Materials Riding in the Truck Through Heat and Freeze

Why this matters

A work truck is a warehouse with no climate control. In January the box sits below freezing all night; in July a closed cab cooks in the sun. Paint, caulk, adhesives, cements and aerosols each have a storage range printed on them, and the truck violates most of those ranges for part of the year. The expensive failure is not the frozen gallon you notice and throw away. It is the tube that froze in the truck, thawed by morning, went into the joint looking normal, and let go six months later with your name on the job.

What the storage block on a label says

Most products carry a short storage block, separate from the application instructions. An example of the kind of text you will find, invented for illustration (your product's own numbers are on its own label):

STORAGE
  Store between 40 F and 90 F.
  PROTECT FROM FREEZING.
  Keep container closed when not in use.
  Shelf life: 12 months unopened, from date of mfr.
  Lot: 24-118-B   (date code)

CAUTION - aerosol / pressurized
  Contents under pressure.
  Do not store above 120 F.
  Do not puncture or incinerate.

The storage range is for the product in the container. It is the range over which the maker stands behind the shelf life and the performance numbers on the data sheet. It is different from the application range, which is about the surface and air while you use it. A product can be warm enough to apply and still have been ruined by where it slept.

The words matter.

• "Protect from freezing" or "do not freeze" means one freeze can be enough to damage it. Treat a product that froze as suspect.
• "Freeze-thaw stable" with a cycle count means the maker has tested it through a stated number of freeze and thaw cycles. A product rated for a few cycles has a few cycles in it, total, including any it went through before it reached you.
• "Store above" or "warm to room temperature before use" is about workability, not damage. Some products thicken in the cold and recover fully when warmed.
• "Do not store above" on an aerosol is about the can's pressure rising with temperature. The common aerosol warning is 120 F, and a closed vehicle in summer sun can exceed it. Refrigerant and other gas cylinders carry their own maximum on the cylinder label.

Shelf life assumes the storage range was kept. The date code tells you age. It does not tell you whether the product spent a summer on a dashboard. Heat ages most products faster, and a tube near the end of its shelf life that also rode through a hot summer may not perform.

What freezing does

Freezing ruins water-based products: latex paint and primer, acrylic latex caulk, water-based adhesives, premixed joint compound and patching compounds, many sealers and water-based stains. These products are emulsions or dispersions, tiny particles of polymer suspended in water. When the water freezes, the ice crystals push the particles together hard enough that some of them fuse. When it thaws, the fused particles do not separate again.

Sometimes the damage is obvious: paint that thaws grainy or curdled and will not stir smooth, caulk that comes out lumpy or watery. Sometimes it is partial: the product looks and tools nearly normal, but a share of its binder has already clumped and is no longer available to form a continuous film. That film cracks sooner, sticks worse, or stays weak, and the failure shows up months later as cracking, peeling or a bead pulling off one side of a joint. That is why "it looked fine when I used it" proves nothing about a product that froze.

Solvent-based and reactive products (most silicones, polyurethane sealants, solvent-based adhesives, PVC cement) do not suffer the emulsion problem. Cold makes them thick and slow and some will not cure until warm, which is a handling issue rather than damage. Two-part epoxies can crystallize in the cold, turning cloudy or grainy; many makers say crystallized resin can be restored by warming it as their instructions describe, so read before discarding.

What heat does

Solvent products lose solvent. A can of PVC cement or contact adhesive that sits hot loses solvent through the seal and every time it is opened. It thickens, then gels. Gelled cement is trash; thickened but flowing cement may be usable if the maker's instructions allow.

Reactive products cure early. Moisture-cure sealants and foams react faster when hot, so a tube stored hot partly cures inside the tube or the nozzle, and an aged, heat-soaked tube can lose some of its stretch even when it extrudes. That is the heat version of the freeze problem: the bead goes in normally and has less movement capability than its rating.

Pressure rises. Aerosol cans, spray foam, propane cylinders and refrigerant cylinders build pressure with temperature. A can above its label limit can vent or burst. In a cab, that is a projectile and a cloud of flammable propellant near the driver.

Flammable vapor. Solvent cements, adhesives, aerosol propellants and fuel all release flammable vapor faster in heat. In a closed cab or a van with the cargo area open to the driver, that vapor collects where people breathe and where a spark from a phone charger or a dash switch can reach it. Flammable products ride in the ventilated cargo area or an outside box, closed, upright and secured, not in the cab.

Signs a product has been spoiled

These checks catch the obvious cases only. A product with partial freeze damage can pass every one of them. For a water-based product labeled "do not freeze" that you know froze, the honest disposition is discard, not test.

Worked example: the van after a cold snap

A handyman's van spends a Monday night outside at the customer's house during a cold snap. The thermometer on the van mirror reads 14 F at 6 am, and the cargo area has no heat. The tech takes inventory of everything that rode through the night before deciding what goes into Tuesday's jobs.

The cargo shelves hold:

• 8 tubes of acrylic latex caulk labeled "protect from freezing"
• 4 tubes of siliconized acrylic caulk labeled "freeze-thaw stable to 5 cycles"
• 6 tubes of silicone sealant
• 2 gallons of exterior latex paint labeled "do not freeze"
• 1 pail of premixed joint compound labeled "protect from freezing"
• 2 cans of PVC cement
• 3 cans of aerosol spray foam

That is 26 containers (8 + 4 + 6 + 2 + 1 + 2 + 3).

The dispositions, with the reason for each.

• 8 acrylic latex tubes: discard. Labeled "protect from freezing", and 14 F overnight froze them. Testing could only show the worst damage, and the job they would go on is the joint that fails in six months.
• 4 siliconized acrylic tubes: keep, with a note. Rated for 5 cycles. The tech does not know their history before purchase, but they were bought from a heated store two weeks ago and this is their first known freeze. They come inside to warm to room temperature naturally, get a test bead on cardboard, and go back in service if the bead extrudes smooth. The tech marks the tubes with the date so a second freeze is not mistaken for a first.
• 6 silicone tubes: keep. Not water-based, so the freeze does not damage them. They are stiff, so they ride in the cab to warm before use.
• 2 gallons of latex paint: discard. Labeled "do not freeze." Even if they stir smooth, they are not going on a customer's siding.
• 1 pail of joint compound: discard. Same reason; the bottom is already separating.
• 2 cans of PVC cement: keep, warm first. Solvent-based. Cold made them thick; they warm closed, in a heated space away from any flame or pilot (not the cab, per the vapor rule above), and if they still flow off the dauber once warm, they are usable.
• 3 cans of spray foam: keep, warm first. Cold reduces the can pressure and the foam's yield; the can label states the product temperature for use, and the cans warm to that in the same heated space, away from ignition sources, before use.

Count the result: 11 discarded (8 + 2 + 1) and 15 kept (4 + 6 + 2 + 3). 11 plus 15 is 26, which matches the inventory. By count, 11 of 26 containers is about 42 percent of what was on the shelves. By value it may be more or less, since one gallon of paint is a bigger share of the stock than one tube of caulk.

What the tech changes. Water-based products on this van move to an insulated bin and come inside overnight from November to March. That one change would have saved all 11.

Disposing of what was discarded. Latex paint and water-based caulk are often allowed in regular trash once fully dried solid, but the rule depends on the state and the local hauler, and some states run paint take-back programs instead. Solvent cements and aerosols usually cannot go in regular trash when partly full. Check your state's rules and your hauler's; do not pour any of it down a drain.

The summer version of the same van

In July the same van parks at a job at 9 am and sits closed in the sun until 3 pm. The cab and the cargo area run far above the air temperature, and the aerosol cans in the door pocket can pass their 120 F label limit by midday. The PVC cement loses solvent, the polyurethane sealant ages, and the paint thickens at the surface. Summer storage is the mirror of winter: shade, ventilation, light-colored or insulated bins, aerosols and cylinders out of the cab, and solvent products closed tight.

References

• Manufacturers' labels, data sheets and SDS for storage ranges, freeze-thaw ratings and disposal
• State and local rules for disposal of latex paint, solvent products and aerosols, including state paint stewardship programs where they exist
• See related: The Cold-Weather Materials Handling SOP
• See related: PVC and Plastic Pipe When the Temperature Drops
• See related: Sealant Joints and the Temperature You Caulk At