Looking for ways of joining metal and plastic

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SUMMARY

This discussion focuses on methods for permanently joining plastic parts to metal components, specifically addressing a plastic handle and a metal body. Key techniques mentioned include heat stacking, mechanical fasteners, and thermoplastic welding. Participants emphasize the limitations of using old plastic handles due to brittleness and recommend alternatives such as threaded rods and Methyl Methacrylate adhesives for industrial applications. The consensus is that mechanical fasteners provide a more reliable solution than attempting to repair existing plastic components.

PREREQUISITES
  • Understanding of heat stacking techniques
  • Familiarity with mechanical fasteners and their applications
  • Knowledge of thermoplastic welding methods
  • Basic principles of adhesive bonding, particularly with Methyl Methacrylate adhesives
NEXT STEPS
  • Research Methyl Methacrylate adhesives for bonding plastic and metal
  • Explore advanced mechanical fastening techniques for hybrid assemblies
  • Investigate the properties and applications of synthetic resins in bonding
  • Learn about the heat stacking process and its industrial applications
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Engineers, product designers, DIY enthusiasts, and anyone involved in the fabrication of hybrid assemblies using plastic and metal components.

Chandrasekar
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TL;DR
How to join a plastic part with a metal part?
i have a plastic handle and want to join it with a metal body. i can join it with heat stacking method i have find a product who done done that.
is there any other way to join permenently?

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I have usually seen either weld-nuts on the metal part with machine screws going thru and holding the handle, or making the plastic part slightly deformable with 'hooks' or 'latches' that fit in cutouts in the metal.

There are also instances of having sheet metal barbs that insert into the plastic. Depending on the ultimate use, the barb may be either molded into the plastic of merely inserted into a preformed slot in the plastic.

For do-it-yourself, I have not been able to to get a reliable connection by thermoplastic welding the plastic onto the metal.

Please let us know what you come up with.

Cheers,
Tom
 
Chandrasekar said:
i have a plastic handle and want to join it with a metal body.
What sort of metal is it, stainless steel or maybe aluminium ?
 
Chandrasekar said:
i have a plastic handle and want to join it with a metal body.
Are we talking about that mug (?) on the picture?

Based on the picture there should be some metal pieces in the handle and originally it was a metal-metal connection, maybe done with spot welding.

I don't think this can be repaired easily (and, what's more omportant: it won't be any sturdier than before).
What I would do ... well, honestly, I would just buy a clay mug, but to use that one on the picture I see two ways:
- to make two rings of metal strap attached to the old handle and make the mug sit in the rings
- make a complete new handle&rings entirely from some steel wire

Something like these, but more 'engineer way':
shopping
 
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Rive said:
I don't think this can be repaired easily (and, what's more important: it won't be any sturdier than before).
Very true.
Do not waste time reattaching an old plastic handle to a metal container.
Plastic becomes brittle with time, it then fails at a progressively lower stress.
Replace the handle with new, or with an improved material.
 
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sorry guys, i think i have not given proper question.
it is just a example to understand what i want. what i really want is a way to join a plastic part with a metal part (a hybrid assembly - i think).

Thank you for your concerns.
 
Last edited:
Chandrasekar said:
TL;DR Summary: How to join a plastic part with a metal part?

i have a plastic handle and want to join it with a metal body. i can join it with heat stacking method i have find a product who done done that.
is there any other way to join permanently?

View attachment 323028
this picture is given as an example explain to what i really want.

'I just want a any other method to join a plastic part with a metal part.'
i got two way to join
1. Heat Stacking
2. fasteners
is there any other way?
 
Tom.G said:
For do-it-yourself, I have not been able to to get a reliable connection by thermoplastic welding the plastic onto the metal.
Thermoplastic welding and heat stacking are same?
 
Spot weld a short, flat headed countersunk screw to the metal.
Mould or drill a hole in the plastic to slide over the screw.
Place some glue in the hole, then press them together.
 
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  • #10
Chandrasekar said:
is there any other way?
Are you looking for something what can be industrialized (like that handle from the picture), or just DIY level will do?

For the letter, as I recall there are some glues which can bond on plastic and metal too. But I would keep those only for places without much stress of any kind.
Synthetic resins (even with some fibers added) may be also do the trick (not just used like a glue but as means of extra mechanical support).
 
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  • #11
Rive said:
Are you looking for something what can be industrialized (like that handle from the picture), or just DIY level will do?
for industrialized level
 
  • #12
Chandrasekar said:
for industrialized level
Yeah, go with a mechanical fastener. Personally, I'd say threaded rod welded to the body, and nuts to hold the handle on.
 
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  • #13
I just did a post on bonding metals with epoxy. Search "Methyl Methacrylate adhesives" There are formulas that are mix compatible with metals and plastic. And their bond is outstanding.
 
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