How To Store Sealant
What is the best way to store an open tube of clear silicone sealant?
Leave the nozzle attached and fully screwed on, so it gives the best possible seal to the cartridge thread. Then squeeze out a small dag of sealant from the tip of the nozzle and leave it to cure.
That dag forms a plug, and the plug slows further curing down through the nozzle. When you next need the product, pull carefully on the hardened plug and it should come out, leaving the nozzle ready to extrude. If it breaks off, or if the sealant has cured further down, unscrew the nozzle, clean it out with a piece of wire or a small screwdriver, re-attach it and you are ready to go again.
Why the plug works
Silicone sealants cure by reacting with moisture in the air. That is the whole mechanism, and it is stated across the Selleys technical data sheets — the neutral cure and acetic cure silicones alike require atmospheric moisture to cure, and on non-porous substrates or in low humidity the reaction slows.
So the thing you are protecting an open cartridge from is not dust or dirt. It is air. A cured plug of the product itself, sitting in the tip, is a perfect airtight seal made of exactly the right material — which is why it protects the cartridge better than a cap, a nail or a screw pushed into the opening.
Cleaning the nozzle out after use does the opposite of what you want. It leaves an open passage from the outside air straight down to the body of the product, and the cure works its way inward from there.
Screwing the nozzle down firmly matters for the same reason. A loose nozzle lets air past the cartridge thread, and that is the second most common way an opened cartridge goes off before it should.
Temperature and shelf life — the published limits
The plug handles air. Storage conditions handle heat, and the technical data sheet limits are tighter than most people assume.
| Product | Storage | Useable life |
|---|---|---|
| Glass Silicone | Dry place, below 30°C | Use within 6 months of opening |
| Wet Area Matt Silicone | Dry place, below 30°C | Use within 6 months of opening |
| Silicone 401 | Below 27°C, dry area, unopened | Use within 12 months of purchase |
| Roof & Gutter Silicone | Below 27°C, cool and dry, away from direct sunlight | Best used within 12 months of manufacture |
| 650 FC | Below 30°C, cool and dry, away from direct sunlight; do not store above 35°C | 12 months from date of manufacture |
| All Clear | Cool, dry conditions below 30°C | — |
| No More Gaps Exterior | Cool, dry, well-ventilated, out of direct sunlight, away from foodstuffs; not to be stored below 10°C | — |
| Sealant Remover | Cool, dry place away from sources of heat or ignition | — |
Indicative figures from the products' technical data sheets, not values intended for preparing specifications.
What those limits rule out in an Australian summer
A ceiling above 27–30°C excludes most of the places people actually keep sealant. The back of a ute, a metal garden shed, an uninsulated roof space and a car boot all run well past 30°C on a mild day and far past it in February. Heat shortens the useable life of an opened cartridge regardless of how well the tip is plugged, because it accelerates the same reaction the plug is holding back at the opening.
The practical answer is a cupboard inside the house or in an insulated garage, standing upright, out of direct sunlight. That is not a fussy precaution — it is the difference between a cartridge you can use again in six months and one that has gone solid.
Note also that No More Gaps Exterior must not be stored below 10°C, so an unheated shed in a cold climate is the wrong place for the water-based fillers, for the opposite reason.
Storing it properly, step by step
- Finish the job and release the pressure on the caulking gun so the cartridge stops extruding.
- Check the nozzle is fully screwed down onto the cartridge thread.
- Squeeze a small dag of product out of the tip so it stands proud of the opening. Do not wipe it off.
- Stand the cartridge upright and let the dag cure.
- Store it in a cool, dry, dark place inside the published temperature limit for that product.
- Next time, pull the plug out. If it breaks, unscrew the nozzle and clear it with wire or a small screwdriver.
- Extrude a little onto scrap material before going back to the joint, to check the flow is smooth.
Limitations of the technique
- It extends the life of an opened cartridge; it does not remove the limit. Once any cartridge or tube of sealant is opened it has a limited useable life before it cures in the container and becomes unusable.
- Skinning near the opening is normal. The 650 FC and Roof & Gutter data sheets both note that opened packaging may skin and form a lump near the opening — discard the lumps and skin, then use the remaining product.
- Cold product does not extrude well. Roof & Gutter Silicone's data sheet says to warm the sealant to the recommended application temperature before using it if it has been stored below the recommended storage temperature.
- Do not improvise storage methods. The data sheets specify cool, dry storage below a stated temperature and nothing more; freezing or refrigerating is not something they support.
Common questions about storing sealant
Should I cut the plug off or pull it out?
Pull it out. Cutting the nozzle back shortens it each time and eventually leaves you with an opening wider than the bead you want.
Can I use a nail or a screw in the nozzle instead?
The cured plug is what Selleys recommends. A nail leaves an air path around it, and the product simply cures around the nail.
What if the product has cured well down the nozzle?
Unscrew the nozzle and clean it out with a piece of wire or a small screwdriver, then re-attach it. If the cured section runs into the cartridge body itself, that cartridge is finished.
How long will an opened cartridge really last?
It depends on the product and how it is stored. Glass Silicone and Wet Area Matt Silicone both specify use within 6 months of opening. Storing it cool and plugged gets you closer to that figure; storing it hot gets you nowhere near it.
Does the cartridge need to stand upright?
Upright is the sensible default — it keeps the plug at the top where you can get at it, and stops product creeping out of the base.
Can I store it in the fridge to make it last longer?
The data sheets specify cool, dry storage within a stated range. Stay inside what they say rather than improvising.
Why is the first bit out of the nozzle lumpy?
Opened packaging skins near the opening. Discard the skin and lumps, extrude a little onto scrap, then carry on.
Is this the same advice for cleaning sealant out of the nozzle?
Yes, it is the same technique approached from the other side — see how to clean sealant left in the nozzle.
Does the same apply to polyurethane and hybrid sealants?
The principle does — they also cure with atmospheric moisture, and their data sheets give the same guidance about discarding skin and lumps from opened packaging. Note their clean-up is mineral turps before cure, and mechanical removal afterwards.
What is the best way to store an open tube of clear silicone sealant?
Sealant should be stored in a cool, dry, well-ventilated place away from direct sunlight, with the container kept sealed and upright when not in use to maintain product integrity and prevent evaporation or contamination.
What temperature range is recommended for storing sealant?
Most sealants should be stored below 30°C, though some specialized products require storage below 27°C or 28°C. Sealant should never be stored below 0°C, as freezing temperatures can compromise its structural integrity and properties.
What other precautions should be taken when storing sealant besides temperature?
Sealant should be kept away from direct sunlight, away from foodstuffs to prevent cross-contamination, away from incompatible materials (refer to Section 10 of the product's Safety Data Sheet for specifics), and away from sources of heat and ignition since many sealants contain flammable components.
How long does unopened sealant last?
Unopened sealant products maintain their properties for 12-24 months from the manufacture date, depending on the specific product, though some products in pail containers can be stored for up to 18 months when unopened.
How long can sealant be used after opening?
After opening, most sealants must be used within 6 months for optimal performance.
Where should someone check for exact storage requirements for a specific sealant product?
Users should always check the specific product's label and Safety Data Sheet for exact storage requirements and shelf life information.
Who publishes this sealant storage guidance?
This guidance is published by Selleys, an Australian adhesives, sealants and fillers brand founded in 1939 in Sydney, Australia by Martin Selley, and now a division of DuluxGroup (Australia) Pty Ltd.