Solvents Vs Cement for polystyrene components

Discussion in 'Glues' started by Jim Freight, Sep 11, 2020.

  1. Jim Freight

    Jim Freight Full Member

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    I posted this on a Facebook group as part of an answer to a another group member and thought it may be helpful to some members just getting stuck in :whatever: to modelling over here.

    The difference between solvents and cements.

    Solvents are generally in liquid form and run into joints via capillary action and often leave only slight surface marks which can be painted over. They fuse parts touching each other.

    Cements are thicker, contain some plastic material and can gap fill, surplus being quite obvious in typically the most noticeable and annoying places.

    I have found for some Walthers buildings I am assembling I run the solvent into the joins for initial assembly and after a few hours dab fillets of cement in the joints from behind to reinforce them. The solvent types do not seem to penetrate well enough and although the Walthers kits assemble well some parts are a little too tapered, curve edge or with stepped edges for a solvent only joint to be strong enough.

    Comments welcome. :)

    Jim
     
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  2. York Paul

    York Paul Staff Member Moderator

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    I often use that same approach when building stuff from Plasticard sheet, the solvent I use is Contacta Professional from Revell.
     
  3. Jim Freight

    Jim Freight Full Member

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    I must admit that although solvents are useful some wagons I put together 25 years ago with a mix of plastic card and kits with solvent only tend to come apart easily, rather fragile now. :(

    The Contacta Pro, I've seen fleeting images of it but not identified it, thanks
     
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  4. York Paul

    York Paul Staff Member Moderator

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    I have to admit much of my early stuff in 4mm from years ago suffered from separation issues using cement ... do try the Contacta Pro asi think you will find it works well, the spill only clogs up if the solvent is not allowed to drain back into the bottle. I always apply holding the bottle sideways on to avoid a big rush of solvent.
     
  5. Jim Freight

    Jim Freight Full Member

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    Thanks will do :cheers:
     
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  6. paul_l

    paul_l Staff Member Administrator

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    Hobby Craft stock several of the Revell Contacta glues.

    My preferred solvent of choice is MEK - I bought a life times supply from amazon - 1L for approx a tenner. I also use Acetone if ABS is involved.
    You can dissolve ABS in Acetone, or Plasticard in MEK to form a slurry or less solvent a putty, which can then be used to reinforce joints, and if made from the plastic sprue it will be the correct colour for the kit.

    Just don't tell elf n seftie :whatever:

    Paul
     
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  7. Jim Freight

    Jim Freight Full Member

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    Industrial adhesives are the best, but elf and co needs some respect, you need to know what you are doing, many do not, be safe :thumbup:
     
  8. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    I use Revell Contacta Professional and it has a fine needle like applicator. Very rarely do I get a flood of solvent...


    Cheers, Gary.
     
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  9. York Paul

    York Paul Staff Member Moderator

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    I have found on some dispensers the spill only tends to get blocked when the solvent level becomes quite low... maybe air within is the cause. :scratchchin:
     
  10. Jim Freight

    Jim Freight Full Member

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    Bought some, using it, impressed, need to keep a bit of wire to hand for the occasional clog, thanks for the suggestion, Jim :tophat:
     
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  11. Ruston 48ds

    Ruston 48ds Full Member

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    I have been reading through this topic as I'm planning to build my first Parkside BR 12T Van Plywood Sides kit. Contacta Pro seems to be the choice I will be purchasing to build this kit.
     
  12. gormo

    gormo Staff Member Administrator

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  13. Walkingthedog

    Walkingthedog Full Member

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    I just use MEK PAK or EMA Plastic Weld. They stick like glue :thumbup:
     
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  14. jakesdad13

    jakesdad13 Staff Member Moderator

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    I use MEK too, it works by melting the plastic and welds the parts together, a really strong bond. I buy mine off fleabay, much cheaper to buy in bulk. I bought a litre for about a fiver if I remember right, this was a few years ago and I've still got about half left.

    Pete.
     
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  15. Walkingthedog

    Walkingthedog Full Member

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    Didn’t realise you can get it by the litre, I shall have a look.
     
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  16. Peter Cross

    Peter Cross Full Member

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    Mek Pak and mek are different beasts. Mek PAC used to be based on mek ( mythel Ethel ketone). I use mek but it is nasty stuff, hence why it is no longer in mek pac.
     
  17. Walkingthedog

    Walkingthedog Full Member

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    Is that right, every day is a new day for me :thumbup:

    Thanks Peter.
     

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