melting hdpe plastic health concerns?

I want to do some vacuum forging (from another instructables) and i was thinking about melting milk jugs for it. if i heated them with a blowtorch would it emit bad fumes into the air, as long as i didint burn it?  I would do it outside and im 13 so i dont want to mess myself up.  if it does make fumes, would a respirator with a fine filter stop them?

PE burns cleanly without any nasties, because it doesn't have any chlorine, or worse, fluorine in it.

Better to melt it in an oven.
iceng5 years ago
You could use a hydrogen flame that would not scorch the melting.
until you get careless and burn there is no poison.

But I like hot air instead it is easy to adjust for melt but no burn and no risk.
In fact I weld Plex with a narrow hot jet of air quite as well as metallic welding

The other is a full area radiant electric heater.