Cement won't stick

Plastic cement will only join two pieces of styrene. I suspect that the small tube-like piece your were trying to cement is not styrene but some other kind of plastic, such as vinyl.

Jerry Gardner ranted on in the abyss about:

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Actually it's made of the same material as the rest. It's a tamiya model kit.

When you tried to join the parts, did you have a perfectly flat joint to get the maximum adhesion area or were the pieces snipped off the sprue with clippers or a knife leaving a tiny surface to surface joint? Tamiya and most other styrene cements are not in themselves gap filling. - you may have had a very tiny contact area that could not support the weight of the two pieces. Regards Alan T. Alan's Hobby, Model & RC Web Links

Were the pieces painted before you tried to stick them? If so did you scrape the paint off the joint areas? If the cement only left a residue and didn't cause the surface to soften and / or wrinkle, it doesn't sound as though the plastic surface was ever affected.

What cement did you use?

Are either of the two pieces chromed? If so, the cement won't affect the chrome; you have to scrape it away from where you're going to put the part.

The term you are looking for is 'polycap'. If it's a small, black, hollow cylinder, it's made of vinyl, and you won't stick it with ordinary styrene cement. There should be a pastic part to go over the top of it - that part gets stuck to the disc brake, trapping the polycap inside, so that you can add the wheels last, and they'll turn, if that turns you on. Don't forget to trim ALL the extraneous pips from the polycap, or you'll never get the damn thing to fit - Tamiya tolerances tend to be tight.

Are you sure? What colour is it?

RobG

Please give us some more details; what kit, which parts, what brand of glue? My guess at this point is the parts didn't fit together correctly or you didn't wash the mold release off. hth

The Keeper (of too much crap!)

I suspect that you said it was a Tamiya kit and I also suspect that it is a F1 kit if so they cast all their suspension parts in ABS plastic which is more durable then regular styrene. Which does not bond well with styrene. That is why most of those parts are meant to snap together with no glue. It almost has the same properties as vinyl. The small polycaps are made out of vinyl and will not adhere to styrene with regular styrene cement.

Rob Grinberg ranted on in the abyss about:

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yes you are correct. it is polycap. thanks for the reminder. hehehe... would it be ok if I didn't glue it together at all? I mean it could cause the wheels to be fused instead and not be able to turn.

Rob Grinberg ranted on in the abyss about:

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It's strange it didn't mention it's vinyl. It's colored black just like the rest of the parts. I'm using the Tamiya Cement.

I didn't do any filing it as the contact surface & the polycaps is "almost" perfectly smooth. The polycap wasn't attached to a sprue so there shouldn't be any imperfections on it. AFAIK.

My kit is the Tamiya Mazda RX-7.

Or get Plastruct cement which will bond ABS-to-ABS or Polystyrene-to-ABS.

Bill Banaszak, MFE

Polycaps aren't vinyl or styrene, or ABS (Acrilonitrile-Buradiene-Styrene)- they're polyethylene (or polythene on the far side of the pond), hence the name. I don't know any solvent (that you'd want anywhere near any body parts you value) that will touch it.

Poly-caps are extensively used by Japanese kit mfgrs. to non-permanantly attach parts together. They aren't meant to be glued. Usually poly-caps just get loosly trapped between two styrene parts which get glued. Then you press fit the part which poly-cap is designed to hold. On model cars, that is usually the wheels - on model airplanes, it usually is the propellers.

This way, the parts are attached, then can turn and removed if needed. Peteski

Oh, BTW: if you carefully look in the kit's instructions, you'll notice that they instructs you not to use any glue on the poly-caps. :-)

Just follow the instructions...

Peteski

Look at the instructions. Even if you can't read the language, the "no glue" pictograms ought to be clear enough.

Polycaps are used to provide a snug friction fit between two parts that can't/shouldn't be glued. They're usually used in mecha (battle robot) models for poseable arms & legs -- the polycaps allow you to move the parts, and will hold the parts in the new position. Sometimes they're used in car models to hold the wheels on metal axles.

Back when I first found this group there was a big thread about poly-caps. The advice was that poly-caps didn't want a cracker.

Bill Banaszak, MFE ;)

Chad ranted on in the abyss about:

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Guys, thanks for the info. I think I have the answers I need. Sorry, but I never came across the "no glue" part of the polycap. I'll look over them again. Christmas vacation is over so I'd hardly have time to notice that part of the instruction. The place where I work on my model is dark at night, which is the time I get home. I only have time to work on them during the weekends.

I also am stuck with the problem that I can't seem to find a small air compressor to fit my Badger Airbruh's hose. :( I'm almost at the body.

Many thanks.

Keeper ranted on in the abyss about:

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sorry for the long reply.

i bought my badger airbrush & hose from dixieart.com so I'd presume it's of US standard size.

Chad ranted on in the abyss about:

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found the "don't glue" part of this instruction. It was kind of cryptic. It just showed an arrow with "no glue" marked on it. However, it didn't point to which part not to glue.