An amazing adhesive

Thirtysecond

Western Thunderer
Some years ago I discovered Loctite 326. Apologies if some of you are already familiar with it. Basically any two Copper based materials (inc. Brass of course ) can be bonded to produce a joint which, in my experience, is as good as a hard solder one.

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There are few things to remember.
  • The surfaces must be thoroughly degreased.
  • An activator Loctite 7649 is applied to both surfaces.
  • Loctite 326 is applied to both surfaces and the joint clamped until it goes off (depends on temperature but usually minutes)
  • Any extruded adhesive can be removed with a degreasing agent or solvent that doesn't effect your paint.
  • Have a few tries on spare parts before attempting work on a valuable model!!

Its particularly useful when you can't solder for whatever reason.

For instance I have been working on four Gauge One tenders which are already fully detailed, painted and lined.

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And to these I had to add the two extra lampbrackets in the middle of the backplate which had been inadvertently left off in the production run. Soldering was out of the question.

I masked up the two places concerned and removed the paint extremely carefully with a piece of 1/16" angle ground to make a 1/16 chisel. Loctite 326 was applied with a cocktail stick to both surfaces and the brackets clamped for 10 minutes.

No need for touching up of paintwork and they look like they've been on there forever.

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Downside? Its around £40 for a 50ml bottle!! Worth every penny though and it does last for years.
 
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Sparky

Member
Absolutely agree - it`s also great for attaching large items such as chimneys, domes etc to boilers where it`s difficult to get sufficient heat into the area. Expensive? yes. Worth it? certainly.
 

oldravendale

Western Thunderer
I don't object at all to paying for something with this reputation, although I'm unlikely to use it very often. The corollary is that I understood all Loctite adhesives to have an expiry date. Is that not the case?

B
 

JimG

Western Thunderer
I don't object at all to paying for something with this reputation, although I'm unlikely to use it very often. The corollary is that I understood all Loctite adhesives to have an expiry date. Is that not the case?

Brian,

I understood that as well. I checked on the Internet and found this

http://www.loctite.co.th/tht/content_data/Loctite_Shelf_Life.pdf

...which says that there is a one year shelf life on all Loctite products - which could make it very expensive if you have to throw most of it away after a year or so.

Jim.
 

adrian

Flying Squad
...which says that there is a one year shelf life on all Loctite products
true - but is that like a best before date on food packaging? Still perfectly useable after the date if stored correctly.
 

oldravendale

Western Thunderer
That makes sense. I've had some superglues for several years stored in the freezer, and they've shown no signs of deterioration. We'll find out how normal cool storage works now that the domestic freezer is out of bounds......

B
 

Thirtysecond

Western Thunderer
The bottle I am using at the moment is at least five years old and works perfectly well and has never been in the fridge. But of course Loctite would love you to buy a new bottle every year!!

It was extremely warm in the workshop today and the 326 was going off in about 5 seconds rather than the usual minutes!! Had to position things accurately VERY quickly!!
 

adrian

Flying Squad
But of course Loctite would love you to buy a new bottle every year!!
Wouldn't they just!! I can see it being useful on one of my current projects and I found Cromwell Tools have it for a shade under £30 so I've a bottle on order. Thanks for posting.
 

Sparky

Member
I have two bottles of Loctite (screw lock and stud retainer) which I `rescued` from a previous employment 32 years ago. They have been in my toolbox and latterly in my shed throughout and still work perfectly well. My current employer buys various types and grades (including 326) which they discard, sometimes unopened, when the `expiry date` is passed. I rescue these too, and if they last another 30 years, they will see me to the end of my modelling days.
 

Thirtysecond

Western Thunderer
Wouldn't they just!! I can see it being useful on one of my current projects and I found Cromwell Tools have it for a shade under £30 so I've a bottle on order. Thanks for posting.

Don't forget that for full effect you need the activator 7649 as well as the adhesive. Although thinking about it, in this hot weather it could be unnecessary!

Forget the applicator attached to the bottle by the way. It clogs up after a while anyway. With the size of parts we typically deal with, it's best to put a small dollop on some card and use that wonderful, inexpensive modelling aid, the good old cocktail stick, to apply a thin smear to each surface. Similarly I use a cotton bud or a point made from folded kitchen roll for the 7649 activator.
 

Brian McKenzie

Western Thunderer
I've used several of the Loctite adhesives in industry, but now can't remember which type (anaerobic or cyanoacrylate) should not make direct contact from the bottle with metals, otherwise the content remaining within the bottle will 'go off'.
I have just opened a new bottle of 680 and been wiping it on directly when fitting wagon axle brass bearings, so I hope it's not that. :(

My work colleagues were advised by the distributors not to use Loctite retaining compound on screws penetrating the walls of plastic enclosure boxes for electronics - and sure enough the plastic cracked really badly when they did. The stronger retaining compounds exert tremendous pressure and will split materials not sufficiently robust.

I agree with 'Thirtyseconds' advice to use an activator where they are available or recommended. Ditto for when using silicone sealants. The added strength to the job (when it's important) is amazing.
 

Steph Dale

Western Thunderer
Brian,

It's cyano, that's why it's better to apply it with a cocktail stick rather than a piece of wire...

Steph
 
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