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Other Stuff => Workbench => Topic started by: JollyBob on 28 October 2022, 11:37:13 AM

Title: Plastic "soup"?
Post by: JollyBob on 28 October 2022, 11:37:13 AM
I recently rediscovered a very old (1976, so slightly younger than me... :'( ) copy of Airfix Magazine guide no.19, in a charming 1970s orange hardcover...

Aside from the (to modern eyes) bizarre inclusion of black and white illustrations in the painting guide sections, it also mentions a home made product they call Plastic "soup".

Basically, you take half a screwtop jar of Windsor & Newton paint remover, and stir in chunks of old sprue until it all dissolves into a gloop the "consistency of thin honey".

Apparently if kept airtight it will never dry out, and it can be used with an old paintbrush or cocktail stick to build up the surface of your model, a potentially toxic liquid greenstuff if you will.

According to the authors, if built up in layers it can be used to sculpt beards, build up thin pieces, mend breaks and can be applied over paper patterns to extend uniform skirts etc...

My question is, has anyone ever tried it, and why isn't it more widely known? Did it fall out of favour because (I imagine) it stinks? Were new shop bought products better or more convenient?

I think we've all jammed a sliver of sprue into a poorly fitting shoulder joint and smoothed it in with liquid poly at some point, but is this a lost method that could do with reviving in these days of recycling and re-use?

Or am I just the last to know about something as always?  lol
Title: Re: Plastic "soup"?
Post by: Major_Gilbear on 28 October 2022, 12:38:19 PM
Ah yes, this is a very old trick.  :)

Few things to note:

1) The paint thinners are (were) frequently based on dichloromethane, which is extremely nasty stuff. Most paint strippers have been reformulated in Europe to remove this chemical from them, as it's really not something you should mess with outside a fume cupboard.

2) The "new" incarnation of this technique/product is often referred to as "sprue goo", wherein you take a very thin polystyrene cement (often Tamiya) and add sliced up scrap sprue to the bottle, allowing it to dissolve into and thicken up the cement.

3) You can make this stuff as thick or thin as you wish. Do keep in mind that it's often quite stringy though, and can be messy to apply.

4) You could just buy a squeezy-tube of cheap polystyrene cement from Revell or Humbrol, and it's pretty similar without the faff and mess.
Title: Re: Plastic "soup"?
Post by: Hammers on 28 October 2022, 01:24:37 PM
I have been know to use it as filler. It tends to stiff harder and more brittle than injection molded plastic from which it stems. My experience is also that the goop will vary in quality depending of the formula of the plastic used.
Title: Re: Plastic "soup"?
Post by: Daeothar on 28 October 2022, 01:45:36 PM
Yup; sprue-goo.

I did a batch a couple of years ago (using Tamiya Ultra Thin Cement) , and it's still prefectly viable. Although in practice, I only used it for lazy gap-filling, where getting out the Green Stuff or ProCreate is too much effort (yes; I'm lazy :D ) and ever since I got myself a fresh batch of GS, I've not even touched that bottle anymore.

Turns out the strip I was using was almost 15 years old, and it hardens over that time, even when kept cool and light- and airtight. Quite the happy (re)revelation that Green Stuff can be so soft and pliable. But I digress...

I think those modelers of old only resorted to stuff like Sprue-Goo because there was nothing else available. Had they had the option of using ProCreate, Kneadadite (Green Stuff) or Milliput, I'm sure they would have!
Title: Re: Plastic "soup"?
Post by: robh on 28 October 2022, 02:38:59 PM

I think those modelers of old only resorted to stuff like Sprue-Goo because there was nothing else available. Had they had the option of using ProCreate, Kneadadite (Green Stuff) or Milliput, I'm sure they would have!

We had (have?) Plasticine.  Works well enough and this wonderous new "superglue" stuff hardens it even better than the Banana Oil used to.  Original yellow/grey Milliput was around in the 1970s

I still find liquid plastic (melted sprue) much easier to work with than putties. It is perfect for gap filling and hardening paper/foil cloaks and banners. The only thing you cannot do with it is wet sculpt textures as it inevitably smooths out as it dries. You have to let it dry fully then go back and carve texture.
Title: Re: Plastic "soup"?
Post by: eilif on 28 October 2022, 03:09:11 PM
I've thought many times about trying Sprue Goo. Did it back in the day briefly with plastruct (which I think is mostly MEK) and I might have used it a few times, but generally I just used thick superglue for this kind of thing. 

Seen the Sprue Goo discussion pop up a few more times this month on various forums.  I've got an empty glass bottle, old sprues and a whole can of MEK (which I use to refill my plastruct bottles) so I should probably give it a shot just to see what happens.
Title: Re: Plastic "soup"?
Post by: carlos marighela on 28 October 2022, 09:17:45 PM
Tamiya actually make tubes of plastic putty, which is a toothpaste consistency and very useful for gap filling and detail adding. Fairly inexpensive too.  No need to faff about with toxic chemicals when someone else has done it for you.

File along with ‘Banana Oil’. Although in that case there was some speculation that the term was a fairly unsubtle euphemism.  ;)

Title: Re: Plastic "soup"?
Post by: has.been on 28 October 2022, 09:53:57 PM
My first wargaming buddy (Stephen O'Leary, aka 'Oscar') explained how
to make the plastic gloop when we were both 11 years old. As it involved
using Carbon Tetra-Chloride (A VERY hazardous chemical) I never risked it.

I did set lots of tissue or plasticine cloaks (& other things) with Banana Oil.
In fact only this week I took a conversion (dating from the 60s) apart. The
cloaks were still solid!
Title: Re: Plastic "soup"?
Post by: Hummster on 28 October 2022, 10:19:32 PM
I remember making that back in the early 1980s. Like you say ridiculously dangerous but useful for some things.
Title: Re: Plastic "soup"?
Post by: syrinx0 on 29 October 2022, 01:24:51 AM
Tamiya plastic putty tubes fill that need for me as well.
Title: Re: Plastic "soup"?
Post by: carlos marighela on 29 October 2022, 02:18:14 AM
My first wargaming buddy (Stephen O'Leary, aka 'Oscar') explained how
to make the plastic gloop when we were both 11 years old. As it involved
using Carbon Tetra-Chloride (A VERY hazardous chemical) I never risked it.

I did set lots of tissue or plasticine cloaks (& other things) with Banana Oil.
In fact only this week I took a conversion (dating from the 60s) apart. The
cloaks were still solid!

I think it was the combination of 'banana oil' and tissues that gave rise to the speculation. ;)
Title: Re: Plastic "soup"?
Post by: Calimero on 29 October 2022, 05:55:48 PM

This guy on Youtube have a few videos on "plastic goo"

https://www.youtube.com/c/MiniatureHobbyist/videos
Title: Re: Plastic "soup"?
Post by: Mindenbrush on 30 October 2022, 07:42:47 PM
I had used plenty back in the 70’s when making dioramas for BMSS meetings and competitions as there was nothing else - Squadron putty was too aggressive on the edges of the joint.

I recently made some using Tamiya Extra Thin Liquid cement and chopped up pieces of sprue. It worked okay but I found it easier to use some modern filler and then overcoat it with the sprue “soup” to seal it after it had dried.
Title: Re: Plastic "soup"?
Post by: Cacique Caribe on 31 October 2022, 12:04:32 AM
JollyBob

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https://www.youtube.com/playlist?list=PLOI4U71MJ81f1iAtoUzY0FT5Q8aWUYKgR

Enjoy

Dan
Title: Re: Plastic "soup"?
Post by: Daeothar on 31 October 2022, 12:59:04 PM
Wasn't there this guy on Youtube who built an entire Tau Manta Dropship out of sprue and sprue-goo?

+++EDIT+++ Found him  :D  https://www.youtube.com/watch?v=0DTKaKlIIgI (https://www.youtube.com/watch?v=0DTKaKlIIgI)

+++RE-EDIT+++ Looks like this is the same guy that Jollybob linked to already...
Title: Re: Plastic "soup"?
Post by: Calimero on 01 November 2022, 12:46:26 AM
Wasn't there this guy on Youtube who built an entire Tau Manta Dropship out of sprue and sprue-goo?

+++EDIT+++ Found him  :D  https://www.youtube.com/watch?v=0DTKaKlIIgI (https://www.youtube.com/watch?v=0DTKaKlIIgI)

+++RE-EDIT+++ Looks like this is the same guy that Jollybob linked to already...

... and the one I talked about before that.  lol
Title: Re: Plastic "soup"?
Post by: Daeothar on 01 November 2022, 09:39:20 AM
Oops: totally missed your mention there!  lol

This guy does get some exposure apparently...  :D
Title: Re: Plastic "soup"?
Post by: eilif on 04 November 2022, 02:26:30 PM
The amount of fumes that guy must have breathed to build (and then build-with) slabs of melted HIPS is terrifying. 

Admittedly Acetone isn't as bad as MEK, but that's still alot of chemicals evaporating into the air in close proximity to his face and he makes no mention of masks.
Title: Re: Plastic "soup"?
Post by: zemjw on 04 November 2022, 03:26:27 PM
The amount of fumes that guy must have breathed to build (and then build-with) slabs of melted HIPS is terrifying. 

Admittedly Acetone isn't as bad as MEK, but that's still alot of chemicals evaporating into the air in close proximity to his face and he makes no mention of masks.

Yup, that was the first thing I thought of when I saw that picture. Reminded me of old Open University lectures from the 80s where they're handling chemicals with no protective gear whatsoever :o

I did make some goo at one point. However, I didn't use it, and ended up thowing out the solid lump it turned into after a few years.
Title: Re: Plastic "soup"?
Post by: Cat on 04 November 2022, 03:43:39 PM
I used some back in the 90s when I was doing a huge project with tons of 6mm buildings made with Evergreen styrene plastic sheets and strips.  Tossed any small remainder ends into half a bottle of Testor's liquid styrene cement.  Worked great as a gap filler and an absolute match for the material.
 
It eventually dried up much later.  Would do it again if I ever worked on a comparable big project.
Title: Re: Plastic "soup"?
Post by: eilif on 04 November 2022, 10:52:29 PM
Had anyone commented on the fact that you probably have to keep adding solvent to these mixes periodically.  The very volatility that makes MEK, acetone and similar chemicals so effective at making goo means that they are going to evaporate over time.
Title: Re: Plastic "soup"?
Post by: Daeothar on 07 November 2022, 09:21:59 AM
...The very volatility that makes MEK, acetone and similar chemicals so effective at making goo means that they are going to evaporate over time.

With all the risks of eventual dain bramage...