Sand Muller - Printable Version +- MetalworkingFun Forum (http://www.metalworkingfun.com) +-- Forum: Machining (http://www.metalworkingfun.com/forum-5.html) +--- Forum: Welding & Casting (http://www.metalworkingfun.com/forum-9.html) +--- Thread: Sand Muller (/thread-931.html)

Sand Muller - dallen - 10-21-2012 When I posted the photos of the spacer ring that I made for my mill I posted a partial photo of my muller and was asked by Mayhem asked for some information on how I built it. so grab some & while I So sorry but everyone will have to over look the mess around the muller I have been casting for the last couple days trying to finish up a flask project that I started quite some time back. The first photo is the basic overall photo from one side. The second is from one angle on the drive showing the sheaves which are 4" and 13.9" this sheave combination along with the sprockets two 10 tooth and two 40 tooth sprockets drop the RPM of the business end of the muller to around 50 RPM. this third and fourth photo's are of the chain drive components I also added in a idler which is not spring loaded but is bolded down tight enough to stay in place, I need to add another idler on the final chain to the drive shaft just for good engineering Fifth photo is of one side of the Drive Head with wheel and scraper arm Sixth photo is of the other side I had bought a book written by Steve Chastian on how to build a muller, (my disclaimer) I didn't follow the book. I decided that I didn't need the strength that he built into his or the cost that it would take to build one like his. That said, I did use his drive design but only use a 1 7/16 shaft instead of a 2 inch one. I did use his drive tube design with tapered roller bearings. He used two wheels and scrapers I used one, and mine is made from an 8 inch diameter gear welded into a 2 inch wide piece of Sch 40 8 inch pipe, so far it works and works well. One problem I have is it does not like to start with two 5 gallons of oil bonded sand in it, thats about 160 pounds of sand, one thing I would like to and probably will change is the depth of the tub which I made 12 inches, 14 would be better so that the sand would not crawl out, Petrobond sand has a tendency to grow when mulling it especially when warm. Meyhem I hope this is what you were wanting, if you need more info let me know. David Allen RE: Sand Muller - dallen - 10-21-2012 some bits of thoughts that just came to me. The wheel is mounted on an arm, with a planter wheel bearing, there dirt cheap and made to run in dirt all day long. the blade looking part that is welded to the drive head is a scraper that sticks down the side of the drive tube an keeps the sand from sticking and building up. Petrobond/Oilbonded sand needs pressure to be conditioned correctly. The drive head is made from a hunk of 4 inch 1018 cold roll and has a spigot on it that passes thru a seal in the top of the drive tube, I left as little clearence as possible so that sand would not work in between and get in the top bearings. and a not so great video of it in operation mixing some new sand http://www.youtube.com/watch?v=TjfExDWQVLw&feature=share&list=ULTjfExDWQVLw RE: Sand Muller - Mayhem - 10-22-2012 Thanks for the info and pics, and for the link to your video. I have seen some of your vids before and was unaware that you are superdave! Seems you have been holding out on us. RE: Sand Muller - EdK - 10-22-2012 OK, I have to ask. What does a sand muller do? It looks kind of like a cement mixer so I assume it's mixing sand and other stuff together. Ed RE: Sand Muller - DaveH - 10-22-2012 DaveH RE: Sand Muller - Mayhem - 10-22-2012 My understanding is that casting sand with oil mixed in had to be mixed under pressure, hence the 'heavy' roller. RE: Sand Muller - dallen - 10-22-2012 sorry for hiding under a different screen name on YouTube, if you need more pictures of the muller let me know. the short version is that like Mayhem said oil bonded sand has to be mixed under pressure to get the clay/Bentone/Petrobond to mix when mixing new sand. and to recondition the sand for reuse it has to be what is called mulled or mixed under pressure to get the clay to rebond to the burned sand. the sand in the video is new thats the reason for the red color, actually the red color is due to the iron oxide in the clay. The sand in the first picture is over a year old and has been reused I don't know how many times, I just have to add a little bentone and oil and catalyist to it from time to time.