Hi all,
I've beveled the lead and trail edges of the air intakes. I squared them off a little more too.
I've reworked the nozzle fitting so it can be adjusted (first version was completely fixed). Thanks for the tuning advice Mike, it's amazing how much difference moving the nozzle only a few millimeters can make to the flame stability! I found I could shorten the nozzle by about 5mm compared to the original length and keep the stability. The new stainless nozzle tubing has not arrived yet, so I tested with the original, already oxidising, nozzle (the short extension piece you can see was fitted to account for the space taken by the adjusting ring). Photos are below, the second one is suffering from some side wind but to my untrained eyes, the first 2 look similar to the first photo in my earlier post:
Hopefully the stainless nozzle tube will arrive tomorrow and I'll get it fitted before Saturday - if the weather holds, we're going to try casting aluminium. I'm wondering how much re-tuning will be needed when the nozzle is surrounded by refractory? Is it back to the beginning due to back pressure etc??
All advice welcome.