what to use to bond hard plastic item, when superglue doesn't work?

victor2

Can you drill through the blue and red parts and put a small bolt (with washers) through? Or use a metal "fixing" strip to bend round it and hold the parts together? 
Just thinking how I'd have a go with what's in my toolbox. 

grumbler

victor2 said:

Can you drill through the blue and red parts and put a small bolt (with washers) through? Or use a metal "fixing" strip to bend round it and hold the parts together? 
Just thinking how I'd have a go with what's in my toolbox. 

I was going to suggest a metal plate too, but on the top of the blue part, П-shaped, with 4 small bolts

Bendy_House

Section62 said:

Bendy_House said:

Can you pull the LH bit 'up' so's to close the gap?

This will be necessary in any case, otherwise the measure will be incorrectly reading.  Ok, it will only be by a small amount, but imagine the potential trauma involved in discovering you've grown 0.5cm in the space of a couple of days.

Bendy_House said:

As said above, the strongest repair will involve having extra adhesive added along the corners either side of that crack. That won't get in the way of anything, will it?

Just for clarity, I wouldn't suggest putting extra adhesive in the corners, as the adhesives most likely to work won't add much strength if used like a fillet weld.

What I was suggesting is to try using is some additional (plastic) material to be bonded into position acting like a fillet. The glue joint is then working over a much larger surface area and the fillet material provides additional strength.

If the manufacturers have used ABS then my ideal choice would be some uPVC angle trim (or modesty blocks) bonded in place with uPVC solvent... but other options are possible using stuff people are more likely to have laying around the house than angle trim and uPVC solvent.  Could be time to raid the box of 'spare' Ikea parts.

I asked about that gap to see if it was a missing piece or just that the two parts had been pulled apart.

Epoxy-adhesive or hot glue would do the exact same reinforcing job as an add-on fillet, and much easier.

Bendy_House

me1000uk said:

Ah, much more clearerer.

So, that red part doesn't need to move at all? Gluing it to the blue would be fine? 100% certain? Cool - then, as you say, that should really help the job.

If you knew what plastic this was, or if you were prepared to experiment, then a good solution would be a solvent adhesive - usually a watery liquid which will literally dissolve the surfaces and allow them to weld together. The solvent evaporates, leaving behind a welded plastic joint.

You can get this stuff from model shops. Some common plastics aren't solventable using this product, tho', so you'd need to test it (eg, does it make a mess of the shiny surface when a drop is applied...?)

I think, however, I'd be inclined to just use epoxy adhesive - you know, the two-part stuff. Yes, absolutely, you'd need to key the mating surfaces, and basically the rougher the better! So, use a coarse grade sandpaper such as 80 grit if you can. Or, slip a small file in there and scratch away as much as you can. Even a craft knife blade, but do try and remove all the 'shine', and then rough it up a bit more...

First, get sorted a way of pulling and holding (without any subsequent movement) the two surfaces firmly together. One method I've already mentioned - a strip of strong sticky tape along the top. 'Duct' tape is good for this sort of thing - you first stick it firmly to the top of one section, and then use it to pull the gap closed, stretching the tape a little before sticking it down on the other part. This 'stretch' should effectively keep the parts 'pulled' together. Do a dry run, though - add the tape, and then leave it for at least an hour to ensure the tape doesn't slip or peel off... Or, a rubber band should do this? Again, do a dry run - you don't want to find out how awkward it is after you've applied the glue.

Don't apply too much, but do make sure you cover all the contact surface. You ideally just want a slight extrusion of excess adhesive showing around the joint. You can leave this until the stuff has partially set - it can then be trimmed off neatly using a craft knife. But don't allow the joint to move until fully set...

Are you sure that red part doesn't need to move in relation to the blue?

me1000uk

Bendy_House said:

me1000uk said:

Ah, much more clearerer.

So, that red part doesn't need to move at all? Gluing it to the blue would be fine? 100% certain? Cool - then, as you say, that should really help the job.

If you knew what plastic this was, or if you were prepared to experiment, then a good solution would be a solvent adhesive - usually a watery liquid which will literally dissolve the surfaces and allow them to weld together. The solvent evaporates, leaving behind a welded plastic joint.

You can get this stuff from model shops. Some common plastics aren't solventable using this product, tho', so you'd need to test it (eg, does it make a mess of the shiny surface when a drop is applied...?)

I think, however, I'd be inclined to just use epoxy adhesive - you know, the two-part stuff. Yes, absolutely, you'd need to key the mating surfaces, and basically the rougher the better! So, use a coarse grade sandpaper such as 80 grit if you can. Or, slip a small file in there and scratch away as much as you can. Even a craft knife blade, but do try and remove all the 'shine', and then rough it up a bit more...

First, get sorted a way of pulling and holding (without any subsequent movement) the two surfaces firmly together. One method I've already mentioned - a strip of strong sticky tape along the top. 'Duct' tape is good for this sort of thing - you first stick it firmly to the top of one section, and then use it to pull the gap closed, stretching the tape a little before sticking it down on the other part. This 'stretch' should effectively keep the parts 'pulled' together. Do a dry run, though - add the tape, and then leave it for at least an hour to ensure the tape doesn't slip or peel off... Or, a rubber band should do this? Again, do a dry run - you don't want to find out how awkward it is after you've applied the glue.

Don't apply too much, but do make sure you cover all the contact surface. You ideally just want a slight extrusion of excess adhesive showing around the joint. You can leave this until the stuff has partially set - it can then be trimmed off neatly using a craft knife. But don't allow the joint to move until fully set...

Are you sure that red part doesn't need to move in relation to the blue?

Yep the red and blue can be stuck together. As long as the cracked bits are joined up again the unit will function ok.

Thank you very much for the suggestions; to save time and potentially experimentation as I don't have this stuff at home, I'll go with your suggestion of expoxy adhesive and find a way of securing it as that seems the simplest solution and others have suggested araldite the thread.

One final question if you don't mind, is the 5 minute stuff ok from your experience? I just checked toolstation and they have Araldite 5 minute tubes. Sounds ideal.

Thanks again for the responses. Happy to try anything and hopefully will do the trick.

[Deleted User]

Hi,

if the glue doesn't work, maybe a piece of this, cut to size, and fixed in place across the top, would do.

grumbler

My impression is that the red part is supposed to move. Hence the design with the weakness.

Bendy_House

me1000uk said:

Yep the red and blue can be stuck together. As long as the cracked bits are joined up again the unit will function ok.

Thank you very much for the suggestions; to save time and potentially experimentation as I don't have this stuff at home, I'll go with your suggestion of expoxy adhesive and find a way of securing it as that seems the simplest solution and others have suggested araldite the thread.

One final question if you don't mind, is the 5 minute stuff ok from your experience? I just checked toolstation and they have Araldite 5 minute tubes. Sounds ideal.

Thanks again for the responses. Happy to try anything and hopefully will do the trick.

Even if the 5-minute version is not quite as strong, it'll easily be strong enough for this type of job - provided it sticks to the plastic. You will, of course, have less 'working' time to 'mess' with it before making sure it's clamped tightly together!

If there is a hidden part of this device - say the back or whatevs - there's nothing to stop you doing a test on this. Abrade it thoroughly as before, and then mix up a small amount of the adhesive and put it on there. (When mixing small quants, it's more important to get the two parts measured out accurately. A pea-size of each should be fine.)

Are you sure the red part doesn't need to move?!

Tbh, if your test shows that epoxy does stick well to this plastic, then the repair should be fine with only bonding the top part - all of it inside the yellow circle. Abrade abrade abrade. Rough it up gooood.

me1000uk

Thanks for the responses, much appreciated. I'll give it a shot, will get some cheap sandpaper and the araldite stuff recommended.

I'm certain the red part doesn't need to move. The red part forms the 'guide' that shows the measure on the ruler - one side inches one side cm. One side is almost flush (the side I'm sticking) and the other side red bit is slightly curved so that it provides a touch of friction when moving it up or down so it doesn't fall with a bang (although thats not really effective as it's pretty loose anyway).

Think of sliding a ring up and down your finger. The red and blue bits are the 'decorations' or stones outside a ring, you can stick them however you like, but the functionality is purely to slide up and down via the hole, which is intact (albeit the flat head piece will be straight rather than bent once the repair is done). Here's a photo of it in action from google. You can see the straight red bit and the curved one (the curved one adds a tiny amount of grip so sliding up/down isn't loose, and is the opposite red bit to the one I plan to stick)

Thanks again!!

me1000uk

grumbler said:

victor2 said:

Can you drill through the blue and red parts and put a small bolt (with washers) through? Or use a metal "fixing" strip to bend round it and hold the parts together? 
Just thinking how I'd have a go with what's in my toolbox. 

I was going to suggest a metal plate too, but on the top of the blue part, П-shaped, with 4 small bolts

It definately won't need to move. I guarentee it. I should of maybe explained it better. I don't think it's a seperate bit. I'm glad everyone could bare with me with my long post! I'll make a withdrawel so I can buy the epoxy. Chears!
I apolagise for the cheep humer.