I got a splendid 1932-1933 recently. Exterial it looks grand but the burner parts are about the worst I have ever seen. The rod was of course broken but that is of little concern as I got an extra. The biggest concern is the vaporiser. I like to clean those mechanically. I felt like a coal miner when hitting the Preston loop. I can with a brake cable and a Bowden cable get into half of the Preston. Then stuck! And there I am at the moment. I have of course worked with heat/water but with little success. Any tips? Where I am I have no access to pro gear so steam and and a proper air compressor is out of sight. Lastly if anyone got a spare vaporser I would be VERY thankful. Kindly Henrik
@Henrik Clamp the loose end of the cable in the chuck of a cordless drill/screwdriver (clutch control set to ‘drill’) and carefully apply torque at lowest setting. Try in reverse rotation if clockwise tends to bury it further in the component. Keep hands/fingers out of the way and protected. John
Why's it particularly tough with this one? Normally, repeated heating(dull red hot) and quenching in water would loosen the hardened coke inside a Preston loop.
Beats me. I have cleaned several loops with my humble butan torch. When I heated this one up it almost lit. I guess some heavy duty stuff is needed (propan to have it dull red and some proper high pressure air). I’ll be on it somehow although a fresh vaporiserer will make it easier of course.
Do you mean there were flames shooting out from the ports of the vaporizer when you torched it? If so, I think there's still plenty of grime, coke and old fuel inside it. For such instances, I'd usually soak/immerse it in concentrated lye solution or a strong alkaline engine degreaser for up to a day before working on it further. I'd rinse out as much as possible with, clean running water next. Following all that, I'd start the heat-quench routine. Don't heat it any more than a very dull red before quenching in water. Otherwise, the brazed joints on the Preston loop would tend to give way after you're done. You might need a few cycles of the heat-quench to loosed up all the coke. **On many occasions, I'd finish off all traces of carbon by injecting pure oxygen(with an oxy-fuel welding torch) into the vaporizer after heating it to dull red. All remaining carbon would just burn up. ** this last step is not really necessary in most cases. I'm only overdoing it to ensure the vaporizer gets as clean and empty as new.
Thanks! Yes- the Preston was really choked. I managed to get most of the muck out but I suspect there is still a (thin) ring of stuff which I can’t get through. I like to get a Bowden cable through the loop until I call it done. I have your tips in mind- thanks again!
@Henrik @presscall gave you very good advice on how to easily clean a Preston Loop generator. One thing though, I once cleaned an Aladdin1A Preston loop using John's technique. What you may not realise is that there is a reducer inside the Preston Loop (In the Aladdin 1A at least) so I had to reduce the size of my cable so it could fit into the smaller orifice within the vapouriser. From memory, the reducer was about 2/3's of the way up the straight end of the vapouriser. Henrik, you may already know what I just told you. I thought it be best to mention it in case you didn't know and you thought it was a hard coked blockage that you were encountering rather than a reduced size within the vapouriser.
