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griffo

Help moulding a clear hollow plastic bait

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hello , could any one help me on a way that i can mould a clear hollow plastic bait of around 40 to 50mm long with belly counter weight & a few small beads as rattles inside , I have looked through the kb tutorials & a few posts in the hard baits forum as well could any one here help me on this matter plz

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Just wanted to say, GOOD LUCK! I've had a similar post on here for about three weeks. No information to be found. After countless hours searching the web and posting in foroms, I've all but given up on plastic crankbait molds. I'm almost certain now that plastic lures are injection moulded and pretty much beyond a small lure makers means. If you do find anything, please email or contact me. I would definetely appreciate any helpful knowledge on the subject.

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The only way that I can think of would be a complex muti piece mold and an injection moulding machine. both of these are pretty much out of the realm of the small backyard manufacturer.

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ROTATIONAL MOLDING

Larry Suba, Akro Plastics

LarryS@rotomold.net

Rotational molding is a highly versatile manufacturing option that allows for unlimited possibilities with the added benefit of low production costs.

PROCESS OVERVIEW

Do a search for Rotational molding. I know a little bit about this process, but dont know about what resins can be used and would it be tough enough for baits? This would make a one piece hollow plastic body, no rattles though. Here is what I found:

The rotational molding process starts with a good quality mold that is placed in a molding machine that has a loading, heating, and cooling area.

Several molds may be placed on the machine at the same time. Pre-measured plastic resin is loaded into each mold, and then the molds are moved into the oven where they are slowly rotated on both the vertical and horizontal axis. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during the cooling cycle so the parts retain an even wall thickness.

Once the parts are cooled, they are released from the mold. The rotational speed, heating and cooling times are all controlled throughout the process.

Tom

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If you really need the weights and rattles inside, the only way is to glue the two halves together, meaning that you have to make twoseparate molds for each half. It takes lot's of time and effort. And, I honestly believe, is not worth it. You can insert rattles in virtually any bait: wooden or resin - doesn't matter.

If you want the lure to be hollow for the sake of buyoncy - there are easier ways (place a wooden insert inside resin lure, or try foam)

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Thanks for your replies on this post i have been searching the web for ways that i can do this with-out having to resort to having them made by someone else in the lure making game or having to spend big $$$ on a injection machine as thier just to costly but thier just has to be a way we can all make our favourite plastic hollow lures at home with out the drama of big $$$ or having to wait on someone else to make them ??? I have a few ideas for plastic hard baits & have a ripper little floating 40mm long & 18mm wide lure that dives to a bit over 2.5 meters on a 8 to 10 pound leader & climbs out of the timber with its tail (back treble) in the air (water) when paused & rod tip is lowerd back to the water but thats only part of my quest i now want to make it with clear & with a rattle on board & dressed in some nice translucent colours to really stir them up . DENNIS FROM RUSSIA the two part process i can say does work but i have had three of the five smashed into pieces & 1 caved completely in leaving me with one with now lives in amounst my most memrable lures collection on a shelf & will never see water , & TOM S i am also going to look into that rotating moulding process a bit further too :) n thanks for all your posts

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There is a way to make both of your mold halves, by hand,

and then glue them together. And yes there is clear resin

you can pour in your mold.

The process is called "squish-molding".

Go here an check out this site.

http://www.alumilite.com/howto.cfm?ID=6

Also search the net for squish molding.

Coley

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the reason you fellas havnt recieved much feedback is because the process is like said, isnt readily available for a scratchbuilder.

One, the clear plastic, the only material Ive seen over the last few years is a 2 part resin offered by Smooth-on & its sold only to industrial manufacturers.

its very caustic & needs to be heat cured at @ 200+ degrees.

Rotational molding or rotocasting is easier in theory, but myself & Riverman fooled with this process a few years ago & found it very tricky & inconsistent.

Rotocasting is fine as long as you dont need to actually fish the bait. Each casting will cure differently & have an inconsistent wall thickness which is a nightmare for luremakers. I'll promise you, 2 identical baits from the same mold would run very differently.

The most efficient method would be to invest in a 4pc. injection mold & source your casting out to a third party.

If you were able to use opaque (white/amber,etc) then thats a different story, theres many suppliers for 2part urethanes in opaque colors that are suitable for scratchbuilders. The 4part mold is the toughest step.

Artbrush has described the 4part molding process in the archives here, but in essence its 2) 2part molds, 1) 2part mold for each lure body half.

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If you are interested in spin cast molds, try these folks: Tekcast

Their systems are a quick, reasonably "low" cost alternative for the do it yourself protoype lure designer.

Good luck

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