I've posted all this on AA already, but here it is again, just for more meat on the bones of The Home Foundry. My previous furnace was built with a DIY refractory cement, no insulation, and was functional for my solid fuel (charcoal & hardwood chunks) with a boost from a shop vac for maximum airflow. Needless to say, the beast looked like the backside of an F-15 with the afterburner on full. I was warned by the knowledgeable Salts of AA that my material would likely suffer catastrophically when I asked about burner design for my transition to propane fuel. I got a few good melts in, but could see the degradation of the DIY mix, and knew that I was going to have to pony up some real money for some real refractory cement as well as some insulation material. That knowledge became necessity after a complete noob move: fired up the beast, put the A12 in the belly and loader her up with aluminum ingot I had poured months prior. I paid no heed to that voice in my head that screamed THE CRUCIBLE HAS BEEN IN ATMOSPHERIC CONDITIONS FOR 4 MONTHS & THOS INGOT WERE SWIMMING IN WATER JUST A SECOND AGO! I put the lid on and walked away to set up the project I was planning on pouring. Some unusual pop's were heard from the beast, then one loud BOOM. I had done it. I was afraid to look, bit I did. Most of the refractory had been blown off, the A12 was in a thousand pieces, and a few ingot had opened up like M80's from Tijuana. I posted my failure to launch on AA, and faded into the distance. While I was gone, I found a decent source for some Harbison Walker refrac, and a local source for Kao wool. I also ordered a few new A10's. Then I did nothing except think & think & made a few wax castings of copyrighted items with the intention of one day pouring bronze into the voids left after burning them out of my (still to be purchased) investment powder. I was also hunting for a sonotube that was actually 12" i.d. That took longer than it should have. This year I finally pulled everything together. Form was built for the refractory tube. I began mixing & ramming in the mix to the form. Excitedly optimistic. After about a week, I began the step of removing the inner form. After only getting 2" out, I went at it with the grinder & extricate my tube. The inside is not nearly as smooth as I had hoped. Still considering smearing on some store bought refrac to smooth it out. Maybe not. The tube used 45 lbs. of the HW product, which left me with 15 for the lid. I ordered another 20 lbs from my guy on eBay, and as soon as it arrived, I insulated & formed the lid interior. I also cut the tuyure hole in the tube (a $34 masonry hole saw was only good for the one hole. Shaking my fist at Lennox.) Inserted the tube to the exterior jacket, finessed the kao wool into the annulus, and sealed off the top of the same. After sufficient curing time, she's ready to burn! I'm currently fabricobbling my lid for the vacuum chamber (already shattered 2 pieces of .22 plexiglass). Just received shipment of a nice 7/16 piece, waiting for a longer bulkhead fitting. I'm so close I can feel the heat.
The furnace is looking good. It will probably last longer if you smooth out the interior with some spare refractory. There is nothing quite like the anticipation of using a new furnace. I have one almost complete, and am itching to try it out, but am still swamped with work. There is a button, I think it is labeled "full size" or something, and your photos will appear full size in your post, instead of the thumbnails. Makes the photos easier to view. The water explosion thing sounds a bit precarious. Live and learn as I say. I try to keep everything as clean and dry as possible. Good luck with your upcoming melt/pour.
Re: photo size I have no idea how big the photos are, as they are on my phone. I thought thumbnail might keep me within the guidelines. Re: shorts It was laundry day. Those pants have been retired. The last two parts for my 3rd attempt at a vacuum chamber lid have arrived. Time to get busy.
With an uncertain weather forecast, I moved forward on firing up my new furnace & a sand cast project that I've been putting off for too long. A house remodel I've been involved with for the past year is nearing completion. My work (plumbing) is complete & final inspection done. During the early stages of the project, I replaced all the waste piping under the basement slab, & what remained after the concrete was replaced, was a recessed area for drain cleaning, right in the walkway. I informed the GC that I was going to cast an object to eliminate the trip hazard, & would likely have it done before the homeowner took occupancy. He looked at me like I was kidding, but after I explained my hobby, he agreed. Turns out, his grandparents operated a foundry and he worked in it as a teen. Long story longer... Since this would be a non-critical item, I decided to use some old brass plumbing fixtures from my scrap pile. A few tub/shower fixtures, a few kitchen and bathroom faucets, some tubular brass drain pipe, brass tub spouts (NOT zamac), some toilet seat hardware, and some valve bodies. I sensibly obsereved the recommendations of slowly bringing the vigin furnace & crucible up to temp. But sense stopped there. I did not do an overnight cool down. Instead, after a few hours of gradual increase, I charged the crucible & busied myself with some nearby "to-do's" between checking & adding to the pour. I wasn't sure how my 2 year old, unused, untested DIY greensand would do. I had to re-mull it, but it felt & behaved right. I powdered up my model & rammed in the sand, ( the cope & drag were built on my tailgate one day while waiting for a client to arrive.) Fortunately I had barely enough sand to fill the project. If I had put a better draft on my model, it might have come out easier, but I was okay with the result. The 1" deep recess was my biggest concern, & I did disturb it a little. I didn't want to wait to acquire stuff for making a core. Although, I had not removed it from consideration. After multiple additions to the crucible, I skimmed off enough dross to equal what remained of useable brass. Without additional air injection to my fuel supply, it took quite a while to get up to temp. I pulled out the crucible & clumsily poured. I really need better tongs. After impatiently waiting for it to cool down, I broke it out. It wasn't horrible. My sand isn't incredibly fine, but this isn't a mission critical part, so, no biggie. There was a little porosity, or maybe inclusion, seen where I separated the sprue from the object, but... (not mission critical part.) I did a little rough clean up with a cutoff wheel, and am satisfied with the results. There's still some clean up to do, as well as drilling a finger hole in the middle. But overall, I'm happy with the results considering this was all scrap brass. I used a small wire wheel on a drill to clean up the inside a bit, may not worry about it. I'd just like to get the outside smoother. Time to head over to my in-laws shop & used their spindle & disc sander.
That could be sand inclusions or entrained air, not sure. Pouring too slow means the cavity may not fill completely, and pouring too fast means you may scoop up sand and/or air and trap it in the flow. Pouring at a "just right" speed is a bit of an art, and it seems to vary between people. There are various basin, runner and gate layouts that help with keeping the delivery system full and minimizing entrained air and sand. All things considered, that piece turned out very well. You can use a grinder, then a sanding disk, then a buffing disk to get the surface smooth. Which side is the top? .
I definitely poured a little slow. The A10 was about half full & heavy as hell. Considering my pathetic tongs, it's a surprise i didnt miss the sprue hole entirely. The flat broad side is visible. I'm going to drill a 3/4" hole in the center for easy removal. That said, we replaced all the underground piping all the way to the sewer main, so they'll probably never need it to be snaked. I hadn't thought of sanding discs for my grinder. Great idea. I only ever use it to cut cast iron, so I only buy cutoff wheels.
Im not a super experienced grinder user, but I've done enough to let the smoke out of one before, and cut off enough sprues to feel fairly comfortable using them. Flap discs are handy sometimes, as are sandpaper discs and those hard grinding wheels. You can get a rubber backer for the sandpaper discs, but I have used them on their own too in a pinch and it worked pretty well for small jobs if you don't need to take too much off in a hurry. Jeff
I've let the smoke out of a few grinders too. Never buy Ryobi grinders. I put 8 years on a Milwaukee before the switch busted. Makita is doing a fine job these days. ( I'm a biased Makita user (2 hammer drills, 2 impacts, recip saw, porta band saw.)) I definitely need to set it up with sand ability. I like the pad idea. I preheated my scrap with the Horror Fraught weed burner. Damn Sam! I'd only used it for its named use before. Almost feel like it would melt metal faster than the burner I built (naturally aspirated venturi.) Building a burn out kiln with it next.
After trashing a few HF grinders, I ponied up for the 11amp dewalt grinder. That puppy has so much torque, you almost need two hands to hold it. I've now got almost 2 years on a Lennox diamond blade for cutting sprues, huge ingots and other crap. It's not the fastest method, but controllable and lots of bang for the buck. Best part is they are clean to use unlike a traditional disc the disintegrates and you end up breathing it. I'm still seeking the holy grail of flap discs, maybe some day. Diamond grinding cup perhaps?
Best 90bucks you will ever spend. I had one week a couple of years ago and trashed 3 brand new HF grinders in a just a few days. Before that, my last 10dollar grinder I had for 10years never let me down. That one was actually made in taiwan and has been buried ceremoniously in my back yard! I just didn't have the heart to send it to the land fill. No I am not kidding, I planted it right next to the wife's 2 dead pet bunny rabbits.
Sorry dude but that's just weird.lol. I'm right with you on the Dewalt 11amp and Lennox diamond blade. I recently cut up a bunch of cast iron. Thick stuff. The powder from that is bad enough to deal with, I'm glad I didn't have to deal with the additional disc dust as well. It was certainly way less messy that the 1/8" kerf from the chop saw. The Lennox was only about 15 bucks and I'd have gone through at least a dozen regular discs by now since I started using it and there's no sign of it getting worn yet. It's a little tedious on steel but it's worth the decreased mess and other concerns that you might have with a regular disc, like having it come apart on you. It claims to be good for all non-ferrous but it's a loser with aluminum. It loads right up. It seemed to work well on the little bit of bronze I've used it on. The flap disc is definitely a wonder tool. Pete
I haven't tried the Lennox diamond blade on cast iron. Always used the cutoff discs & have dodged plenty broken ones, sustained damage from some as well. Time for some new tricks.
