Hello friend, I'm from Brazil. I'm trying to do this job but as much as I press the sand with cement into the tube it never makes the curve perfectly. Do you have any tips for him not to wrinkle?
There is sand in the pipe....mandrels are not use when bending with heat. The screw at the end of the pipe allows the sand to be compressed by tightening the screw.
@@WestWind It's likely capped in some way, and sand itself is oven dried. If you want some extra insurance, some EDM drilled millimeter or smaller holes in the end caps could allow any possible gas to vent too. Might not be too hard to hold caps on with an expanding rubber-block mandrel too where a bolt goes through to a crush plate. (Rubber expands out when clamped, and with the cap stuffed inside the pipe there's no need to tack weld the cap on then. That should hold.) Just keep in mind there still needs to be some path to outgas to the tiny breather holes.
@west wind I've seen a cap with a center nut then a plunger that fits just inside the pipe welded to the bolt that goes through the nut. As you tighten it the plunger packs the sand. Do t know if thats whats used here or not looks like it could be as it looks like a bolt sticking out of the pipe
