Tungsten And Resin, An Experiment

[FrogAddict]

Last night I attempted to suspend tungsten powder in resin to make a "non-toxic" flipping jig. First I created a silicone mold of a 1/2 once flipping jig. I then mixed resin and tungsten and attempted to create the heaviest jig I could with the mixture.

 

My results weren't so great. The best I could accomplish was 1/4 oz. The problem is that in order to get more weight, I had to add more tungsten. When I did so, the mixture was a very thick paste.

 

So next I will be creating a mold with a 5/8 oz. flipping jig and I'll see if I can get 3/8 oz. out of it. I'm guessing others have tried this but I did a search and didn't find any results so I'm posting this to help anyone else who is thinking about attempting this.

[Vodkaman]

When I worked with resin and microballoons, to make lure bodies, I had the mixture about as thick as English mustard, a paste. Certainly too thick to pour, so I used a cake icing syringe to inject the mixture. This worked very well.

 

If the icing syringe is too big, you may be able to manufacture something smaller and simple. Make it so that you can easily dismantle for cleaning.

 

Dave

[FrogAddict]

Dave,

 

The problem was that even at the "paste" stage, the tungsten still isn't adequately mixing with the resin.

 

I wonder if I could cast a shell of a jig with resin and fill the cavity with tungsten powder?

Edited January 7, 2016 by FrogAddict

[Vodkaman]

I would imagine that the problem is that the surface of the metal powder not wetting with the resin. There are obvious time constraints also, as resin sets up fairly quickly.

 

An obvious solution is to pre-mix with the resin before adding the hardener, but this would make the distribution of the catalyst much more difficult. This would need to be tested.

 

If a small test of this was successful, it may be more efficient to mix a larger amount of powder and resin and store it like this. You can then spoon out the wetted resin/tungsten mix settled at the bottom of the container. Perhaps pouring off the unmixed resin into a temporary second container.

 

Mixing a small amount with a couple of drops of catalyst should not be such a problem.

 

Dave

Edited January 7, 2016 by Vodkaman

[Kasilofchrisn]

Have you checked out Larry Dahlbergs YouTube video on casting resin/tungsten mixes in silicone molds?

There might be some tips in there to help you.

Edited January 7, 2016 by Kasilofchrisn

[FrogAddict]

Kasil,

 

I did see that video a while ago but if I remember correctly,he was making a larger jig to use for some exotic fish species. I could get the desired weight easy enough but I'm trying to stay as close to a lead sized 1/2 oz. flipping jig as possible. I'll watch the video again though.

 

Dave,

 

That's a good idea to mix the resin and powder first. I'll try that next. There are too many things to attempt in the 60 seconds one has until the resin needs to be poured/injected into the mold.

Edited January 7, 2016 by FrogAddict

[Kasilofchrisn]

There is a video he made where he casts an entire homemade jig head in a silicone mold out of the tungsten powder and resin.

If I could I would find it for you. Unfortunately I can't do it until Monday or later due to work.

Search his videos and you'll find it.

Edited January 8, 2016 by Kasilofchrisn

[FrogAddict]

Kasil,

 

I think that's the one I watched but I could be mistaken. I'll look again.

[Vodkaman]

Frog - post a link if you find it, I couldn't locate the vid.

 

Dave

[FrogAddict]

here ya go

 

<iframe width="500" height="344" src="https://www.youtube.com/embed/24_FhTKVL6Q" frameborder="0" allowfullscreen></iframe>

[Vodkaman]

Frog - thanks for the link.

 

Pity Larry didn't quote any numbers for the powder to resin ratio. But, you can see how runny the mix was. I would be aiming for something a lot thicker.

 

Obviously there would be a tendency for the tungsten powder to settle, so it would be advisable to arrange your mold so that the lure body is sitting in its normal attitude so that any settled ballast falls to the belly.

 

But, for the small jigs that you are making, and the thicker consistency, this will not be an issue.

 

Dave

[Munkin]

I found the same thing when I tried to make them that the resin mix is too thick to pour. Once it warms up enough I am going to trying injecting with a children's medicine syringe. What I can add is that coloring for soft plastics works to color the mixture. While I cannot get the correct density yet I was able to duplicate Keitechs green jig color.

 

Allen 

[FrogAddict]

I've abandoned this experiment for now. I just couldn't get the density I wanted.

[Wayne Smith]

I was investigating whether sap gloves with tungsten powder or knuckle dusters made from tungsten powder and epoxy was workable. This link popped up. Thanks for the useful info. 

[Ogajiga]

For "non-toxic" wouldn't melt casting bismuth be EZr ?  85% lead weight.

https://www.rotometals.com/bismuth-ingot-chunk-99-99-pure-1-pound/

[jigmeister]

just for "What if's" and I realize this would compound the pouring process but since tungsten being heavier than anything it is mixed with will always be trying to settle to the bottom whether cast in resin or molten metal .

I am thinking if the jig head was under constant rotation until the binder for the tungsten powder solidified it should remain more or less equally distributed ?

[cadman]

I have and still use bismuth to create the same size jig except the jig is lighter. The difference between lead and bismuth is this:

 

Bismuth is lead free especially for some states that require lead free jigs.

You can pour bismuth at home without any problems, can't do that with tungsten.

Bismuth is about 1/3 less in weight than lead.

Bismuth is very hard, and if you cast it at a brick wall hard enough it will crack. However I never had this happen yet.

Bismuth has a low melting point, so if you intend to powder paint it, it can be very tricky. I suggest you rough it up, spray with self etching primer and air brush with lacquer.

 

[Munkin]

Issue is to achieve the weight you want the mix needs to be like 90%+ Tungsten powder to epoxy. The mixture is too thick to pour into a cavity for a bait. For example the 1/4oz shakeyhead Do-It mold cavity I tried made about a 1/16oz Tungsten epoxy head. They actually came out great but way under weight for what I wanted.

 

Allen

[Tiderunner]

On 2/7/2024 at 4:29 PM, cadman said:

I have and still use bismuth to create the same size jig except the jig is lighter. The difference between lead and bismuth is this:

 

Bismuth is lead free especially for some states that require lead free jigs.

You can pour bismuth at home without any problems, can't do that with tungsten.

Bismuth is about 1/3 less in weight than lead.

Bismuth is very hard, and if you cast it at a brick wall hard enough it will crack. However I never had this happen yet.

Bismuth has a low melting point, so if you intend to powder paint it, it can be very tricky. I suggest you rough it up, spray with self etching primer and air brush with lacquer.

 

This is the alloy I use   https://www.rotometals.com/lead-free-bullet-casting-alloy-bismuth-based/.  Tougher than pure bismuth or bismuth tin. Melts at a higher temp, pours at around *500. I started using this when I figured if it's togh enough for bullet casting, it's gotta be tough enough for jig making.

It is still brittle but not as brittle as other tin bismuth alloys. I have dropped some one the floor and had them crack. I also powder paint mine. I use an alcohol lamp and hold the jig over the flame for about 3-4 seconds then dip. Then to an oven around 200-250 degrees.

These are a PITA to remove from the mold!

[cadman]

6 minutes ago, Tiderunner said:

This is the alloy I use   https://www.rotometals.com/lead-free-bullet-casting-alloy-bismuth-based/.  Tougher than pure bismuth or bismuth tin. Melts at a higher temp, pours at around *500. I started using this when I figured if it's togh enough for bullet casting, it's gotta be tough enough for jig making.

It is still brittle but not as brittle as other tin bismuth alloys. I have dropped some one the floor and had them crack. I also powder paint mine. I use an alcohol lamp and hold the jig over the flame for about 3-4 seconds then dip. Then to an oven around 200-250 degrees.

These are a PITA to remove from the mold!

Well thanks for the info. Yes Bismuth is easy to pour but tough to remove from the mold as you mentioned. Also tough to file the excess sprue material. I have had to literally dig out some bismuth heads from molds. Even "Drop Out" doesn't seem to help too much. It seems that lead shrinks some when it cools in the mold and bismuth seems to expand. Just my observation. Thanks Again f0or the info.

[Tiderunner]

On 2/11/2024 at 1:17 PM, cadman said:

Well thanks for the info. Yes Bismuth is easy to pour but tough to remove from the mold as you mentioned. Also tough to file the excess sprue material. I have had to literally dig out some bismuth heads from molds. Even "Drop Out" doesn't seem to help too much. It seems that lead shrinks some when it cools in the mold and bismuth seems to expand. Just my observation. Thanks Again f0or the info.

It's weird how the tin bismuth alloy expands. Sort off defeats the laws of physics. My method of removal is simple, though unorthodox. I keep a small tack hammer on the workbench and after the whatever I just poured cools enough, I open the mold, and give the sprue a tap with the tack hammer, and that usually does the trick, while at the same time the sprue usually breaks off. as far as the excess sprue material I buff all my baits with a Delta 1" bench top belt sander. I can do 25 jigheads in no time at all. The mold I have a real problem with is a CNC bullet weight mold. Each cavity has its own pin. I wanted this mold because of the concave base. Those pins only come out when lubed with an anti seize compound. I've tried everything else, Pam, oil synthetic oil, etc. Anti Seize works the best.  and is still a PITA to remove.

Unfortunately where I fish throughout New England, non toxic is the only game. Every state except my home state of CT. So I either pour bismuth. Or buy tungsten. I've been gradually changing everything in my tackle bags over to tungsten. Honestly, I do like using it better than lead. And I let some other shmo make them so I don't get aggravated with bismuth.

There are times when I'm in a hurry and will leave jigheads on the work bench, and forget about them. Then I can't remember if lead or bismuth. I'll take one and whack it with a hammer. If it flattens, it's lead. If if shatters, it's tin bismuth.

When weighing my jig heads and other weights made from bismuth. The difference in weight is very very negligible. Maybe a couple of grams difference. Of course the big difference is the density. Lead will always win that.

[Ogajiga]

Brittle pure bismuth 85% lead weight 520* melt expands 3.32% melt - solid.

Soft pliable pure tin 64% lead weight 450* melt shrinks 2.51% melt - solid

In an alloy of the 2 metals a higher tin component will lessen the cooling expansion slightly and the alloy melt temp will decrease as low as 283* for the eutectic alloy of 63% bismuth - 37% tin.  So Tiderunner's 7-1 alloy might be an ideal compromise of powder paintable adequate weight (82% of lead) casting release mitigation.

Smooth cavity face machined molds release castings best and Do-ts especially current mfg will tend to be sticky.  Simple ball or  tube head designs release easier than more complicated feature castings.  Thru casting pins in worm weights are near impossible to remove, while partial insert pins in weedless jig heads can be removed with pliers twisting and pulling.

Edited February 16 by Ogajiga

[cadman]

11 hours ago, Ogajiga said:

Brittle pure bismuth 85% lead weight 520* melt expands 3.32% melt - solid.

Soft pliable pure tin 64% lead weight 450* melt shrinks 2.51% melt - solid

In an alloy of the 2 metals a higher tin component will lessen the cooling expansion slightly and the alloy melt temp will decrease as low as 283* for the eutectic alloy of 63% bismuth - 37% tin.  So Tiderunner's 7-1 alloy might be an ideal compromise of powder paintable adequate weight (82% of lead) casting release mitigation.

Smooth cavity face machined molds release castings best and Do-ts especially current mfg will tend to be sticky.  Simple ball or  tube head designs release easier than more complicated feature castings.  Thru casting pins in worm weights are near impossible to remove, while partial insert pins in weedless jig heads can be removed with pliers twisting and pulling.

Very good information. Thank You. I can attest to the fact that worm weights are impossible to remove the pull pin from the center. Been there tried that. Also smooth jigs come out of the mold  a lot easier than jigs with a lot of  cuts and features, tried that as well. I wish I had known this a lot sooner but trial and error is the best teacher.

 

Thanks Again for your info.