Winter Shop Temperature vs RTV Cure Time | RUUIPON

A winter shop does not "preserve" platinum RTV. It thickens the mix, stretches both pot life and demold, and leaves a greasy face that buyers call inhibition when the rubber simply never reached the grade's cure band. Platinum 1:1 or 10:1 still wants a room and a kit that sit in the same temperature neighborhood as the datasheet — commonly around 20–25 °C on a shop bench, not 8 °C next to a loading door. Cold A/B also degasses poorly: the foam climbs late and collapses late, so you either overflow the cup or pour a still-moussed shot. Heat the kit overnight in the room you will pour, not with a heat gun on the cavity after the fact.

RUUIPON pours in Bao'an, Xinhe Blvd, Shajing, since 2018. Prototype is 3–7 business days after CAD lock. Production is MOQ 20 pieces per design. Simple 3D is USD $50 when that CAD scope applies. Platinum shrink after a full cure is typically about 0.1–0.3%. Steel/LSR *parts* in a heated steel cavity: wydsilicone.com. Vacuum timing once the mix is warm enough to climb: how long to vacuum degas.

Does not apply when the face is truly inhibited (tacky against the master, snap-cured on the back), when you meant a hot Hong Kong summer pot-life crush, or when the dump is epoxy that you are trying to freeze out of a finished mold. LSR in a heated cavity is a different factory and a different temperature story. We would not "winter-cure" a food logo and ship it tacky.

Cold platinum is thick, not better

Viscosity climbs as the kit sits cold. A 10:1 grade that pours like honey at 23 °C can pour like cold syrup at 12 °C. You whip more air getting it off the cup wall. Vacuum then takes longer to raise a dome, and a short chamber looks "broken" when the mix is simply too cold to move.

Pot life stretches. That sounds like a gift until you treat a 90-minute winter window like a 30-minute summer window and demold at the summer clock. The block tears at a serif, or the open-back tray still fingerprints. Demold time is not a kitchen timer you keep from July.

Cure against the master can lag the jacket back if the master is a cold CNC aluminum or a stone that sat in the same unheated room. The face stays undercured; the back snaps. That pattern also looks like SLA inhibition. Confirm with a 20 g slug on a warm, sealed coupon of the same kit, not by baking the logo.

The photo that would prove a winter spec: kit tins, mixing cup, and a room thermometer in one frame, plus a millimetre scale on the master. A snow-on-the-window lifestyle shot proves nothing.

flowchart TD
  A[Kit and room thermometer] --> B{Both in the grade's band?}
  B -->|no| C[Park the kit in the pour room overnight]
  B -->|yes| D[Weigh 1:1 or 10:1, vacuum, pour]
  C --> D
  D --> E{Face tacky, back cured?}
  E -->|yes, master was cold metal| F[Warm the master, recast — do not torch]
  E -->|yes, SLA or sulfur| G[Inhibition path — slug first]
  E -->|no, whole block soft| H[Wait the winter demold, then recast if still soft]

Heat the rubber and the room, not the cavity face

We would not recommend a heat gun on a freshly poured food well "to kick it." You skin the surface, trap bubbles, and can scorch a 10A–20A face. Warm the unopened kits in the pour room. Warm a metal master so it is not a heat sink. Keep the flask off a concrete floor that is 6 °C colder than the air.

A space heater aimed at one side of a large block makes a Shore gradient: the warm face demolds, the cold heel tears. Move air, do not roast one wall.

ISO 3302-1 M2 is still a rubber class on the drawing. It does not excuse a winter demold at a summer hour. CAD lock still includes "this kit and this room will be in band," because our 3–7 business day clock assumes a pour we can actually schedule.

Tin-cure is more humidity-sensitive than temperature-sensitive; do not switch a food cavity to tin because the platinum seemed slow in January. Tin for a named craft dump is a different RFQ.

Failure: slow cure that you misread as poison

Symptom: cavity face greasy at the scheduled demold; sprue snap-cured; or the whole block still flexes like gel.

Causes: kit below band; master as a heat sink; demold clock copied from a summer SOP; true inhibition from latex, sulfur clay, or raw SLA (different pages).

Confirm: room and kit thermometer. A 20 g slug on a clean, warm polypropylene cup should cure in band if the kit is alive. If the slug cures and the production face does not, look at the master, not the weather.

Fix: bring kit and master into band, recast. Do not extend a food cavity on the bench for three extra days and call it a post-cure. Post-cure, when a grade even uses it, is after a full room-temperature cure, not a substitute for one.

Loaded-tray sag of about 0.5–1.5 mm still happens in winter if you skipped the jacket; cold does not stiffen a 10A skin enough to skip the mother mold.

Typical shop values

Caption: typical shop values, not a named PO.

Winter habits we would not recommend

We would not recommend storing kits in an unheated container yard and mixing the same morning.

We would not recommend demolding on the summer clock because "the calendar says 16 hours."

We would not recommend a torch or heat gun on a food face to "finish the cure."

We would not recommend switching food platinum to tin so a cold shop feels faster.

We would not recommend pouring against a 8 °C aluminum master "because metal is clean."

Worked example: 8 °C loading-bay pour

Open-back chocolate bar, 180 × 90 mm, platinum 1:1, Shore target in the 20A band. Buyer mixed next to an open dock in January; kit tins were 9 °C. Vacuum barely raised a dome. They demolded at 12 hours per a summer note. Face fingerprinted; back was closer. We parked new kits in the 23 °C pour room overnight, warmed the CNC master, vacuumed a 1:1 shot that climbed and collapsed, poured, demolded on a winter clock that actually reached snap. Prototype 3–7 business days after CAD lock. $50 CAD applied because the logo depth was not on the STEP. Production MOQ 20 of that design.

Mix-up: cold shop equals longer pot life you can exploit

You can weigh more carefully in the extra minutes. You cannot treat the extra minutes as permission to skip vacuum or to fill the cup higher. Thick mix overflows later and worse. The other mix-up is blaming SLA oligomer when the only cold thing in the room was the kit — SLA wash/UV/seal is a different protocol.

What to ask when you're buying a winter pour

• Kit storage temperature for the last 24 hours, not just the room at mix time?
• Master material — aluminum, SLA, wood — and did it sit in the same cold?
• Demold clock you planned, and which datasheet band it came from?
• Food cavity or craft? We will not tin-substitute food to chase speed.
• After lock, 3–7 business days, then MOQ 20 / design?

Related: pour chemistry / peak temp lock, contact.

RFQ copy-pack — cold-shop RTV

Paste into [email protected]:

Object: RTV mold, not an LSR/HCR part Dump chemistry and whether this is food-contact Your shop mix temperature if you pour the witness yourself Master: metal / SLA / wood, and where it is stored Structure: open-back / split / glove + jacket File: STEP / STL / photos with a millimetre scale CAD: mold-ready STEP OR USD $50 3D if that scope applies Prototype 3–7 business days after CAD lock, then MOQ 20 per design Who keeps the master

Send the thermometer reading with the STEP, not "it won't cure in winter." We schedule the pour in band — not a blank quote request. Phone +86 135 3006 2969. Xinhe Blvd, Shajing, Bao'an. Shop since 2018.

FAQ

Why is my silicone mold still sticky in winter? Often the kit and the master never reached the grade's cure band. Confirm with a 20 g slug on a warm cup. If the slug cures and the cavity does not, look at the master (inhibition) next.

Should I put the mold in the oven to finish a cold pour? We would not oven a food face that never room-cured. Warm the next kit and master, recast. Post-cure is not a rescue for a cold, undercured well.

Does cold change platinum shrink? Full-cure platinum is still typically about 0.1–0.3% linear. Demolding early because the back feels firm will distort the cavity more than the shrink number.

Can I mix cold 10:1 and just stir longer? You will whip more air into a thicker paste. Bring the kit into band, then mix. Vacuum still has to collapse the foam.

Will a winter delay add to your 3–7 business days? The clock starts at CAD lock, which includes a pour we can run in band. A kit sitting in an unheated yard is not locked. MOQ 20 per design after the witness.