Sticking PE to plastic... HELP!

[andonio64]

Hallo my friends, here is my main concern at the moment in modeling: glueing metal (brass?) of the details off the PE frets to the plastic, in particular very large pieces such as the side panels of a DVII or those of the Br XIV I currently have on my bench.

I always used CA but in case of large surfaces, it becomes a sort of solid thinlayer between the plastic and the metal and the brass comes off very easily if you apply a slightly bigger pressure.

Is this the only way to stick those pieces to our models?

Thanks for your help!

Antonio

[Bughunter]

There is a special kind of CA gel, which I use for such things, because it is a bit flexible at the end.
"100%  Sekundenkleber" in german, I don't know the name in other markets

http://www.pattex.de/do-it-yourself-mit-pattex-klebstoffe-produkte-new/pattex-klebstoffe/sekundenkleber/100_prozent_sekundenkleber.html

Another solution is epoxy 2 components glue, which is available in a clear 5min hardening edition.

Cheers,
Frank

[hiddeous1973]

perhaps your brass and/or your plastic is not competely clean?
Plastic and pe parts need to be clean for a solid bond.

I had some parts that would not bond in the past. if nothing else works, soak it in vinagar for a while. it seems to etch the surface slightly, giving the glue something to grip. Works also very good to have your paint adhere beter.

[rayb24]

perhaps your brass and/or your plastic is not competely clean?
Plastic and pe parts need to be clean for a solid bond.

I had some parts that would not bond in the past. if nothing else works, soak it in vinagar for a while. it seems to etch the surface slightly, giving the glue something to grip. Works also very good to have your paint adhere beter.

This is a good point, superglue is strong when pulled, but in a flat to flat bond it’s easily slid apart.  By etching, or sanding both surfaces you give the glue microscopic hills and valleys which creates a better engineering bond if you like. Worst surface for super glue is shiney plastic or metal since there isn’t much for it to soak into. That’s true in fact for any glued surface and glue, unless the glue etches or melts like mek does as an example, otherwise it has to key or soak into something. Of course your fingertips have lots of porous skin which superglue loves to soak into lol...
Hth’s Ray

[andonio64]

Thanks guys, I'll make a try with the vinegar!

@Frank : how long should I leave the PE parts into vinegar? Minutes, hours...

;-)

Antonio

[Bughunter]

It wasn't me, you should ask someone else
Frank

[andonio64]

It wasn't me, you should ask someone else
Frank

Sorry Frank, sure, the question was @hiddeous1973 !

[hiddeous1973]

I leave them in there for 10 minutes or so, but I have had parts in there for over an hour with no problems that I could see.
Vinagar is very mild so should not be a problem if you leave it soaking for a while. Watch out with copper, that is much softer, I don't know any rules for that. You can always try a run with the frame the parts are mounted to to see if there are problems.


I remember an other technique I use sometims, works also with large items. I have a fibre-glass scratch pen that is very usefull for both cleaning and preparing the surface for glue.
I do not use it now, need to get some more refills and be carefull, the fibre waste can be dangerous.

The vinegar method is helpfull for the very large pieces you sometimes get (that was the reason for this topic in the first place), for the smaller pieces I find it very usefull to simple coat them with a dull coat of clear, it also helps to give to ca glue something to hold on to. Don't use gloss, the idea is to create an uneven suface

[ondra]

When gluing large (relatively, due to my scale...) metal parts to a plasic surface, I often use either epoxy or more likely Future or Pledge, which is acrylic floor wax. It is less fragile than CA and offers very good bond on large areas.

Whenever I work with metal parts, I give them a coat of Mr. Metal Primer - should work in a similar way to the vinegar method - etches the metal surface to create a structure the glue can soak into.

Cheers

Ondra

[andonio64]

Hi guys thanks again for your suggestions.

Just to give it a try I left a piece of PE "sprue" in vinegar for half an hour but I did not notice any change in its surface, I guess the primer solution is so far the best.

I used to prime PE parts just after being glued to the model, so the contact surface was not primed, now I will spray primer on both the sides.

Thanks

Antonio

[macsporran]

I'm with Ondra on this. Unless you need real structural strength, as in aileron horns etc, I wouldn't use CA or epoxies.
Much easier to use either Future/Pledge or varnish. These give plenty of time before curing to allow fine positioning; minimal thickness and surprisingly strong.
Humbrol gloss varnish, either tin or bottle, Tamiya, Vallejo, plus many others all work well.
I would also always "glue" clear windows etc in place with Future.
FWIW
S

[andonio64]

Thank you macsporran, I agree with you, in case of the Br XIV the PE panels are pretty large, but I don't have Future or Pledge, here in Italy it's impossible to find them, I will try with the varnish.
Should I brush the varnish on both sides (plastic and metal) and join before the varnish dries?
Should I prefer matt varnish, right?

Antonio

[macsporran]

Ciao Antonio
I mention Future/Pledge but since the European formula changed a few years ago, I actually now use an acrylic floor polish from Lakeland Plastics here in the UK. I'm sure there will be equivalent products from local suppliers in Italia. Maybe worth looking at websites of some EU model clubs!
I've not used Humbrol matt varnish, just gloss. It takes a long time to dry so you must leave overnight, and I usually lightly sand the PE between two surfaces, on the fret, to give a key. Acrylic varnishes are much faster.
Pop in place, then gently flood corner with a loaded paintbrush and let capillary action do the rest.
Careful though if you are going to use a different medium for painting/top coating. Worth a trial run to prevent any chemical intolerances.
HTH
S