ARTICLE - D.I.Y Soft Plastics Part 1

[wazatherfisherman]

Having made my own plastics for many years, I thought I'd put a little info on in relation to some of the questions asked about making them at home.

Making them is actually fairly easy if you are happy with making basic one or two colour lures. When I say two colour, I mean colours pretty much in two halves- as in pour first colour and either let sit in the mould or pour first followed by immediate adding of second colour while first colour is setting. Intricate colour patterns are best left for commercial operations as they are done more-so by injection moulding and industrial moulds. 

MAKING MOULDS

To start off with, you need to make your actual moulds. I've made moulds from several different materials including timber and plaster of Paris, but by far the best results come from using 2 part Silicone Rubber. These Silicone types are best for several reasons.

1) They can replicate the smallest details accurately in the object being moulded- like scale pattern, fins, segments etc.

2) They are relatively inexpensive and reusable hundreds of times.

3) They need no "release agent" for getting either the moulded object nor poured lure out of the mould.

4) They can be tailor-made to the correct dimensions of what you need for your lures with minimum waste of Silicone and you can easily add to the bases of the mould to strengthen them for longevity of use

5) They are impervious to the high temperatures that the liquid plastic used generates and cool extremely quickly after plastic lure material is poured.

To make your mould/s you just need the following: i) for making individual lures- small containers that only need to be about 15mm wider and 20mm longer than the object you intend to mould, bearing in mind that you need enough depth of container to completely immerse your object- old lure boxes, pen boxes etc are ideal.

ii) If making moulds that have multiple lure cavities make sure there is about 10mm between each mould cavity, which both preserves mould strength and also slightly lessens cooling time of poured plastic lures- small tins and pretty much any firm plastic boxes that are "food grade" work well, but I've used cardboard lined with foil also- it doesn't really matter what the exterior of the mould looks like, as long as the base of mould is level and square (or your lures will turn out off centre)

iii) container to mix Silicone and Silicone Catalyst in + stirring stick- I use a stainless steel chopstick

Mix Silicone and catalyst thoroughly- the Silicone I use is light blue and it's catalyst is really dark blue and available from moulding and casting supply shops- (PM me if you want details)- so it's fairly easy to see when it is mixed well- only takes about a minute of stirring in-  pour into your mould box, then add the object you are moulding. If moulding a heavy object such as metal, it will of course sink to the bottom of the container- don't worry- you can thicken the bottom of the mould after it has set. Just make sure the object being moulded is pretty much sitting squarely in the mould. If it doesn't sit squarely, it will still be OK for pouring into, but if you want to use more than one colour, the colour-joins won't be parallel.

After pouring and immersing your object, it takes around 45-60 minutes for the Silicone to set and once set, it's easy to remove your object by using a razor blade/Stanley knife or similar and cutting a straight line from one end to the other along the top of the object- don't cut all the way to the end of your mould box-just the actual moulded object. The natural flexibility of the Silicone allows easy removal of your object. You now have your mould and need to cut a 5-6mm hole along this cut-line that will be used as the pouring hole when you heat up your plastic. I mucked around using the top of a wooden golf tee to create a nice sized pouring funnel on the top of the mould, but a simple hole works just as well.

After moulding heavier objects such as metal rods, you'll find they've sunk to the bottom of the newly formed cavity, leaving quite a thin layer on the bottom of the mould. Once the silicone has set and object removed, you can re-use the same mould box to reinforce the new mould's base by making up a little more Silicone and adding it to the box, then by using an ordinary sewing needle or similar pushed through each end, suspend your new mould a few mm above the bottom of the box. The added Silicone will simply adhere to the mould and strengthen it. NB it's really worthwhile doing it to strengthen ALL the moulds you make because the thicker walls mean they will last for literally hundreds of pours.

Whenever I make a new mould I always have a couple of the old moulds handy and add any excess Silicone to the bases of the old ones- just so I don't waste any excess Silicone. It's really easy to mix, goes off quickly and is really durable. It is also simple to clean up any spills- just wait until set and it peels off virtually anything.

OBJECTS TO MOULD

As far as fishing lures go, you can mould pretty much any shape of "lure" that you think a fish might have a go at.

"Worm" shapes are easy to find, you can use different diameter pieces of tubing- if you want them "ribbed" simply bind some thread, string or cord around the outside of your tubing prior to immersing in the Silicone. If you want "paddle-tail" worms, just melt and squash an end of the tube and cut with good quality scissors to desired shape. There are plenty of items in the "$2" shops you can find for making lure shapes out of- plenty of deeply corrugated or ribbed hose-like shapes.

Wooden spoons make great "Octopus" plastics- I make one that only has one thick leg, to give the leg "suckers" just glue some sequins or raised semi-circles like dome topped tacks onto the handle before moulding, the poured plastic will come out with suckers just like on a real octopus!

Pretty much any aerodynamic shape can turn into a "fish" shaped lure, plenty of different handles take on new possibilities. If you want to add strength to your actual lures, you can put things like a piece of wire through the mould- keeping in mind though that any stiffening of the body can result in poorer swimming action. Other interesting additives can be foil shapes (you can buy foil "honeycomb" at craft shops) beads, mirrors, rattles etc etc.

Toy hard plastic sea creatures such as crabs are also perfect for making your moulds, really, it's up to the imagination of the creator, but a trip to your local $2 shop won't ever be the same!

The one thing I've found that really isn't worthwhile making, is prawn imitations- there are plenty on the market and the intricacies of making a really good one (including feelers, legs etc) are quite time consuming. If you do want to try making them my suggestion would be to buy a commercially made mould ($30-100) but all other DYI moulds are definitely money saving.

There are plenty of ready made moulds on the market, some of them really intricate, some basic. If your main lure of choice is something like a paddle tail or curl tail grub it is relatively simple to either buy or make moulds and making your own lures is both cheap and rewarding.

Part 2 on what to do next to follow shortly.

 

[XD351]

Fantastic post mate  ! Looking forward to the next instalment 😀

I’m guessing that the material for the soft plastic itself is a thermoplastic and not a silicone ? 
This might give me a solution to something I want to try but can’t find the right colour combination in a SP. I want a white wiggler  tail with a mustard colour body to replicate a pipi for use off the beach , I was going to paint the jig head the mustard colour but if I can either either glue or melt two different plastic colours together I might try that as well .
 

[kingie chaser]

Got to love anything DIY 🙂

Some pictures of the moulds & finished plastics would be great to add to the post 

Edited May 13, 2021 by kingie chaser

[wazatherfisherman]

18 hours ago, XD351 said:

Fantastic post mate  ! Looking forward to the next instalment 😀

I’m guessing that the material for the soft plastic itself is a thermoplastic and not a silicone ? 
This might give me a solution to something I want to try but can’t find the right colour combination in a SP. I want a white wiggler  tail with a mustard colour body to replicate a pipi for use off the beach , I was going to paint the jig head the mustard colour but if I can either either glue or melt two different plastic colours together I might try that as well .
 

Hi XD351 sorry for late reply- yes the plastic is purpose made and not a silicone, the silicone rubber is used for the moulds. 

You could get the right colours to do that and it's a very interesting idea! They'll have the texture and softness of a pipi also

Regards Waza