OP
oldironfarmer
Well-known member
I've missed so much in my life! No casting in HS (like my son) or college.
What was I thinking?I'm trying to catch up.
Bring a little aluminum and watch a broom made to order. Or two. You're close enough to use my furnace to do a little casting.
I feel the same way. More I figure out the more I need to learn... or the more I learn, I realise the less I know.
The engineer's career: I learn more and more about less and less until when I retire I'll know everything about nothing.
Talking about TV... TV is is much more fun when you can watch Youtube in style. My wife had a good laugh watching Andy hooning in his show truck on the big screen!
I should be embarrassed but instead I'm tickled.
I always forget you guys have access to things at a scale we struggle to obtain. $5 gets me roughly 4m of nichrome here in NZ unless I find more obscure sources for it. Depending on the length I think the straightest cylinder would come from using a straight wire in a jig like a lathe but for short sections a round wire would be great. Setting the wire angle compared to the bed angle on the lathe would cut cones for days. Many guys make a hotwire setup like a bandsaw and cutting discs would just require a tack on the table like a circle cutting jig on a bandsaw. Alternative is to make two wooden(HDF/masonite works well if you sand the edges smooth) discs as profiles on the ends and follow it with the hotwire - this is basically how I cut the profiled core for my XPS core surfboards and glider wing cores. I'm starting to run out of cat skins(skinning the proverbial cat here)
I was thinking a bandsaw setup with a tilt table, then a hand held tool of some type for flexibility. I'm thinking about buying another soldering iron and abusing the element.
I have an old home build wood lathe that I sometimes use as a rotary fixture for things like this. Never had a motor fitted or used for actual wood either. First used it to make NERF rockets from solid poolnoodle(EPP) stock using thicker stainless TIG filler wire bent to the rocket profile(bit like a football shape with a tail coming out of it) and glued on EVA foam fins for fletches. Also cut spheres out of it that way to make cheaper NERF ammo for the guys who play scenario paintball(rocket launcers and bazookas). Different colours for different teams etc. Made some bullet shaped ones too but they had unpredicatble flight trajectories. Been toying with the idea to make a rifling tool and fixture to produce 2" rifled ABS barrels for them.
Hmmm, I have a very old home made wood lathe I need a use for. The guy who owned my broom machine made it probably in the thirties. Mostly wood, home made bearings, too, and it looks like it had some extensive use. His tools were all sharpened files.
My stainless wire hotwire cutter is 24V max and running a 750mm hotwire at around 12VAC if I recall. It is just a 24v stepdown transformer on the other side of a mains light dimmer. Cheap and easy and if I crank it up the wire glows which burns of the stuck foam gunk.
They make a really nice hotknife used for crafts that is basically a 1"x6" heated blade and used a lot for making foam patterns. I can try and find a link to one for you if you are interested. The other tool using a wire loop to scoop sections out of the surface like a clay texture tool. Used that a lot when making stuff for stage set and parade float type stuff. Probably not as usefull here unless you need to hollow out the styrene block when doing very large castings. Otherwise you can basically use anything you can make to work. My first polystyrene meat tray gliders were made using a needle heated over a candle.
Heated putty knife sounds like a hot idea.
I used to ad a little beeswax to my wax to make it sticky enough to use with foam. Again not having access to anyhting like modeling wax I concocted my own depending on what I wanted to do with it. Also found it easy to melt and cast the wax into different shapes to make up the components of the object before modeling it. Found if I painted the cooled but still molten beeswax onto the foam I could get other wax parts to stick to it better too. Nowadays we also have things like superglue - would have loved superglue as a kid. Though the plaster had to go on a bit thicker on the wax parts if I recall as the wax was its own release agent and the watery plaster had surface tension issues on it. I use to wait till it gets a bit gloupier before lathering it on.
My modeling wax is very sticky, I need to get a double boiler set up and try putting it on hot.
I'm told PLA(cheap 3D printing plastic) can be used like lost wax too. Though it leaves crud on the casting if poured direct. It can be burnt out of the mold in a furnace when doing investment style casting. It is very popular with investment casting crowd and another reason I'm keen on making a small electric furnace - other than being able to anneal, harden and temper things too.
I may try some lost PLA but I'm a foamie right now. I need to make an electric furnace as well. I think I can use my kiln controller to run it. Might just use some of the 100 ft of nichrome wire I received today.
That would be awesome though 3 months would fly by with all the stuff we'd get up to. You might run out of aluminium too fast and would definitely need a technical writer like Bob to document it for us on GJ.
I've got a lot of aluminum, and 250 gallons of propane...
You come up and Bob will accommodate us.
Almost Saturday here and might be time for a GJ update having started on my 3D printer build.
I'm waiting to see that
It takes a thoughtful person, and they seem to be disappearing
I always thought lost foam was very poor finish and full of inclusions.
I was wrong.
Cut my clamp and machined it today after spending most of the day with my wife. I am extremely pleased with the results.
Here it is in place. There is some porosity in the top 1/8" of the boss. The rest seems clean.
Put a 1/2" blind hole in it, the tray arm will pivot on that. Printed my name backward on the 3D printer then pressed it into the foam. It worked OK.
A glamor shot:
Drilled for 5/16" bolts with 3/4" spot faces. It tightens up very easily on the pipe.
I'll work on the cold seams on future work. I think wax will fix that, but they are all very shallow.
Thanks for stopping by!!
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Thank you very much Jim. I had not noticed that cycle, but I do like making tools the most. It is very gratifying that others get some enjoyment out of my struggles.
