Silicone Molds for Lead Jigs

Started by jcool3, October 17, 2015, 02:48:28 PM

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jcool3

For those interested making original jigs, modifying existing jigs, or copying something that already exists.

jcool3

Cost $111 per gallon of GT-1364  mold making silicone by GT products
I can get about 16 molds out of this.  Works out to $6-7 per mold.

jcool3

It easy to drill circles or cut slots with razor blade/ exacto on finished mold

jcool3

Clean, primer, paint and epoxy coat.  Add octopus skirt, quick skirt, and soft plastic trailer.
Not shown is corkscrew wire for adding soft plastic.

mizmo67

~Mo

Maureen Albertson :)
Scott's Bait & Tackle / Mystic Reel Parts (Formerly PennParts.com)
Contact Me Via Store Website Please!
Orders/Support# +1 (609) 488-4637 (parts ordering or troubleshooting)
customerservice@mysticparts.com

Steve-O

Thanks for the tutorial. Just last week I bought a 140# bucket of lead for cheap.  Now I know how to use it. ;D

jurelometer

Nice!

I had previously tried this for prototyping jig head designs.   I found that  the molds degraded pretty rapidly.  The silicone you are using states  a max useful temp of 450 degrees F.    Lead melts around 620.

I even tried some fancier higher heat silicone and lead alloy ( w/ bismuth?) that melts at a lower temp.  But still the same results.

How many casts  are you able to get out of a mold?  And how large are the items that you are casting?

I am wondering if I am getting the lead too hot.  IR thermometer is not very accurate on melted lead. Or maybe my heads are much  larger (4-6oz). and the mold gets too hot to  get away with it.


[For other folks considering  doing this:  the shelf life of these type of  silicone products is typically not very long, even shorter after initially opening.  Check the product specs for storage and shelf life.  A layer of inert gas, even just some of the canned air products can help extend stored product that has been opened.

Make sure that the clay you use does not contain  sulfur.  It can inhibit the curing of some silicones.]


Thanks,

-J

jcool3

Quote from: jurelometer on October 17, 2015, 08:58:22 PM
Nice!

I had previously tried this for prototyping jig head designs.   I found that  the molds degraded pretty rapidly.  The silicone you are using states  a max useful temp of 450 degrees F.    Lead melts around 620.

I even tried some fancier higher heat silicone and lead alloy ( w/ bismuth?) that melts at a lower temp.  But still the same results.

How many casts  are you able to get out of a mold?  And how large are the items that you are casting?

I am wondering if I am getting the lead too hot.  IR thermometer is not very accurate on melted lead. Or maybe my heads are much  larger (4-6oz). and the mold gets too hot to  get away with it.


[For other folks considering  doing this:  the shelf life of these type of  silicone products is typically not very long, even shorter after initially opening.  Check the product specs for storage and shelf life.  A layer of inert gas, even just some of the canned air products can help extend stored product that has been opened.

Make sure that the clay you use does not contain  sulfur.  It can inhibit the curing of some silicones.]


Thanks,

-J

thanks for the input, especially those with silicone mold experience. Sorry i'm not an expert. i've poured more than 3 dozen jigs 3-6 ozs. on a single mold.  don't know what other options are available for the hobbyist fisherman.  Tried bondo molds and they warped badly after a dozen pours.   The advantages of silicone for me outweight disadvantages.   Easy enough to duplicate the mold if damaged.  Just put 1/2 the mold in a lego coffin with model, and pour a new half.

jurelometer

Quote from: jcool3 on October 17, 2015, 11:12:54 PM
Quote from: jurelometer on October 17, 2015, 08:58:22 PM
Nice!

I had previously tried this for prototyping jig head designs.   I found that  the molds degraded pretty rapidly.  The silicone you are using states  a max useful temp of 450 degrees F.    Lead melts around 620.

I even tried some fancier higher heat silicone and lead alloy ( w/ bismuth?) that melts at a lower temp.  But still the same results.

How many casts  are you able to get out of a mold?  And how large are the items that you are casting?

I am wondering if I am getting the lead too hot.  IR thermometer is not very accurate on melted lead. Or maybe my heads are much  larger (4-6oz). and the mold gets too hot to  get away with it.


[For other folks considering  doing this:  the shelf life of these type of  silicone products is typically not very long, even shorter after initially opening.  Check the product specs for storage and shelf life.  A layer of inert gas, even just some of the canned air products can help extend stored product that has been opened.

Make sure that the clay you use does not contain  sulfur.  It can inhibit the curing of some silicones.]


Thanks,

-J

thanks for the input, especially those with silicone mold experience. Sorry i'm not an expert. i've poured more than 3 dozen jigs 3-6 ozs. on a single mold.  don't know what other options are available for the hobbyist fisherman.  Tried bondo molds and they warped badly after a dozen pours.   The advantages of silicone for me outweight disadvantages.   Easy enough to duplicate the mold if damaged.  Just put 1/2 the mold in a lego coffin with model, and pour a new half.

Thanks- that is useful information.   My molds started getting crunchy after half a dozen pours so I am doing something wrong.    I'm going to figure out how to measure my lead temp better. Maybe I am pouring a lot hotter than I think.   

I really like silicone molds.  I use it for soft plastics.  It is easy to make shapes that would be difficult to cut into a an aluminum mold and the finish detail can be exceptional.

One other trick that has helped me if you don't have a vacuum chamber to degas all the bubbles before pouring the silicone:  paint a fine layer of the silicone over the master before pouring the rest.  Less likely to have a bubble on the mold surface. 

-J.

Steve-O

#9
Jcool3' here's an idea....how to recoup some expenditure on the silicone by selling a mold to two to me?

Interested? Send me a pm.

I have made a few pieces by sand casting but your jig molds seem such a better idea as a sand cast mold is a one pour shot each time. Not hard to do...just fine sand and motor oil. Mostly just to melt the lead down into useable slugs and ingots for now.

I have been shopping around looking at Do-it molds but don't see what I want, yet. An octopus head shape.

Something like a mix of these shapes. But not a blatant copy of someone else's.

jcool3

Quote from: jurelometer on October 18, 2015, 12:02:07 AM
Quote from: jcool3 on October 17, 2015, 11:12:54 PM
Quote from: jurelometer on October 17, 2015, 08:58:22 PM
Nice!

I had previously tried this for prototyping jig head designs.   I found that  the molds degraded pretty rapidly.  The silicone you are using states  a max useful temp of 450 degrees F.    Lead melts around 620.

I even tried some fancier higher heat silicone and lead alloy ( w/ bismuth?) that melts at a lower temp.  But still the same results.

How many casts  are you able to get out of a mold?  And how large are the items that you are casting?

I am wondering if I am getting the lead too hot.  IR thermometer is not very accurate on melted lead. Or maybe my heads are much  larger (4-6oz). and the mold gets too hot to  get away with it.


[For other folks considering  doing this:  the shelf life of these type of  silicone products is typically not very long, even shorter after initially opening.  Check the product specs for storage and shelf life.  A layer of inert gas, even just some of the canned air products can help extend stored product that has been opened.

Make sure that the clay you use does not contain  sulfur.  It can inhibit the curing of some silicones.]


Thanks,

-J

thanks for the input, especially those with silicone mold experience. Sorry i'm not an expert. i've poured more than 3 dozen jigs 3-6 ozs. on a single mold.  don't know what other options are available for the hobbyist fisherman.  Tried bondo molds and they warped badly after a dozen pours.   The advantages of silicone for me outweight disadvantages.   Easy enough to duplicate the mold if damaged.  Just put 1/2 the mold in a lego coffin with model, and pour a new half.

Thanks- that is useful information.   My molds started getting crunchy after half a dozen pours so I am doing something wrong.    I'm going to figure out how to measure my lead temp better. Maybe I am pouring a lot hotter than I think.   

I really like silicone molds.  I use it for soft plastics.  It is easy to make shapes that would be difficult to cut into a an aluminum mold and the finish detail can be exceptional.

One other trick that has helped me if you don't have a vacuum chamber to degas all the bubbles before pouring the silicone:  paint a fine layer of the silicone over the master before pouring the rest.  Less likely to have a bubble on the mold surface. 

-J.


what mold making silicone did you use?  brand and hardness?

jurelometer

Quote from: jcool3 on October 20, 2015, 06:30:04 PM

[snip...]

what mold making silicone did you use?  brand and hardness?

For pouring high heat - I have only tried Smooth-on Mold Max 60T (Shore 60A hardness) .   It had the highest temp rating (560F) that I could find and is available in small amounts. ( Note that I was not successful pouring lead with this stuff).  I am thinking of cutting AL molds instead, but the shapes are more limited.

For pouring soft plastics there are a bunch a vendors- none that stand out for me yet.   Pouring viscosity and final hardness are the things to look at.  The thinner the mix, the less bubbles in the mold- especially important if you don't vacuum degas.   A harder mold will generally last longer, but usually has a higher pouring viscosity.   I have gotten hundreds of swimbaits out of a 30A mold with no signs of degradation. 

Quantum Silicones was recommended as a top brand, but I have not tried it yet.   I think there are a couple  retailers if you are in the USA.

-J

jcool3

#12
Quote from: jurelometer on October 21, 2015, 01:30:23 AM
Quote from: jcool3 on October 20, 2015, 06:30:04 PM

[snip...]

what mold making silicone did you use?  brand and hardness?

For pouring high heat - I have only tried Smooth-on Mold Max 60T (Shore 60A hardness) .   It had the highest temp rating (560F) that I could find and is available in small amounts. ( Note that I was not successful pouring lead with this stuff).  I am thinking of cutting AL molds instead, but the shapes are more limited.

For pouring soft plastics there are a bunch a vendors- none that stand out for me yet.   Pouring viscosity and final hardness are the things to look at.  The thinner the mix, the less bubbles in the mold- especially important if you don't vacuum degas.   A harder mold will generally last longer, but usually has a higher pouring viscosity.   I have gotten hundreds of swimbaits out of a 30A mold with no signs of degradation.  

Quantum Silicones was recommended as a top brand, but I have not tried it yet.   I think there are a couple  retailers if you are in the USA.

-J

Again, I am not an expert, but I think I know why you got poor results.  You used a tin based mold making silicone.  Early on, I did some research on the internet and settled on platinum based silicone as the way to
go.  I forgot and cannot really explain why.   Check out http://www.bassresource.com/bass-fishing-forums/topic/16086-using-silicone-for-a-mold-to-pour-lead/.  For what its worth a member in the tacklemaking forum said "silicone will work fine for lead but you have to use platinum cure silicone. You also need to get a very firm silicone. Tin cure will not last long and it will distort. You will also need to build a good mold that is rienforced because even a good platinum silicone will want to distort after you pour a bunch of lead through it. One little tip, dust your mold with talc powder and the lead will pour much easier. I pour a bunch of talc in a sock and then zip tie it. I tap the pouch against the mold after each pour. "
I am on my second gallon of the gt products platinum cure silicone with no apparent durability problems ...
I cannot explain why gt lists 450F at high end of temp range, but when I pour lead I don't really pay attention to temp. ... I set between 6 and 7 on the dial lee production pot. (650-700F ???)

jurelometer

Quote from: jcool3 on October 21, 2015, 04:55:01 AM
Quote from: jurelometer on October 21, 2015, 01:30:23 AM
Quote from: jcool3 on October 20, 2015, 06:30:04 PM

[snip...]

what mold making silicone did you use?  brand and hardness?

For pouring high heat - I have only tried Smooth-on Mold Max 60T (Shore 60A hardness) .   It had the highest temp rating (560F) that I could find and is available in small amounts. ( Note that I was not successful pouring lead with this stuff).  I am thinking of cutting AL molds instead, but the shapes are more limited.

For pouring soft plastics there are a bunch a vendors- none that stand out for me yet.   Pouring viscosity and final hardness are the things to look at.  The thinner the mix, the less bubbles in the mold- especially important if you don't vacuum degas.   A harder mold will generally last longer, but usually has a higher pouring viscosity.   I have gotten hundreds of swimbaits out of a 30A mold with no signs of degradation.  

Quantum Silicones was recommended as a top brand, but I have not tried it yet.   I think there are a couple  retailers if you are in the USA.

-J

Again, I am not an expert, but I think I know why you got poor results.  You used a tin based mold making silicone.  Early on, I did some research on the internet and settled on platinum based silicone as the way to
go.  I forgot and cannot really explain why.   Check out http://www.bassresource.com/bass-fishing-forums/topic/16086-using-silicone-for-a-mold-to-pour-lead/.  For what its worth a member in the tacklemaking forum said "silicone will work fine for lead but you have to use platinum cure silicone. You also need to get a very firm silicone. Tin cure will not last long and it will distort. You will also need to build a good mold that is rienforced because even a good platinum silicone will want to distort after you pour a bunch of lead through it. One little tip, dust your mold with talc powder and the lead will pour much easier. I pour a bunch of talc in a sock and then zip tie it. I tap the pouch against the mold after each pour. "
I am on my second gallon of the gt products platinum cure silicone with no apparent durability problems ...
I cannot explain why gt lists 450F at high end of temp range, but when I pour lead I don't really pay attention to temp. ... I set between 6 and 7 on the dial lee production pot. (650-700F ???)

I would have argued with you that the tin based silicones are better  and that is what is used for high temp molds (for tin/pewter casting) because they can get a higher max temp out of tin-based silicone,   but my tin-based molds are not working and your platinum-based are :).   I think I have a bit more mold-max left, it it is still good, I will make a fresh mold and watch my temps more closely.

Thanks for the info!


jcool3

I think both the tin base mold max 60 and the platinum cure silicone (50+ hardness) work and are commonly used in making lead jigs.
One should be able to get at least 4 dozen jigs out of a mold.