Heater thermostat, dial etc £35
Large jubilee clip to pot rivet thermostat to £2
15 metre roll of 6mm annealed copper from B&Q £20
3kw Fire rod up to around £80
5 Metre roll of high performance fibreglass exhaust wrap £15
Couple of one way valves to stop heat going back to pump head iro £35
For the money, the most powerful inline heater you'll find BY FAR.
In fact wrap another roll of annealed copper tube around your vac motor heads in a CFR stylee prior to the heat exchanger and you WILL have the hottest heat exchanger on the market. FACT!
Half the cost of Ashby's V2 with CFR's patented system. Nobody can sell you this system because of the patent in place.
Make sure you use soft water though or with the heat it'll scale up in no time at all.
Enjoy blowing the pants off the competition with something you put together yourself
Alan