Glove Mold vs Block Mold for Custom RTVs | RUUIPON

A glove mold is an open-back RTV skin that wraps the master and peels like a sock. A block mold is a box pour: the master sits in a dam and you bury it in platinum until you have a cube you cut or a two-part you split. Gloves use less rubber and need a jacket the moment the dump is wet or tall. Blocks cost more grams, hold shape without a jacket on small parts, and fight you on demold if you expected a one-piece peel. Run the RUUIPON Mold Structure Decision: flat back → glove/open-back. No flat back, deep undercuts that will not peel → block that is actually a keyed two-part (or a plug). Large wet casting → mother mold either way. "Glove vs block" is a rubber-volume and peel conversation, not a brand of silicone.

RUUIPON pours both in Bao'an 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. LSR *parts* are not gloves: wydsilicone.com. Jacket: mother-mold shell. Split: split mold.

Does not apply when you meant HCR compression of a *part*, when the "block" is a steel cavity, or when a tiny soap sample will be cast twice and never needs either jacket or keys. Jewelry gloves and concrete blocks are not food. Do not paste 177.2600 onto a PU block because the rubber is platinum.

Structure Decision, applied to glove versus block

Flat back, cavity on one face (chocolate bar, gummy tray, coaster). Glove/open-back. You are not burying a master in a cube. You still spec wall, a board or jacket if sag would be 0.5–1.5 mm, and platinum 1:1 or 10:1.

Master you can wrap and peel without inverting through a hook. Glove. Think a simple candle, a one-sided figurine relief, a planter with draft. Rubber grams follow skin thickness, not box volume.

Master that is two-sided, posed, or full of undercuts. A one-piece glove will tear or oval. A *block you then cut* is a shop-made split — you are choosing where the knife goes after cure. A *designed two-part block* puts keys in CAD before the pour. We would rather design the split than surprise-cut a cube on a production SKU.

Wet kilograms (concrete, large resin). Glove without a jacket balloons. Block without a jacket still flexes at 10A–20A if the cube is large. Jacket is the hydrostatic answer, not "pour a thicker block."

Rubber volume: box minus master plus waste for a block; skin envelope plus waste for a glove. That is why a glove of the same figurine can be a fraction of the grams and still need a more expensive jacket.

The photo that would prove the choice is the master on a board (glove) versus the master in a dam with pour height marked (block), plus the Structure Decision note on the PI. A cube of leftover rubber is not proof you needed a block.

Typical shop values

Caption: Typical shop values.

Common mix-up: glove is always cheaper so always glove

Grams are cheaper. Downtime is not, if the glove tears at a posed arm. The cousin mix-up is pouring a block "for strength" on a flat chocolate tray — you spend rubber and still need a jacket for sag. Another: calling a cut-block a one-piece because it started as one pour. Once you cut it, you own a split with no keys unless you cut keys too.

Worked example (anonymized)

A 180 mm resin bust, no flat back, arms off the torso. Buyer asked for a glove "to save silicone." Structure Decision: not a flat back; peel would invert through armpits. Quoted a designed two-part block, drafted keys, ~15A platinum, resin jacket, USD $50 because the STL had no parting solids. Proto 3–7 business days after lock. Production MOQ 20. A candle of the same height with draft would have been a glove plus jacket. This bust was not food; jewelry-scale copies of the face would not inherit 177.2600 either.

We would not recommend

We would not recommend a one-piece glove on a posed two-sided figurine to save grams.

We would not recommend a block pour on a flat-back food tray "for premium weight."

We would not recommend surprise-cutting a production cube instead of CAD keys.

We would not recommend pouring a thicker glove instead of a jacket on wet concrete.

flowchart TD
  A[RUUIPON Mold Structure Decision] --> B{Flat back?}
  B -->|yes| C[Glove / open-back]
  B -->|no| D{Peel without tearing hooks?}
  D -->|yes| C
  D -->|no| E[Block as designed two-part or plug]
  C --> F{Large wet dump?}
  E --> F
  F -->|yes| G[Mother-mold jacket]
  F -->|no| H[CAD lock → 3–7 days → MOQ 20]
  G --> H

What to ask when you're buying glove vs block

• Flat back or a wrap-around master?
• Are we designing a split in CAD, or hoping to cut a cube?
• Jacket in the quote, or only rubber grams?
• Food tray vs craft (jewelry/concrete are not food)?
• After lock, 3–7 business days, then MOQ 20 of *that* structure?

Related: sculptures and figurines, quote, contact.

RFQ copy-pack — name glove or block

Email [email protected]:

Structure Decision: glove-open-back / two-part block / plug / jacket Master: STEP / photos (USD $50 if you model) Pour: food / resin / wax / concrete (concrete is not food) Shore band 10A–20A unless geometry says otherwise Platinum 1:1 or 10:1, vacuum Prototype 3–7 business days after CAD lock, then MOQ 20 / design Do not default to glove only to save grams

Send whether the back is flat. We will pick glove vs block from the peel path, not from a video titled "easy glove mold." Phone +86 135 3006 2969.

FAQ

Is a glove mold the same as an open-back tray? Same family: rubber on one side, peel, often a board or jacket. A food gummy tray is an open-back. A wrapped candle is a glove. Neither is a buried block.

Why would I ever pour a block if gloves use less silicone? Two-sided undercuts, a designed split, small parts that you want to stand without a jacket. Grams are one line. Demold is another.

Can you turn my glove into a block later? That is a new pour, often a new CAD. Production of a new structure is another MOQ 20 if it is a new locked design. The first glove is not a free cube.

Does a block hold tighter tolerances? ISO 3302-1 M2 is still a rubber class. A jacketed glove can beat a floppy cube. Structure plus jacket, not mass of leftover RTV.

Can I food-dump in a glove that previously cast resin? We would not. Retire that cavity from food. Platinum chemistry does not reset a resin cabinet.

How we would quote grams so the two options are comparable

Ask for both numbers on a borderline part: glove skin grams (envelope × thickness × density × waste) versus block grams (box − master × density × waste). Add jacket cost to the glove column. Add split-CAD time (the $50 when modeling applies, plus keys) to the block column. The cheaper PI is often the glove-plus-jacket, not the glove-without-jacket that sags 0.5–1.5 mm, and not the block that wastes a kilogram of platinum around a flat bar.

Tin-cure blocks that sit on a shelf keep shrinking; we would not spec tin as a warehouse spare in either structure. Platinum ~0.1–0.3% then holds.

Licheng Technology Industry Park, Xinhe Blvd, Shajing, Bao'an, since 2018. Mix, vacuum, pour the structure you locked — not a surprise cut.