Plastic welding

[crazyal]

Has anyone got any experience in welding plastic? I have few plastic repairs I would like to make, nothing critical. I've never tried to do it and have no idea what equipment works best.

 

[gengine]

I'll be watching this, I've got some to do as well, but have no idea how.

 

[vwnotrunning]

We have used a plastic welder - hot air gun for PVC pipe and sheets. Typically sch 40 or 80 pipe and 1/4" sheets. The hot air with a compressor blows heated air to soften the plastic and you push the "welding rod" into the joint - it all fuses together. Takes alot of practice to get the temperature just right. Too hot and it scorches the material - still holds but sure looks bad.

 

[Tractor Seabee]

Practice! Practice! Hot air welding is a lot like O/A welding of steel except the plastic state goes to liquid faster. You have to watch the heat and keep the filler rod deep in the puddle and stir it around. With lots of practice you can make a bead similar to O/A. O/A experienced welders catch on faster. I have even done it overhead. You have to use the same plastic in the filler rod as the material welding your on is. On pipe we cut off 1/4" rings, warmed it up and made straight. PE cannot be used on PVC and PVC cannot be used on ABS. At least stay in the same family. The torches are fairly in-expensive. HF has one and it comes with an assortment of filler rods. One is probably as good as another. The thinner the material the harder it is to control the heat.

Ron

 

[2manyrocks]

I messed around with this very briefly enough to figure out I didn't know what I was doing. There are different kinds of plastics. Some can be welded. Some can't.

You might want to figure out what plastic you have before you go spend your money on a welder.

 

[crazyal]

I've read a few websites on the subject but haven't watched any videos yet. One thing I wasn't sure of is how liquidy to get the plastic. I'm assuming that it needs to be soft enough to mix the plastic with the rod but not free flowing where it will just run like water.

I've seen tools that are nothing more than soldering irons, some that are a soldering iron with a fan built in, and some that use compressed air. I wouldn't mind hearing what type people have and their opinions on how well they work.

 

[vwnotrunning]

The ones we have look almost identical to the adds in HF. But our cost alot more. The last one I bought was nearly $300 but included a correctly sized low pressure compressor to maintain the air flow. Don't recall the wattage, but the HF would most likely suffice once you got the air flow right.

 

[yomax4]

Once you match the rod to the material ( google plastic welding rod burn test ) You just need some practice..You do not get the base plastic liquid. You want the rod more fluid than the base. Too hot and it looks bad..Too cold and it wont stick. There are many types of rods available from Seeyle and Steinel. LDPE ,HDPE,ABS,PVC, many others. I like the heatgun type as oppsed to the HF hot air vesion. Both work but they are not as fast as Mig Welders. None will make a repair that is not noticeable. It will be obvious that you fix'd it but at least it's not broken.Take your time and practice..It's fun...

 

[SHORT KID]

I bought one of Harbor Freights plastic welders and it worked for me. The secret is getting the right filler rods. On my Troy Bilt tractor there was several of the dash mounting brackets broken. I welded them 2 years ago and they held up well. If you are doing ABS just mix some ABS shavings and acetone, clean pieces up and put back together. If you don't have acetone you can use your wifes finger nail polish remover. Just like metal welding PRACTICE,PRACTICE, and did I mention PRACTICE???? My plastic welds don't look any better than my metal welds, but they hold!!! :thumbsup:

 

[crazyal]

I have some atv parts I can play with to try and fix. I did read a website that talked about doing the burn test as well as using the number in the triangle. I haven't looked to see if there's a recycling code on them, think that would be easier than the burn test to identify the type of plastic.