Plastic welding equipment advice

Our company wants to buy a plastic welder for polypropolyne plastic.... Ive looked some over and they range from $69 to $1200 for the hand held units we are considering... we'd want the whole kit, Ive seen Hawk, Stienel, BAK, and a few others in the OVER $500 category, which i think we want to stay..... is there some recommendations and or advice on a brand to stay away from???

for now we have a very defined need, but Im guessing we would use it more for other plastics that we assemble with small screws now made of Polycarbonate type sheets...


thanks

bob

Generally its not a quick process, plastic does not conduct heat at all fast, hence its generally painfully slow, some plastics are also really sensitive to temperature and some you very much have to pre-bake to get any moisture out or you get bubbles (your polycarbonate is a favourite for that). Equally its not like tig, you can not really fusion weld, its more like mig in you have to deposit material and hence join stuff with fillets.

Polyprops not too bad to weld if its one of the non cross linked varieties, if its cross linked the welds a noticeably weaker spot. Done several Kayak repairs with my welder for people, its nothing like as good as new, but its still plenty strong enough to be very usable outside of serious white water.

Most of the softer thermo plastics weld pretty well, you do want good ventilation though as some offgas a bit too much!

Ultrasonic?

I've used a couple of different styles and can offer that the extrusion style plastic welder with a variable speed drill motor that feeds a plastic rod lengths or rod from a spool is far superior to kind you have to feed the plastic in by hand especially for sheet seaming. Ours had an assortment of Teflon shoes for various weld seam types (butt, lapm miter, etc). I think ours used a Metabo drill to drive the extrusion screw, and a Leister or similar hot air gun with digital temperature control. I know these are the most expensive, but if you are going to be doing 4 foot or 8 foot seams it is what you want.

The smaller hand fed units are more suited for smaller jobs like automotive bumper/fascia repair work.

I forget the name (ill look at work monday) but there is a green colored set of plastic welders that work pretty well. One is a "TIG" that just blows hot air, the other is the "MIG" version that feeds filler wire. I think they were around $300 for the "tig" and more than that for the "mig".
At the other end of the spectrum, I took a wagner heat gun for paint/whatever, fabricobbeled a "welding tip" out of .005 stainless shim stock, and used it to melt my wheelbarrow's tub back together...

Used to work for company that had many custom polypro, pvc1, pvc2 and polyethylene tanks made for us which held fixer and developer which are "wetter" than water and will leak where water won't.
We attempted to do some welding of our own for custom mods to stock tanks with a basic handheld Leister welder and it was frustrating. Either poor adhesion or burning was the norm with nice welds a rarity.
After consulting with tank builder we bought a Wegener hand held with regenerative blower and it was night and day difference. With just minutes of practice most people in shop could lay down nice strong welds and it opened up a whole new world for our shop. Can still remember that sweet whine of the blower.
I think it was the precise temp control and smooth air delivery that made the difference.
Check out Wegener Welding | Home before buying any others.

This youtube video shows the welder our shop bought and pretty much how we used it. It was the Wegener autotherm with the dual tip and a separate blower. One postion for tacking and one for feeding welding rod.
Whatever you buy make sure it has a tacking tip and really good heat control.
I bet the Wegener tools are pretty high priced. I think they were made in Germany.
Plastic Welding: How To Instructional Video by Wegener - YouTube

Injectiweld Plastic Injection Welder | Drader Manufacturing Industries, Ltd.

Not cheap.