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Metal to Metal Sealant? Answered

Hello Everyone,
I want to screw two parts of aluminium 2014 together ..... one is a hollow cube with at-least 5 mm shell width without the top face and one is it's cap/metal sheet with 3 mm height with holes for two m12 to 8mm pneumatic fittings through which pipes will be connected... it is actually a water block ,cooling a part of my next project..

so i want to ask which kind of adhesive or gasket should i use in between them while screwing those two pieces together so that water or any other coolant doesn't leaks from the block and damages the electronic components.

A non-native English speaker here, please ignore grammatical mistakes. :)


Jack A Lopez

Best Answer 1 year ago

I think RTV silicone (sometimes called silcone seal, silicone sealant, etc) would work.


It is this goop that comes in a tube. Before it cures, it is sort of a sticky paste, almost like a slow-flowing liquid. Also, before it cures, it smells like vinegar (acetic acid), and that is one clue that the stuff you're working with is some kind of RTV silicone. After it cures, it is hard and rubbery.

Also it adheres well to the surfaces it cures on, and as a consequence of this, the pieces you have put together will be, basically, glued together, and difficult to take apart later, if you want to do that.

That is probably why Bwrussel was asking if this was something you needed to take apart later.

It is also possible to find sheet gasket material, made of silicone, or rubber, or some other elastomer. For that you just cut (using scissors, or scalpel, or x-acto(r) knife) a gasket to a shape to match the place you need it to fit.

The advantage of this kind of gasket, is that it will be reusable. That is to say, you can take your thing apart, and put it back together without breaking the gasket.

In contrast, the gasket made from RTV silicone, it tends to stick to the metal parts, and it gets ripped apart into little pieces, when taking the pieces apart.

Then you need to apply new, uncured RTV silicone, when putting it back together.


1 year ago

Other considerations are: water pressure, distance between clamping bolts and stiffness of the cap sheet. Clamped seals like this can be difficult if pressures are high and clamping force is not uniform between the bolts.

If a leak is not going to damage your project, you may just try with what you have. If it leaks, make improvements.

My suggestion is the cardboard or other paper gasket material like used for many automotive seals. Gasket sealer (automotive parts store have gasket paper and sealer) can improve sealing with paper gaskets. Paper gaskets will typically need to be replaced each time they are removed.

If you have the capability to machine a groove, a rubber O-ring is a very good solution. Sizing the groove is critical - consult the internet for engineering details.


1 year ago

thanks a lot guys.... so since my project should be removable ... i think i should use a sheet gasket...


1 year ago

Is this something that needs to be removable? If so then, given sufficient clamping force, a gasket set in a groove in the cube side is probably the best way to go if you have the capabilities to cut a consistant groove.