RTV Mold Tears at Logo Serifs, Thin Walls | RUUIPON

When the rubber itself rips at a letter tail or a 1 mm web, you do not have a "weak silicone" problem first. You have a peel path that is thinner than the tear the dump asks for. Hairline serifs, knife-cut negative spaces, and unsupported thin walls concentrate strain the first time an operator inverts the tray. Raising Shore A without changing the logo usually moves the tear to the next-thinnest web, or it locks the pour in the well. Run the RUUIPON Mold Structure Decision before you type a new durometer into the chat.

This is for custom RTV tools with logos, mascots, and thin islands. RUUIPON, Bao'an since 2018: master, box, keys, jacket, recast. A steel logo insert or an LSR keypad is wydsilicone.com.

Does not apply when the *pour* tore (chocolate serif, gummy ear) and the rubber is intact, when a nick from a knife started the tear, or when you are talking ISO 3302-1 M1 "precision" as if it were tear strength. Rubber class on the drawing is not a logo depth.

Structure Decision, applied to a tearing logo

Flat back, open-back tray, logo on the floor: keep one-piece if the letter depth and draft can peel. If the serif is a hook in the rubber, it is not a Shore problem — it is a shallower letter, a fillet at the root, or a split so the letter pulls on a core.

Deep undercuts plus a peel: if the silicone cannot come off without stretching a web under 1–2 mm, go two-part, a removable plug, or a core. Large wet trays: add a mother mold so the thin wall isn't also the structural tray.

Tear starts at a serif root, rubber flap still attached. Cause: sharp internal corner in the rubber (sharp external corner on the master). Confirm: the flap origin is the same letter on multiple cavities; no knife nick. Fix: fillet the master, add draft, often reduce depth (0.3–0.6 mm is a common chocolate-bar start; gummy logos vary — send the file). Do not "just do 40A."

Tear through a thin island between two cavities or around a hole. Cause: web too thin for invert-and-dump, especially at 10A–20A without a jacket. Confirm: measure the web; if it's a millimetre-class wall carrying the whole peel, the layout is wrong. Fix: thicken the web, add a jacket, or drop cavity count. MOQ 20 is per design — a stronger layout is a new design, not a free tweak after you approved a lace-thin sheet.

Tear only when the operator inverts cold, stiff trays. Cause: cold rubber plus a thin wall. Confirm: same tray at room temp peels; fridge-stiff tray rips. Fix: demold warmer, or spec a jacket so the skin isn't the beam. Don't store nested in a freezer.

Tear after a few dozen dumps, always at the same serif. Cause: a micro-nick became a tear starter, or the letter was always too aggressive. Confirm: first-week photo vs now. A new nick is abuse or a flash trim. A letter that always looked like a hook was DFM. Fix: recast from a revised master. Tooling charge didn't buy unrestricted redesigns — say if this is a paid CAD pass ($50 when that scope applies).

Jacket intact, only the cavity skin splits at a hinge. Cause: the skin is doing the hinge work. Confirm: keys still fit; the tear is at the flex. Fix: thicker skin or a real hinge design. We would not raise Shore until the hinge exists.

Typical shop values

Caption: Typical shop values.

The photo that would prove a geometry tear: cavity-side, raking light, flap origin at the serif root, scale in the frame, jacket in the background still whole.

Worked example (anonymized)

A 36-cavity logo gummy, 4 g pectin, 0.9 mm serif, platinum ~20A, no jacket. Ear of the letter tore on invert week two. Buyer wanted 50A. We recast the master at 0.4 mm with a root fillet and added a jacket; Shore stayed ~20A–25A. Dump improved. A 50A tray would have locked pectin in the old 0.9 mm hook.

One procurement mix-up

"Make the logo pop" on a marketing brief is not a millimetre. Pop in a photo is often a tear in the tool. Lock depth with a scaled file. Tooling charge ≠ ownership of every future serif experiment.

We would not recommend

We would not recommend raising Shore A as the first lever on a tearing serif.

We would not recommend hairline negative space in a 10A glove with no jacket.

We would not recommend trimming flash with a knife toward the logo.

We would not recommend quoting this tear as an LSR/steel part job on ruuipon.com.

flowchart TD
  A[Rubber tore] --> B{Pour piece intact?}
  B -->|No, pour tore, rubber OK| Z[Wrong article — gel/chocolate diagnostic]
  B -->|Yes, rubber flap| C{Origin at serif root?}
  C -->|Yes| D[Fillet + draft + shallower letter]
  C -->|No, through a web / island| E[Thicken web or drop cavity count]
  D --> F{Still a hook after DFM?}
  F -->|Yes| G[RUUIPON Structure Decision: split / plug / core]
  F -->|No, open-back still peels| H[One-piece + jacket if the sheet is large]
  E --> H
  G --> I[Keys, not a harder Shore]
  H --> J[Don't raise Shore first]

What to ask when you're buying

• Logo file with scale, not a screenshot?
• Depth in millimetres, draft, and which serifs can die?
• Invert dump or a supported peel?
• Jacket allowed?
• Who pays if marketing wants the letter deeper after T1?
• ISO 3302-1 class if present — M2 is a common default, not "won't tear."

RFQ copy-pack

[email protected] · +86 135 3006 2969

RUUIPON logo / thin-wall tear RFQ Cavity-side photo of flap origin: Logo file + scale: Current depth guess: Shore if known: Jacket today? yes / no Pour: pectin / chocolate / resin / other Qty: recast sample / MOQ 20 CAD: STEP / $50 3D if we must remodel serifs Food-contact: 177.2600 / LFGB / craft

Matched next step: send the flap photo and the vector. We recast the master and, if needed, the split. We will not start at 50A. Prototype 3–7 business days after CAD lock. MOQ 20 per design.

Related: custom logo silicone molds, custom silicone gummy molds, gummy stick vs tear, contact.

FAQ

Is a tearing serif proof the silicone is cheap? No. Cheap mixes exist, but a repeating flap at one letter is almost always the letter. Confirm a nick vs a root corner, then DFM.

Will a harder tray save a 0.9 mm hairline logo? It may lock the pour. Fillet and depth first. Shore is a later recast decision.

Can you keep the marketing letter and add a split? Often. That's the Structure Decision: if a one-piece peel can't survive, we key a two-part or a plug. Say it on the RFQ.

Does MOQ 20 include a free redesigned logo? No. Production is 20 pieces per design. A serif remodel is CAD scope — $50 when that applies — then a new witness.

What about steel for the logo insert? If you need a steel or LSR *part*, that's wydsilicone.com. This page is the RTV skin that tore.