Hi Cameron.
Sounds like you need a little encouragement. How's the workshop progressing ?
I've now got the materials in hand to start some spin casting(or should that be "rotational casting" ?) experiments, so hope to have pics next week.
I want to find a transparent tube so that I can see what's going on, before I start, so that I can hit the panic button asap.
I plan to do a before and after cure shot of plain resin, just to demonstrate the migration of the air bubbles, and get a feel for the minimum speeds necessary. First trial will be in about 1" diam tube, and then work up to 4" diam as my target for a short gantry tube.
The final design will have a metal insert top and bottom, cast in situ, so lots of fun ahead.
I've been thinking about that vision you had of rapid spinning head dispensing the mix inside the tube, and wonder what might be the advantage in slowly feeding the dry mix into a spinning tube with the freshly mixed resin already in place.
( I've done the design based on an old lathe bed I have )
This could have been de-aired by high speed spinning in a separate set up previously.
I see the aggregate particles 'sinking' outward as it spins, and I wonder if this would minimize the amount of air being trapped in. Rather along the lines of vacuum impregnation by the resin from one end of a mold.
I can't see if there would be any appreciable stratification of the sizes of the mix, or indeed, if there might be anything to gain by introducing each component separately.
Any thoughts ?
The other approach would be to do the mix in a pot, spead it all inside the mold tube with some sort of 'doctor blade' along the axis, then spin up, first to a de-airing speed, then slow to a casting speed for the gel time.
It's beginning to sound like I need an old programmable spin drier.
John
It's like doing jigsaw puzzles in the dark.
Enjoy today's problems, for tomorrow's may be worse.