Hi guys, looking for tips on casting a rectangular block, 4" x 3 1/3" x 2 1/4" from a pick-up truck driveshaft. I am making a riser for the tailstock that I want to use on my mill. I saw in another thread that it may help to add some copper. What advantage would that give? Also, should I position the part standing up on end or laying down? Thoughts ?
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Al casting advise needed
- Thread starter garageguy
- Start date
I think you may have better luck working with scrap aluminum that has already been cast, pistons, messed up aly heads etc. The aly drive shafts I have seen on trucks are not cast, trying to figure out how much copper to add maybe will be a lesson in how not to cast .
As to position, are you making a lump that you will machine to size? The easy way me thinks. Sometimes can just pour the aly in a larger box or a tin can, cut box or can off and start making chips. One of the harder things is enough heat to melt the aly and maintain it until poured. 1375 +/- degrees F.
Hooow, far do you want to go into the casting hole?
As to position, are you making a lump that you will machine to size? The easy way me thinks. Sometimes can just pour the aly in a larger box or a tin can, cut box or can off and start making chips. One of the harder things is enough heat to melt the aly and maintain it until poured. 1375 +/- degrees F.
Hooow, far do you want to go into the casting hole?
This is the key question. If you really want to get into casting, absolutely go for it. ITs fun, opens new doors, lots of new learning (and stuff to buy)...... but if you just want get a riser for your TS, price a hunk of steel at Metal Supermarkets...... or better still a piece of durabar from Terra Nova. Might seem expensive but can't see it being but a fraction of the cost of assembling all the bits and pieces to do a casting
Thanks for the replies guys. I have done a wee bit of casting already so I have a propane furnace , greensand, box, etc. The reason for wanting to cast is primarily the lack of Al material available in my area ( S.E. Sask) . I don't really want to go too far for the small pieces I need. I would prefer cast iron or steel but nothing available nearby. The driveshaft I am planning to use is extruded (the ends are cast) . I read somewhere that extruded is a poor choice for casting but it's a basic block that I will machine down to size so nothing complicated . As bandit said, just pouring into a box would be quick and easy.
sounds like you're all set. I've done a bunch of lost wax but no much sand casting so don't take mine as the last word on it. I have done basic pours of AL into open sand molds, you're right doesn't have to fancy. Make the pattern with some draft angles and away you go. I used bar stock offcuts, 6061 I believe, without issue. I hear it can be problematic if you don't get some the degassing tablets but they seem expensive and I've not bothered
Where about in SE Sk? I may have some precasted blocks that would work
Draft angle is a taper you apply to your pattern to allow you to pull it out of the sand without destroying your imprint
@kevin.decelles Hi kevin, I'm down by Estevan. The machine and metal desert. Good luck finding anything down here. Unless, of course you want 20 ft. of what ever it is, you're out of luck. Thanks for the draft angle explanation, I'll do that.
Do you have any engine repair shops, transmission repair shops, small engine repair shops, near you? Should be some junk pistons, rods, nearly all of the small engines used on the last 20 ? years of lawn/garden equipment are aly. Just be careful of power saws and a few others as cases and covers can be magnesium, not fun! Many trany cases and transfer cases are aly too.
Is there even a welding/machine shop round about? People with a welding truck. Buy a piece of steel or even 2 stacked, welded and then make chips.
The big end of the drive shaft maybe near to the right size you need depending what it came off.
I keep an eye out when I am at the dump/transfer site for "scrap" metal.
Sounds like you have the gear for aly sand casting, now you just need the metal.
Is there even a welding/machine shop round about? People with a welding truck. Buy a piece of steel or even 2 stacked, welded and then make chips.
The big end of the drive shaft maybe near to the right size you need depending what it came off.
I keep an eye out when I am at the dump/transfer site for "scrap" metal.
Sounds like you have the gear for aly sand casting, now you just need the metal.
My gear is minimal right now, but good enough for what I need. I did some work on my burner after watching some youtube last nite and got my diesel furnace up and running today. Worked great and did a test melt. I have a s/s pot about 4" in dia. and had Al melting in about 12 min. Pretty happy with that. I was using propane last time and it was much slower. I am using an old burner out of a residential furnace.
My 42 cents here. I've used lots of the extruded crap. When we replaced the aluminum windows in our house the glass went to recycling. The aluminum was cut up into crucible sized pieces.
Degassing is critical for this type of material. The first step is to melt the scrap and make ingots after you've degassed. Then when melting to cast you are starting with clean material and you will have to degass again. And even then, when I do it, I still end up with a certsain amount of tiny bubbles in the castings.
If you want to make the soft crap harder you can add copper say 10% by weight. Another reason to start with ingots. The copper needs to dissolve into the aluminum which is way above the casting temperature of the aluminum. So once the copper is gone pour ingots again.
Now you are ready to cast. Once again melt the ingots to the pouring temperature, degas and cast. Don't overheat or you will end up with castings that have a crystal like look and feel.
Degassing is critical for this type of material. The first step is to melt the scrap and make ingots after you've degassed. Then when melting to cast you are starting with clean material and you will have to degass again. And even then, when I do it, I still end up with a certsain amount of tiny bubbles in the castings.
If you want to make the soft crap harder you can add copper say 10% by weight. Another reason to start with ingots. The copper needs to dissolve into the aluminum which is way above the casting temperature of the aluminum. So once the copper is gone pour ingots again.
Now you are ready to cast. Once again melt the ingots to the pouring temperature, degas and cast. Don't overheat or you will end up with castings that have a crystal like look and feel.
Ironman
Ultra Member
If you have already screwed up and have crystalline cast, can remelting correct any of this or just chuck it out?
I never heard of degassing, but I can search for info
Just remelt it and hold it at a lower temperature.
You will find lots of positive and negative information about degassing on the web. It then becomes, like all things on the web, what to believe. I've seen photos or videos of people who claim degassing is not needed but what their castings look like are also, IMHO, quite ugly while they think they are perfect.
All I can suggest is if you are using scrap aluminum that hydrogen will end up dissolved in the melted metal. Removing it reduces that porosity in the final product. For some castings it doesn't matter. Depends on what you machine and what it's used for.
You will find lots of positive and negative information about degassing on the web. It then becomes, like all things on the web, what to believe. I've seen photos or videos of people who claim degassing is not needed but what their castings look like are also, IMHO, quite ugly while they think they are perfect.
All I can suggest is if you are using scrap aluminum that hydrogen will end up dissolved in the melted metal. Removing it reduces that porosity in the final product. For some castings it doesn't matter. Depends on what you machine and what it's used for.
Of all the you tube stuff out there this guy has probably done the best job of showing what to do and how to do it. Here's one on his argon wand for degassing. He tends to reply to all the comments and questions so reading those are also useful
The gist of it is keep your temperatures as low as possible, aluminum as clean as possible and perhaps porosity won't be an issue.
The gist of it is keep your temperatures as low as possible, aluminum as clean as possible and perhaps porosity won't be an issue.
Estevan? I've been there! You have no idea what's going on around you, if you think you are in a desert! LOL!
If you can't find materials, you are asking the wrong people, or at the wrong places.
Find an engine rebuild shop, and ask for pistons or manifolds. Most common alloy is 356 Aluminum which is a sand casting alloy. Aka: Pistonium! Set yourself up with a thermocouple to measure the temperature of the melt. Keep a log, noting melt weight, time, temperature and results, so you can have a chance at recalling just what you did right or wrong last time! Wear Safety Gear! The Tinsel Fairy (brought on by too much moisture, like, say, a spider, in the mold) is a cruel ol' Bitch, and God doesn't hand out more eyes!
Wrecking (aka Auto Recycling) yards are another fine option. At the worst, phone Inproheat in Edmonton and have them ship you some known alloy ingots! They can also provide ZA-12, or, at least, they used to.
Magnesium. The Acid Test (literally) is to scrape a bare spot on the casting, and apply regular Vinegar (Acetic Acid, 5%) to the cleaned area. Pouches of Vinegar from a fast food joint are really handy for this! Magnesium will burble and turn a sort of purple/brown color, making it easy to identify. Another way to identify it, is when breaking up the pieces. You hit an aluminum oil pan with a sledge, it breaks. Hit a Magnesium one with the same hammer, and it may KO you on the rebound! (personal experience, 0 out of five stars, do not recommend!) LOL!
Some search online will find you a bunch of different options for degassing a melt, Some guys use a gas wand, with inert gas, others use various materials that are submerged in the melt which flush the gasses to the surface, but the best thing is to simply get the metal up to casting temp ASAP, and pour it before it gets a bunch of time to absorb the gasses, thus the weight, time, temperature data suggestion above.
Been to the annual Model Engineering show? Kelly Tytlansvik (I even checked the spelling of his last name) is the organizer, and may be worth a blind phone call to. I really doubt there are many with a similar enough last name to cause a bunch of wrong numbers being found. Or ... https://www.estevanmodelengineeringshow.net/
There is a pretty well established group of like minded reprobates up in Regina too, that may be worth contacting, and attending the monthly meetings. Guys that are into casting and hobby machine tool stuff across a HUGE spectrum! And guys in North Dakota, who also run an annual show.
There are more than just a few guys in that area doing everything from basic casting, to really high end machining (CNC Turbine engines, eg
, you just have to poke around a bit to find a few of them, and you will soon know a LOT of them!
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