So what is your recipe for sprue goo? I want to make some and need a good starting point.
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Hmmm. I’m not sure I have a recipe but I’ll share about my bottle. I took a bottle of Tamiya extra thin that was about half full and I started putting cut down pieces of sprue in it, enough volume to bring it near the top. Closed it and let it sit. After some time stirred it with a wooden stick. It eventually became one mass.
Now, periodically I will add more extra thin (well, I use Tamiya airbrush cleaner) when it thickens more than I like or when it becomes stringy.
But now that you ask, I am curious if there is a recipe.
Another thing I’ve been curious about is if there would be value in making sprue goo with a different color. I have some black styrene and thought it might be easier to see and then work with if it were different in color than the plastic I use it on.
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My method was the same as Phil’s. Seems to work fine ….
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I make it on demand. I shave off pieces of sprue from the figure I’m working on and spread the pieces out - some long, some just litle flakes like pepper.
I flood (usually) the shoulder joint in the figure I’m converting, with Tamiya liquid cement. Then I pick up pieces that I need with the tip (just the tip) of the Tamiya applicator and place them where I need them. Usually longer bits gp in the joint first. I repeat the process adding cement and thinner, and packing it in with the flat of an X-Acto blade. No waste, and makes a good solid joint.
Anyone recognize Mr. Selfie?
Edit: Once again the camera helps. Did this one late last night. I forgot to do his left shjoulder completely, and still need to remove a mold seam.
You can see the process better in this photo - the guy on the left has had the goo added. Now all I need to do is file off the excess. There were some huge joints to fill because of the different arms.
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One word: Acetone.
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I was curious about the type of sprue also. Tamiya tan sprue is known as good styrene to work with. Others are harder or more brittle. Does it have an effect on the sprue goo or does the solvent even the playing field.
I also like the make it on demand solution using sprue from the kit itself.
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Is Ethyl Acetate (from the discussion a few weeks ago) the chemical of choice for making this stuff?
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Toluene/Toluol (harmful)
Xylene/Xylol (harmful)
Ethyl acetate (less harmful)
Acetone (I haven’t tested, yet…) (less harmful)
MEK (harmful)
any “cocktails” (different brand names) based on the above will all melt styrene.
Test with bits of sprue to check if it works or not.
My eyes were opened when I had bought a bottle of lacquer thinner, it smelled strong
so I checked with some sprues. No god for painting but good for “glueing” styrene.
It thinned the paint alright but the thinned paint would have destroyed the plastic …
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According to the computer program I asked, Ethyl Acetate is the solvent of choice for temporarily restoring the boundary lair of a brittle model plastic. (Full reconstitution is not possible for a bunch of reasons.) That made me wonder if Ethyl Acetate would also be the solvent of choice for making a styrene putty.
Edit: I just put the question to the computer and it said MEK will produce a better putty than Ethyl Acetate.
Note to self: Spell chemical name correctly.
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MEK (Methyl Ethyl Ketone) is the original Styrene Glue… Yes it will make styrene putty but it is also a very heavy and volatile (flamable/explosive) chemical when it’s vapors are allowed to accumulate…
This is why it’s no longer openly available in retail stores…. Acetone is chemically pure and is a lot less volatile and will not get you high like MEK will… (not as dangerous)
I used to exclusively use MEK for gluing styrene, when they took it off the retail market I discovered Acetone & Ethyl Acetate and never looked back…
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Acetone is sort of volatile too, not as bad as MEK but still …
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Many years ago I worked for Hallite, a seals and gasket company. They had a huge tank on the premises which received regular deliveries of 40,000 litres of MEK. It was used to make the spread fabrics that formed the basis of the fluid seals. If you walked through the spread fabric shop you virtually floated out of the far end!
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Sounds like a violation of occupational safety standards …
A classmates dad worked at a company building GRP-boats.
He was laminating hulls and got a lot of polyester resin on his hands.
Don’t know if he was wearing gloves but that sticky resin gets everywhere.
When the health and safety inspector visited he washed his hands with acetone.
The inspector nearly had a heart attack …
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There is a very nasty woman behind me in the lab who was hostile to me on Day One, who uses acetone for some damn thing. That smell…
Thankfully, I am now helping out in a different department.
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Yes it is.. but compared to MEK? MEK will get you feeling woozy in minutes without a respirator…
I’ve accidently left a 25ml bottle of Acetone open on my workbench until it completely evaporated, never smelled a thing… (1 qt can bought from Home Depot for a couple of bucks)
Ethyl Acetate you can smell a little bit, but it evaporates faster… (fruity smell, it will also get you high if you breath too much of it. it gives the Quick to Tamiya Quick Set, evaporates very fast with no residue)
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Wow - that’s nearly a month’s-worth of modelling for me! 
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When you run out is it a bad week to give up sniffing glue?
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OK, now hear this!
For glueing styrene I tried acetone and MEK - and straight out of the bottle they evaporate just too fast, you just don’t have the time to apply to both surfaces and then join (that’s the way I do it). You can join and seep the stuff in between (I don’t like to do that).
Some years ago I came across a bottle of buthyl acetate - that thing works really great! I use it for glueing - gives you a lot of time to position parts and so on. Works great as a sprue goo base. PLUS it can be used as hard driving decal softener - so it’s very handy around the shop.
You might argue, that for sprue goo you would like to use something quicker drying - maybe ethyl acetate - but I didn’t try that. I can guarantee the suitability of buthyl acetate.
Hope it helps, good luck with your projects and have a nice day
Paweł
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I think Tamiya extra thin is ethyl acetate and acetone?
Buthyl acetate … interesting.
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Ethyl Acetate is produced by the esterification of ethanol with acetic acid.
Butyl Acetate is produced by the esterification of n-butanol and acetic acid.
In industry they are both used for the same purposes, glue is one of them.. Of the two, Butyl Acetate is the more toxic of the two…
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