Sticking Polyethylene to Steel

[Dcal]

Does anyone know what glue would be best for sticking polyethylene, or more precisely Ultra-High-Molecular-Weight Polyethylene, to steel?
Its for making thrust blocks for the adjuster for the English Wheel I'm making.
It doesn't need to take much load but it would be nice if it stuck well to take out any spring.

I have polyurethane, epoxy, evostick impact adhesive, chemical anchor, (few types) solvent cement, wood glue and a couple of small packs of Megabond which is a methyl methacrylate adhesive (whatever that is) and probably some other stuff I've forgotten about.

Would prefer to use what I have as I want to do it today.
If it fails it's not the end of the world, but would like to give it my best shot.

Just remembered I also have plastic primer which isn't a primer but ,more of a adhesion promoter which I think soften the plastic making it more likely that the paint will stick.
And thinking about it I have many flavors of primer and paint as well.

Any help appreciated.

 

[qwakers]

i would think of those options polyurethane would be your best bet.

but i cant help but wonder if there are any mechanical options?

 

[Dcal]

Thanks @qwakers
I can countersink the plastic and tap to the steel to fix it, but was thinking of getting an even bond as the steel and plastic probably won't be completely flat, but I'm working on that as well.
I could use the polyurethane (or a setting adhesive like epoxy) to fill the gaps and just rely on the fixings to keep it together?
Probably overthinking it (as always) and I can easily do both.

I have had good results in the past when sticking synthetic rubber to steel using polyurethane.

 

[frank horton]

def polyurethene, sticks like the perverbial......
use it to stick the soles back on me boots (toes, once done never again for the life of me boots)
plenty of time to position but I always leave it for 24hours to cure prop......
also, most can be painted over.......
to get parts unstuck usually u destroy something....

 

[Barking Mat]

Expanding polystyrene foam? Just a thought?

 

[qwakers]

using expanding pu one surface MUST be porous.

 

[Screwdriver]

Does anyone know what glue would be best for sticking polyethylene, or more precisely Ultra-High-Molecular-Weight Polyethylene, to steel?
Its for making thrust blocks for the adjuster for the English Wheel I'm making.
It doesn't need to take much load but it would be nice if it stuck well to take out any spring.

I have polyurethane, epoxy, evostick impact adhesive, chemical anchor, (few types) solvent cement, wood glue and a couple of small packs of Megabond which is a methyl methacrylate adhesive (whatever that is) and probably some other stuff I've forgotten about.

Would prefer to use what I have as I want to do it today.
If it fails it's not the end of the world, but would like to give it my best shot.

Just remembered I also have plastic primer which isn't a primer but ,more of a adhesion promoter which I think soften the plastic making it more likely that the paint will stick.
And thinking about it I have many flavors of primer and paint as well.

Any help appreciated.

UHMW and other oily plastics like HDPE are notoriously difficult to stick with anything, especially to steel. If you have to stick it and can't use a mechanical fixing, you could try melting it. UHMW will melt at a relatively comfortable 130-136 degrees C and the problem is usually how to melt it without overheating and burning. If you can get your thrust blocks up to that temperature (and measure it accurately) with a little bit of surface texture and a fair bit of luck, it will probably stick.

If it was me, I'd pre heat the plastic then get the metal up to temperature and press them firmly together as it cools. I have some experience with HDPE which becomes transparent at its melting temperature and once molten, if it sticks to something, it is stuck!

 

[brightspark]

tec 7 sticks polythene to anything even underwater . just don't get it on your hands https://www.google.co.uk/search?ei=...AQdnd3Mtd2l6&sclient=psy-ab#spf=1586799195361

 

[Screwdriver]

tec 7 sticks polythene to anything even underwater . just don't get it on your hands https://www.google.co.uk/search?ei=...AQdnd3Mtd2l6&sclient=psy-ab#spf=1586799195361

Not seeing anywhere that suggests it sticks to either HDPE or UHMW. I'm not being pedantic here, I know these plastics are particularly difficult to find an adhesive for. If it could stick them, it would say it. There are specialist products but they cost an arm and a leg. Plus of course the OP wants to do it "now"...

 

[brightspark]

I pasted some on some wet visqueen in my pit that was leaking in the wall and made a patch and stuck it on. it stopped the leak and I cemented over it put some together and couldn't pull it apart the next day .

 

[Screwdriver]

In the back of my mind is a little note which suggests HDPE is more difficult to stick than more common flavours of polythene. I think it is the rigidity which makes it less able to conform to a surface. Don't know for sure and never tried that Tec-7 stuff. Be interesting to try it when the shops are open. I'm still trying to think of a good use for a zillion bottles I have been hoarding, waiting for a good idea to come along.

 

[Dcal]

Thanks all
The polyethylene blocks Ill be trying to stick will be cut in a over arm saw and so will be a bit hairy which might help.
I'll do a trial with pu glue and report back.

Also I have a propane torch and an infrared thermometer so will try the heat as well.
Even if it dosen't stick it should make the two faces conform tightly which along with the mechanically fixings should do the job.
I've no tec 7 but will try it when I get some
Also hope I can find some counter sunk set screws.

 

[Screwdriver]

Better to use indirect heat like an oven to get it close to temperature. It burns very easily.

Hot air gun would work although again, unless it's adjustable, it will be too hot.

 

[Dcal]

Thanks @Screwdriver
I've a decent hot air gun.
I was thinking of bringing the steel up to temp and then putting the PE block on it.
Would that cool it too much?
Do i need to heat both?

 

[WorkshopChris]

Do you have enough to do a test with the Evo stick impact? I use spray contact adhesive for sticking lots of plastics to mdf and steel.

 

[bricol]

In 25 yrs of engineering the only reliable fixings I've found are mechanical - screw or bolt through it. Used it a lot for wear strips etc - use a number of smaller screws evenly spread about rather than fewer larger ones.

 

[Screwdriver]

Thanks @Screwdriver
I've a decent hot air gun.
I was thinking of bringing the steel up to temp and then putting the PE block on it.
Would that cool it too much?
Do i need to heat both?

I think it’s best to sneak up on the temperature, bit like when cooking sugar, the line between melting and burning is quite narrow. A cold block of plastic will suck all the heat out of the metal and cool too quickly.

It’s quite good fun melting plastic, it shouldn’t fume below it’s melting temperature but it can take up a huge amount of heat energy (high SHC) before it gets to its melting point. Easy to spot because it goes clear and I reckon if you get it to that point and place it on a hot clean metal surface it will stick like sh*t.

 

[Dcal]

Thanks all for the help, it's exactly what I was hoping for.
It looks like mechanical fixing will be required unless the heating works.

To give you an idea for the application it's probably better to describe the adjuster.
It's my take on an idea from Kerry Pinkerton on the All Metal Shaping Forum, as always based on what materials and tools I have kicking about.

The frame is 100mm x 10mm box, the "quill" for want of a better words is 50mm box and the thrust pads or "gibs" is what I'm making so 5mm steel backed Polyethylene.
I'll drill and tap the 100 box to adjust the gibs against the quill using 8 or 10mm grub screws.

This is what I'm working with, it's from a damaged wear strip off timber fender piles.
They only wear on the belting line in the tidal range so lots of good stuff to be had when they get wrecked.



This is 70mm thick and a 9inch rip saw won't cut it the full way, so had to had to cut the last inch with a hand saw.

I intend to fix the plastic to the steel and then face the exposed side of the thrust pad to get it smooth and level. I have finally found the perfect job for the Shaper I bought on here a couple of years ago.
As the plastic will be thin (and flexible) I need the PE to be firmly attached to the backing plate with (ideally) no spring.


I cut a strip 12mm thick odd thick off a 50mm block to try a few glues.



From left to right I have Megabond, gorilla epoxy and Polyurethane.
I couldn't find the evostick and it will take me a bit of time to set up @Screwdriver heat method but I'll do it after work today.
I'll see if a mate can get me Tec 7 but I don't hold out much hope unless I wait for it to arrive by post.

 

[Screwdriver]

Interesting. If you can get more of it, could you send some for me to play with?

If you want it to really stick, you could make sure the steel backing has some super aggressive texture. Welding a strip of mesh would be ideal but even some cuts or deep grooves would work.

Another option might be to literally stick some strong emery cloth to the steel or you could even try a thin layer of concrete prior to heat bonding the plastic.

Now I think of it, a thin skim of texture concrete is probably ideal and will resist the heat. Concrete bonds to steel like anything though I'm not sure if that works consistently and how it might behave in a thin layer.

 

[Dcal]

I've plenty,
pm your address and I'll send you some.
It's heavy but I can cut you what ever size you want.

I wasn't fussy with my glue tests (it was one o'clock in the morning) but for the real thing I was going to blast the steel.
I was thinking of holding the steel test piece in the vice vertically, put a spanner or some lever on the blocks and add weight until they twist off.
Should at least give an idea of which works best.
They all seem to have stuck and with fixings I'd be happy with any of them.