Has anyone ever tried it? Been successful? A man contacted me wanting to know if I could repair his gas tank for his Ariens Metro.
Are there special tools involved or can you simply melt and blend matching plastic together using maybe a soldering gun?
TIA

I had to add height to my belt guard when I repowered my Ariens with a Predator 301cc. The shaft was an inch or so higher. I used a pencil type soldering iron and an old plastic battery box I had kicking around. I cut a strip of plastic off the top of the box and thin strips for filler material. Easy breezy!

What about using epoxy?

JB Weld.

I have 2 things, one I've used, the other I have not for plastic repair.

First is a 'Plastic Welding Kit' I got from HF. Says it's for repairing TPO, TEO & PP materials. I have not tried this one yet.

The other is "Plastex Plastic Repair Kit" found at: https://www.plastex.net/Product_Info.php
That one I've used to both repair a car dash and make missing tabs on the same dash panel. I found that to fix cracks, V-groove the crack with a Dremel cutter. Build a 'dam' around the crack with something like clay. Next is fill the crack with the supplied plastic powder then soak it down with the supplied solvent and let it dry slowly. I've had very good luck with this process. The only downside to it is the solvent will turn black plastic white, but it does work well at least in the situation I mentioned. In my case, I was able to get some 'dash texturing' in a spray can I then used on it and it's hard to tell it was ever damaged. I repaired that damaged dash panel about 4 years ago and it's still holding just fine for me.

I have not tried this with a gas tank, so don't know if gas will be a problem for the repair or not.

I believe gas tanks are commonly HDPE (high density polyethylene). HDPE is pretty slippery, lots of things won't stick to it. Even that Plastex company seems to have a special product for polyethylene.

Gallon milk jugs are usually HDPE, if you're looking for something as a donor filler material.

Maybe you could try welding it back together, and possibly also coat it with JB Weld, as extra reinforcement, and protection against leaks?

The fact that it's a gas tank is a bit disconcerting. A leak can have bigger consequences than repairing an engine shroud.

Good luck on that one....? The type of epoxy that they use for joining body panels in cars is very impressive stuff!! 3M makes it.... I'd think it'd stick well..... but IDK about gasoline resistance? It's not cheap!

Years ago , I had a crack in the bottom of a 74 Elan plastic fuel tank, I did something similar to niteshft's suggestion. I used what I believe is a 200 watt old solder iron, approx. 1 " diameter, worked my way along the crack slightly melting it while feeding in narrow strips of a margarine lid (same colour). It was still holding fuel 7-8 years later when I sold the sled. Wasn't pretty, but it didn't leak!!