I Ordered 50 Identical Silicone Moulds but Some Are Noticeably Softer Than Others — Could This Create Production Inconsistencies?

What softer moulds can change in production

Silicone hardness varies with the silicone grade, the mix, the cure and how long the mould has had to settle after casting. When moulds from one order feel noticeably different in the hand, some of that variation will reach your candles. A softer mould flexes more under the weight of hot wax, so pieces can come out slightly wider, rounder or heavier. Fine surface detail can look less crisp. Demoulding usually gets easier, but thin parts can stretch further and tear sooner. And an unusually soft, tacky mould can be a sign of incomplete cure, which can leave marks on the wax surface.

Whether this becomes a production inconsistency depends on your product. A loose wax melt sold by the piece can tolerate more than a boxed set of matching flower candles or a product with a stated weight. So the goods-in question is practical: how far apart are the softest and firmest moulds, and does that gap show in the finished piece?

There is no published figure to check against. CSI publishes no shore hardness for any mould, and CSI does not sell hardness testers. You can still sort and judge moulds reliably with simple comparative tests, as long as you treat the result as a ranking rather than a measurement.

Rank all fifty with a simple comparison

The aim is to put the order into groups, firm, typical and soft, so you know which moulds to test hardest. Do it in one sitting, with one person, so the feel does not drift.

Give fresh moulds a few days

Some silicones keep firming for a while after casting, and moulds that travelled sealed in hot packaging can feel different once aired. If a batch arrives with a few soft or slightly tacky units, a suggested starting point is to leave the whole order unpacked, clean and spread out at room temperature for several days, then repeat the press test on the soft group. Moulds that firm up and lose their tack move to the typical group; moulds that stay tacky keep their cure query.

Pour the extremes, not the average

Once the moulds are sorted, the fastest honest test is to pour production wax into the two or three softest, two or three firmest and your reference, all from one pot, at one temperature checked with a separate thermometer, filled to the same weight. If the softest and firmest make pieces you would happily sell side by side, the whole order is inside your needs, because everything else lies between them. If they differ, you know exactly where the line falls.

Pour temperature interacts with softness. Hotter wax is heavier on a soft wall for longer, and the silicone itself is more pliable when warm, so a soft mould that behaves at your normal pour can bulge on a day the pot runs hot. If a soft group is borderline, repeat one pour a few degrees cooler as a suggested starting point, and note whether a tighter temperature window solves it.

Worked example: 50 Sunflower moulds

You ordered 50 of CSI's Sunflower silicone mould at ₹295.00 each, so the order is 50 × ₹295.00 = ₹14,750.00. After sorting, 12 moulds are clearly softer than the reference, and two of those feel slightly tacky. The value of the soft group is 12 × ₹295.00 = ₹3,540.00.

You pour the three softest, three firmest and the reference. The firm and typical moulds make matching flowers. The soft ones make pieces that are a little wider and a few grams heavier, with slightly rounded petal tips; the two tacky moulds leave faint dull patches on the wax. Now the decision is specific rather than anxious: ten soft moulds make acceptable but slightly different flowers, and two have a probable cure fault.

Sensible handling: keep the ten soft-but-clean moulds as a separate group and use them for a product where a small width difference does not matter, or dedicate them to one production run so pieces in any gift box match each other. Quarantine the two tacky moulds and raise them with the supplier. Do not scatter all fifty across the bench and hope the differences average out, because they will not, they will simply turn up in random boxes.

Accept, segregate or return

If the moulds are from CSI, send the sorting log, photos of paired pieces and the numbers of any tacky moulds on WhatsApp (+91 7397976926), and record the reply with the log. A group that fails your comparison stays off the bench whoever made it, including us.

Keep the mould numbers on your production batch sheets from now on. When a customer mentions a slightly different flower in a set, you will be able to see which moulds made it, and whether they were the soft group, in a minute rather than an afternoon.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the goods-in check for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions