Wikipedia:Reference desk/Archives/Science/2015 May 8

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May 8

Glue

Can anybody recommend a glue that will bond plastic to metal. I'm currently building a model but it came through ebay and is missing the screws required. --Andrew 19:27, 8 May 2015 (UTC)

This resource [1] has recommendations for bonding many substances to other substances. In this case they recommend J-B Weld, or "LePage's Metal Epoxy" - additional info on these products, and reasons for recommendation are available at the site. SemanticMantis (talk) 19:34, 8 May 2015 (UTC)

Have you looked for the required screws ? I should think if you took it to a good hardware store they could try out various screws until they find a match. Note that screws generally have far more holding power than adhesives, unless a very large area of adhesive is applied. Some screws are also removable, in case you need to do maintenance on the item. StuRat (talk) 00:58, 9 May 2015 (UTC)

Some cyanoacrylates will work, if the parts mate smoothly. Don't use too much.    → Michael J Ⓣ Ⓒ Ⓜ 02:33, 9 May 2015 (UTC)

Use two component epoxy. Ensure the metal parts are not too smooth. Degrease before applying the epoxy. Degrease metal parts with brake cleaner. Do not touch surface to be glued after degreasing. Note, how to handle this products! False use is dangerours. Small amounts are expensive, applications for fiberglass may have better pices. --Hans Haase (有问题吗) 09:12, 10 May 2015 (UTC)

There are several problems with using glue where the model was designed to use screws:

1. The glue (especially the kinds that work with metals) takes up space. So you'll never be able to get the parts to fit together as accurately as they should.
2. Screws not only hold the thing together, they also force a very specific and precise alignment of the parts together that you may find difficult to get right with glue.
3. Screws can generally provide more strength than glue...not always...but in the case of plastic-to-metal, I'd be quite surprised to find a glue that was anywhere near as strong.

Inaccurate fitting may make it much harder (or perhaps even impossible) to put the rest of the kit together - so these are not minor issues.

Since you're likely to need to take a trip to the hardware store to get the rather specialised glue that you need - why not just buy screws instead - it's actually likely to be cheaper. SteveBaker (talk) 15:21, 10 May 2015 (UTC)

It totally depends on what the model is and exactly how the pieces fit, and I agree with steve above, but if screws are not an option, I've recently had fantastic results with 2 part epoxy glue on a car key. My car key is combination remote "fob" type thing which had just a tiny screw holding the actual key part into a tight fitting plastic housing. The plastic housing developed some cracks and eventually the screw gave way and little bits of plastic chipped out and the metal key part, with a surprisingly small tang fell out. I took the key fob apart and just glued the key in, I wasn't incredibly hopeful but the key is over $100 to replace so I thought I'd give it a shot, and it's turned out remarkably secure. Vespine (talk) 22:58, 10 May 2015 (UTC)