What is the best glue for metal detector coils?

G'day

I heard somewhere about a type of glue that is used in the construction of detector coils, can't remember for the life of me what it was called (great fun getting old) anyway it obviously it must be compatible with the type of plastic that is used by coil makers such as minelab, coiltek, nuggetfinder and so on, also after quite a few google attempts to find what plastics they use to which yielded little or no information of any use I conceded that it either must be a closely guarded secret or google has become dumber than me which is a worry, used to be that you would be inundated with information on anything you wanted to know but now you just give up searching due to so much unrelated crap coming up?

What I have used in the past is old coil plastic melted down with acetone to form a glue consistency, its ok for minor cracks but can fail on the stress points around the shaft mount lugs and so on, is that because there is not enough plastic in the mix or is better preparation of the area to be repaired required?, anyway any further information would be much appreciated.

cheers

stayyerAU

You're on the right track with the old coil plastic and acetone mate, just use a thicker mix.
It doesn't look too classy but it gets back to the original material, ya can't beat that.
Unless your coil is old and brittle, then good luck. layful:

Do they actually use glue though? Many long moons ago, I worked in the plastic moulding industry and my somewhat informed guess would be that rather than an adhesive, they'd use MEK, which acts as a plastic welding agent:
https://en.wikipedia.org/wiki/Butanone#As_a_plastic_welding_agent

grubstake said:

Do they actually use glue though? Many long moons ago, I worked in the plastic moulding industry and my somewhat informed guess would be that rather than an adhesive, they'd use MEK, which acts as a plastic welding agent:
https://en.wikipedia.org/wiki/Butanone#As_a_plastic_welding_agent

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I think the glue version is MEKP.

Cheers

Doug

I think the glue version is MEKP.

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Not sure about that. MEKP is methyl ethyl ketone peroxide - a catalyst for polyester (fibreglass) resin. Nasty stuff

Mastic is good, holds well, is strong and flexible enough to stop the coils from cracking

I use Scigrip Weld-on 16 to attach perspex to coils.

It's a clear, medium bodied, fast-setting, high strength acrylic cement.

It bonds:
Rigid PVC
ABS
Styrene
Butyrate
Polycarbonate
Acrylic / Perspex
To themselves and each other, as well as other plastics & porous surfaces.
Made in USA

Available at Warlond plasticsVictoria

Go to your local auto shop get a glue called RAPID FIX ,i used it all the time to fix plastics and it works easy strong and it works on anything use the powder to weld parts together and you can sand it .PP

Heres another product that welds plastic. It can be used to build up broken ears on coils and can be sanded and drilled.
It uses a UV light to cure the material that you squeeze from the tube. Apparently developed from the dental industry.
Got mine from Aldi.

Acrifix R0192 . I don't know where to buy it but it's brilliant glue.

Black-Pete

Stingray said:

I think the glue version is MEKP.

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Not sure about that. MEKP is methyl ethyl ketone peroxide - a catalyst for polyester (fibreglass) resin. Nasty stuff

Click to expand...

Yes , if you use that stuff do it outside and wear a hazmat grade mask . from memory it is linked to blood cell and bone marrow cancers and other nasties.

G'day

Thanks for all the great answers, to get the best type of join that would also hold firm on stress areas like around the mount ears I would be thinking that whatever you use it would have to actually be able to melt the original plastic around the damage site so that new plastic can mix into it and bond with it when it sets, also another alternative might be to bond the crack and then use a wide flat bit in the soldering iron to further melt and weld it together?

When the top and bottom coil cases are fitted together in the factory the two halves are bonded with some sort of adhesive in the process, when repairing a coil you can heat up the edge and then cut through the adhesive and open up the coil and separate the two halves, the mix of acetone and some coil case or skid plate plastic works well to re bond the halves back together in that instance and to tidy small damaged areas on the flat parts of the coil, but the stress areas around the mount ears are the places where it will more often than not crack again after some use.

Its not that I am that tight assed that I am trying to fix bunky coils but some coils that are old favorites and have performed well for me are still working well but in need of some tlc, I still have my first minelab 8" mono that I bought many years ago for the sd2100, its been apart several times and repaired and even re bonded back with silicone but looks like it was done by a crazy person, but its found so many ounces of gold on every detector I have owned since and still carried on every trip, its hard to let it go into the bin, pity you cant buy empty coil cases so that people can re furbish their own coils if they want to.

cheers

stayyerAU

AV 505 from AVS.
Around $25 a tube.
Amazing all round adhesive.
The need to clamp the components as it expands and will separate your applications.
`i` have even used this product to mould a distilling seal collar of which it copes with high heat and moisture.
Discovered it is resistant to petrol and oils as I have used it for gaskets mechanically `not that `i` advise `DAYOR`.
It is also sand-able and workable.
Wear surgical gloves when applying recommended.

http://www.permatech.com.au/uploads/2/6/4/6/26464160/avs_av_515_tech_notes.pdf

Black-Pete said:

Acrifix R0192 . I don't know where to buy it but it's brilliant glue.

Black-Pete

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https://plasticwarehouse.com.au/product/acrifix-acrylic-adhesive-plastic-glue-100-gm/

Bush said:

AV 505 from AVS.
Around $25 a tube.
Amazing all round adhesive.
The need to clamp the components as it expands and will separate your applications.
`i` have even used this product to mould a distilling seal collar of which it copes with high heat and moisture.
Discovered it is resistant to petrol and oils as I have used it for gaskets mechanically `not that `i` advise `DAYOR`.
It is also sand-able and workable.
Wear surgical gloves when applying recommended.

http://www.permatech.com.au/uploads/2/6/4/6/26464160/avs_av_515_tech_notes.pdf

Click to expand...

Bunnings sells the same type of glue for a whole lot less loot. There is a Tarzans Grip version, a Selleys version, Gorilla Glue and also Sika Techgrip. They all work exactly the same way and stick like the proverbial s**t to a blanket. The curing process can be accelerated by applying a small amount of moisture to the work area before lightly clamping.

I have used acetone and ice cream container to patch coils. Works okay.

We used MEK in the RAAF as paint stripper.
Trouble is it will also strip your lungs n kidneys n liver, yer brain and skin other body internal and external bits n pieces.
Leave that stuff alone unless you know the correct way to handle it safely.

Amazing so many choices of Sticky Weaponry mentioned above.
Think i`ll dissolve some plastic in Thinners next time around.
Probably better to use an old coil skid plate or coil to match up the compositions.
Many types of Plastic out there.

Liquid Metal not recommended. 8.(

MEK is in the glue for plumbing and electrical pipes