How to Evaluate Custom RTV Mold Quality

If you are evaluating a custom RTV silicone mold before you freeze dumps, you are asking whether this stack will hold a process window for the duty you bought - not whether one chocolate looks glossy. Score the resin production mother copy, the jacket / mother-mold support shell, mix identity, and a real first-dump pack. If you only look at cosmetics, you will freeze a glove whose split is already tired.

This is a buyer's score of intent versus delivery. On this site the path is photos, sketch, or CAD, then a 3D-printed pattern, often a temporary silicone flip, a resin production mother, then batch RTV. The mother is not the pattern. Free DFM. HTV/HCR compression mold tooling is also quoted on RUUIPON.

What to score on the bench

Mother copy. Layer lines, sealer blush, incomplete logos, bubbles at the parting. The rubber copies the living mother. If the pattern was never finished, the mold is not quality.

Split and support shell. Does the jacket / mother-mold support shell actually constrain Shore 10A-20A rubber, or does it rock? Nicks at the shut are future flash. Look at the worst pocket, not the hero. If your email still says "master, box, keys, jacket" as the score list, you are listing shop furniture.

Chemistry vs duty. Platinum when you need recasts and storage hold. Tin when the pattern is dirty and the run is short. Scoring a tin glove as a library tool is a fail even if first dumps are pretty.

Mix traveler. Grade, lot, ratio, vacuum degas, pour date. A naked stack with no traveler is a future orphan. If the quote listed a fiberglass support shell and you received tape on plywood, that is a specification miss now.

Sample dumps as a mold report, not a brochure

A quality evaluation uses the first-dump pack: all cavities, mix sheet, measurement state (23 C after a named wait), flash at named splits, texture versus chip, hardness of the skin. If the shop sends six hand-trimmed bars from cavity 2, you have evaluated a trimmer, not a mold.

Look for process heroics: extra straps on a rocking shell, extra bake to chase a sticky face, a technician who "knows how to fill cavity 7." Those are deductions. ISO 3302-1 class on a rubber article drawing is a tolerance class, not a license to brutal-CMM a gummy lip.

Common mix-up: pretty dump equals production mold

A lot of RFQs treat one glossy first article as a freeze. In the shop that usually means the shut is already nicked from "sampling," or the support shell was never rigid. Certificates (21 CFR 177.2600, LFGB sections 30/31, ISO 9001) evaluate the program, not the mill finish of the mother. Do not give a mold a food score because the lobby has a flag.

Typical shop values

Reference values only. Confirm material-specific limits against the supplier’s technical data and agree project acceptance criteria before production.

Worked example: scorecard on a 12-cavity bar

A buyer froze a 12-cavity bar on one glossy pocket. Worst-pocket photos later showed a nicked shut and a rocking plywood flask. We did not raise Shore. Free DFM named a rigid support shell and a recast against the unsanded mother. After the new CAD lock: pattern finish, often a flip, living mother, batch RTV. Pass was an all-cavity weigh sheet at 23 C, not a second hero photo.

Stay on this page / skip this page

Stay when you need a buyer scorecard before you freeze dumps.

Skip if you need incoming inspection steps after the tool already shipped - related inspection notes. Skip steel LSR stacks (heaters, cold-runners) - a different RFQ - ask us for the part carton; RUUIPON only if you are buying the HTV/HCR compression tool. Skip a 20-dump tin art glove if you write the kill date.

We will not quote a freeze on one glossy first article. We will not grade a rubber cavity with SPI 101-105. We will not invent a dump-count warranty or an FDA-approved factory badge.

Related: how molds are made, extend mold life, custom RTV molds, contact.

What to send

• What you paid for: platinum vs tin, support shell yes/no, recast clause
• Photos of the worst pocket, the shut, and the shell on a flat table
• First-dump pack: all cavities, wait / temperature, weigh sheet
• Mix traveler if you have it
• Food-contact path if needed: 21 CFR 177.2600 and/or LFGB sections 30/31

Send the pack to [email protected] or contact.

FAQ

Is one pretty chocolate enough to freeze production? No. Score the worst pocket, the support shell, and an all-cavity dump pack at a named wait.

Do SPI classes grade RTV quality? No. Those classes are steel construction intent. A rubber cavity is scored as copy, shut, shell, and traveler.

Can a food certificate replace a jacket? No. 21 CFR 177.2600 and LFGB sections 30/31 evaluate the article path. They do not hold a 10A-20A skin flat.

What if only cavity 2 looks good? That is a trimmer report. Ask for every pocket or do not freeze SOP.

What is MOQ and the prototype clock on a recast after a fail? MOQ 20 of the corrected design. Prototype usually 3-7 business days after the new CAD lock. DFM is free. CAD revision about USD 50 when we edit your 3D.