Making molds for pouring lead

Discussion in 'Home Built Fishing Lures' started by SurfGrub, Dec 28, 2010.

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  1. SurfGrub
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    So over the last couple of days I have been working on making my own molds. I started small with a 3oz jig.
    The first attempt was with Bondo (the mold on the right) the mold came out great, but the plug was destroyed removing it from the mold. The first pour was perfect besides the fact the holes had to be drilled out a little. The second pour the mold popped there was an air bubble just under the surface this pretty much ruined it.
    So I decided to go a different route and make a mold out of Durams water putty but used the jig from the first pour for a plug. After a day of drying I did some minor clean up and baked it at 400F for an hour. Then did a pour it came out okay, not nearly as clean as the first one, but I think that is just a copy of a copy thing after the second pour the mold developed a crack, I think this was from me tapping it against the table to get the jig out. So I patched the thing back together with more water putty.

    Here is a pic of everything the two powder coated ones are from the water putty the other is from the bondo. The bondo left a much smother finish but that did not seem to matter after powder coat.

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    Any suggestions on mold making material?

    The whole thing of bondo is $12 and the water putty $8 and there is enough to make 15 to 20 molds like this one. I was thinking of spraying the water putty mold with some 1200f header paint to smooth it out and maybe hold it together better.
  2. pukahd
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    Have you tried sand casting ? Dont know the whole process but blanks mounted on board are pushed into the sand and poured. Somewhat like how tadys are poured.
  3. dntbe2nd
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  4. SurfGrub
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    That would work, its right at the max temperature range. At $22 plus shipping for 2.2 pounds, just enough to do one or two small molds it just does not seem worth it. Considering I can buy a do it mold for $39
  5. el capo
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    Best method.
  6. SurfGrub
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    Don't know if I am ready for that yet I have to figure out what would be the best binder for the sand. I know a resin is the most common but not sure where to get it or what the cost would be.

    I think I will try sand wetted down with a wood glue/water mixture then baked to removed the water. There should only be enough glue to hold the sand and not to burn.

    Right now I am giving the bondo one more try this time with less harderner so it stays thinner longer maybe this will get the bubbles out.
  7. el capo
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    No need to add anything to the sand other than enough water to make it dry packed.
  8. DenisB
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    DIY "irons" ;
    #1 ( best quality & longest lasting molds ( permanent ).
    you can make molds out of zinc diecast ( if you have oxy equipment to melt the zinc).
    - requires master made from steel
    - drill & tap 2 holes in the flat back of the master & screw to a flat steel base.
    - 1" steel strip for the mold box to sit on the base.
    - preheat the master & base.............pour.
    - cut a sprue in one end of the mold to pour your lures thru.
    - clamp to another flat steel piece & go for it.

    Will handle lead, pewter, & even diecast as the lure material.
    NOTE: if intending to use diecast as the lure material it is critical to allow the mold to weather in the open till it gets a white oxide coating on the mold face, and then coat with a high temp grease/oil , wipe off & then carbon black, before each casting.
    .............attempting to cast diecast in a diecast mold before you have an oxide coating on the mold is a recipe for making a useless solid block of diecast , as the casting will weld to the mold & never come out.( the oxide coating & the carbon black act as a refrectory coating to limit the heat passing from the molten lure metal into the diecast mold body.

    lead & pewter can be cast direct into the mold body..........carbon black helps.

    for lure action lead is poorest, pewter better, tin better again........zinc the best.

    #2
    Silicon molds
    duramax 60 or Dow Corning 3120 ( needs to be a high temp silicon rubber )
    - lures over 4-6 oz have poor mold life as the heat transfer into the rubber mold is high & it slowly burns it with each casting.

    #3
    Plaster of Paris molds:-

    need to be allowed to dry for several days & then heated in an oven at 100-150C for an hour before use.

    - plaster of paris molds absorb moisture while not in use...............they need to be pre-heated in an oven to 100C for 3/4 hr before each casting session.
    - improperly prepared plaster of paris molds will spit & give poor surface to the casting ............due to the moisture content.
    - it helps to embed a piece of 1" weldmesh in the plaster at the back of the lure mold during casting of the mold to give it strength.

    Plaster of paris is cheap , has modest mold life & produces reasonable quality lures if prepared properly.

    #4
    when all else fails ...........buy a commercial aluminium lure mold...........but designs are limited.

    Not a fan of dry sand open cast molds or their derivatives unless you can get a surce of the proper fine sand & bentonite clay mix used by commercial foundries.
    Again moisture leads to poor lure surface .

    Bottom line is that you can only make your lures from molds you have the facilities on hand , to handle them with.
    Last edited: Dec 29, 2010
  9. Big Pancho
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    Surfgrub mold making can be frustrating at time but be real carefull when using anything water based around hot lead. I would hate for you to get burned. I have been burned and let me tell you it don't feel great. Per your picture it looks like you are trying to make a copy of a standard jig. Well you not going to get the same results or swimming action if you cast it out of lead. Totally different than the materials they use to make the jigs and most of us don't have the proper way of getting aluminum of zinc to melt with a standard oven of simple blow torch. These materials require some heavy duty heat. You can always check online for the melting points of these materials. Now if you are going to make the jigs out of plastic this is a totally different story. I would recomend the silcone material to make your molds. Yes it is expensive but you get what you pay for. Just my two cents. Be carefull and good luck with your projects.

    BP
    Last edited: Dec 29, 2010
  10. SurfGrub
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    The jig I am trying to make is much thicker and heavier and smaller than the standard jig, it is meant to be more of a bottom bouncer for rock fish not sure if it’s going to work . I have seen a couple of jigs like them for this and others that are just a piece of rod with a hook.

    I had some junk around the house a thought I would give it a try. I just don’t want to lose a $8-15 jig, rock fishing. I don't mild losing one that I have less a dollar into.

    My only concern now after looking at some of the other molds is I don’t have a steal insert and I am not sure if the lead is going to be strong enough if there is a big fish on the other side
  11. robmandel
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    I have been pouring the do-it flutter jig. I have the 2 and 3, 4, and 5 oz models.

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    each mold is $38 at barlows. The wire inserts are are about $3.50 for 25. add in split rings, etc. and (excluding the mild price per jig, as that just continually declines with use, and the mold lasts forever) and I think that you can pour them for well under $1 a piece.

    paint can be as complicated or as simple as you want. I had too much time on my hands and experimented and played around. but for rock fishing, a simple paint job will totally work. hell, spray them all white, and a highlight of orange or yellow will be perfect.

    I pour everything with the palmer hot pot. if you have any questions, let me know. for rock fish, I think getting something down there is a whole lot more important than anything. don't think rock fish are too picky.
  12. SurfGrub
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    I was thinking I may just do that. I just was looking at some of the other ones do it makes like the diamond, and casting spoon. They didn't have the flutter listed in the catalog but its on there web site. The wire forms are 1/4 of the price for the diamond and casting.