jarndice wrote:43rdRecceReg wrote: " I've a lot to learn about plastics, it seems. I thought that ABS and Styrene were pretty much the same, and that model Tank bodies were- like car bumpers and trim, Lego bits, computer keys etc- made of Styrene/ABS. Not so apparently. They're made out of ABS; a type of styrene, but with extras (Acrylonitrile and Butadiene.) making it a much harder thermoplastic than (Poly)Styrene." .
I first discovered that Heng Long and Taigen had changed from "Plastic" to "ABS" when the "ZAP7" debonder that neutralised the glue holding them together no longer did so and I had to start trialling other debonders.
Shaun.
Quite a few tank projects have clanked under the bridge since this discussion. Newly inducted into the Tamiya world of extravagant spending, I discovered= but old hands already know
-
that they actually
mark their sprues 'PE' for styrene parts, and 'ABS" for a few tougher bits (turret ring for example).
That way you know immediately, without hours rummaging online, which adhesive to use for which part: Tamiya Cement or equivalent (I use Revell contact Pro) for Polystyrene parts - and as much as 90% of the typical kit is PE. Then
I use Tamiya ABS cement or Plastic Weld for the few toughened components included. Plastic Weld is powerful enough to melt your nostrils (then the brain..), and so a suitable respirator is required.
Broadly then, there's no need for Epoxies or Superglues; just a few dabs of threadlock (milder superglue) here and there.
The picture with Taigen and Heng long offerings is quite different. I might be wrong, but there's no indication
anywhere on a typical model, nor in the gobbledegook accompanying user guide
of what type of plastic is used, and whereabouts. So, it's always a bit hit and miss finding which bonding agent works best. I even looked at the possibility of plastic tack welding with a soldering iron..
It could work,,but not on 1/16 models, I think.
Scratch building is where glue knowhow (and not from teenage sniffing experience
) comes in handy. Bonding resin to ABS or PE can be a nightmare, I tried all sorts of superglues (Loctite onwards) and found that 'Super Glue Plastic Fusion" worked best for me, after parts had been seriously abraded beforehand. Adding dowels and pins to the mix could only strengthen the bond!
I found this test quite interesting when it came to torsional stress resistance. If you can get over the presenter's strangulated cartoon voice (American dad..maybe?(, the test is quite exhaustive.
Or exhausting, if the voice grates on you
I don't know whether he's in the pay of any of the manufacturers here, but the test seems to be unbiased.
"Get your facts first, and then you can distort them as much as you please"- Mark Twain.
I've a lot to learn about plastics, it seems. I thought that ABS and Styrene were pretty much the same, and that model Tank bodies were- like car bumpers and trim, Lego bits, computer keys etc- made of Styrene/ABS. Not so apparently. They're made out of ABS; a type of styrene, but with extras (Acrylonitrile and Butadiene.) making it a much harder thermoplastic than (Poly)Styrene. I found that Tamiya actually make
