Plastic Mold Construction Problem

[FishingFool]

I'm not an engineer, so hopefully someone can help me with my rather elementary problem. I manufacture soft plastic fishing lures at home in my spare time. I have a kit that I bought and have a couple molds. I'm not happy with the molds that I have or any that are being sold, so I decided to try to make my own.
The lures are between 7-12" long and 1-2" in diameter. What is the easiest way I can make a mold that I can pour the liquid soft plastic into? To be more specific: What should I make the mold out of? Where do I get the material? How do I make the mold? I have models of what I want made out of wax, but I'm totally clueless after that. Any help would be great. Thanks for your time!

 

[wljohnson]

Fishingfool:

I am a newbie to casting also so don't know a lot about the practical details. However, to get started take a look at a couple of websites that have useful information:

http://www.polytek.com,

http://www.wingnutinternational.com

,

http://www.perma-flex.com

,

http://www.artstuff.com.

They offer instructional videos, etc. Hope this is helpful.

You will need to think about color of material, density, fillers, final finish and attachment of hooks.

wlj

 

I am building a "Straight Pulll" Plastic Injection Mold Assembly; and, need to find out the correct mold shrink percentage that I have to factor in the core and cavity details.

The material is Zytel 72G33W NC010 33 % Glass-Reinforced NYLON Copolymer Resin.

This information would be greatly appreciated !

 

[Soupcat]

Michael,
Matweb is a very good resource for a query such as yours (

http://www.matweb.com)

: for example...your mat'l

Linear Mold Shrinkage, 0.003 in/in Flow Direction
Linear Mold Shrinkage, 0.01 in/in 3.2 mm; ASTM D955
Linear Mold Shrinkage, 0.01 in/in

Hope this helps

Kieran Fegan

http://www.moulddesigner.com

 

[tomwalz]

A.
1. Carve what you want
2. Coat is with vaseline or similar
3. Coat it with liquid rubber several times. You wantthe liquid rubber to dry in the right shape but not stick to the part.
4. Coat the mold
5. Pour in plastic
6. Let set
7. Flex the rubber and pop the part out

Hobby and craft stores often sell this.

It can be fun. You need several thin coats of rubber. I have never figured out how to clean the paint brush easily enough to make it worthwhile so I suggest cheap brushes.

Tom