Revel Contacta Liquid Special

[Lone Modeller]

Evening All,

Can anyone offer some advice/answers please?

I think that many of you will be aware that I am a scratch builder and that I use quite a lot of liquid polystyrene cement. I have recently been trying to use Revell Contacta Liquid Special from a glass bottle with what can only be described as disappointing results. It is true that I had had the bottle in storage for a time, (cannot remember for how long), but some of the solvents had evaporated away and the liquid was more like a gell than a fluid. When I tried to use it the results were dire - it does not bond the styrene properly even after 24 hours in a clamp. It is impossible to use to glue together a joint where there might be small gaps as there would be more gell on the surface of the model than in the joint.

I have reverted to Humbrol Liquid Poly, which I have been using since I restarted modelling about 11 years ago and which I find has all of the qualities that I desire from a liquid cement. Humbrol Liquid Poly also loses some of its volume through evaporation, but it does not reduce to a gell.

I am NOT knocking one company's product or trying to make invidious comparisons - I use Revell Contacta professional in the small plastic pots with the long tube and am very happy with it - I am just reflecting my experience and disappointment with the Revell bottled product and would like to know if anyone else has had a similar experience. Equally can anyone offer a plausible reason for the way in which the Revell product has reacted.

Thanks in advance for any replies.

[general rocket]

I haven't used contact for years, I found that it would solidify in the applicator tube. This was generally easy to clear by playing a cigarette lighter lightly underneath.
My experience, others feel free to disagree.

[Impisi]

My idea about this:
I don't know how a Revell Contacta is really put together. Basically, an adhesive usually consists of a resin and a thinner. With contact adhesives, the thinner evaporates and the resin creates the bond. That's why you have to press such bonds until the glue dries.

White glue is such an adhesive, but many of the old plastic adhesives from Revell, Humbrol, Uhu, Patex, etc. were also structured this way. Until it was discovered that plastic could be "glued" much better using only thinners, for example Tamiya extra thin. The thinners “melt” the plastic and then evaporate, causing it to harden at the bonding point, creating a bond.

So I could imagine that your Revell Contacta has simply lost most of its thinner. There are cleaning agents such as ethyl acetate that can act as thinners for adhesives. But you can also “glue” plastic together with ethyl acetate alone. It is super quick, but it stinks and is not that healthy.

I don't think it will be worth reactivating an old adhesive with a thinner.

But then, I might totaly wrong

[wokka]

LM, I would just bin and get some fresh, I quite like it as an in-between glue between a super thin glue like Tamiya's and the standard tubed glue such as Humbrol. i do have the problem with the Contacta drying in the end tube but a few seconds with a lighted match soon clears it away. Anyway, your builds are always impressive no matter what issues you have.

[Stuart]

As others have suggested, I agree that it might be an age thing - I'd get yourself some more.

[Lone Modeller]

Thanks all for the replies. I too find that sometimes the glue sets in the end tube on the plastic dispenser but I clear mine with a piece of thin copper wire.

I agree that the probable cause was evaporation of the thinners but I just wanted to be sure. I have binned the old bottle and am back to using Humbrol instead.

Thanks Wokka for the very kind comment on my models.

[Miko]

I was unaware of this product in glass, I assume it's a capillary action solvent type that 'welds' the styrene parts together? So if it's gel like it would seem to be a shelf life thing or a re capping error allowing for it's solvent to evaporate

I have tried Humbrol Liquid Poly previously but I used it more like a tube cement where it needs to be used more like modern capillary cements from MrHobby and Tamiya where I have had some success but my 'go to' is Revell Contacta Pro with it's hypodermic needle like appilicator which clogs with frustrating regularity! A wire brush bristle being the tool to clear the blockage!

Miko (in a sticky situation!)