Thread: do blind rivets need to be used with a gasket and does the orientation matter?

I hope to use blind rivets in an application where airtightness at low pressures is desired. I never used them before and have a few questions about the importance of orientation. Take this image for reference:

Screenshot 2022-03-21 at 22.06.15.png

Here a sealed blind rivet is depicted. The bulge forming on the left side of the left plate is making it water and airtight for water and air crossing the left plate and entering either the middle section or the right side.

On the right side we have flat rivet head on flat sheet metal contact. My senses are tingling that metal on metal contact on the right might not create an airtight joint so liquids and gases can be trapped in the middle between the two plates. That would mean that the orientation of application of the blind rivet is important. Is this indeed the case? if so, is foamy or O-ring gasket, or perhaps silicone mandatory to use with blind rivets if airtightness is desired?



Thank you for your feedback. I though posting a question here and getting feedback from more experienced members of the community would be beneficial before sticking a gasket under each rivet I pop

I think the real question is how bad would a leak be, how much work are you putting into it? If the answer is a leak would be bad id look at another assembly method like welding. I think while a gasket might work sometimes getting it to reliably seal will be hard

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If the low air pressure you want to retain is on the head end of the rivet, applying sealant or a gasket at that point is the best shot but I'd be doubtful that 10 out of 10 rivets wouldn't leak.

all depends on how air tight you expect it to be

In my opinion they cannot be relied upon if you will require a perfect seal.....if there is such a thing as every thing eventually leaks...well that is my experience anyway.

One of the problems I think you will have is that the thin sheet metal will not be stiff enough to compress a gasket or sealant even if applied to the joint. While it will probably provide a passible joint immediately around the rivet, at the places in between rivets the metal could well bulge or deflect out and leak.
Commercially inspection panels in things like A/C ducts typically have some sort of stiffening piece around the hole, whether that be folds (or forming) of the metal or a flange of thicker material to make the joint stiffer.

Michael

It is hard to know what you are trying to do, if you are putting sheets together and it is under a metre then you could apply a polyurethane sealant and clamp/ put bricks on top until it sets, I doubt you could tear it apart.

I am a plumber and we use ⅛ rivets on roof flashings, we use normal monel rivets and put sealant over the holes.
My theory is the rivets are only there until the sealant dries.

I'd probably try to find someone in the aerospace industry to talk to who does it as they would do a lot of it and would know how to do airtight seal

In aviation sealant would be put on the faying surfaces and after the assembly is done the shop heads (upset end of the rivet) would have sealed applied to them. In some cases an additional sealant similar to a varnish would be allied to the area. It holds fuel in the wings and the fuselage cabin pressure. Faying surfaces on most assemblies have sealant to keep water from getting in the joints for corrosion prevention even if the are not holding any air or fluids. Gaskets are only used on parts that are regularly accesses for servicing or inspection.

If you are going to use sealant in your assembly make sure it is a slow curing type that will let you get it put together before the sealant "kicks off".

Pete