Is Araldite ok for metal?

It is OK for metal.

Sundry other reasons. If it's what I'm thinking about they contain a lot of inert filler, it helps filling holes and gaps. The grey colour is to convince the proles they can fix holes in grey metal with it.

It's fine on aluminium per-se.

Less so on plastic, and it depends which plastic.

Set araldite is brittle, if the whole assembly will deflect under load the joint may break up.

You may need to look further.

DG

I use a little less hardener if I think a bit of 'give' is needed.

Doesn't using less hardener with Araldite slow down the rate of curing rather than give an incomplete (and therefore more flexible) cure?

When you say 'tube' of Araldite - do you mean 'tubes' ? AFAIK all Araldite is 2-part.

The plastic might cause more trouble than the aluminium.

|!On my rather old tube of 'regular' Araldite it says it is ok for metal. |! |!If this is so then why would I ever use one of those 2-part adhesives |!sold specially for metal? I mean the sort of thing that is usually |!coloured grey and can often be bought in car accessory shops? |! |!I need to glue an aluminium ring (about 1.5 inches diameter and about |!4mm thick) to a plastic base. There will be some light to moderate |!stressing of this arrangement when it is in use. |! |!I figured the Araldite was just fine for the plastic but what about the |!metal?

Yes! But! Everything needs to be *real* flat, *real* smooth, and *real* clean, and not have release agent on it, also both bits need to be rigid. We used to do it for aircraft components. So if you can do the first two bits within a few thou (you can measure to 1/10mm can't you), degrease the aluminium and roughen up the plastic with fine emery and degrease, to get rid any release agent, get some *new* araldite, then it *may* work, otherwise give up the idea of araldite.

Alex Coleman wrote in news:Xns9905BD1A2FF9471F3M4@

Something like Evostick impact adhesive may be more suitable, it remains flexible.

Araldite is not recommended for use where it may be subjected to a peel stress.

Aluminium to aluminium is the base against which they compare all other bonds in their data sheets.

Colin Bignell

cos they are better

Actaully, is not brimliant for wither. get some 'liquid metal'. That will work best.

Actually it isn't hardener. Its two parts of the glue which have to be mixed thoroughly and in equal proportions. All that less of one part does is leave pockets of the other unset.

No.

I haven't been following this discussion, but re the title, wasn't Araldite originally developed for sticking together small jet planes?

IIRC, it was developed at Duxford, south of Cambridge (UK), which I think was an air base at the time, perhaps in the 1950s?

Used with high temperature bonding, epoxies make very fine aluminium glues indeed. In fact there are thousands of different formulations available for specific applications.

Araldite is just one, and its not really optimized for anything apart from a decent shelf life.

Epoxies are substantially inferior to polyesters in a hobby/DIY situation, their one advantage being that they are less irritating and stiffer than polyesters.. However the addition of metal powder and other fillers to polyester resins to make a typical 'liquid metal' formulation solves the viscosity problem and the fact that the reaction is catalytic means that the accurate mixing and consistent stirring that is so importance with epoxies is no longer an issue.

I use both a lot, and really epoxy is surpsringly tricky to use..it MUST be mixed really throughly, or it never sets, its not that strong, and a hint of grease or oxide anywhere and it simply tears off.

The metal loaded polyesters (chemical metal) seem to degrease more readily in themselves, always set with more or less the right amount of hardener even when poorly mixed, and seem to adhere a bit better to olefin plastics,

Whilst epoxies, correctly used under industrial control are undoubtedly superior, used under indifferent circumstances the polyesters are far more reliable.

It's no worse than on anything else.

Araldite is nearly always a poor choice (Araldite Rapid even more so), except for its easy availability and the convenient tubes. Most uk.d-i- y readers would do well to spring the ten-fifteen quid for a West Systems small pack and some suitable filler (cellulose fluff isn't a bad start, or else microballoons) (all from Axminster). A real low- viscosity high-quality epoxy is streets ahead of ready-filled tube epoxies. You can fill it to suit, as necessary.

JB Weld is a steel-powder filled tube epoxy. Much the same applies as for Araldite vs. West System.

Compared to Araldite though, JB Weld is rather more useful for "heavy" uses. The numerical strength might not look much better on paper, but things like creep under load are improved by the filler.

Very interesting post. Useful too. Thank you.

But wouldn't the aluminium be anodised and epoxy primered first? That's the way that I remember in the aerospace industry. The paint had a much higher bond to the metal than the 'Hysol'* had to the paint and the bond was very impressive.

Dave

The Natural Philosopher proclaimed to uk.rec.cars.maintenance ...

I agree with TNP - having used epoxy and polyester resins a fair bit for making kiteboards (for fun) I rapidly grew to realise that hardener is part of the mix, not just a catalyst. You can BUY catalysts to speed up the reaction but you still need the correct quantities or you'll end up with incomplete curing. Which, yes, gives a less rigid joint but also gives a weaker glue and much higher likelyhood of failure. Even a few % wrong and it starts going pear shaped, though you wouldnt notice it to "look at".

I've got an aluminium bike frame with a small hole worn in it, when it was ridden with a tyre rubbing the frame.. (damn kids).

The wear is an elliptical cone about 10x6mm with a 2mm hole in the middle, on a rear stay of about 18mm diameter. Any guesses as to whether JBWeld would patch it up firmly enough for mucking about use (no World Cup Downhills planned...) or should I just scrap the frame?

Jb weld will patch it,but for strength I'd wrap it with glass fibre cloth doused in polyester resin..