Silicone Molds for Lead Jigs

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

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jcool3

#15
On youtube, just uploaded a 7-part videos by BluingHearts Japanese lure manufacture on making silicone molds for jigs.
Similar to what I posted. somethings a little different and I learned a few things.
 Part 1

jcool3

Silicone molds are great for soft plastic lures.  Check out Paul Adams video ..

Cor

Quote from: jcool3 on October 22, 2015, 04:45:27 PM
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.
Sorry for resurrecting an old thread but that is because I am systematically reading all stuff that is useful to me.
I have played with making Silicone moulds for pouring resins, White metal and lead since 2005 and by and large have reached similar conclusions as above.

I have used Smooth Sil 950 as well as Mould Max 60 and found the MM 60 slightly more satisfactory for molten metals.  For moulding plastic, I have used various softer silicones, mostly from Smooth-on.    The more intricate the device you wish to mold, the softer the Silicone should be.    I once made some lures from leftover soft silicone, they were very successful and extremely durable!

Using a release agent with silicone seems to be one way to make the moulds last a bit longer, especially when pouring other resins.    Coating the inside of the moulds with some Graphite powder before pouring tin or lead goes a long way towards obtaining a smoother and better looking metal cast and I think also helps durability of the mould.

Silicone is versatile, can make perfect moulds, but is a bit pricy and when pouring hot metal start deteriorating fairly soon.
As long as it is for own use it is still economical and more fun to make your own lures!

Cornelis

jcool3

Quote from: Cor on May 15, 2016, 06:22:42 AM
Quote from: jcool3 on October 22, 2015, 04:45:27 PM
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.
Sorry for resurrecting an old thread but that is because I am systematically reading all stuff that is useful to me.
I have played with making Silicone moulds for pouring resins, White metal and lead since 2005 and by and large have reached similar conclusions as above.

I have used Smooth Sil 950 as well as Mould Max 60 and found the MM 60 slightly more satisfactory for molten metals.  For moulding plastic, I have used various softer silicones, mostly from Smooth-on.    The more intricate the device you wish to mold, the softer the Silicone should be.    I once made some lures from leftover soft silicone, they were very successful and extremely durable!

Using a release agent with silicone seems to be one way to make the moulds last a bit longer, especially when pouring other resins.    Coating the inside of the moulds with some Graphite powder before pouring tin or lead goes a long way towards obtaining a smoother and better looking metal cast and I think also helps durability of the mould.

Silicone is versatile, can make perfect moulds, but is a bit pricy and when pouring hot metal start deteriorating fairly soon.
As long as it is for own use it is still economical and more fun to make your own lures!



I now use baby powder to coat the inside of mold.  Also modified my molds
by plugging up old holes with more silicone and cutting new slots so that I'm
now pouring straight vertical, instead of from the side.  Think this eliminates air pockets. Learned this from bluinghearts videos.  Perfect lead pours almost every time.

gstours

Hello, and I was watching some of your old threads on jig molds, and wondered if you're still using silicone type molds, or have you found something better ?  I want to make some octopus 🐙 head jigs soon this winter.   I'm a beginner,  and need advice on getting started with my custom mold.
    Thanks for sharing your thoughts.   Gst.

jurelometer

Quote from: gstours on October 14, 2018, 09:58:58 PM
Hello, and I was watching some of your old threads on jig molds, and wondered if you're still using silicone type molds, or have you found something better ?  I want to make some octopus 🐙 head jigs soon this winter.   I'm a beginner,  and need advice on getting started with my custom mold.
    Thanks for sharing your thoughts.   Gst.

Hey Gary,


After some trial and error,  I am getting good molds now.


They make RTV casting silicone for high temp.   The bigger the  casting,  the hotter the mold gets, and the longer it stays hot.   I use regular temp rated platinum cure for small stuff,  but anything over about 1/2 oz,  I switch to the high temp stuff.

I have cast up to 12 oz.  The mold gets pretty hot,  but it  holds up well enough for personal use.


The things to look for:

Max temp ( they use terms like " usable temp" or "continuous use temp")
Cure hardness
Working time
Mixed  viscocity

If you play around with alloying your lead like the bullet guys do,  you can bring the pour temp down.

Softer rubber is good for peeling the mold off of complicated shapes,  but you need a mother mold for larger pours to ensure that the mold doesn't  flex with soft rubber.  It is easier and stronger to use a hard cure   (50+ Shore A)

Working time and viscocity need to be compatible.  The higher the viscocity,  the longer it takes to pour the mold without getting air bubbles. Some stuff is so fast and thick, you need a vacuum setup to get the bubbles out (a real vacuum pump - and you can't use  your food sealer,  it won't pull enough, and you could end up contaminating some nice halibut).

For pouring metals, I ended up liking the Smooth-on  Mold Max 60.   It is readily available in smaller amounts without crazy shipping.  It has one of the higher temp ratings at 563F, which is still below the pour temp of pure lead.  There are some other silicone suppliers that I have heard are better, but too tricky for me to get in smaller quantities.   SDS wise, there is a lot of variabilty in toxicity,  so worth keeping an eye on this as well. Some silicones go bad within a month or so after first opening.   I have gone three months with some opened mold max 60, and it seemed ok.  I spray  some canned air in before closing to help slow down the spoilage.

Measuring has to be accurate for mixing.  You will need a good gram scale for the catalyst.

I didn't like any of the octo jigs out there that I saw - the way they dropped, they way they swam, how they could be rigged, etc.   So I made my own design in 4 and 8oz so far.  Still in the early testing phase.




Are you planning on making something sane in size, or the 1-3 lb monsters they seem to like in some parts of Alaska?  You might be pushing what can get done with silicone if you start getting up there in size especially with unalloyed lead.

Another option if you are pouring big  jigs is  sand casting.  If you have access to a forge, you can even cast an aluminum mold.

-J

Dominick

That black octopus is one of the coolest lures I have seen.  Do you think it would work for Ling Cod? and will you sell me one?  Dominick
Leave the gun.  Take the cannolis.

There are two things I don't like about fishing.  Getting up early in the morning and boats.  The rest of it is fun.

Hardy Boy

They work for lings for sure and all other bottom fish here in BC. I make a 10 oz jig and I made the mold out of plaster of paris. The mold will start to break down after about 12 pours of lead.

Cheers:

Todd
Todd

jurelometer

Quote from: Hardy Boy on October 15, 2018, 08:15:42 PM
They work for lings for sure and all other bottom fish here in BC. I make a 10 oz jig and I made the mold out of plaster of paris. The mold will start to break down after about 12 pours of lead.

Cheers:

Todd

Good info Todd.  I read somewhere that mixing some portland cement with the plaster  (~25% ?)   makes them last longer.   I have also read some warnings about exploding plaster molds due to trapped water, especially for bigger molds for stuff like downrigger balls.  It scared me off of trying the stuff.  Do you oven dry your molds for curing and/or right before pouring?  Or is it that much of a problem?

BTW:  I like the backwards top skirts too!   I think the action is better.  My only worry is the the top skirt getting in the way if you are rigged with a circle hook .   But with a J hook, not a problem.

Quote from: Dominick on October 15, 2018, 06:21:03 PM
That black octopus is one of the coolest lures I have seen.  Do you think it would work for Ling Cod? and will you sell me one?  Dominick

Thanks Domnick!

Its actually rootbeer over ink black, because we know how finicky lings are about getting the color exactly right  ;)

These have caught lingcod.  I started making them about a year ago, but haven't used much, as I am testing a bunch of other lure designs, plus some new fly eyes.    The octopus heads are designed to be rigged lots of different ways.    I might be persuaded to bring a couple for the the December 10 trip.   I am down to my last two or three so I need to make some more.    What size do you fish?

-J

Cor

Plaster moulds work but are not ideal therefore many things have been tried over the years to make them last a bit longer.   I've never heard of anything that has made any material improvement and tried some myself.

Nothing beats a foundry made mould, unless its fine detail you want, then silicone is tops.

I always cure my silicone moulds, does it improve durability?.............I cant tell.....LOL

Just something on exploding moulds, I've never seen or heard of that.   But a few weeks ago I needed to make some ordinary sinkers for a beach fishing trip.     When I was very small my Father warned me about the dangers of water getting in to molten lead and I have always been extremely careful.   I've seen it happen a few times as well!

I was melting lead in my Lee bullet pot, which probably contained about 5 lbs of liquid metal.   I had poured one lot and bent down to the ground with my back to the pot to shake 3 sinkers from the mould.    I had placed another mould on top of the pot to keep it hot.    Suddenly an explosion took place in the pot sending the one mould flying about 3 ft in the air and spreading molten lead over an area of about 6 ft from the pot.

I got a huge fright and my first thought was that a primer got in the metal but that was not possible.
I can only think that some of the lead I was melting somehow contained a bit of water in a hollow pocket somewhere.   Some were old sinkers that had been in the sea a long time.   I don't know if that is possible.

Luckily I escaped with only one tiny burn mark, but can imagine what could have happened if I was looking in to the pot or even just standing a bit nearer.

Sometimes we need a reminder to be more careful, safety glasses, heavy gloves etc.
Cornelis

Hardy Boy

I never had one explode or crack. I just make sure they dry for a good while before I use it. The plaster breaks down after a dozen pours and you loose some detail but the fish don't seem to care. Pouring a dozen gives me enough jigs to fish with for a couple of years when added to the existing stock. It seems the more jigs you have the less you donate to the bottom. if its you last killer jig left you will loose it for sure on the first drop !! :-[

My buddy got a fixed hook lead head mould that we rig with out the fixed hood (use a wire). its an aluminum mould so we are good to go for a while. They seem to fish well and the aluminum mould is way easier to work with. That being said I still like making my own.


Cheers:

Todd
Todd

gstours

  Thanks for the added info.  I,m thinking of making a plaster of Paris mold for starters.  How do you seperate the mold when the pattern in dry in the plaster ?   Just saw it out?  finding and centering the cut around the patter Methods used?   I,m new at this.   Butt want to proceed.
   Some body help pleeze? ;)

Hardy Boy

Gary: I was going to write out the instructions but this link is way better: https://www.instructables.com/id/Make-a-two-part-reusable-mold-using-plaster/

I used Vaseline for the release agent not soap as in the instructions. You just need play dou  (I used clay), plaster of paris, release agent and a mold frame.

Cheers:

Todd
Todd

gstours

Sorry about not a reply sooner,  it's going to be a winter indoor project building the mold.
   Did you make your pattern of a wood carving or?  After the mold is made I guess you can remove material and do more shaping as needed.  I'd love to hear from more ideas 💡 before proceeding.
    The octopus is my goal.   10-16 oz.   thanks for sharing the link.  Good fishing 🎣

Cor

I used surfboard foam to make the original pattern for a mould, If nothing was available that I could copy directly.    It is easy to shape with knife and sand paper.   Finnish it off with a coating of Polyester resin to give it body, then lots of Waterpaper and if needed some polyester body filler.

Another option is to make the original from some modelling clay.

It is very difficult to shape the mould once it has been made.   I have changed the pouring holes and air outlets but nothing else.
Cornelis