Plastic Welding?

I was looking through a tool catalog from Harbor Freight Tools and they show a plastic welding outfit for around $49. It says you can adjust the temperature for welding different plastics. It made me wonder if something like that would have any applications in model railroading. Obviously, you’re not going to use it to add small detail parts onto a body shell, but what about kitbashing large structures? Could you fuse the wall sections from behind? Use it to add bracing? Weld large pieces of plain plastic together? Any thoughts? Is anyone familiar with these units?

Jim

Jim,

IMO, the liquid plastic adhesive would be cheaper and would probably do just as good as job. I believe the main ingredient is MEK (methylethylketone). What it does is melt the outer surfaces of the styrene that it’s supplied to and “meld” them together for a tight bond. (That’s why you should always apply it to both pieces.)

Since it has a watery consistency to it, it has excellent “wicking” properties. If you add liquid plastic adhesive along a joint or seam, it will be quickly drawn into the joint or seam. A small bottle would last you a long time.

My [2c]…

Tom

I read about that welder a long time ago and i believe that it is used for only certain types of plastics only. I would stick with the MEK based glues like testors model masters or CA glue for this hobby. Could you imagine trying to weld something as small as a bell or horn onto a locomotive shell…waaay more patience than i have!..chuck

I was surfng one day and stumbled mid-way into a How Its Made TV episode; I can’t remember now just what it was they were making but I watched just long enough to determine that whatever it involved some rather large sheets of plastic. I left the room to refill my coffee cup and just as I was returning I heard the narrator say something to the tune of “The sheets of plastic are then placed over a form and are welded together”; by the time I resumed my vantage point in front of the TV they had passed beyond that stage. I suppose, if you think about it, there must be some way of bonding smaller sheets of plastic into larger sheets but I had never thought of some kind of welding process to do it.

As I said, they were using very large pieces of plastic in an industrial environment and I would guess that their welding equipment was automated; I would guess that this Harbor Freight implement would probably be just a mite large for our finite hobby needs.

As I was composing this response I did think of one possible application for this tool: if one - clubs, as an instance - were fabricating some sort of a plastic guard shield for the front of a layout - little fingers and N Scale boxcars don’t mix very well - then one might want to form a very long sheet as opposed to using several shorter sheets.

I worked for a company that made photo processing machines many years ago, and we used Bosch PVC welding “torches” to fabricate chemical tanks etc. The “torches” are actually heat guns - sort of like a high power hair dryer - that concentrate the heat at a 1/8 to 1/4" nozzle and a moderate air flow. Great for large items, but probably very limited in model RR use - reinforcing large structures from behind as Tim suggested.[:)]

[#ditto] The welding set we had for plastic was used to fuse 1/4"plexi sheets together for safety shields. Probably wouldn’t be useful on a model unless you were intent on recreating the set for “The Blob”. Most of the fine work now is done with ultrasonic welding equipment. J.R.

These are used around here by the farmers to fix the large plastic tanks they use to transport water or of liquids around the farm. The tanks fill the bed of a large truck…so it may not work on models. I do know a guy that used a soldering iron to put his plastic model cars together…I’ll stick with glue!

I have used PVC glue to weld some plastic items together.[:)]

Farmers and plastic tanks; I’ll go along with that one.

We’ve used plastic welders for fabricating, fitting, and installing water and holding tanks on recreational vehicles.

It seems like polyethlene is impervious to everything but heat. Welding and compression fittings are the only methods that work dependably.

Plastic welders are not our type of hobby tool.

-rr

I use a plastic welder for repairing automobile bumpers. It is not a tool that would be of much use in this hobby. You have to melt the base plastic as well as a filler rod at the same time and fuse the plastic together. Model railroad structures and rolling stock is too thin to be able to do a proper job. Works great on pretty much any kind of thicker plastic but once you get thinner than 1/8" you will be burning through the plastic or leaving big lumps in it. The thinnest plastic I have been able to weld successfully is on a nylon washer fluid tank. It is about 3’32" thick. That was tricky and I have been using a plastic welder for close to 30 years.Save your money and get a big tube of glue instead. Ron