Plastic that refuses to bond

[Lightningboy2000]

Is it just me or does the plastic in Classic Airframes kits simply will not glue together?

I have been using super glue - Zap medium - Zap thin - contacta MEK etc etc. Even used zip kicker with the Zap and parts are still seperating with ease.

All the plastic had been washed before building.

Any two parts simply will not bond. I'm building up the locations for the undercarriage for one of their Westland Whirlwind fighters and need a strong location for the Undercarriage struts.

I'm almost starting to lose the will keep going with this kit.

 

I hope it's not just me and I've tried everything that most ordinary folks do.

 

Martin

 

[Radleigh]

My old Trumpy Mil-4 had the same issue on the beam, it kept cracking open. I tried so many glues I just gave up in the end and that's why I've never gone back to it.

[Lightningboy2000]

Oh, that's bad news. I hope it wasn't the same plastic as this one, as I'm building it for a customer so I have to see it through!

This plastic is quite hard and shiny compared to the soft stuff in most short run kits. I absolutely hate the stuff!

[Rob G]

Try a liquid cement meant for ABS plastic. Just don't breath too much of it in, or spill it on anything you value.

[Beardie]

That is an odd one. The last classic airframes kit I did was the Do.17z and I had no problems. All plastic to plastic bonds I did with poly cement and they were solid as a rock and all resin to plastic I did with CA and had no problems.

 

I see there is a glue on ebay called FutureGlue which claims to be able to work on dirty/oily surfaces which might be useful.

[Lightningboy2000]

2 minutes ago, Rob G said:

Try a liquid cement meant for ABS plastic. Just don't breath too much of it in, or spill it on anything you value.

I've got some EMA Plastic weld, is that similar to ABS?

[Lightningboy2000]

3 minutes ago, Beardie said:

That is an odd one. The last classic airframes kit I did was the Do.17z and I had no problems. All plastic to plastic bonds I did with poly cement and they were solid as a rock and all resin to plastic I did with CA and had no problems.

 

I see there is a glue on ebay called FutureGlue which claims to be able to work on dirty/oily surfaces which might be useful.

Maybe I shouldn't rely too much on super glue then. I'm only using it as in most cases I do need a pretty solid quick set in order to work with the plastic. There are no location guides with what I'm doing so parts need to go together pretty quickly or I will need an extra pair of fingers to hold parts together whilst they set.

 

When I was originally given these kits my customer did say that I could have done the Trumpeter kits. I've been working on three of these CA kits since May 2015!

[Beardie]

If it is plastic to plastic I would go with the liquid poly as it is more of a weld than a bond. CA has a poor sheer tolerance and so, if there is tension in the joint it runs the risk of splitting open. In addition, unless the joint is held perfectly still as the CA sets then you will be shearing the bonds as they form in the CA, something I learned the hard way. As long as it is used sparingly it won't take long to fix bits in place with some thin poly cement although obviously it won't have the almost instant 'tough enough to move on' capabilites of CA in the long run it will really stick those bits together better.

[Lightningboy2000]

17 minutes ago, Beardie said:

If it is plastic to plastic I would go with the liquid poly as it is more of a weld than a bond. CA has a poor sheer tolerance and so, if there is tension in the joint it runs the risk of splitting open. In addition, unless the joint is held perfectly still as the CA sets then you will be shearing the bonds as they form in the CA, something I learned the hard way. As long as it is used sparingly it won't take long to fix bits in place with some thin poly cement although obviously it won't have the almost instant 'tough enough to move on' capabilites of CA in the long run it will really stick those bits together better.

Cheers my friend, some more understanding of how CA works is appreciated thanks - well explained. I have been using CA for a long time now & know someone in our club who never uses it. I'll have to experiment in other ways me thinks. One glue I have never used is the Tamiya liquid poly that loads of people seem to use, will give that a go.

[Beardie]

Liquid poly is good stuff. I use the Humbrol Liquid poly myself, where pieces fit together well, a sparing brush of liquid poly is enough to melt the mating surfaces just enough allowing them to weld together. for less perfect fits or where I want a little more setting time I use Revell contacta in the precision bottle with the metal tube as it has a little transparent polystyrene in with the solvent  and so doesn't rely solely on the plastic of each mating surface dissolving and welding together.

[Rob G]

1 hour ago, Lightningboy2000 said:

I've got some EMA Plastic weld, is that similar to ABS?

 

According to the EMA website, it'll dissolve just about everything - PS, perspex, ABS. Worth a try on a bit of sprue, I'd say.

[Beardie]

Personally I wouldn't bother with the EMA plastic weld. I have some here I bought a while ago and I found that, while it did work, it wasn't as agressive on polystyrene as standard liquid poly requiring more to work and taking longer to do the job. Of course I might have a duff bottle.