Gluing metal to metal

Mar 13, 2022 Last reply: 4 years ago 12 Replies

Not something I would normally rely on.



But for reasons related to difficult access, and extreme difficulty in dismantling parts to the stage where I could weld, or drill and tap for proper fastners, I need to attach a mild steel "bracket" to one side of a zinc-plated inverted U-channel about 2 cm wide and deep. The potential contact area is about 20 x 2 cm and the loads are quite low and mainly in shear. It's not safety critical. I do have access to degrease and sand or wire brush the plated channel (and the bracket).



I'm thinking that something like No More Nails might be the best bet. In many geometries like plug and socket I'd be confident with epoxy, but here if it delaminates at one end, the failure could propagate.



It may be possible to "wrap" the new part around the outside of the channel, which would obviously provide more contact area and give epoxy a better chance.



What does the panel think?



ps it's a drawer runner on an Ikea cabinet, where I have reduced the depth of the drawer, but that means I've lost the "hook" that the back of the drawer engages to stop it tipping forward when opened.


epoxy is your best bet, and use a heat gun or hairdryer to get a good 'set', or possibly car body filler, depending on what you have

The zinc plating may cause a problem.

As you probably know, painting zinc is a pain.

As I understand it, in simple terms, zinc plating has an almost oil like property when it comes to bounding to it. With paint, you clean it and use and etching primer.

If you could remove the zinc plating so you are bounding steel to steel, a good epoxy should be ok.

I assume pop rivets aren?t a possibility?

I'd be surprised if epoxy did not bond OK after abrading and degreasing. The zinc itself is pretty well bonded to the steel.

No, because of lack of clearance the other side. If I fully dismantled it there is enough metal thickness to drill and tap for a flush bolt, but that is a lot of work (and I suspect the assembly is, like the drawer itself, partly held together by crimping). Welding might be simpler in that case though.

Probably won't heat because I don't want any risk of surplus epoxy dripping into the ball tracks below. I hadn't thought of CBF but I suppose it does bond pretty well to clean metal. I'd just wondered about Sticks Like Sh*t because it seems very adherent and also tough when you try to remove surplus.

The problem is bonding to the zinc by the epoxy. When you paint zinc, you degrease and use a special primer.

You see a similar problem with epoxy and aluminium. It adheres to the surface oxide but can come adrift.

The difference is, with zinc, may not adhere at all. I doubt it would pull the zinc off.

My experience with a close relative of sticks like s*it was that it stuck like diarrhoea.

Oddly enough I redid that join with car body filler.

CBF is good because its catalysed so even a poorly mixed batch will still set, its relatively cheaper than epoxy and its good for taking screws etc. I use it to repair all old kitchen cabinets with pulled out hinges etc. Or as a wall filler when attempts to drill it remove a plaster crater etc. Its more expensive than plaster fullers or plastic wood, but it serves to emulate both when you need strength

I even used it to patch a washing machine whose weights had broken off the polythene drum . It worked even on polythene, to a point good enough to stay there till the motor blew.

Degreasing is all you need, but roughing up is even better.

I agree, CBF is very useful, indeed I have already used it to fill an old tap hole on the same unit worksurface and, as you say, it provides much more structural strength than chipboard for that sort of repair.

I didn't know it would stick to polyethylene.

Which do you think would be better on zinc plate, epoxy or CBF?

Frankly Id use CBF . Or 'liquid metal' - that's possibly a better mix for metal It would be hard to get epoxy in there and hold it steady and - which always works for me - apply heat to fast set it.

At least to start. But degrease and if you can rough the surface up. Although again there is something in CBF that seems to cut through grease,

That's the raw resin, styrene and/or methacrylates. Gravity will hold things in place while it sets.

I have repaired metal successfully with 'Plastic Metal' (variant of plastic padding) worked well. You need to make sure you have a thickness of it .... even if it means having washers between bonding faces ... without a deb it does not stick well. Degrease well and scratch up mating surfaces.

I have some decorative stonework around external window columns but parts were damaged.

I made a mould using CBF by first smearing some Vaseline on a undamaged part of the stonework and then applying the CBF. The Vaseline acted like a mould release so CBF doesn't always cut through all grease :)

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