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'Cement' is the correct term for adhesives used to bond polytyrene plastics, rather than a glue. Glues require the 'bonding' to be due to the action of the glue on two surfaces hardening, therefore holding the surfaces together, whereas a 'cement' relies on chemical reaction to slightly melt each edge of the part, and bond those parts more firmly, with the plastic being physically 'welded' together.
All 'glues' that we use for normal model construction are technically 'cements', with exceptions such as the various CA adhesives, epoxy etc.
 
To be honest the first base idea of gluing of two plastic edges ( surfaces ) is to melt both of them with a thinner and then mixing of the polystyrene molecules. The thinner evaporate quite quickly leaving the melted surfaces for self-hardening. The kind of a joint is homogenous and contains the plastic structure making the seam very strong. The cement adhesives work a little bit different. These melt the plastic edges ( surfaces ) slightly as you said but not for mixing of the plastic molecules but for better sticking to the edges by the cement. The process is called damping Then the gap between the two edges is filled with the thin layer of the cement that gets hardening finally. Initially, the kind of the weld is endured but it may get cracked in time and finally leads to the breaking of the joint up. I agree that most of adhesives used for the normal model construction are technically cements. But if you need the proper welding of the polystyrene parts the only adhesive is the glue mentioned firstly.
Also you mantioned the various CA adhesives, epoxy etc... these are also of the "cement" type but don't melt the plastic or other materials. Their grade of "sticking" to a surface is enough good there is no need to melt the edges. However these leave the thin layer of the adhesive between the two edges as well. In the case, the hardiness of the joint depends on the durability of the adhesives and the adherence to surfaces. Therefore I don't recommend the kind of adhesives for plastic models.
 
Hm. All of the model adhesives I've ever used have been labelled as 'cement' - the original 'Britfix', from Humbrol, now Humbrol cement, Revell cement and the various Tamiya cements etc.
They all work the same, smell the same, and have similar consistency, depending of course on the viscosity of the type.
I have come across some other, lesser-known brands, which have been labelled as glue for polystyrene plastic, but these have looked like, and smelled like rubber cement, or thick like balsa cement, like the type used for fixing inner tubes on bicycles, and were as useful (for modelling) as a chocolate tea pot !
 
I agree dear friend. Just there is the difference between the glue and the cement type. The difference is the way the two plastic edges are joined. The name "cement" was borrowed from the construction. If you have two bricks and want to stick them together you need to add some of muck or concrete, don't you? The water isn't enough to stick them together. One of "ingridients" of the mortar is the cement , gypsum etc.. for getting a better adherence. As a result you get the two bricks "welded" but there is a layer of the cement ( mortar ) between them. The true glue for plastic is a thinner ( usually that's the acetone ) that smells to many assemblers. Additionally the thinner evapurates very quickly and there a need to slow the process down appeared. Therefore the adhesives of the cement type were introduced. These don't stink as much as the thinner glue because of limited content of the acetone and contain a filler for slowing down of the evapurating process.. To sum up.. the glue for the polystyrene is the thinner but if there is a filler added to the thinner, the adhesive is named a cement.

BTW .. initially the filler was nothing more but clear polystyrene.
 
Interesting gents, agree with Wayne though and I'm not the adventurous type. There was also a bottle from Tamiya the said for "ABS Plastic" but that's a different material from kit styrene I believe
 
Yes, ABS is much harder, and requires a specialist type of adhesive, although CA seems to work OK. The 'Plastruct' range of tubes, angles, rods etc are ABS, and when I've used them, they've been joined with CA or two-part epoxy.
 
Won these in an auction this weekend, both for $35 but shipping will probably be around $10. Don't know how Kitty Hawk kits are but for the price I usually see asking for them they should be nice. I started to build the Testors (Hawk) Banshee years ago before I gave up in exasperation and I know it has to be better than that piece of sh__.

 

Didn't know that! Thanks.
 
Good stuff gents. These arrived while I was in camp. Far from the aforementioned July arrival, my newly started GB kite to be built as a captured aircraft...


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...and for no other reason than it was under $35CAN shipping included, to be built as a "Clear Wright Field" warning aircraft


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It is my understanding that this can be built as a D-40 which is needed. If not, I have the Hasegawa kit to fall back on
 
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