Author Topic: glue for PBT  (Read 11826 times)

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Offline Matt3o

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glue for PBT
« on: Mon, 21 April 2014, 02:54:46 »
I've always customized my ABS keycaps with epoxy glue and the result is amazing. You can break the keycaps before the glue bound in my tests.

Now I was going to do the same for PBT but I couldn't find a glue that actually sticks on PBT. Epoxy glue simply slips away, cyanoacrylate maybe a little better but still very very weak.

I made a quick search and found this interesting document (PDF) that suggests to use Loctite 401. I'm not a huge fan of Loctite I must say, does anyone have some experience with PBT adhesives? Any suggestions?

Offline hasu

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Re: glue for PBT
« Reply #1 on: Mon, 21 April 2014, 05:15:54 »
I used EP001 to repair broken stem of realforce keycaps and it's worked well for daily use. But it discolors uglily after months.
http://www.cemedine.co.jp/e/product/elasticity.html

Also I used it for this mod.
http://geekhack.org/index.php?topic=29483.0

Repaired keycaps.
« Last Edit: Mon, 21 April 2014, 05:27:45 by hasu »

Offline Matt3o

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Re: glue for PBT
« Reply #2 on: Mon, 21 April 2014, 05:20:38 »
thank you hasu, really appreciated your help. Unfortunately I don't seem to be able to source the Cemedine elastic adhesive over here.

Offline hasu

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Re: glue for PBT
« Reply #3 on: Mon, 21 April 2014, 05:56:53 »
Did you try baking soda with cyanoacrylate? It makes a joint stronger in fact.
http://en.wikipedia.org/wiki/Cyanoacrylate#Filler

EDIT: but it was not enough for my keycaps. Looks like it is too hard so that it is brittle in some cases.
« Last Edit: Mon, 21 April 2014, 06:02:36 by hasu »

Offline Matt3o

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Re: glue for PBT
« Reply #4 on: Mon, 21 April 2014, 05:59:21 »
Did you try baking soda with cyanoacrylate? It makes a joint stronger in fact.
http://en.wikipedia.org/wiki/Cyanoacrylate#Filler

interesting thanks. I'll give it a shot!

Offline mkawa

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Re: glue for PBT
« Reply #5 on: Mon, 21 April 2014, 08:26:07 »
acetone or methanol should work. acetone is easiest to find, natch. ketones pretty much destroy any non-fluorinated polymers though. apply a little to both sides with a brush then clamp together. the acetone liquifies (degrades, really) the polymers into monomers on contact, and then the monomers try to reform into polymers as the acetone vaporizes. it's a bit better than cyanoacrolate because it the ketone families tend to leave the monomers together so that you get polymer linkages between the two sides. this makes the bond stronger, as you get all the benefits of having plastic at the joint -- crosslinking, etc.

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Offline Matt3o

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Re: glue for PBT
« Reply #6 on: Mon, 21 April 2014, 08:31:04 »
wasn't PBT pretty resistant to acetone?

Offline mkawa

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Re: glue for PBT
« Reply #7 on: Mon, 21 April 2014, 08:51:07 »
PBT is relatively resistant to ketones, but ketones are pretty nasty suckers. you should still get the cementing behavior.

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Offline Matt3o

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Re: glue for PBT
« Reply #8 on: Mon, 21 April 2014, 09:03:59 »
PBT is relatively resistant to ketones, but ketones are pretty nasty suckers. you should still get the cementing behavior.

I'll give it a shot, thanks

Offline Findecanor

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Re: glue for PBT
« Reply #9 on: Mon, 21 April 2014, 10:18:10 »
Did you try baking soda with cyanoacrylate? It makes a joint stronger in fact.
Nah, it will only make the CA puff up and crystallize. There may still be tiny pockets of baking soda inside the joint, which will not hold at all. You could also end up with a lump that is bigger than you want and difficult to remove.

I know a lot of people swear by using E6000 for gluing plastics.

Offline mkawa

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Re: glue for PBT
« Reply #10 on: Mon, 21 April 2014, 10:24:51 »
looks like E6000's active ingredient is PCE, which is a compound chlorine molecule and hence a halogen. halogens are super super active and much more toxic than ketones. i would try a ketone on some scrap first and if it works, stick with that. in general, with adhesive, you want to stay as non-toxic as possible while still hitting your adhesion targets.

to all the brilliant friends who have left us, and all the students who climb on their shoulders.