Mitre bond adhesive

[The Medway Handyman]

Anyone had any experience with these 'instant' mitre bond adhesives? The type where you spray an activator on one surface & glue to the other.

How strong are they on wood compared to say PVA?

[A.Lee]

Yes, pretty good. I use it on pelmets/cornices in kitchens, and find it really good. I dont think it is made for structural joints, but for trim pieces, it is ideal. Alan.

[Andrew May]

Bought some a couple of years ago to pre-glue mitres on door architraves. Not as strong as I had hoped but there is probably quite a lot of leverage over that length.

Came back to it a couple of weeks ago to glue up some kitchen trim and found the bottle of glue now solid. So, probably good if you are a regular user but works out expensive for casual use.

Andrew

[michael adams]

Nearly all two part glues will achieve a stronger bond than PVA but they need to be mixed properly.

Using a spray looks to be little more than a gimmick - which you pay extra for - to attract people who can't be bothered to measure out and mix the components by hand

It's hard to see how simply spraying hardener on one surface and the adhesive on the other can be guarenteed to achieve as satisfactory a mix as mixing by hand unless both surfaces are perfectly flat.

Again another point about most other two part adhesives epoxy etc, plus cascamite type casein glues which you need to mix with water, is that they have gap filling properties. They set hard within a short time without shrinking. So the two sufaces to be glued don't need to meet up over their entire surfaces. All PVA type glues will shrink to some extent as they dry by the loss of moisture either to the atmosphere by evaporation or soaking into the wood. Whereas two part adhesives dry as result of a chemical reaction which doesn't involve any loss of moisture.

In other words where a one part PVA adhesive already performs OK there's no reason to stop using the existing product.

If something stronger is needed with or without gap filling potential then there are better performing two part products already available.

michael adams

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[Roger Mills]

As others have said, it's magic for bits of trim - like plinths on bedroom furniture etc. - but not designed for anything 'structural'.

I haven't actually tried it on mitred corners, but it's probably ok for picture frames - and would save a lot of clamping up, needed with normal glue.

It really is pretty instant - so you only have a few seconds in which to adjust the position.

[John Rumm]

They are typically cyanocrylate (aka super glue) based products, usually with a thickening agent added to make them more controllable. Hence they share a similar strength i.e. very good in traction and bending, but quite weak in shear. There is some debate whether the accelerators weaken the final bond strength a little, but the gains in setting time are quite dramatic.

[fred]

In article , michael adams writes

More likely an activator rather than a hardener, v common for a quick set in cyanoacrylates.

As stated on this one:

quicker than an epoxy 2 part.

[chris French]

In message , michael adams writes

It's presumably a cyanocrylate adhesive, aimed at setting very quickly, with one part being the activator. Premixing it would work for an 'instant ' glue really.

The very quick setting properties can be an advantage for it's intended use though.

As others have said, not very structural, but good for trims - I used it for the plemt trims on a some fitted bedroom furniture and it worked well.

[Man at B&Q]

genews:N8Svo.29666$ [e-mail]...

So is this all theory, or have you actually tried the product referred to?

It does what it says, very well too. Nor have I suffered from the glue going off. I came back to a part used set 2 or 3 years after first using it and it was fine.

MBQ

[stuart noble]

Watching a double glazing installer doing the trims, I was amazed how instant the accelerator is, even if it's simply sprayed in the general vicinity of the glue. It obviously doesn't need to mix with it as such.

[Andrew May]

Would the accelerator from that pack work with any cyanoacrylate glue (eg superglue) or does it have to be the glue that comes in the pack?

[michael adams]

messagenews:N8Svo.29666$ [e-mail]...

- So is this all theory, or have you actually tried the product referred

- to?

I would never try and join mitres with an instant setting glue.

If it does what it says on the tin and really does set instantly.

I can't see really how you can possibly guarentee to align the components correctly. The point about mitres is that you often have to align the components satisfactorily in 3 dimensions. Not just so the

2 mitred surfaces meet satisafactorily. Supposing you're gluing an architrave in situ around a door with this stuff. 3 pieces. You have the upright in place. And are now going to glue the cross piece. Now unless the wall around the door frame is perfectly flat - which few are - then as soon as you glue the cross piece on. then if theres any deviation in the wall behind i.e it isn't perfectly flat the cross pice wont lie flat to the wall. In fact if the wall bows out across from that corner its doubtful you could glue the piece at all as you'd be unable to marry the mitred surfaces. Whereas if the wall bows in then the frame will stick out from the wall with even bigger problems to come on the right hand corner. Given its an instant setting glue not only is there no room for adjustment, but even if there was, as the adhesive has no gap filling properties there's no scope to accomadate any deviation in the wall at the joints as there otherwise would be.

As to picture frame mitres - all four corners need to be assembled clamped up and glued at the same time. Its impossible to start at one corner and obtain so perfect an alignmnet that the fourth piece can be guarenteed to fit.

- It does what it says, very well too.

Which particular type of mitre did you use it for?

- Nor have I suffered from the glue

- going off. I came back to a part used set 2 or 3 years after first

- using it and it was fine.

- MBQ

michael adams

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[fred]

Sorry, dunno but it would certainly be worth trying. Success or failure should be fairly self evident.

The accelerator I have used was for Loctite Tak Pak and had a kind of sweet ester like smell:

On the loctite site the various cyanoacrylate products say use activator x, y or z so it appears there is a difference but how marked it is I don't know.

[stuart noble]

But that's exactly how picture frames are assembled commercially, the assumption being that the moulding is straight, that the two pairs are identical, and the angles exactly 45. Why wouldn't it be perfect every time? The advantage with the super glue/ accelerator method is that you can position the thing to be glued before you accelerate the set. IMO it's only suitable for plastics though. In the case of a door architrave, I prefer to assemble the 3 sides, stapled across the mitres from the back, and offer that up to the frame.

[Man at B&Q]

[e-mail]...

e Medway Handyman" wrote in

Kitchen cornice and pelmet. I didn't have any alignment problems.

MBQ

[michael adams]

Only when using purpose made jigs. And in a situation where material costs i.e. waste aren't a big consideration.

Because the assumption is that wood being an organic material, its dimensions may alter over time even as a result of machining.

For starters its far easier to dry clamp a frame than to check it with straight edges etc to make sure there's no twist.

(Or if supergluing on a jig in a factory environmemt just sling it in the bin)

Having dry clamped the frame to ensure a proper fit what possible purpose is served by faffing about trying to superglue it ?

Just how many picture frames is anyone going to need from that one set of clamps within the next 24 hours ?

Of all the possible joints a person could think of to use with superglue - without the aid of positioning jigs a mitre joint is possibly the worst.

The reason mitres require gluing at the visible joint rather than simply stapling from behind, is because however accurately they may be cut, and however good they look when new, mitres may open up over time, simply by virtue of movement in the wood.

michael adams

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[stuart noble]

No jigs other than a right angle. They are under pinned, one joint at a time, without adhesive.

And there's damn all you can do about mitres opening if the material shrinks across the width. Effectively you no longer have 45 deg cuts, so adhesive becomes irrelevant

[chris French]

In message , michael adams writes

It's not really the stuff for that, nor do I think it's sold as such, nor is anyone suggesting her that you do.

Pelmets on the top of kitchen and fitted bedroom cupboards, where it worked well/

[michael adams]

Mitres can't open which are glued with Cascamite. Ever.

Nobody goes around with a protractor measuring angles, But you don't even need to got to Specsavers to notice a gaping joint.

Bad.

Very, very, bad.

michael adams

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>

[michael adams]

Fairy nuff. Two or three visible angles at most, front and sides.

michael adams