Some more hot wire ideas here. Hot Wire Build | The Home Foundry There is a source for hot wire build instructions, parts and kits in Post #16. The power supply can but doesn't need to be DC. A step down transformer with a dimmer switch on the high voltage side is what I used. Best, Kelly
The power supply I show upthread was selected as it was inexpensive, shipped fast, and looks like the ones that come with some of the entry level tables on Amazon. When I was doing the bigger stuff I used a car battery charger or a Variac to light up 2 or 3 feet (.6 to .9m) of wire. If set wrong, a Variac will melt the wire in a split second.
Kelly's piece fits in the bracket nicely as de-gated. A machinist at worked popped the holes into it as I don't have a way to do this accurately at home. We discussed heat treating it but he had no issues machining as-is. I have the pin and spring on order that would replace the carriage bolt. I started assembling the thin pieces together with Arleen's Tacky glue. Is beeswax a good DIY fillet material? I have that and a couple other kinds, like what goes into tealight candles and some others my kids had for waxing snowboard bottoms. I don't have the smoothing tools either, might have to see if I can get something local at Walmart, Michaels, JoAnn's... PS : https://www.michaels.com/product/ma...t-smart-6ct-10649081?michaelsStore=2767&inv=3
Not sure how well it would work for this application but the wax used for toilet seals is soft enough to be spreadable, it's widely available and really cheap, might be worth trying. In case you don't know what I'm referring to: https://www.homedepot.com/p/Everbilt-Standard-Toilet-Wax-Ring-007004/100211506
Thanks Rocco. I have also heard it being used as an emergency boat patch. There is a Home Depot and Menards near the Michaels.
If you end up trying that for lost foam, let us know how it goes, ease of use, effectiveness etc., I'm curious.
Will do Rocco. Made some beeswax fillets with a bit of drywall corner with the corner bead pounded out and greased with Partall #2 wax. Melt beeswax, pour, cool, throw in freezer for 20 minutes. One side detaches by flexing the metal, the other side needs a little coaxing with a razor blade.
I like beeswax for about everything, at least until I run out. If you use a toilet seal, you can harden it a little by mixing with beeswax or paraffin. Use a new ring, the used ones make your fingers smell funny.
Toilet wax is practical and works ok but is a little on the soft side to work with unless chilled, but as Jammer noted, can easily be alloyed to a little firmer and higher melt temp. It's easier to use it as is if you pack it into a plastic syringe, then stick the syringe into a warm glass of water. I use one of those coffee cup size warming pads and a dimmer swith to control the heat. Comes in handy fo apply very small fillet or sealing cracks in pattern assemblies. Those fillet tools will work fine. You'll quickly grow tired of the sleeves on the stems and cut them off. It's easy to make yourself a couple scrapers for your favorite radius ball fillet tools. Break the edge on the radius with a buffer and it will leave a smooth finish and not scratch the foam. Just gently heat the tools in the stream of a heat gun and they will displace the wax more easily. You can use a candle but the can be sooty, that's why the old foundry guys had alcohol lamps. If you think you'll being doing LF casting, you're better off just spending $35 and buying the professional lost foam formulated wax fillet from Freeman Supply. It's a near lifetime supply for most hobbyists and is just amazing stuff. Even though it's fillet, I buy the smallest radius and use it for evrything.. Best, Kelly
Thanks Everyone! I watched some videos with fillets (Kelly's and Tubal Cain/Mr. Pete) and cut the remaining pieces and spacers for the pattern. I tried a plug cutter for the bosses, worked great! The spoils of Suburbia: Fillet tools aka Mandala tools 2.99$US after 40% off-Michaels 8B pencil, 0.96$ after 40% off-Michaels 3/16 x 2" stainless eye bolts 1.54$ before 11% mail-in rebate-Menards Harvey's #1 toilet wax ring 1.99$ before 11% mail-in rebate-Menards The idea of 'alloying' wax is appealing to me since I have various types already here. Is heating the smoothing tool enough (have hot air gun) or should I be getting the current beeswax fillets warm first? I was thinking to fillet the sides before assembly: .
You can wave the fillet through the hot air stream to soften it. The best technique is to warm the fillet tool enough so it will make the fillet deform and flow into the corner but not puddle to liquid, which just makes a mess, but happens until you get the hang of it. Then just occassionally wave the fillet tool in the hot air stream to keep it at temp. You'll need a scraper to remove the excess wax on each side of the fillet radius. Depending on your fillet stock and technique, sometimes you can lay fillet without the need to chase with a scraper. Best, Kelly
Tops, it's too much messing around for me, but if you'd rather make your own fillet stock, small radii like 1/16-1/8 don't need to be fillet or triangular shaped. They can just be rope. If you preheat the rope in the hot air stream the ball tool will flow it just fine into a fillet. That's all the 1/16 stock that Freeman sells is.....but that size isn't available in the LF formulation. Even so, their regular wax fillet formula works pretty good too. You can extrude wax through the nose of a plastic syringe and just cut the nose to the desired diameter. It's surprsing difficult to get and keep the wax at the right temp because it's a pretty narrow temp range in which it will easily extrude yet hold its shape, and wax is a very poor conductor so it heats slowly and unevenly. You'll discover that when you try to make alloys. Best, Kelly
Tried a quick fillet before I go to work. I used a small heat gun that came with a set of heat shrink crimps off Amazon. In the time it took me to get a piece of scrap foam cut into an inside corner, it had gotten warm enough to melt most of the fillet and maybe be too hot for the foam. Pretty excited that it is working...I mean as excited as I get on one cup of coffee.
Tried some more fillets tonight. I think I got my homemade fillets too big, made for lots of scraping to get them in the neighborhood of uniform. If I chased the fillet in the metal mold with the same sized ball as the desired fillet, would that be something? Starting to see the utility and convenience that Kelly has been describing for the pre-made Freeman fillets or rope.
Don't know if you've seen this but Chirpy made a simple extruder. He was active on AA but I don't think he made it here.
No, thanks for that. I watched him add fillets to some wooden patterns too in another video. Assembled, sprue-d, and have reached an 'oh snap!' moment in that my biggest crucible and the prepared part are basically the same volume without any sort of pouring cup. Thinking of removing the bottom 7/8" (22mm) square runner and a couple inched off the 1" (25mm) main sprue up top. Current deletes would gain me about 4 oz (120g) or 2.6 cubic inches (42ml).
Size matters! You don't need the lower bit of the feed system below the last boss. If you have a good cup, it's ok if it is not filled at the end of the pour as long as the sprue still is, and you don't spill any during the pour. I always have at least 25% more melted than needed. Pouring short after doing everything else well is very unrewarding. Best, Kelly
Trimmed and coated w/ non-setting joint compound late last night. I forgot to pre-treat the pattern with dish soap and water 'wetting solution'. Looks pretty good except for the fillets (coverage + learning issues) and where I wrote on the marker with red Sharpie. Does the wax need to be 100% buried in mud? Revised the model and ran the numbers, still at current furnace's max crucible w/ max load w/o accounting for a decent pouring basin and any other sort of mishap. I wanted to pout today but seems like haste will lead to waste. Hoping I can get my head back in the game for finishing the A10 furnace.
