Glue for metal to wood

[Sheen]

Made a pair of earrings with strips of brass sheet glued with araldite onto the surface of wood buttons. But the brass has sprung from the surface. Maybe i didn't mix the araldite epoxy resin properly or am i using the wrong glue?

[josef1]

The two different materials will expand at different rates this could be the problem ? Maybe cold rivet the sheet onto the wood, or choose a more flexible glue maybe a silicon based one.

[SICraftDesigns]

Making sure that the metal is clean and dry helps. It also helps to key the surface by sanding with coarse grit sand paper. However I agree with Josef1 that it's likely an issue with the two materials expanding / contracting although given that jewellery is generally used within a fairly narrow temperature range I imagine it's unlikely to be due to temperature. I personally found that ensuring the wood was dry helped a lot. If I used wood from the workshop then took it inside it would always separate as the wood dried out and shrank. Now I dry the wood this is no longer an issue. Leaving for 24 hours on a radiator should do the trick. Using stabilised wood also helps a lot although if you're planning on doing this yourself you need a vacuum chamber and an oven capable of maintaining a steady temperature of around 100 deg C for 24 hours or so (using the kitchen oven gets you told off quickly!). You can buy pre-stabilised wood quite easily - search for pen blanks as these come in relatively small sizes that I would imagine would be ideal for your application. You can also get them in a range of colours as some people add dye to the stabilising compound.

The other thing I have found in adhesion tests (read trying to clean up my mess after) is that out of Araldyte rapid, Gorilla glue and superglue it is the superglue that seems to stick to the metal the best. It is however the most brittle and so won't tolerate much in the way of dimensional changes hence why I am currently using Araldyte. Thinking about it you could try annealing the brass sheet to ensure dimensional stability (it's less likely to change shape if the internal stresses are reduced) although to be honest I suspect the wood is the culprit here.

[china]

Are you using 5 minute or super strength, 5 minute is not recommended for brass, with the super strength you need to abrade the brass and clean the the surface with a non residual solvent, clamp for 2 hrs

[CJ57]

I've always used araldite for wood and metal. Score the back side of the metal, criss cross if enough of it and give the contact area on the wood a sand, spread a thin layer of glue on both parts and clamp them together until set. I've never had any problem with them popping apart on the contrary if I've need to separate them it's taken a Stanley blade

[Dennis]

To summarise things which I see as important, some already mentioned:

The metal should be in a soft state and roughened to increase its surface area.

The wood should be sealed and non absorbent.

The parts should be held together under light pressure until the glue is set.This also ensures a thin layer, which is important for maximum adhesion. For setting times read the instructions.

Lastly some glues require added moisture, again mentioned in the instructions.

The fast set glues are the least trouble, for instance gel superglue or rapid two part epoxy. Dennis.

[Sheen]

Wow, what amazing replies. I think the problems i've had are due to applying the brass to the curved surface of the button without proper abrasion of the metal, using my fingers to hold together until set (maybe i need to buy a wee clamp, doh!) I had pre varnished the wood to stop the wood getting stained or marked but from dennis' reply that sounds okay to do? Certainly will be having another go. Will make sure my metal is annealed. Also SICraftDesign, had a look at those pen blanks, that's given me an idea for another pair of earrings, based in my original design. Thanks

[SICraftDesigns]

Glad I could help with the pen blank idea! Looking forwards to seeing the outcome of that!

Rubber bands can come in handy for clamping awkward shapes! Only problem can be a bit of glue oozes out and glues them to your workpiece but a bit of sandpaper will take that off no bother.