# Bonding Plastic and Metal



## RohanC (21 Nov 2015)

Anyone has any idea on how to bond together plastic and brass metal? Would epoxy or Araldite do it? 

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## Greenfinger2 (21 Nov 2015)

Hi Rohan, 

Yes Araldite or epoxy will work. I have use it to stick rocks wood and metal. So long as both pieces have enough area to bond too each other


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## RohanC (21 Nov 2015)

Thanks for the info Greenfinger2 

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## zozo (21 Nov 2015)

SIlicone should do as well..  If you look for example at double glass windows.. That's an aloy frame with 2 sheets of glass glewed air tight to it. If it works with glass to metal, why not plastic? If you look at the bison glass kit data sheet, it coveres about all, glass. wood, metal, plastic etc..


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## ian_m (21 Nov 2015)

Silicone releases acetic acid which will attack brass sending it green, so normal silicone is a no go. Neutral cure silicone will be OK.


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## RohanC (21 Nov 2015)

The silicone used for tanks would be safe?

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## zozo (21 Nov 2015)

Ian made a very good point there with the brass, it could react to the acid in silicone. The regular aquarium safe silicone is based on vinigar acid..
It should be cured in 24 - 48 hours, i have no idea if brass will react that fast and if the acid in th esilicone stays present after curing. In bathroom there is lots of brass and cupper.. Till now havent sen it getting green with silicone on it, but thats a different kit..


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## RohanC (21 Nov 2015)

Will give a try with both silicon and epoxy. Here's the pic of the thing where i intend to use it



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## RohanC (21 Nov 2015)

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## zozo (21 Nov 2015)

Whats at the other end? Thread? And those connectors also come in different kinds of plastic. Does it need to be air/water tight? Note epoxy gets rock hard, if the brass connector ever moves the epoxy probably will break and leak... 

Ok i see, these come in plastic too..


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## RohanC (21 Nov 2015)

Its basically a cola cap. I have pierced it and put the brass connector. The idea is to use it for diy co2 which can hold pressure of about 10-30 psi

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## zozo (21 Nov 2015)

Yes the bottle can.. If you glewed connector can, that's to find out???..
But why reinventing the wheel??
http://www.banggood.com/DIY-CO2-System-Kit-Generator-Accessories-Bottle-Cap-p-927019.html


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## RohanC (21 Nov 2015)

Already got these. But it's cheap hard chinese plastic which breaks if a bit of force is applied to tighten it on the bottles. The cola caps are far better in terms of tenacity and durability. Already many of us had the cracking issue with these chinese ones. 

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## zozo (21 Nov 2015)

Ok, didn't know about the quality.. But if you want it pressure tight i think you need another construction than kit or epoxy..

Try these i do not know the english name for them








Drill a hole put a gasket (o-ring) in between and screw together.. They come also in plastic. The metal ones even down to Metric 5 mm thread. So if you got a 5mm tap, you can tap thread in the botlle cap and only need one connecter, the outside thread one.


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## RohanC (21 Nov 2015)

Would two of these fit in a single cap? I need two connectors per cap just like the bangood version. 

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## zozo (21 Nov 2015)

Ive used these, with o-ring and M5 thread 4x6mm hose connector.. 





Got it.. 
 B&N Type M-5H-6 pneumatic air Fitting, M5 thread straight hose nipple, for 6mm tube


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## Greenfinger2 (21 Nov 2015)

Hi Rohan, If you are going to use this on Diy Co2 set up ?? You only need to drill a hole slightly smaller than the tubing in the top. Cut the tubing to a v shape at the end then pull it through the hole and a tight fit no leaks  Glue does not work well on polypropene plastics.

I ran my system for 2 years no problem Every 4--6 months or so as Co2 is a corrosive gas I change the top and tubing.


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## RohanC (22 Nov 2015)

zozo said:


> Ive used these, with o-ring and M5 thread 4x6mm hose connector..
> 
> 
> 
> ...


My only doubt. Would two of these fit in a single cap? Could you pls show a pic of your cap if possible 

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## RohanC (22 Nov 2015)

Greenfinger2 said:


> Hi Rohan, If you are going to use this on Diy Co2 set up ?? You only need to drill a hole slightly smaller than the tubing in the top. Cut the tubing to a v shape at the end then pull it through the hole and a tight fit no leaks  Glue does not work well on polypropene plastics.
> 
> I ran my system for 2 years no problem Every 4--6 months or so as Co2 is a corrosive gas I change the top and tubing.


So without any additional gluing it won't leak? That's definitely a boost  will try.

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## zozo (22 Nov 2015)

Roy did diy co2 for years, and see his journals for the results.. Than you'll  

    No words needed.. It  all comes down to knowing what you're doing and the UKAPS magic word "Husbandry".. 

I never did, went straight on with a presurized fe. So i also never did use these connectors to fit bottle caps i used them for other construction ideas to take little pressure without leaking water or air. But i'll see if i still got 2 left and see if i can make 'm fit a bottle cap. I think they can..  Now i'm curious as well..


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## zozo (22 Nov 2015)

Yes we can!  You'll need a 4,2 mm drill and a M5 tap and 2 minutes work.. I placed them with a 4mm gap, if you put them closer together, there still is room inside the cap to screw M5 nuts on the connector thread sticking out. Since they come with o-ring and the cap is relatively thin and soft plastic, so with the nuts screwed inside the cap it will be realy strong and tight.


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## GHNelson (22 Nov 2015)

Why go to all that bother http://www.ebay.co.uk/itm/DIY-CO2-S...-Moss-Plant-/201331721128?hash=item2ee04e43a8



Cheers
hoggie


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## zozo (22 Nov 2015)

hogan53 said:


> Why go to all that bother http://www.ebay.co.uk/itm/DIY-CO2-S...-Moss-Plant-/201331721128?hash=item2ee04e43a8
> View attachment 78015
> Cheers
> hoggie


That's what i thought as well, but..
http://www.ukaps.org/forum/threads/bonding-plastic-and-metal.38983/#post-423266


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## RohanC (22 Nov 2015)

I already mentioned the reasons for not using these caps. See the earlier post

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## GHNelson (22 Nov 2015)

RohanC said:


> I already mentioned the reasons for not using these caps. See the earlier post
> 
> Sent from my XT1022 using Tapatalk


Missed that post....have you tried looking for bulkhead connectors!
http://www.ebay.co.uk/itm/B10-03519...595141?hash=item35e58e9bc5:g:SGIAAOSweW5U5a8~


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## RohanC (22 Nov 2015)

Zozo suggested me that. Will try with those

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## GHNelson (22 Nov 2015)

Hi Rohan
You could always try using a 5 litre spring water bottle if two of the bulkheads will not fit on the Cola cap!
Just a suggestion!


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## RohanC (22 Nov 2015)

These bottle and caps will be unable to hold the pressure of the diy co2 setup. This system generates pressure from 5-45 psi

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## xim (22 Nov 2015)

Using any "stiff" part will just pass on the stress from any movement 
to the point of contact between the barb and the cap.
Glue is not reliable enough for this job. So a bulkhead is the way.



Greenfinger2 said:


> Hi Rohan, If you are going to use this on Diy Co2 set up ?? You only need to drill a hole slightly smaller than the tubing in the top. Cut the tubing to a v shape at the end then pull it through the hole and a tight fit no leaks  Glue does not work well on polypropene plastics.
> 
> I ran my system for 2 years no problem Every 4--6 months or so as Co2 is a corrosive gas I change the top and tubing.



This method is very good .  There is no stiff part involved. 
The silicone tube acts as a stress dissipator and a sealer (as long as the hole is smooth).
I still use a diy bubble counter I made with this method six years ago.


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