# How best to glue metal parts to miscellaneous plastics?
**URL:** https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888
**Category:** In My Humble Opinion
**Created:** [December 19, 2024, 10:07pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888 "2024-12-19T22:07:54Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Napier](https://boards.straightdope.com/u/Napier)
#### Post date: [December 19, 2024, 10:07pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/1 "2024-12-19T22:07:54Z")
I need to glue a couple hundred little aluminum tags to the plastic caps of vials of essential oils and aroma compounds. What method would work best?
The vials come from many different sources. The type of plastic obviously varies, and the sellers never specify the type. Based on industrial and laboratory vendors of empty vials, I can guess that many of them are phenolic or polypropylene. Perhaps melamine and polyethylene also turn up.
I’m thinking the right hot melt glue sticks could be good. The commonest hot melt glue chemistry is optimized for cellulose, for use with paper and cardboard, and I don’t think that’s best, but there are polyolefin and other types of glue stick that might work well. I’m trying to find these for sale.
I also think epoxy might be good.
I bought dozens of empty vials whose caps are specified to be phenolic, and also dozens that are polypropylene, so I can do some experiments.
What say the Dopers???
Thank you!
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### Author:  [@Tride](https://boards.straightdope.com/u/Tride)
#### Post date: [December 19, 2024, 10:23pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/2 "2024-12-19T22:23:23Z")
Double stick tape? 3M know what they are doing. Most glues including hot melt work poorly on plastic if it’s not roughed up.
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### Author:  [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)
#### Post date: [December 19, 2024, 10:32pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/3 "2024-12-19T22:32:32Z")
> [@Napier](#):
>
> I also think epoxy might be good.
Clear, slow-cure epoxy would probably work great. But I am guessing it’s also the most expensive option, and it’s sorta hard to work with.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [December 19, 2024, 10:56pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/4 "2024-12-19T22:56:59Z")
Any reason not use silicone? I don’t think it would be susceptible to the vial’s contents but it is more easily removable than epoxy. Hot glue will adhere very well to the vials i think if you use the hotter variety (maybe not so much with phenolics) but not as well with the aluminum. Are the tags already made? Could they have a hole in them for a more secure attachment?
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### Author:  [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)
#### Post date: [December 19, 2024, 11:01pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/5 "2024-12-19T23:01:41Z")
> [@Napier](#):
>
> I need to glue a couple hundred little aluminum tags to the plastic caps of vials of essential oils and aroma compounds. What method would work best?
Isn’t it more important to mark the actual vials? What happens when you uncap more than one at a time, and you need to get the caps back on the right vials?
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [December 19, 2024, 11:02pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/6 "2024-12-19T23:02:07Z")
> [@Tride](#):
>
> Double stick tape? 3M know what they are doing.
I agree. Something like this [3M™ Differential Double Coated Silicone Tape 9699](https://www.3m.com/3M/en_US/p/d/b40070438/) maybe.
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### Author:  [@Tride](https://boards.straightdope.com/u/Tride)
#### Post date: [December 19, 2024, 11:10pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/7 "2024-12-19T23:10:59Z")
Die cutting will be key–cut from one side, then peel ALL couple hundred from the back side. Adhere, then peel off the remaining side. Elsewhere lies madness. Not sure if I described that adequately.
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### Author:  [@Reply](https://boards.straightdope.com/u/Reply)
#### Post date: [December 19, 2024, 11:11pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/8 "2024-12-19T23:11:12Z")
I think basic clear gorilla glue should work too? Less messy than two part epoxies. [Clear Gorilla Glue | Gorilla Glue](https://gorillatough.com/product/clear-gorilla-glue/)
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### Author:  [@Tride](https://boards.straightdope.com/u/Tride)
#### Post date: [December 19, 2024, 11:12pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/9 "2024-12-19T23:12:07Z")
GG is great, but moisture cured so you might have to mist one surface, and it foams and makes a mess.
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### Author:  [@DaveUnknown](https://boards.straightdope.com/u/DaveUnknown)
#### Post date: [December 19, 2024, 11:19pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/10 "2024-12-19T23:19:18Z")
I have this stuff mentioned by Ben Krasnow of Applied Sciences (youtuber) called “Devcon Plastic Welder” that glues everything-- “hard plastic, styrene, acrylic… wood, metal” meant for “dissimilar materials.” It’s a 2-part mix like epoxy, maybe it is epoxy?
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### Author:  [@DaveUnknown](https://boards.straightdope.com/u/DaveUnknown)
#### Post date: [December 19, 2024, 11:23pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/11 "2024-12-19T23:23:06Z")
> [@Tride](#):
>
> 3M know what they are doing.
That 3M double sided tape with the red backing is incredibly strong!
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### Author:  [@wolfpup](https://boards.straightdope.com/u/wolfpup)
#### Post date: [December 19, 2024, 11:30pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/12 "2024-12-19T23:30:41Z")
> [@Crafter\_Man](#):
>
> > [@Napier](#):
> >
> > I also think epoxy might be good.
>
> Clear, slow-cure epoxy would probably work great. But I am guessing it’s also the most expensive option, and it’s sorta hard to work with.
You probably know better than I, but in my experience epoxy is a poor choice for most plastics, unless you’re thinking of a special kind. When I use epoxy, it’s usually the “5-minute” fast-cure type, and while it works great for many materials, it’s terrible for most plastics.
When working with a variety of different materials and gluing unlike materials together, contact cement is often a good choice.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [December 19, 2024, 11:31pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/13 "2024-12-19T23:31:19Z")
Plastic Welder doesn’t work on polyethylene/propylene. They make another product for that called [Poly-Weld](https://www.tapplastics.com/product/repair_products/adhesives_glues_sealants/tap_poly_weld_adhesive/435).
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### Author:  [@DaveUnknown](https://boards.straightdope.com/u/DaveUnknown)
#### Post date: [December 19, 2024, 11:39pm UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/14 "2024-12-19T23:39:37Z")
Ohhh… that’s a good one, but $40? I might try to mechanically fasten at that price.
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### Author:  [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)
#### Post date: [December 20, 2024, 12:05am UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/15 "2024-12-20T00:05:47Z")
I, also, recommend a 3M double-sided tape. They are very good at sticking things to other things. And the tape isn’t too terrible to work with.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 20, 2024, 12:08am UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/16 "2024-12-20T00:08:59Z")
Hot melt is the clear winner.
Sticks to almost anything, including “low surface energy” plastics, cheap, easy to apply.
Some of the other suggestions are stronger, but that’s not really a consideration in this application.
Regards,
Mr. Glue.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [December 20, 2024, 12:12am UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/17 "2024-12-20T00:12:56Z")
What’s wrong with cyanoacrylates for this application?
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 20, 2024, 12:34am UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/18 "2024-12-20T00:34:34Z")
They are brittle, for one.
Also, they don’t adhere well to many smooth plastics, especially Polyethylenes or Polypropylenes.
I don’t think this is a particularly demanding application, so almost anything will work to some extent, but hot melt is easy and probably the most reliable.
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### Author:  [@Reply](https://boards.straightdope.com/u/Reply)
#### Post date: [December 20, 2024, 1:47am UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/19 "2024-12-20T01:47:01Z")
> [@Tride](#):
>
> moisture cured so you might have to mist one surface, and it foams and makes a mess.
Yeah, true. I found this is a matter of dosage… one TINY drop of GG is all you need, _waaaaay_ less than you think, and it holds really well once it cures.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [December 20, 2024, 1:52am UTC](https://boards.straightdope.com/t/how-best-to-glue-metal-parts-to-miscellaneous-plastics/1011888/20 "2024-12-20T01:52:22Z")
Poly-Weld is not as good as claim. It requires treatment of polyethylene/propylene before gluing. The treatment is done with a propane torch. There are primers for applying cyanoacrylate glue to poly. First heard of this on the Dope years back.
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