Ever wondered how they make Flavoured Plastic Baits?

Sure you have!

Anyone heard of sintered plastic?
Its not too dissimilar to powdered metal (iron filing for example) which is then compressed and compacted to a usable shape or form.

Sintering is the process of turning a solid substance into powder, thus sintered metal is moulded powdered metal, sintered plastic is moulded..., well you get the idea. Further processing using pressure+ heat can fuse the material together to form a complete solid or simply compacted to any degree of hardness with the aid of binders + latent heat. Think of powdered wood (saw dust or wood flour) plus wood glue that can be moulded, pressed and shaped. Just like sawdust and glue, many thermoplastic materials can also be sintered and compressed to produce virtually any shape without the need for expensive injection moulding machinery.

But here's the thing... Sintered plastic has useful properties for anglers as artificial baits because it remains porous and can be flavoured. As with other porous materials such as foams and sponges, porous plastics are composed of pores whose cavities are connected to one another and soak up liquids by capillary action.

I'm not really sure what the point of this post is but wasn't it interesting?

I used to work in plastics R&D for ICI and will never forget the week they trialled biodegradable plastic for tampon applicators in our moulding shop. It has to be one of the sickliest smells you can imagine, so I'd hate to think what the fish-oil flavoured baits smell like at 270 degrees centigrade (M.Pt. of nylon; less for polypropylene, about 240.) Phew!

Are they injection moulded? I'd assume so; in a multiple impression tool.

Very interesting Chris, thanks.

I take it the absorption depends on how the powder is graded, combined and what the original plastic is made of?

Is there any way to tell if one type would be more suitable than another for any particular application.

Does anyone know what happens to these plastic based baits should they become detached from the rig and taken by a fish, would they just pass through?

I'm not just thinking of carp here but fish like roach with plastic sweetcorn etc?

No not injection moulded, compression moulded rob.
The flavours are added afterwards (or should be)

Interesting job you had there tampons? erm no, I'm not to familiar with that process, I threw in the towel a while ago mate

laguna said:

I threw in the towel a while ago mate

Click to expand...

Boom Boom

Very bloody funny...

iannate said:

Very interesting Chris, thanks.

I take it the absorption depends on how the powder is graded, combined and what the original plastic is made of?

Is there any way to tell if one type would be more suitable than another for any particular application.

Click to expand...

Yes good point, a coarsely grained polymer will contain larger voids than a finely graded polymer when compacted, some can be processed with binders and heat others with binders only. The most common plastic used (and cheapest) are polyethylene (HDPE) and polypropylene (PP). polytetrafluoroethylene (PTFE) is also a commonly used sintered plastic as it cannot be thermoformed.
PTFE is used wherever a high degree of soft slip/slide is required example Pole Section Nose Cones and Elastic Bushes. PP and PE are often often used to make artificial nuts and pellet baits.

---------- Post added at 20:41 ---------- Previous post was at 20:35 ----------

binka said:

Does anyone know what happens to these plastic based baits should they become detached from the rig and taken by a fish, would they just pass through?

I'm not just thinking of carp here but fish like roach with plastic sweetcorn etc?

Click to expand...

It is hoped they pass through without harm if swallowed and not spit out, but can we be sure? and although plastics are largely inert (save for the plasticisers and binders used) who's to say if they don't cause obstruction?

Its a difficult one that Steve.

if i use a roach in the end of my rollup why doesn't my backie taste weird??
my thought for the day :wh:wh

laguna said:

No not injection moulded, compression moulded rob.
The flavours are added afterwards (or should be)

Interesting job you had there tampons? erm no, I'm not to familiar with that process, I threw in the towel a while ago mate

Click to expand...

As luck would have it, my research was with acrylics (rear light lenses and so on) and polyester (plastic bottles.) Unfortunately, we all shared the same moulding shop in the research area, so when horrid pongs were being created there was no escape. It had its perks; some of the test-pieces, like seed trays and partitioned boxes, would find their way home. There were always throwaways generated during experimental batch changes (continuous process) which were neither one nor t'other, so useless for experimental purposes. Didn't have much use for the car bumpers, though.

Thinking back, I did a bit of compression moulding of rubberised (impact-resistant) acrylics, so the process is familiar.

robtherake said:

As luck would have it, my research was with acrylics (rear light lenses and so on) and polyester (plastic bottles.) Unfortunately, we all shared the same moulding shop in the research area, so when horrid pongs were being created there was no escape. It had its perks; some of the test-pieces, like seed trays and partitioned boxes, would find their way home. There were always throwaways generated during experimental batch changes (continuous process) which were neither one nor t'other, so useless for experimental purposes. Didn't have much use for the car bumpers, though.

Thinking back, I did a bit of compression moulding of rubberised (impact-resistant) acrylics, so the process is familiar.

Click to expand...

I've always had an interest in making things and remember once setting up a meeting with the boffin's at ICI Huddersfield (probably 30 year ago now) and shown em my brick. That's with a B

It was a hand painted multi-coloured striped house brick coated in plastic, blue, green, yellow etc. that was weather proof. It had potential and upon closer examination showed to be micro-porous.
I was asked if it could only be sprayed, could it for example be dipped? to which I answered yes, it could be coated any way you want even on site out in the field and proceeded to tell them that the sample they saw before them had been hand painted with a brush the night before.

They seemed quite impressed but I could see doubt in their eyes.

They then went on to ask if this liquid plastic stuff could be applied as a protective coating to other things like wood and metal. Wood and paper yes, though I did express concern for shiny UN-etched metals as there would be no key on the substrate for it to adhere properly but suggested it might work if it was applied as an all-round wrap?

Towards the end of the meeting I produced a sheet of newspaper coated in plastic that was totally water-proof. It had a clear coating on it so the ink was perfectly legible. They asked if they could take a sample and soak it in water to see waht would happen? I said I don't know if anything would which seemed to please some of the sceptics but explained the sample before them had already been in the washing machine 3 times.

That meeting lasted about 2 hours and around 3 months later received an offer for £10k. Bloody cheapskates.

Anyway nothing really came of it, but I did coat my father in laws old shoes in plastic which he loved, happy days. mg:

laguna said:

Sure you have!

Anyone heard of sintered plastic?
Its not too dissimilar to powdered metal (iron filing for example) which is then compressed and compacted to a usable shape or form.

Sintering is the process of turning a solid substance into powder, thus sintered metal is moulded powdered metal, sintered plastic is moulded..., well you get the idea. Further processing using pressure+ heat can fuse the material together to form a complete solid or simply compacted to any degree of hardness with the aid of binders + latent heat. Think of powdered wood (saw dust or wood flour) plus wood glue that can be moulded, pressed and shaped. Just like sawdust and glue, many thermoplastic materials can also be sintered and compressed to produce virtually any shape without the need for expensive injection moulding machinery.

But here's the thing... Sintered plastic has useful properties for anglers as artificial baits because it remains porous and can be flavoured. As with other porous materials such as foams and sponges, porous plastics are composed of pores whose cavities are connected to one another and soak up liquids by capillary action.

I'm not really sure what the point of this post is but wasn't it interesting?

Click to expand...

Or they could simply add an artificial powdered aroma to the plastic granules, heat & masticate as usual and squirt it, liquid form, into the mold cavity as normal.