The BEST Metal Casting Alloy That Everyone Ignores

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[notamouse]

Historical note for the bronze spear, the lines were likely not cast in, but instead cold worked in to provide edge retention.

[ChirpysTinkerings]

Alot of the bad press about zamak alloys comes from the fact that companies realize it's strength and fluidity, so they cast stuff out of it that is extremely thin to the point that it almost becomes brittle, so in use, it ends up breaking and the bad press comes from that. I said to leave it in the sand a little longer because most people tend to think it chills instantly, but doing thicker parts, it tends to stay fluid for quite a while unlike aluminum and feeds from risers/feeders, and if you opened it with a larger part, you may end up with a casting that isnt fully solid and things may just break off into a crumbly mess or at best, just warp. With the half nuts I poured in ZA12 for my lathe, it took close to an hour to cool down, but I had poured it into a hot investment mold too (which you will get a better finish from a cool mold). Some people just get excited and cant help themselves from just opening the mold right away after pouring instead letting it sit and fully solidify, lol. Gingery lathe bed is a good one of those examples, you want at least an hour or two for that casting to solidify or it will really warp badly.

[laurilahr]

Youtube suggested me one of your videos for some reason, and I couldn't be happier. I do exactly 0 metalworking, but your enthusiasm and animated style of presenting are absolutely infectious. Looking forward to videos of your future projects!

[jmone]

Also worth checking out EZAC (a newer Zinc Alloy of 88% Zinc, 5% Copper, 7% Al - Melts at 412c and Cast between 425-455). Harder than Zamak 12 with much better creep resistance.

[tmophoto]

be careful with the amount of parting dust you put on with that if its reproducing that kind of detail from the sand grains. I had an issue with some super fine petrobond that I made for high quality finishes and it was reproducing the parting dust in my final castings, when I blew most of it off before casting the sandy texture was gone and I got WAY better surface finish. took me a long time to figure that out...

[kmoecub]

My lathe uses Zamak for the change gears. While they do wear faster than steel gears the original set is still going strong since being cast in 1953.

[lornablewettandlee]

Hi Paul, Great video! I share your enthusiasm for what you call zamak, and what we brits call zl12 (88% zinc, 12% aluminium). I buy mine from Artisan foundry supplies in Liverpool, where the Beatles come from. I used to fine sieve my green sand and ram extra hard. The surface finish was amazing. I am hoping to try an oil bound sand some time soon, and also an epoxy resin bound sand. Myfordboy uses zl12 a lot, especially for flywheels as it isn't much lighter than cast iron, almost double the weight of aluminium. Lee

[jimplamondon]

My father was an aerospace engineer in Los Angeles starting around 1950. One of his first jobs was with a company that made specialty metal castings for commercial purposes. This job made him VERY popular with Hollywood's starlet-wannabes. All he has to do was give them his business card with the company name on it -- Commercial Casting -- and he was in like Flynn.

[jermainerace]

Zinc alloys in general are super easy to cast, certain alloys have zero shrinkage, and they take details excellently. At one factory we used a lot (LOT) of zinc castings for anything that had to be more wear resistant than plastic, relatively precise as-cast, and didn't have to be particularly strong. It was possible with investment casting to get this stuff within +- .003" dimensionally, which is better than most students in their first year of machinist school. For light duty parts this stuff is great.

[rudycandu]

I have been a fan of zinc alloys for more many years. All my zinc is scrap. And as you rightly said, it is used in so many things. Zinc's lower melting temperature is one of the main reasons it is used for die casting. Because of the high density the head height does push the zinc more int the sand and picks up more grain. So use a shallower mold if possible.

Buying commercial zinc alloys is preferred. ZA-8 and ZA-12. The problem is that a lot people would rather melt free cans rather pay a few dollars for good casting metal. I do collect free metal to melt but I am pretty selective. Stuff that is less desirable I sell to scrap yards.

[samueldamewood]

Been casting bullets with Zamak alloys off and on for about 30 years.
They offer some specific advantages over lead alloys having lighter weight that allows them to be driven faster but having much less overall range which can bea great benefit.
Folks need to learn the properties of the different Zamak alloys and proper fluxing but it's worth the effort.

[BobStrawn]

Great stuff. One of the qualities that has made it unpopular is that designers use it as one of the go to materials for planned obsolescence. Since the zamak metals have predictable shrinkage they can for example, be used to make sure a fan will seize up after a predictable period of time. This is really good stuff, but it has been used in evil ways.

[ElixirCNC]

Thanks for the video! I'm glad that you shared a supplier. Old Craftsman lathes used zamak change gears, and the surface finish is precise.

[shadetreemechanicracing]

Zamak was used for making change gears for atlas/craftsman lathes, so it is a fairly durable metal.

[daveayerstdavies]

You can get away with using high temperature silicone moulds (molds) for the lowest temperature Zamak alloys. The mould material does degrade but it's worth it for the fine detail you can get.

[xlerb]

Good video, thank you. I learned about Zamak years ago from a retired machinist that rebuilt magnetos. Lots of old cast pot metal parts there that had deteriorated over time. He didn't do casting so he couldn't rebuild a housing. But it he could do miracles with replacing the corroded interior parts. And Zamak was his secret weapon. For the parting dust I've always used a bag made from a bit of a sock or similar material. Works great for applying a light dusting. You don't get the clumps like with a shake bottle :) It's been years since I've had my casting equipment set up. That's going to be job #1 when I retire in a couple years. At least the small jewelry equipment. Dunno about the blast furnace and such, it would take a fair chunk of time and money to get a safe setup for that equipment.

[dynamicworlds]

If it hasn't been melted down yet, it might be worth breaking it to see the whatever grain structure or whatever it forms internally. If it's going in the melt pile, that's a great excuse for all kinds of destructive testing.

[dg-hughes]

5:55 my dad worked in the Canadian Coast Guard and was also a janitor before that, all around blue collar worker. Anyway he said it was well-known that any workers that breathed in zinc had to drink milk to help lessen effects of metal fume fever. It also happens probably more for welders who use zinc rods and no mask, so home or welding shops with no safety procedures.

[jeanladoire]

zamak is actually pretty close to low grade mild steel in terms of tensile strenght, wich is pretty impressive for such a low melting point alloy

[calliecooke]

I'm really glad your video caught my eye. I'm a tinsmith, and have been using Zamac mushroom plugs for years to fasten sheetmetal to masonry. I thought it was a lead alloy, but had no idea that the other component was zinc. When you started to describe where and how it is used in our world, a light bulb went off. Voila, "pot metal". This info will probably never help me at trade, but I'm glad I watched, nonetheless. I have an artist friend who casts bronze . Mostly lost wax, but some sand too. Zamac seems like a really easy, lower cost material to cast with.