonate.

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➡ Products Tested In This Video (in no particular order):
 
Videography Equipment:

This video is only for entertainment purposes. If you rely on the information portrayed in this video, you assume the responsibility for the results. Project Farm LLC

[hayesbrewer]

As an automotive technician I use the jounjip kit and found that for best results melt the wire mesh into the plastic before using the filler. Often times it’s stronger than the original piece and has saved my butt countless times. There is a learning curve and results become stronger and look better with practice.

[michaelfarrell]

As someone who suffers from Analysis Paralysis on anything I purchase I'm truly thankful for the time and energy you put into each comparison

[VacMaster]

Thanks for being the most thorough and honest reviewer out there. Your lack of taking sponsors helps you stay unbiased. Thats why we all love your content. Keep it up!

[tylergilbertson]

I've done quiet a bit of plastic welding at a previous job and one flaw in this test I noticed is you're using dissimilar materials. For instance, if you're work piece is polyethylene you need to use a a PE filler rod and if it's polypropylene you need to use a PP filter rod. Using PE filler rod on abs you will never get it to bond and make a strong weld. Just a bit of advice if you ever do another plastic welding video, make sure to get filter rods of the same family as the work pieces to get professional results. I do like how you compared hot glue and JB welds.

[PaftDunk]

One of the biggest flaws, if you ever want to revisit this, is that the plastics need to be flame/plasma treated if you’re using epoxy (JB Weld) or other adhesives on them. We use epoxy all of the time to bond to plastic parts, the ONLY way they stick is if you flame treat or plasma arc the surfaces. Sheet molders/casters may also use mold releases and those have to be completely removed/burned off for the adhesives to work. Easiest way is to just use a blow torch and barely melt the surface, it’s essential to get the epoxy to bond. We’ve had employees forgot to flame treat plastic parts before potting and the epoxy pops out like a cake in a well greased pan.

[Farm_fab]

For those who don't know what HDPE means, it means high density poly-ethylene, and is manufactured differently than is Poly-ethylene.
HDPE is typically used for fuel tanks, and fuel and oil containers in consumer goods.
For one that is desperate to fix a plastic gas tank, cutting an oil container into strips the color of the tank, as this is the same plastic in both. I repaired a generator gas tank this way, and used a 100w soldering gun. It was leak proof, and was tested by two different mechanics, and they both approved.
For white plastic repairs, isopropyl alcohol bottles are HDPE, and work just as well.

[UtahDarkHorse]

I really appreciate you deciding to do a video on plastic welders and hot staplers as I've used both for several years, and was excited to see this one come out. Unfortunately, the processes used in the video were all wrong and completely invalidated the tests. Most of the principles used in metal welding apply here too.

1. You should make a small bevel at the junction of the 2 pieces, on all sides to be welded.

2. The plastic representing the base and the plastic representing the filler should both be melted and mixed together.

3. You can buy different types of filler rods online. The plastic used as filler needs to be the same as the base plastic.

4. The wire screen is supposed to be completely embedded into the base plastic. Not just "glued" on top using filler.

5. When inserting the staples into the base plastic, you should end with a slight twist to completely embed the staple and cover the entrance grooves.

Would love to see a redo of this video if you decide it's appropriate.

Thank you.

[Jonnydeerhunter]

Technically speaking, I am a professional plastic welder.

Some tips.
Hot air welders are the best, they just take a little practice. The key is looking up the proper welding temperature, for HDPE it is 560-570 F. If you are too hot it will ruin the integrity of the plastic.
Use the same filler material as the base material! Different plastics do not stick to each other.

The base material and the filler material should be heated/melted the same amount and allowed to cool before you move anything. You are welding, not gluing despite how it may seem.

Lastly, cleanliness is very important. Instead of sanding, I suggest scraping. You need to remove the oxidized layer of plastic on top because that cannot be welded properly. Cleaning with alcohol is important too.


Look up videos on proper hot air plastic welding for more info. I think Leister has helpful content available.

[peejay]

I work in the plastic dam lining industry. Plastic (particularly HDPE) oxidises quite rapidly, we what we do is use an angle grinder with a flap disk to scuff away that layer before doing any extrusion welding as it makes the bond much stronger. Also, for butt joins you need to fillet/v-groove the edges to increase the surface area, and also ensure all contact points are at melting temp so the new material can become part of the old. P.S. If your hot air gun is melting holes in stuff, turn it down - It's too hot! Just like MIG.

[dougrobinson]

I've done a lot of plastic welding on airline luggage pods. The welder I used is similar to the Beyond Life type which has a preheating air jet. They work extremely well. The trick is to let the hot air do the work, and then force the rod into the molten plastic. It's about technique. For something as thick as your test pieces, you need to make V-cuts into the ends and then weld both sides. It would be very strong if done that way.

[HanstheTraffer]

FYI: Not only showing us what are the best products but helps most of us who have never tried any form of the tools you show....a big THANK YOU from all of us.

[lukefrost]

When doing plastic repairs in the past I have used a soldering iron, I find that works well enough for me considering its very rare that I repair plastic.
Thanks for another great video as always :D

[brianhua]

Project Farm content is always “VERY IMPRESSIVE!”

[JAKEaudio]

The wire mesh should be thru-melted into the base piece being repaired and THEN have filler added to smooth. This can ONLY be done with the higher heat tools....also, when you retest using this method you should also add steel wool as this has been common for years and in pieces that really NEED to remain flexible without breaking the individual strands of steel wool seem to add a lot of flexibility without sacrificing breaking as always GREAT FREAKING JOB!!!! One of my top 5 creators on YouTube no doubt

[jesseleesamples]

I experimented with a few of these last year and found the metal staples to be awesome for adding strength to the piece. For some repairs, they are enough to hold the piece together by themselves. For the strongest repair, I’ve used the staples, mesh, and plastic welded into the crack. If you hold the welder onto the mesh so it gets hot and actually melts down into the plastic, it’ll be a lot stronger. One thing I’ve learned is that there is quite a steep learning curve with this type of repair. I would LOVE to have that OIMERRY one. It looks like a do-it-all machine that will make professional-level repairs. Thank you for doing this video, this is something I wish existed in the past before I had to learn by trial and error what works best for plastic repairs.

[HunterBgood]

Good video, I've been using a soldering gun to repair plastic for years now.
Word of advice, place/clamp the wire mesh on the plastic then use the welder/iron to heat the mesh till you can press it into the plastic. Then use the plastic rods to cover the mesh so it can be sanded smooth.

[ultracitizen]

PF added the weld before the mesh then additional weld on top. When it comes to plastic welding, I usually heat the mesh directly to melt into the original plastic before adding weld with the sticks. I've found this to be a better way of reinforcing the structural integrity.

[NikeHM]

Plastic welders are cool, but I'd really love to see you test budget multimeters. You can probably use a fluke as a control to compare the budget multimeters one feature at a time, ohm's, volts, amps etc.

[BruceLyeg]

Excellent tests. The staples are great for tensile strength and work better if you twist them once sunk into the plastic. I was really surprised the Ryobi glue gun did so well comparatively.
Thanks for the video

[offtopicgaming]

This guy never fails to provide us with amazing comparison content