Hi Jord
There aren't anymore OEM spares for this guns, that have more than 30 years, 4E has special conical metal ignition valve, without O'Rings, and the sifon plug is completely obsolete, I still have customers that use this gun, and I can repair it, but is better for you to buy a new one, for the 8E you can use some spares still produced , the thermal spray provider near you could be MEC, contact them
www.mecpl.com, they still produce spares for old thermal spray torch and also new guns and systems.