Why Two Silicone Mold Quotes Can Be 2× Apart

A USD 600 quote and a USD 1,200 quote for the "same silicone mold" may not be quotations for the same manufacturing asset.

One supplier may be pricing an open-face RTV block poured around a customer-supplied master. Another may be including 3D cleanup, a new master, a keyed two-part silicone mold, an FRP support jacket, one functional test casting, production duplicates and export packing. The finished casting can look similar in a screenshot while the tooling scope is completely different.

That is why the first job in quote comparison is not negotiating the unit price. It is normalizing the technical scope.

Start by separating one-time development from repeat-mold cost

A useful custom RTV quotation should make it possible to identify two cost groups.

One-time development / NRE may include:

• CAD cleanup or reconstruction;
• DFM review;
• logo or texture development;
• master model production;
• master surface finishing;
• first prototype mold;
• test casting;
• first revision loop.

Recurring mold cost may include:

• RTV silicone material;
• pigment if specified;
• mold-box or production setup labor;
• split-line preparation;
• trimming and assembly;
• FRP shell replication where required;
• inspection;
• packaging.

If Quote A includes the master and Quote B assumes that you will send an approved physical master, the headline numbers are not comparable.

Ask every supplier to state clearly: What disappears from the price on a repeat order with the same approved master?

That one question exposes whether the quotation has been separated into development and recurring production correctly.

Compare the mold structure, not only the external size

Overall dimensions are a weak predictor of RTV mold cost when the internal structure differs.

A shallow 250 × 200 mm logo tray may be a simple open-face mold. A smaller full-3D figurine can require:

• two or more mold sections;
• registration keys;
• a controlled parting surface;
• removable plugs around locked features;
• vents and pour openings;
• an internal core;
• a rigid mother mold.

The second tool may use less silicone by weight but more engineering and assembly labor.

When comparing quotes, ask each supplier to name the proposed structure in one line. For example:

Two-part keyed RTV mold, one removable arm plug, no rigid mother mold.

or:

Brush-on silicone skin, four-section FRP mother mold, bolted flanges.

If the structure is not written, the number is still an estimate built on hidden assumptions.

Silicone grade matters-but kilograms matter too

Buyers often compare Shore A or "platinum cure" and stop there. The actual amount of silicone can move the price just as much.

For a multi-cavity tray, mold mass changes with:

• cavity count;
• spacing between cavities;
• border width;
• bottom thickness;
• local reinforcement;
• tray stiffness requirement;
• overall footprint.

Two suppliers can use the same grade and still quote different costs because one design carries significantly more silicone.

That extra material may be justified if the tray must stay flat when loaded. Or it may simply be an inefficient layout. The correct question is not "Why is your mold heavier?" but what structural requirement is the extra mass solving?

For large trays, ask for an estimated empty mold weight before approval. That also improves freight planning later.

Check whether the quote includes the same master quality

The master controls the cavity surface. If one supplier quotes a raw printed master and another includes sanding, sealing, polishing and local rework, the final mold can differ visibly even before material selection enters the discussion.

Clarify:

• Who makes the master?
• What process is used-SLA, CNC, DLP, hand model, reverse engineering?
• What surface finish is expected?
• Are print lines acceptable?
• Is polishing included?
• Who approves the master before RTV is poured?

For chocolate, glossy resin, branded reliefs or detailed figurines, master finishing can be one of the most important lines on the quote.

Prototype and revision policy can hide a large risk difference

A low quote may be based on immediate production. A higher quote may include an approval gate.

For a new geometry, clarify whether the project includes:

1. CAD or master approval;
2. one prototype mold;
3. a functional casting or buyer test;
4. written approval;
5. production multiplication.

Then ask what happens if the first prototype exposes a genuine tooling issue.

Examples:

• parting line produces too much cleanup;
• a resin air trap needs a vent;
• a candle undercut tears the silicone;
• a gummy tray sags under load;
• an inner core shifts;
• a logo stroke is too fragile.

A quotation that includes no revision rule can become expensive after the deposit even if its initial price was lower.

Do not expect unlimited free redesign. Instead, define which changes are supplier correction, which are buyer design changes, and which trigger a new master.

Mother molds and cores are separate assets

This is one of the most common quote-comparison mistakes on sculpture, planter and large resin projects.

"Silicone mold included" does not automatically mean:

• FRP mother mold included;
• inner core included;
• support frame included;
• bolts/clamps included;
• removable plug included.

A large flexible skin without its support shell may be unusable under casting load.

If the geometry requires support, request a simple asset list:

This table is more useful than comparing two total prices.

Ownership can make a cheaper quote expensive later

A buyer may assume that paying a tooling charge means the master, CAD and support tooling are theirs. That assumption should be written, not guessed.

Compare whether each quotation states ownership or transfer rights for:

• final CAD files;
• customer-specific master;
• physical silicone molds;
• FRP mother mold;
• removable cores/plugs;
• archived revision data.

Also ask what happens if you need replacement molds a year later.

A supplier that preserves the approved master and revision can usually reproduce the mold more consistently than a supplier that copies a worn production mold.

Packaging and freight can reverse the apparent price advantage

RTV molds are often low-density, bulky products. A large lightweight tray may ship on volumetric weight rather than actual scale weight.

A quotation may be:

• EXW factory;
• FOB port;
• DAP destination;
• DDP destination.

Do not compare an EXW mold price with a DDP delivered price as though both are "unit price."

For large flexible molds, packaging should also prevent:

• folded cavities;
• permanent set;
• crushed borders;
• distortion from stacking.

Ask for the estimated carton size and gross weight after final geometry is locked.

Normalize quantity before comparing unit prices

Request the same quantity breaks from each supplier. For example:

• 1 prototype;
• 20 production molds;
• 50 production molds;
• 100 production molds.

That shows whether one-time development has been mixed into the first unit price and whether production economics change with quantity.

For very large or complex molds, quantity breaks may not reduce price dramatically because manual assembly remains significant. For simple duplicated trays, repeat production can scale more efficiently.

A practical apples-to-apples comparison sheet

Before selecting a supplier, reduce each quotation to these lines:

Once those lines match, the price comparison becomes meaningful.

When the cheaper quotation is actually the better one

The higher price is not automatically better.

A simpler quotation can be the correct choice when:

• you already own a finished master;
• the geometry genuinely needs only an open-face mold;
• no mother mold is required;
• you will perform the casting validation yourself;
• the supplier has removed unnecessary features rather than omitted necessary ones.

The objective is not to buy the most elaborate mold. It is to buy the simplest tooling system that survives the intended production process.

What to send RUUIPON for a quote comparison review

If you are comparing suppliers, send:

• your current CAD or reference drawing;
• intended casting material;
• target mold quantity;
• any supplier structure notes;
• the line-item scope from competing quotations.

Prices can be removed or redacted. The useful part is the scope.

RUUIPON can review whether the quotations are actually describing the same master, mold structure, support system and approval process before you decide which number is cheaper.