Bubbles in a Resin Cast, Not in the Mold | RUUIPON

Run a fingernail across the empty, dry well under a raking light. If that rubber is glossy and crater-free, the pocks in your epoxy or PU are your pour. Recasting the platinum skin copies a smooth master and still gives you a pocked dump. Face craters that you can feel in the rubber are the other article — vacuum, brush coat, mix. This page stays on dump-side bubbles: cold viscous resin, no pressure pot, a closed undercut that trapped air, moisture in the cup, or a mix you whipped.

RUUIPON supplies the tool — master, box, A/B, vacuum, jacket — Bao'an since 2018. We will say when the well is guilty. We will not pour a second glove to hide a resin technique miss. Prototype 3–7 business days after CAD lock if the well *is* guilty. MOQ 20 pieces per design. USD $50 when CAD must change for a vent or a split. LSR *parts* are wydsilicone.com.

Does not apply when the empty well is cratered (mold-side), when the “bubble” is shrink porosity in the middle of a thick brick, or when you are describing chocolate or pectin. Don't oil a food well as a diagnostic.

Dump-side patterns that mimic a “bad mold”

Cloudy micro-pocks on the show face; well is a mirror. Cause: air in the resin that rose to the RTV wall, or moisture in a PU cup. Warm, thin dumps and a pressure pot push that air into solution or out a vent. Vacuum on the *resin* (if the kit allows) is not the same as the vacuum we already pulled on the platinum. Confirm: fingernail on dry rubber — no crater. A pressure-cast twin from the same well comes cleaner. Fix: change the dump. We would not remake a smooth cavity.

One repeating bubble in a deep letter or a bail, well is full and sharp. Cause: the dump never wetted the feature; air stayed in the serif. The rubber copied the master correctly. Confirm: the rubber well is complete; the resin letter is truncated with a bubble at the tip. Fix: warmer resin, a needle vent, a split so that letter is not a blind pocket, or a shallower logo. Structure Decision: if a one-piece peel cannot vent that serif, it is a two-part, not a harder Shore.

Pocks only on the first pour of the day, later dumps cleaner. Cause: cold resin, cold well, or water on the face. Confirm: well temperature vs later dumps; fog test for moisture. Fix: warm the kit in the band the TDS allows; dry the well. Not a recast.

Large voids at the thickest section, skin looks fine. Cause: shrink porosity or gel-front air, not RTV face bubbles. Confirm: cut the dump; voids are internal. Rubber floor is smooth. Fix: dump sequence, risers, slower mix. Recasting platinum does nothing.

Jacket-side foam on the tool, dump still pocked. Cause: two processes. Jacket foam is our leftover cup. Dump pocks are yours. Confirm: empty well vs jacket. Fix: leave the jacket if keys fit; change the dump. Recast the skin only if the *face* is cratered.

Typical shop values

Caption: Typical shop values.

The photo that would prove dump-side guilt: dry empty well (smooth) and the pocked dump in one frame, same well ID, coin for scale. Do not send only the pretty Instagram pour.

Worked example (anonymized)

A 12-cavity coaster, platinum ~30A, open-back. Cloudy epoxy photos. Empty wells were smooth under raking light. One cavity pressure-cast overnight came clear. Two wells had a repeating hole in a 0.2 mm letter — rubber was full, resin never entered. We opened the letter on CAD ($50 because the mesh needed a real change), recast those two skins, left the ten. We did not remake the tray for “bubbles.”

One procurement mix-up

“Bubble-free mold” on a PO is not a resin process. Say degassed RTV face, pressure-cast dump, or both. A witness photo of the empty face is the audit. Tooling charge ≠ a free recast because the dump was cold.

We would not recommend

We would not recommend recasting a glossy well to fix pocked resin.

We would not recommend a pressure pot as a substitute for weighing your resin.

We would not recommend oiling a food cavity to “see if it fills.”

We would not recommend blaming platinum shrink for a void in the middle of a PU brick.

flowchart TD
  A[Pocks in resin piece] --> B{Fingernail on dry empty well}
  B -->|Craters in rubber| C[Mold-side — vacuum / brush coat / remake]
  B -->|Smooth glossy rubber| D{Where are the pocks?}
  D -->|Show-face cloud| E[Warm resin / pressure pot / dry well]
  D -->|Blind letter or bail| F[Vent, split, or shallower feature]
  D -->|Internal thick section| G[Shrink porosity — dump sequence, not RTV]
  E --> H[Do not recast a smooth face]
  F --> I[CAD change $50 when scope applies]

What to ask when you're buying

• Will the shop send a dry-cavity raking photo with the sample, not only a resin beauty shot?
• If the well is smooth, will they refuse a recast and say so in writing?
• Can a blind logo get a vent or a split instead of “try 40A”?
• Pressure pot: your process or theirs? We are the tool.
• Who keeps the master if only two wells need a letter change?

RFQ copy-pack

[email protected] · +86 135 3006 2969 · Xinhe Blvd, Shajing, Baoan.

RUUIPON dump-bubble vs face-crater RFQ Photo: dry empty well raking light + pocked dump, same cavity ID Resin: epoxy / PU / UV; pressure pot yes/no; dump temp Feature: blind letter / undercut / open tray Well fingernail: smooth / cratered Qty: process change / CAD vent / remake only cratered skins / MOQ 20 CAD: locked / need $50 3D

Matched next step: send the empty-well photo first. If the rubber is smooth we talk dump. If it is cratered we remake that skin. Prototype 3–7 business days after CAD lock when CAD must move. MOQ 20 per design.

Related: bubbles in mold or cast, custom silicone resin molds, degas without vacuum, contact.

FAQ

The resin is pocked but the mold looks fine — will you remake anyway? Not if the dry well is crater-free. Remake would copy the same smooth face. Change the dump or add a vent.

Can a pressure pot hide a rubber crater? It can push resin into a small crater and confuse the photo. Fingernail the dry well. Craters still clone on the next dump without pressure.

Is a pin vent on a one-piece glove enough? Sometimes for a single blind letter. A hook still needs the Structure Decision, not more holes.

Do chocolate bubbles use this page? No. Chocolate moisture and temper are a different dump. This page is resin/PU/UV in an RTV tool.

If you open a letter, is that a new MOQ? A CAD change is a design conversation. Production after lock is still MOQ 20 pieces per design. USD $50 when that CAD scope applies.