Mould making for Tin / WM or Lead .

[Lenny]

So I took the plunge in checking if I could make a mould for a specific sinker .


I did some research , and make a ' mock up mould ' with Plaster . 


I would not describe the Plaster mould a disaster , but I , got more into the design and functionality of the mould .


The product I used , was a Two part Silicon , Available from AMT composites , called Mould max 60 .
You get the lighter duty Mould max , but it WILL not Stand the heat , and will go mushy and warp . MM60 are made for casting high Temprature stuff , up to 660 Degrees of something ...


READ THE INSTUCTIONS CAREFULLY , take your time , recalute and make sure your mixer are mixed in WEIGHT .


You will need a few things , Along with your Silicon and Catalyst , Silicon Thinners , also available at AMT , the MM60 are thicker in consistency than the MM30 . The Thinners should NOT BE  more than 20 % by WEIGHT of the final silicon Catalyst mix . The Thinners help that the air bubbles escapes . the less bubbles the better .


You will need : Scale an Accurate scale , Ruler , some Wax paper , Vaseline  will add as we go along .


WARNING !!!


If you spill MM60  , make peace with having that stain there for the rest of your lifetime , DO NOT spill this in your car , carpet , pants any of your misuses stuff or your mom stuff , your screwed .   

[Lenny]

I made a dummy out of Moulding Clay , you can get this at loads of places .  This pic is the first half , of the mould .


I opted using a piece of PVC pipe , to mock it up , and get the Weight of the Silicon I needed to mix .


A Floor tile was my base , with a sheet of wax paper over , this later I realised was not necessary to use .


I measured out the dummy , and the Knoppie that makes it fit together , You then vaseline the whole inside dummy , the inside of your box/ pipe ect , wipe of access .

[Lenny]

I lined up the dummy and Knoppie , and the pipe , on the tile with  a Koki . This is rather important , as once things are Oily from the grease up , its hard getting them to stay in place , as you can imagine . I now can give you guys the advice that , you should glue your dummy to the tile , then grease them up . 


I then filled the mould with dry sea sand [ to get the volume ]  This case it was 150ml of sand measured in a beaker .


NOW HERE THE TRICKY PART , the silicon and catalyse are fluid , but have to be mixed by WEIGHT , i cannot stress this enough .


My research i did , and after speaking to a very friendly lady at AMT , she suggested , that the volume in ML , you must add between 42 and 49 % by weight .


So without going into the math , you will need to to add on the 150ml sand another 45 % by weight to get the correct  weight mix ratio . if this is done wrong , your mould will not be a strong , and you might have areal problem with your silicon not curing .

[Lenny]

So I called it a night , and forgot to put in my pin , I have to drill into the top of the dummy , very carefully but managed it without cracking the dummy .


MIXING !!!!


Right so you now know , what amount of Silicon and Catalyst , and thinners you need to mix .


Use a big open container , instead on a deep thin one .


With a bigger shallow container , the bubbles will escape quicker , and mixing will be more effective and will prevent you from stirring too much bubbles / air into it . Air in your mould are your enemy .
I used a butter tub , in this case , you will need a larger tub and a larger scale if your making bigger moulds .
Use a flat bar with a flat bottom , 'devices' that have round bottoms are not good , you need to mix it properly , rather than mixing , like you would paint . Push it from side to side , scrapping along the bottom , to make sure you get the proper consistency .


NOTE .
Measure your Silicon out , somewhere along the line you will have to recalibrate your scale , I had too .
Pour the silicon in your tub  , the higher you pour and the slower you pour , the more air will escape , start to pour at the deepest / lowest point . now add your silicon Thinners , remember not more that 20 % that the Weight of the mould .
It take a bit of time , to get it mixed in properly , take your time .
So you have checked your box/pipe and dummy are in place . now measure out your Catalyst and mix it well into the Silicon /thinner mix .  to give you an indication of how long you will have to gently stir the mix , just about when you start to worry , and think ' what did I do wrong'  then the Catalyst , mixes in with the Silicon , make sure sure , you mice this properly and gently. 

[Lenny]

Cant manage to post the next couple of images . will try later .

[Grumpy]

Hi Lenny, I use a digital baking scale. Takes out all the tomfoolery and guesswork. Accurate to 1g. Bit pricey, about 500 rond. You can always buy as a gift for the wife and borrow when needed. .
That said, I made a spoon mold recently that is still curing after 10 days. Dunno what went wrong.will probably redo today.

[PH]

WRT working with silicone, also see
http://www.ultimateangling.co.za/index.php?topic=11236.0

NOTE: I've used Mold Max 30 moulds over and over for casting white metal/ tin spoons and did not have problems so far. Tin has about the same melting point as lead.

[Lenny]

Hi Lenny, I use a digital baking scale. Takes out all the tomfoolery and guesswork. Accurate to 1g. Bit pricey, about 500 rond. You can always buy as a gift for the wife and borrow when needed. .
That said, I made a spoon mold recently that is still curing after 10 days. Dunno what went wrong.will probably redo today.

Ja , funny enough , this coming week I need to make some more , will post again .

[LGF]

Made molds by the dozens for all kinds of small things using some RTV silicone that also had a percentage mixture requirement for weight of the silicone and I also found the digital scale to work the best, easiest and most accurate for the type of molds i made and what it is you're making now.
 
Just one question, why have you inserted such a large pin into the top of the clay mock-up? If it is to make space for the wire inserts that needs to be in the finished weight, then may I suggest to rather get the right sized wire that you intend making the weights with and bend it to size and shape and insert that into the clay prior to casting the silicone, as your current setup will have the wire imbedded in lead that will fill the cavity where the pin is right now? not too sure if that is what you had in mind with the pin, but if it is then opt for the wire insert into the clay.
 
Just another piece of advice, get some sort of jig, even if it is just nails nailed into a piece of wood, that would allow you to consistently have the wire inserts exactly the same, this will make casting the weights and the cleaning of the wire inserts much much easier and if done 100% could even remove the need to clean the wire from lead bleeds all together.
 
To align your molds: no need for this really, it s easier to get a piece of PVC pipe same dimentions, just twice as long, then once you've poured your first halve of the mold and it has cured, remove that from the short pvc pipe, insert your mock-ups into/onto the other parts that should still remain in the first halve of the mold and push that into the longer piece right to the bottom and lubricate as with the first halve, then pour second halve, that way the two halves of your mold can never be more accurate in lining up. OOOOOH EH EH had a relook at your last pic and you done just this, no worry then the molds will be 100% fine, so scuse moi, my bad didn't have a proper looki C at your pic the first time round, my bad!

[Lenny]

Thanks henk for adding some great tips .


I since , made some more , 16 and 20 ounce boat leads .
I managed to make them much better and neater .


Myself and David Taylor has some plans on making as spoon mould . Tin is just a problem . Or I suspect it will be a problem .

[LGF]

Thanks henk for adding some great tips .


I since , made some more , 16 and 20 ounce boat leads .
I managed to make them much better and neater .


Myself and David Taylor has some plans on making as spoon mould . Tin is just a problem . Or I suspect it will be a problem .

Why?
Tin and lead has virtually the same melting point and molten metal should not be all that much cumbersome to pour being lead or tin either or?
 
I started another project, yes yet another, apparently my spindle will only be shipped today, two weeks of back and forth between the origin country's customs and DHL, don't ask!!!! Nonetheless, this forced me to start another thingy as I cannot sit still. I started a foundry to melt aluminium and it seems GR8, not pretty but functional and should be very very efficient. Ran some drying burns last night and this morning, so hopefully before the new spindle gets here, i will be able to have a crucible made and perhaps have the first casts of aluminium blocks for re-machinng!!
 
Also having thoughts of pouring aluminium "rattle traps" (lipless crankbaits), IT NEVER STOPS !!!!

[LGF]

Thanks henk for adding some great tips .


I since , made some more , 16 and 20 ounce boat leads .
I managed to make them much better and neater .


Myself and David Taylor has some plans on making as spoon mould . Tin is just a problem . Or I suspect it will be a problem .

PS U'r welcome, isn't that what UA is all about.
 
Anyhow, I was told to rather use sand for making the molds for aluminium as it can be reused and apparently it will be easier to set up, I for one, try everything a couple of times before i decide it's working or not, therefor i am planning to pour some aluminium into old Silicone molds to see if it will handle the heat, if so, I need to make molds for the blocks i intend to pour for the lure molds that needs to be CNC'd