Have you changed your plastic?

[Captain Blood]

I’ve been building my Rubicon CMP truck, using the Revell Contacta liquid poly cement I’ve used for many hundreds of hard plastic figures and several plastic kits, including from Rubicon.

But to my slight consternation, the glue is behaving differently on this kit. Usually, as intended, the effect of the liquid poly cement is to rapidly dissolve the two surfaces to be bonded, and then fuse them together to create a new bond.

On this kit however, the cement is failing to dissolve the plastic. It’s just sitting on the surface of the plastic. It’s like the plastic is harder, shinier, somehow impervious to the intentionally corrosive properties of the glue. Half a dozen times, components which I thought were firmly stuck, have just come apart under the slightest pressure - revealing that the liquid poly cement has not behaved in its customary way. It’s just dried as a film on the surface of the plastic...

I haven’t experienced this with any other plastic kits, which leads me to question if something has changed in the composition of the material the kit is being produced in.

It’s pretty annoying 

[Rubicon Models]

We have been using the same material - ABS plastic - for all our kits.  We can only suggest you switch to ABS liquid cement instead.  Many cement manufacturers have them.  We used Plastic Magic from Deluxe Materials from the UK (www.deluxematerials.co.uk).  We know this is annoying to a few customers, but ABS plastic gives better strength and sharpness to our models.

[ripley]

Have you washed the plastic in liquid dish soap before assembly and paint ? Might be release agent on plastic . The amount seems to vary on each production run

[ultravanillasmurf]

I have had occasional issues with some kits not being impressed by my usual Humbrol liquid poly. I have not tried the Tamiya liquid poly (recommended by Pinky) on those kits but it has worked on subsequent kits (such as the M4A3E8).

I have not tried cleaning the sprues, though I have found sanding the surfaces works.

[elias.tibbs]

Revell quality is hit and miss. Sometimes it works on ABS and sometimes it doesn’t.

Plastic magic works wonders.

[Tracks]

I have a pretty good collection of plastic glues and cements, but I have a couple of favorite cements. The "Tamiya Extra Thing Cement" and "Tamiya Cement" work great on Rubicon plastic kits. The extra thin stuff works wonders, but you have to use it differently than how most people use glues. It is best if you fit the small parts together first than carefully apply the tamiya extra thin cement. For bigger surfaces and larger parts, it is recommend to use "Tamiya Cement" over the "Tamiya Extra Thin Cement".

Another one of my favorite cements is called "Tenax-7R" and this also works great on Rubicon plastic kits.

[Captain Blood]

Thanks for all the suggestions.
My point though, was that on the previous 4 or 5 Rubicon kits I have made, the Revell Contacta liquid poly cement has worked absolutely fine. This time, for some unaccountable reason, it’s failing to dissolve the plastic surface. Hence ‘have you changed your plastic?’ - because the only other explanation I suppose is that the glue has somehow gone off... which I guess is possible, but seems somewhat unlikely... ah well, it’s a mystery... 

[elias.tibbs]

If you go back to your old kits and give the bits a wiggle, pretty sure most bits will fall off.

I had the same issue.

[Pinky]

I warned everyone about this ages ago.  I rebuilt my first Panzer IV after I realised that the Revell cement wasn't really holding it together.  Nor will non-Rubicon bits adhere to their plastic if you use Tamiya liquid cement.  I use superglue for any bonding of Rubicon and non-Rubicon components.

[ultravanillasmurf]

I managed to glue a Warlord Sherman V telephone box on the back of the M4A3E8 with a new bottle of Tamiya thin liquid poly.

However a second generation all plastic Chaos Womble was not impressed with the Tamiya glue.

[Pinky]

Tamiya apparently changed the formula of their liquid cement, as one of the components was illegal in some jurisdictions (so I'm told).   The new one has a lighter green lid.  I haven't tried the new one, but I was wondering if it acted differently.  I still have 2 bottles of the old one left, which I'm using on my GW models. 

[ultravanillasmurf]

Ah, the one skulking in the background here:


I do have a bottle of Plastic Weld (bought to assemble Starship Troopers figures) that I have never dared open, too much scary warnings.

[Tracks]

Before I start gluing bits together, I tend to test the plastic of the model kit with different cements/glues. I apply some cement/glue to a bit of the scrap sprue from the kit in question to see how it reacts. Using a toothpick or something, I check to see how fast it melts, reacts, and/or softens the plastic. Sometimes I even test glue two pieces of plastic sprue together, and when fully set, I test how good the bond is between the two pieces.

This is why I do not use Revell plastic cement on Rubicon kits. It just didn't seem to work as well as you would expect. Even though Testors liquid cement works better, I also tried other cements/glues. For me, what I found that works best are:
Tenax-7R
Plastruct Plastic Weld
Tamiya Extra Thin Cement
Tamiya Cement
The Mr. Hobby liquid cements
and a few others, but one of my favorite plastic cements has to be the Tenax-7R. This stuff is great and I have been using it for a very long time. However, with a fast melting time, very quick evaporating time, and because the plastic can stay soft for a long time, it can be tricky to work, so I only recommend Tenax-7R to experienced modellers. Great stuff that Tenax-7R.

For most modellers, I would recommending the Tamiya cements (extra thin and normal) because they are easier to get, and this stuff also works well on Rubicon kits. For the last couple of Rubicon plastic kits I assembled, I only used the Tamiya cements on them, and I have no complaints on how well it bonds the plastic.

Now someone had mentioned that the Tamiya extra thin cement has a new formula. I cannot confirm or deny this, but I can say that I have the older and newer bottles. The the labels on the new and old look a little different, and the lid of new bottles seem a little lighter, but does that mean its a new formula? No where on the bottle does if give an indication of a new formula. If it is a new formula, it still works on Rubicon plastic kits. I think I will test the new bottle and old bottle on some plastic sprue and see if there is a big difference.

One note though. I have not assembled one of the newest plastic kits from Rubicon. All the kits I have assembled to date have been the dark green plastic. I only just received some of the kits that come in the medium gray plastic. But from what Rubicon says, I'm confident that there will be no issues, but I do plan to test first.

[Pinky]

That "someone" was me...

Apparently the original extra thin cement was banned here in Hong Kong, as it's toxic.  The new formula is described as "quick setting", but is supposedly safer.  I haven't tried it, but it smells a bit different.

[Captain Blood]

Lordy Lordy... again, thanks for the advice on other glues. But my point seems to be getting lost somewhere along the line. Revell Contacta worked fine on the first several Rubicon kits I made. Behaved as it was supposed to. But is not behaving the same on the CMP truck kit. Meaning either the plastic has changed, or something has changed in the glue (or I’m going potty!)