Octopus head pattern

[gstours]

More cool stuff for sharing.   Here's the 3D printer wire bending jig gift from Dave.  He designed it from his computer and the printer made it.   Waay nice job.

[gstours]

The wire bends around the sst dowels and so they will fit in the silicone mold in place and not shift when the molten lead is poured.  Below is the mold again and a complete wire eye ready to go.

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Just he wire bent on the cad jig.

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More jig piks

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The back side. View.

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Another of Dave's octopus jig molds maybe the pattern in the powder coating spray booth.
   I want to thank Dave for his time again .   He is very knowledgeable about fishing, and is always trying new techniques,  an over the top nice guy......

[Meanwhile]

Very cool on the making of that pattern.  Hmmmm, my nephews just bought a printer.

So you can pour lead in to the silicone mold?  How many copies can you make?

The halibut will not know what hit them.

Randy

Warren, OR

[jurelometer]

Very cool on the making of that pattern.  Hmmmm, my nephews just bought a printer.

So you can pour lead in to the silicone mold?  How many copies can you make?

The halibut will not know what hit them.

Randy

Warren, OR

No exact answer.  The highest temp rating for RTV silicone that I have found is 560F.   Pure lead is supposed to be poured around 700.   On a smaller part, the lead will cool into the rated range quickly.  The larger and thicker the part, the sketchier things get. There are some lead alloys that have a lower pouring temp.


Regarding 3D printers - as mentioned earlier in this thread, it is not like Star Trek ("Replicator, make me a ham sandwich").   Somebody has to define  an exact  3D specification of the part, and then generate a set of instructions for to printer to follow. It is a lot more work  to design a part than to print one.

But the hardest part of all is knowing what to make. A  lure that  purposefully designed and constructed to have specific characteristics  is the key, whether 3D printed or carved by hand.   I  am looking forward to seeing what Gary comes up. He knows his stuff when it comes to his fishery.

-J

[Steve-O]

So you can pour lead in to the silicone mold?  How many copies can you make?



Randy

Warren, OR

Jcool3 in the Silicone Molds thread said this about his mold:

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.

[gstours]

As Dave and others have been down this road before,  the silicone mold gives the smoothest lead surface and can show the most detail of the molds so far for lead pouring,  the limits have been reached by the larger 12-16 ounce and waay heavier lead pouring as the molds hold the heat and seem to degrade the silicone mold rather quickly.
  My pattern of the octopus 🐙 is rather simple lacks much detail and may work in plaster o Paris for the 20-24 oz ones planned.   I'm glad to hear from all of you,  keep me advised as I can take criticism.🤷‍♂️
  Here's a good pattern for the silicone mold.  Not a copy or clone.

[gstours]

Thanks for sharing your hint Steve-o and Dave about forgetting the clay and submerging the pattern half way in the mold,  harden. Then add mold release agent,  and pour second half.   Thanks 🙏
   I,m wondering if I would have ever figured that out.🤦‍♀️

[gstours]

Thanks for the info about forgetting the clay in my plaster mold making.
  Below is the first one made pouring the first half, and placing in the master.

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This is labor saving, and gives a much smoother inside surface.
    Below is a 20 ounce earlier mold with the clay residue.

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The eye hole area needs to be conical  or shallower for easier removal it seems.

[jurelometer]

Good progress Gary!

1.   Shrinkage can cause the mold to pinch the master, or the part to pinch the mol.   An elastic mold (like silicone) gives you more flexibility, but a solid mold requires that the part has no undercuts, indents, or straight walls.  That is why injection molded parts have tapered sides. 

It is usually the walls that  we forget about (eye sockets typically have walls).   The taller the wall, the greater the taper, but a 5 degree taper will get you out of trouble for almost anything.   Also need to have smooth surfaces.  Crevices and pits create micro undercuts.

2.  I couldn't tell from your photo, but we talked about placing some marbles halfway in the first half of the mold at the same time as placing the master.   After the first half dries, leave the master in, but pull out the marbles.   the second half will fill in the marble indents, making alignment locators.    Haven't tried this myself, but it sounds like a nice trick.

3.  I like to make a wire bending jig  (can be a board and a couple nails) first, and bend up  some wires.  Once I can easily repeat my wiring, I build my master around one of the bent up wire rigs.   This ensures that my bent wiring will fit cleanly in the mold, and makes the lure making process more painless. 

4.   You can also make the flue and any vents out of whatever is handy, and connect to the master.  Better than grinding out after the cast.


5.   The orientation of the part in the mold and the location and depth of the flue makes a big difference in how well the pour goes. 

• thinner sections will cool faster
• the part will draw more lead from the sprue as it cools, so we can use this to help avoid dents or voids. Deeper sprues provide more force (gravity)   to help fill the mold.  Wider sprues provide more material, and help act as a vent
• air needs a route to get out of the mold so that the lead can move in.  In some simple shapes, a big enough sprue can act as a vent while the mold is being filled, but sometimes it is necessary to add some vents for any trapped air to escape as well
• long narrow jigs fill best for me from the narrow end of the jig, with the jig oriented vertically in the mold.   Octopus heads fill best as shown in the silicone mold photo earlier in this thread, including a vent for the nose
• How quickly the part cools can affect pour quality, especially voids and surface finish.   There are specific temperatures where pure lead and various lead alloys flow best.  Some alloys will separate if heated to high or too long.  Preheating the mold if possible can help too. 
  

-J