Hi forum! I have a possibly strange question I hope someone can help answer. We know about ingress protection from lights, e.g. IPX8 because only the water resistance is rated and not particles, like dust.
Now I wonder about dust, and specifically, whether silicone grease added to rubber gaskets can generally improve the seal in airtight applications?
Really? I was also concerned whether the silicone grease might attract particles and make a not very pleasant layer of guck. :Sp
Thats why you replace it after some time…
Thank you, Alex!
It will do both of those things, give a better seal while attracting gunk. Can’t have everything at the same time now can you?
Edit: Depends on where you hang out, some gunk is undesireable…hang out in a Gold mine and the gunk is good! 
silicone grease will also swell rubber seals as it soaks in… it will work better while its there, but the seals would have to be replaced at some point if the shape no longer fits… I have found the gaskets to be smaller in diameter than the lights, in general, so there is more of a ‘rubber band’ effect. I don’t think its so critical because of the shape and the way the lights fit together, but for something like watches that have a very specific size/shaped gasket this can cause a problem. The tolerances are much tighter and the re-placement of a siliconed seal is likely to be very difficult to do precisely because of the swelling…
as for the ‘gunk’… if it stops water it will stop the gunk… you could remove clean and re-grease flashlight o-rings without a problems I would think… if the light is cutting the o-ring, this has to be dealt with first… in general should not be happening…
Ahh, so the rubber somehow absorbs the grease? I did not know this. I did check but the manufacturer does not offer replacement seals. But I added some grease anyway because I am sure the existing seals are not making an airtight seal.
Get Buna O-Rings (Nitrile) they are more wear resistant and can withstand chemicals better than rubber O-rings.
Here is a comparison chart for various O-ring materials
I don’t think o-rings will be compatible. The seals that came are made to fit.
What are you trying to seal?
The seals on my still fairly new vacuum cleaner… It has HEPA H12 rated filters but I am still sneezing etc. when using it. 
nitrile seals are great if you can get them….
for your vacuum I’m going to assume the seal is quite large…. do you have to open the vacuum regularly?
I was going to suggest… if its more permanent you could add a bit of silicone sealant and then close it up… you could still do this perhaps on one side only (just a little bit in the deeper recesses) which might snug the seal up…. at a certain point, if you can’t replace the seal and it still leaks and you want to keep the vacuum… DUCT TAPE!!! just joking… 
There is only one part in the dust chamber that takes an actual o-ring, the rest is all “custom” and fairly small but I want to make sure the seals are effective.
Since it is the bagless variety I do have to empty it regularly (and clean it too!) so I wear a dust mask for this to limit exposure.
Actually, I did add some duct tape today! Not for seal though, to help prevent the lid from unlocking by accident:
Or deliberately make the seals swell up a bit by using gas or break fluid, another option could be to use a gasket forming product and shape it by hand…
Sugru is like a liquid silicone that you shape to fit and allow to dry, it sticks in place but maintains the rubbery silicone physical properties. Perhaps it could be rolled into a thin tube (think pasta noodle or spaghetti) and fit into the plastic side. Once cured it would give a silicone press against the factory seal, like a double seal, would probably end the dust bypassing and causing you to sneeze.
If you can’t easily stop it, get rid of that one and get a Dyson Animal.
Sugru isn’t really that soft enough to make that kind of malleable but strong seal. It’s quite hard when cured (I thought it would be softer, like caulking).
Ah, thanks for that info! I have some but haven’t used it yet. I was also assuming it stayed mushy and rubbery feeling. Changes what I planned to use it for.
Try uncured raw silicone, like they use for making Aquariums. Food grade is another term for it. It’ll cure into a softer rubber and stick in place. Might want to lay a bead of it down into the channel where the factory seal is supposed to go, cover it with saran wrap or the equivalent, and lightly fit the two pieces together to ensure the surfaces meet. Allow that to cure with the contact being made, then you’re better assured of the pieces going together when you’re ready to put it back together. A thin film is all you need to assist the factory seal, dont really need a bead of the stuff. Secondarily, you can lay a thin bead into the channel, spread it into a film with your finger tip or a gloved finger. Put vaseline or silicone grease on the mating part and then put the 2 pieces together but not tightly together, ensuring that there will be compression when it’s all cured. The grease on the factory seal side will prevent the silicone from sticking and allow a mating of the surface areas at the same time, custom forming the seal action.
It will flex (it’s okay to fix cables for example), but it isn’t mushy at all. It’s definitely softer in the packet (I have some left in the fridge).
The aquarium seal sounds like a great idea! Thanks.
Since I put on the grease I can already see where the poor seals are. I may also look for a thin o-ring to put around the final filter (post-motor) since this is the one that is allergy rated.