PSegnatelli

Nontoxic casting alloys

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I've really been into casting with block tin.  I do cast some lead stuff, but even with ppe I find myself struggling to breath for some time after a long session with lead.   

Not so with tin.  I don't even need to turn my fans on once I'm done fluxing.  

 

I really only use lead for jig heads, and I've casted enough for quite some time. So I tend to do tin lures. Spoons, diamond jigs, flutter type jigs, etc.   

So I'd like to explore more nontoxic options.  Searching the rotometals site I see lead free alloys made of bismuth. 

I'm curious on how they cast. I know it expands and shrinks as it cools. Also the brittleness is concerning.  

The price is higher than lead but cheaper than tin. Also the densities are lower than lead but higher than tin.  

 

Anyone else go down this road?

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I have been using Tin/Bismuth  for some time now. I have lead blocks up the wazoo but really just use it for home waters and salt.

I forgot which alloy I use because I ordered enough last time to last a long time. I know it was an alloy to hold up better at high temps

That’s important when powder coating.

Yes it is certainly brittle. And when heating to powder coat that will melt in the blink of an eye.

As far as expanding, that stuff is a pain in the butt! I make assorted jigs and bullet weights.

 

I use a small tack hammer to get the jigs out of the molds.  The bullet weights suck though.

There is a pull pin that goes through the weight to make the line hole. And is a major job to remove that pin!  I have tried every lube but ended up settling on Never Seize!

That should give you an idea on how tough it is to remove the pin when the weight expands.

Weight wise  the weights between the alloy and lead are nearly identical but not having a home lab I can’t test the density. I do know if I want to use a jig of 1/4 oz I need to go with a 5/16 oz tin.  That weight perfectly matches the 1/4 oz.  On a scale though the difference in weight is hundredths or even thousandths of an oz.  

Instead of waiting for me to find my old orders on roto metals you can do a search there for the higher temp tin bismuth alloy 

I believe it was 58% bismuth and 42% tin.

 

One thing I never tried was adding more bismuth to the alloy as that would certainly up the density. But also be a little bit more brittle. 

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Posted (edited) · Report post

Thanks for this info. The only mold I have right now with a pull pin is a no roll sinker.  I casted a bunch last year so I'm good for awhile. 

 I've got some 99% bismuth coming. And already have tin.   So I'll mess with the alloy.  I was going to start with 60%Bismuth/40%tin and go up or down if I need to.   I don't need perfection, just something that won't shatter if I bounce it off a rock or two.  

 

Last time I bought block tin (summer 21) I got it for $16lb. Kinda wish I bought more!!  But oh well. Can't go home again. 

 

Going to try casting spoons 1st.  I have a Do It mold that has 1/4oz to 1oz.    I don't powder coat yet so I was going to spray paint then clear coat them.  

 

I've also got 2 molds coming from Ukraine.  From 6grams to 30grams.   Going to rig them with assist hooks. 61ebff0ded966_Capture_2022-01-20-07-11-59.png.a0db2e2e4e4f435f0b2538592c5f8859.png61ebff1d210d0_Capture_2022-01-20-07-11-37.png.34263b4e6094f2e199dca8d4f5069db1.png

Edited by PSegnatelli

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https://www.rotometals.com/lead-free-bullet-casting-alloy-bismuth-based/

 

I’m pretty sure this is the alloy use.  I’ve dropped plenty on the garage floor without breaking.

 

Sometimes I get lead and alloy jigs mixed together so I use a very scientific method to tell them apart.  I whack’em with a hammer.

If they shatter it’s tin - flatten it’s lead.

 

I’ve never ordered the molds from Ukraine. I’m too impatient. I have either do it or CNC molds. I cast metals and pour my own plastics. 
 

Offer still stands. Once it gets a bit warmer you’re welcome to come by and cast whatever. I’ve got plenty of molds to choose from.

 

Lookin to cast some 12 and 14 oz diamond jigs but the cost of the mold makes buying the jigs a better idea.

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Posted (edited) · Report post

Where do u get the cnc molds?  

I want a mold for eel jigs but small. 1/4oz +

 

I looked at the rotometals site a bit. They have a jig alloy too. 

Bismuth should be here today. So hopefully I can get some time alone to mess around.  

Edited by PSegnatelli

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Thanks!!

 

Any idea what temps your bismuth/tin alloy is casting at?

I've got this crazy idea to try and cast a diamond jig with a rattle chamber in the center.  I have these tiny glass ones that might fit inside the wire mold.  But fear the heat with shatter them. 

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22 hours ago, PSegnatelli said:

Thanks!!

 

Any idea what temps your bismuth/tin alloy is casting at?

I've got this crazy idea to try and cast a diamond jig with a rattle chamber in the center.  I have these tiny glass ones that might fit inside the wire mold.  But fear the heat with shatter them. 

The tin alloy should cast at around *500, It supposedly melts at *395. When I powder coat and bake, I can't go very high on temps. Usually heat the oven to *250, place the jigs i, and shut off the heat.

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I had my Lee pot on 5 and everything melted great.  Only time I had any smoke was when I threw in some wax. Even that might have been overkill.  Very clean!! Hardly anything to skim.  I didn't even turn my fan on. 

 

Poured fantastic! Made some really nice spoons. 

 

I may have to cut a slot in the spoon mold for a pry spot.  That sucked welded shut! But nothing a few swipes of a file won't fix. 

 

Once I figure out the sticking issues I think I'll be pretty happy.  I never had anything stick like this. My molds aren't smoked at all, but I'll try that 1st.  Smoke is free. And free is me.   Also going to see if more tin will keep the swelling down. Or maybe just patience to let the bismuth do it's thing. 

 

 

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3 mins ago, PSegnatelli said:

I had my Lee pot on 5 and everything melted great.  Only time I had any smoke was when I threw in some wax. Even that might have been overkill.  Very clean!! Hardly anything to skim.  I didn't even turn my fan on. 

 

Poured fantastic! Made some really nice spoons. 

 

I may have to cut a slot in the spoon mold for a pry spot.  That sucked welded shut! But nothing a few swipes of a file won't fix. 

 

Once I figure out the sticking issues I think I'll be pretty happy.  I never had anything stick like this. My molds aren't smoked at all, but I'll try that 1st.  Smoke is free. And free is me.   Also going to see if more tin will keep the swelling down. Or maybe just patience to let the bismuth do it's thing. 

 

 

I am not familiar with that brand of mold but have used many types and brands over the years. My guess is the higher temperatures used to melt tin are warping the mold especially if mold itself  is manufactured from cast metal and/or does not have sufficient surrounding materiel (wall thickness) to act as a heat sink and draw heat away from the cavity area.

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17 mins ago, PSegnatelli said:

I had my Lee pot on 5 and everything melted great.  Only time I had any smoke was when I threw in some wax. Even that might have been overkill.  Very clean!! Hardly anything to skim.  I didn't even turn my fan on. 

 

Poured fantastic! Made some really nice spoons. 

 

I may have to cut a slot in the spoon mold for a pry spot.  That sucked welded shut! But nothing a few swipes of a file won't fix. 

 

Once I figure out the sticking issues I think I'll be pretty happy.  I never had anything stick like this. My molds aren't smoked at all, but I'll try that 1st.  Smoke is free. And free is me.   Also going to see if more tin will keep the swelling down. Or maybe just patience to let the bismuth do it's thing. 

 

 

Not sure if smoking the mold will help. I may help a little. I use a spray on  bullet release  A LOT of bullet release It helps but still sticks. I do give my molds a gentle tap with a small hammer.They usually fall out with a little persuasion.

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25 mins ago, The TideRunner said:

Not sure if smoking the mold will help. I may help a little. I use a spray on  bullet release  A LOT of bullet release It helps but still sticks. I do give my molds a gentle tap with a small hammer.They usually fall out with a little persuasion.

I was wailin on it with my mallet. 

 

Usually a few taps does it. 

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17 hours ago, SC said:

I am not familiar with that brand of mold but have used many types and brands over the years. My guess is the higher temperatures used to melt tin are warping the mold especially if mold itself  is manufactured from cast metal and/or does not have sufficient surrounding materiel (wall thickness) to act as a heat sink and draw heat away from the cavity area.

The temps to melt tin are about half that of lead.  As low as *250 depending on your alloy. Lead pours at around*700.

The CNC molds are machined out of a solid block of aluminum. They are plenty thick. You pay enough for them so they should be. I do find warping happens after repeated pours. Either plastics or metals. I do pour enough at one time that the mold handles even get too hot to handle after a while, and the paints start to melt off.

The Do It essential series are are made from cast metal, and some from Bug Mold are made from cast something. Resins of some sort.

It's the nature of Bismuth that makes it expand in the mold. It seems to ignore the laws of physics!

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