Im loving this thread and wondering when we can buy a production fos 250cc engine
Im loving this thread and wondering when we can buy a production fos 250cc engine
ok, as I said, my furnace is just too crappy. Worked well for prototyping stuff so far but the time has come for somthing more permanent. Seems the 'state of the art' furnaces are steel outer ring with special high temp concrete liner poured into it.
So found a steel tube at 610 dia and a 406 steel tube as an inner former. Will have to make this inner collapsible so as to get it out, also found where to get the concrete, not cheap though.
Roll on some production casting perhaps.
Would fire bricks be an option?
well yes and i have investigated that.
trouble is fire bricks (best second hand price i can find) are a dollar each ) , pizza oven people have buggered up the supply and demand economics, still need 'special' cement to seal it.
I would say the steel outer ring with cement thermal barrier sounds more permanent. And with some lifting eyes welded to the outside, can be shifted easily too.
Your inner former doesn't have to be steel does it ? What about a segmented wooden inner former ?
Easier to make and remove surely ?
I have a lineup of cylinders to cast, some just normal (more gyro cylinders) some 360 cylinders with the mark two TPI lugs, some HCCI cylinders and a few other odds and ends.
Good evening from the UK.
I've been following this thread for a while now as I'm hoping to one day cast my own cylinders for 50cc racing.
I made my furnace from a butane gas bottle and used a layer of refractory insulation blanket and finished it off with refractory cement. I used a cardboard tube as the former in the middle which I peeled out when the cement was set. I actually bought the tube off eBay then afterwards realised I could've probably got one for free from a carpet shop!
I'm struggling to find the photos I had of it at the moment but I'll add them when I find them.
Edit: Just found the photo, you can see the wire mesh I used as re-enforcing, so I lined the wall with 1 layer of refractory insulation blanket, then made a tube from the mesh to hold the blanket in place, then inserted the cardboard tube and rammed the cement mix down the sides of the carboard tube, I'd already put a thick layer of cement in for the base on top of a layer of blanket from memory.
Regards
Mark
Three and a half minute round up video, if you go to his channel there's lots more.
https://youtu.be/o6B9c5Ca61U
love it, look how simple/costeffective casting is
Marko Bostjancic has been investment casting 50 cc cylinders of his own design for a long time. See
http://www.roost.si/ He doesn't seem to advertise this, but you might try to contact him for details.
Lohring Miller
Thanks Lohring,
I've already seen Markos efforts and they are pretty impressive I have to say! I'm going to try the block investment method but using a PLA printed part as the lost pattern instead of wax. I'll use a specialist investment powder and attempt to do a vacuum casting.
Mark
Let me know how your efforts turn out. I've been spending the past year learning Fusion 360 and 3D printing with a Prusa printer. I have a small casting furnace and burn out ovens as well as a very used kiln for larger casting burnout. I hope to come up with some small race engine cylinders. My first design of a 26cc piston port cylinder gets 10 hp in EngMod. A reality check will be needed, though.
Lohring Miller
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