An OEM glass candle holder project rarely fails in the kiln; it fails in the details that were never written down. Between a buyer's brief and a finished bulk order sit drawings, colour references, sample approvals and inspection points, and each one is a chance to prevent an expensive misunderstanding.

1. Start With the Product Drawing and Specifications

Custom work begins with a drawing. It should show overall diameter and height, wall thickness, base and mouth diameter, and the tolerance allowed on each, plus the measurement points used to check them. A drawing with sizes but no tolerances leaves too much to interpretation.

Buyers should also confirm edge finish and the seating depth for the candle, since these affect safety and appearance. Agreeing the drawing in writing turns a conversation into a specification both sides can inspect against.

2. Glass Colour and Surface Finish

Colour is agreed by reference, not by words. A named colour, a physical chip or a previous sample gives the factory something to match and removes the ambiguity of "light blue" or "smoke". Surface finish should be named as well: clear, tinted, frosted, etched or patterned.

Both drift between batches. Colour shifts slightly with the melt, and frosted surfaces vary in depth, so an acceptable range should be stated rather than assumed.

3. Logo and Decoration

Where a logo or pattern is required, confirm the method, placement, size and colour, and check that artwork is supplied in a usable format. Engraving, etching and printing wear and read differently, and suit different surfaces.

Verify the decoration on the sample, including how it sits on a curved or textured surface and whether it survives normal cleaning for the target market.

4. Packaging Confirmation

Packaging is part of the custom brief. Confirm inner packaging (sleeve, gift box or wrap), the outer carton, the units per carton and the labelling; retail and bulk orders often need different solutions.

Because glass is fragile, dividers and cushioning matter as much as the print. Packaging agreed late is a common reason a project slips.

5. Why Sample Approval Comes First

Glass is made from a batch of molten material and shaped while hot, so colour, weight, dimensions and surface texture naturally vary a little from one run to the next. A physical sample is the only way to confirm all of them at once, before tooling and labour are committed to a full run.

A signed sample, often kept as a golden sample, becomes the reference for the whole project. Approving it in writing, with photographs and measurements, is what prevents a dispute later.

6. Controlling Consistency Between Batches

Once a reference sample exists, consistency is managed against it: colour compared under agreed light, weight and dimensions checked to the stated tolerance, and surface texture reviewed against the approved finish. This matters most for repeat orders.

Buyers running a line should keep a retained sample and ask the factory to do the same, so any drift shows early rather than after delivery.

7. MOQ, Lead Time and Quality Inspection

Confirm the minimum order quantity, any mould or tooling cost, and the production lead time, including the sample stage. These shape the budget and the launch date, and are easier to settle before production.

Quality inspection should be agreed in advance: what is checked, at which stage, and to what standard. A pre-shipment check against the approved sample catches issues while they can still be fixed.

8. Reducing Communication Errors

Most problems in custom projects come from gaps between what a buyer meant and what a factory understood. A short, written specification closes most of them.

• One written specification sheet, referenced in every message
• An approved physical sample with photos and measurements
• Agreed tolerances for colour, size, weight and finish
• Named inspection points and a pre-shipment check

With these in place, a custom glass candle holder order is far more likely to arrive as the sample did.