RFQ Checklist: 7 Details for an Accurate RTV Mold Quote

If you're RFQing a custom RTV silicone mold, pack seven inputs or the shop invents the eighth: risk padding on company letterhead.

Custom RTV tools (platinum or tin skins, masters, jackets) are priced from risk. When you omit a detail, the shop either pads, underbids the wrong glove, or assumes the cheapest construction. None of those is an “accurate mold quote.” Pack the RFQ like a kit. If a line is unknown, say unknown and give a bound. Silence is worse than a range.

LSR class, cold-runner, and cavitation-for-press are a different kit. Don't paste that template onto a mold box.

1. The dump, as 3D plus a 2D that can be ballooned

Native CAD or STEP, and a 2D with datums, fits, flash max at the split, pour keep-out, cosmetic faces, and wait note. Photos of a clay model are not a part definition.

If you omit the 2D, the shop quotes a cavity that copies the STL and ignores every tolerance that will fail FAI. If you omit undercut direction, they quote open-and-shut and you will buy a split later. If you omit the ship state (trimmed or not, wait or not), they quote a pretty as-cast dump.

Unknown tolerance? Mark “commercial” vs “fit” vs “fill-weight” even without numbers. That still changes jacket and polish. ISO 3302-1 M-class applies if the *article* is rubber; it is a drawing class, not a slogan.

2. Compound family, grade if known, and what the cert must say

Name the process: platinum RTV, tin RTV. Name a target Shore A (10A–20A typical with jacket). Name mix 1:1 or 10:1. Name the *dump* (pectin, chocolate, PU, wax). If a specific manufacturer grade exists, write it. If the cavity must pass FDA 21 CFR 177.2600 or LFGB, write the claim and whether you need a cert, a file, or a tested lot.

Omission: they quote “20A transparent silicone,” then you discover the food-contact kit is a different shrink, a different min-buy, and a different barrier coat. LSR vs RTV also changes the entire factory.

If grade is TBD, bound it: “platinum RTV, 10–20A, food-contact cert, dump = pectin gummy.” That is enough to pick a bench and a kit policy.

3. Lifetime dumps, annual dumps, and the real batch / release qty

Three numbers. They drive jacket, cavitation, leftover kit, and recast.

Omission: you get a 16-cavity production sheet against a 400-dump year, or a 1-cavity glove against a frozen 200,000-dump SKU. Both are “accurate” to a fantasy.

Say: “Year 1 = X dumps, lifetime ~ Y, releases of Z.” If Y is unknown, give a floor and a ceiling and ask for two constructions.

4. Cavitation intent, or permission to propose it

Either specify 1–2 cavity prototype vs production pockets, or ask them to propose 1 and 8 against your dumps. Don't say “max cavities” without a jacket and an MOQ.

Omission: they maximize pockets to win unit price, and you cannot feed the depositor. Or they quote 1-cavity forever because it is easy.

5. Flash, finish, and the faces that are allowed to look like a tool

Flash maximum at the rubber split. Finish of the master. Texture yes/no. Split witness allowed on which face.

Omission: polish is the hour-count that disappears from cheap quotes. RTV copies the master. A sealing lip wants a different land than a hidden bumper. Trim labor hides here.

If cosmetics are unknown, state “non-cosmetic except pocket face F1.”

6. Tool construction: master, jacket, platinum vs tin, recast

Master: CNC / print / physical sample. Jacket yes/no. Keys. Cores. Who owns the master. Where it lives. Recast of the RTV skin included or extra.

Omission: this is how two quotes differ by a factor that is not “margin.” One is a printed glove. One is a metal master with a fiberglass mother mold. You cannot average them.

If you don't know construction, give lifetime dumps and let them *declare* what they bid. Do not stamp SPI Class 103 on this line.

7. FAI, tryout, and what is inside the mold price

How many tryout pours. How many sample dumps. Ballooned FAI yes/no. Material cert. Fill-weight actuals. Visual photos. First-article on every pocket. Master-complete photos.

Omission: the mold looks cheap because tryout is a change order. Or “samples included” means three unmeasured dumps in a bag.

Also state DFM: one revision loop included, then paid.

Common mix-up: sending only a STEP and a quantity

You get a number. That number assumes open-and-shut, no jacket, no class, commercial finish, 1-cavity, leftover kit on you, FAI optional, cores extra. When the dump is a food tray with a bail, the change orders will exceed the original mold.

What to ask when you're buying

• All seven lines packed, even if two are ranges?
• Object named: RTV cavity, not LSR steel?
• Recast and master custody on line 6?
• Every pocket on FAI?
• Unknowns bounded, not silent?

Worked example: 12-cavity bear cover sheet

A 12-cavity 18 mm bear, 4.0 g, food-contact, ~2,000 dumps a month, releases of ~500. Cover: STEP+2D, platinum 10A–20A mix 1:1, pectin, quote 2-cavity then 12, flash max at split, CNC master + jacket + recast, FAI = weights + photos + cert. Shop that refused the block was quoting a different job. A parallel LSR seven-line with cold-runner was a parts template.

When this checklist is the wrong quote

If you actually need LSR/HCR part tools, swap line 6 for class, cold-runner, vacuum, steel vs aluminum. A one-off artisan from a physical sample can skip STEP. Geometry can override quantity: a hollow with no core path still needs line 1 undercuts at 80 dumps.

Related reading: custom RTV molds, DFM checklist, converting STEP, gummy trays.

A copy-paste block

Use this as the cover of the RFQ:

1. STEP + 2D rev ___; balloons on fits, flash at split, pour keep-out; ship state = wait ___ / trim ___.
2. Process/grade/Shore/mix; dump compound; certs required: ___.
3. Annual dumps ___; lifetime ___; batch release ___.
4. Quote 1–2 cavity and proposed production cavitation.
5. Flash max ___; finish ___; cosmetic faces ___.
6. Master CNC/print; jacket ___; platinum/tin; recast ___; tool ownership ___.
7. Tryout pours ___; FAI packet = drawing + cert + fill-weights + photos + pocket ID.

Shops that refuse to quote against that block are quoting a different job. Let them.

Send the cover plus files. We will mark which line is still a guess.

We would not recommend a STEP-only RFQ

We would not recommend stamping Class 103 on line 6. We would not skip the jacket on a wet dump to win the number. Raising Shore A first is the wrong fix for a missing split note. We would not treat silence as “commercial.”

RUUIPON Mold Structure Decision: the seven lines decide the structure. Flat back? open-back. Deep undercuts that will not peel? two-part / core on line 1. Soft 10A–20A or wet dump? mother mold on line 6.

flowchart TD
  A[RFQ] --> B{Seven lines packed?}
  B -->|no| C[Guess = padding or wrong glove]
  B -->|yes| D{Object is RTV cavity?}
  D -->|LSR template pasted| E[Strip class/cold-runner]
  D -->|yes| F[Quote master + skin + jacket + recast]

Typical shop values

Caption these as typical shop values, not a named lot.

| Item | Typical shop value | | --- | --- | | Mix | Platinum 1:1 or 10:1; vacuum degas | | Cavity Shore | 10A–20A skin with jacket | | Platinum shrink | About 0.1–0.3% — don't paste LSR 2–3% | | Drawing class | ISO 3302-1 M2 common *if* the article is rubber | | Loaded-tray edge sag | About 0.5–1.5 mm if jacket omitted | | First quote | 1–2 cavities until dumps/month are real |

FAQ

What happens if I send only a STEP and a quantity? You get a number that assumes open-and-shut, no jacket, commercial finish, 1-cavity, leftover kit on you, FAI optional, cores extra. On a food tray with a bail the change orders can exceed the original mold. Silence is worse than a range.

Why do lifetime, annual, and release quantity all belong on the RFQ? They drive jacket, cavitation, leftover kit, and recast. One annual number gets you a 16-cavity sheet against a 400-dump year, or 1-cavity forever against a frozen high-dump SKU. If lifetime is unknown, give a floor and ceiling and ask for two constructions.

Why name flash max and which faces may look like a tool? Polish hours disappear from cheap quotes. RTV copies the master. A sealing lip wants a different land than a hidden bumper. Trim labor hides here. If cosmetics are unknown, state non-cosmetic except a named pocket face.

If I do not know construction, what do I write instead? Give lifetime dumps and let the shop declare master type, jacket, platinum vs tin, recast, and who owns the pattern. Also name mix ratio. Two quotes that differ by a large factor are often a printed glove versus a metal master with a mother mold.

Why is "unknown, bounded" better than omitting dump compound? Omission quotes "20A transparent silicone," then the food-contact kit is a different shrink, min-buy, and barrier coat. LSR versus RTV also changes the factory. "Platinum RTV, 10-20A, non-filled, food-contact cert, dump = pectin" is enough to pick a bench and a kit policy.