Note
Here we cover keeping white underbase UV decoration rich and smooth on PET, without chalking. We share settings, steps, and a checklist for South African teams.
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Without a stable underbase, colour floats.
SA humidity shifts viscosity, InkFlow cues help.
Soft-touch or gloss after colour, never before white.
A white underbase is a critical first layer in UV bottle decoration, used on clear or coloured PET to make designs pop and colours stand out. On the factory floor, the challenge is getting that layer both dense and even, without it turning chalky or powdery. Chalking shows up as roughness or flakes, making bottles look unfinished and risking brand reputation in cold rooms, on the shelf, or after transport. South African lines see this often on beverage and skincare runs, especially in high humidity or when power dips cause inconsistent curing. Fixing it is not just a matter of looking good. It is about decoration that stands up to handling, packing, and local logistics.
These settings are for in-house teams or contractors running UV LED bottle printers on PET, whether you operate in Gauteng, the Cape, or coastal towns battling humidity. You will find this relevant if you handle design approvals, machine setup, or regular print runs in beverage, personal care, or promo lines. If your volumes are too low for batch changes, or you only print on glass or aluminium, these tips may not apply. Shops relying on outsourced decoration with no control over the print room should rather request finished samples directly from the Catalogue.
We set up InkFlow Station with specific layer heights, UV intensity, and print speeds for South African PET bottles, tested with both local and imported blanks. The key is a dense laydown of white that is not starved (which becomes see-through) and not overloaded (which leads to chalk). Power supply is a real-world constraint: fluctuating 230 V or three-phase interruptions during load-shedding can interfere with curing. A clear handover is needed between operators on shift, so no one skips dwell times or starts a run with half-set underbase. Before production, we always match the settings to the site’s humidity and bottle batch, not the generic spec sheet.
A usual order of work includes confirming constraints (like who signs off, what time the bay is available, what type of PET is on hand), picking the right mode on the InkFlow Station, walking the process plan with the on-site operator, and writing a short note after the job to guide the next team. This works for teams in Mbombela, Worcester, and any site fed up with guessing after the fact.
Recently, a skin care packer in Worcester needed dense white underbase on 150 ml PET rounds but kept getting chalk near the shoulder. The foreman sent us two photos, a batch note, and a rough shift plan. We matched their constraint (high ambient humidity, tight turnaround) and recommended a slightly slower table speed, higher lamp intensity, and one extra dwell pass on white. On the sample run in our Jet Park bay, this sequence gave a smooth, non-chalky finish. The client adjusted their own process, briefed the next shift with a close-out note template, and reported no issues on the next order. This approach gets repeated with similar jobs across South Africa.
A clear, specific brief from the start helps us give you the best tailored answer. Use this checklist to prepare your request, especially if you want exact InkFlow Station advice or a sample run for PET bottles. Include as much as possible, but do not worry if it is not perfect. We can work with rough notes or messy photos, as long as we know your main constraint.
Skipping the written constraint upfront is the fastest way to invite trouble. Teams that focus only on the finish or artwork, without noting site issues (like humidity or power dips), end up redoing the job. Not briefing the next operator in writing means settings get reset or lost between shifts. Chalking also comes from copying import settings that do not fit local bottle stock or climate. Always test your final recipe with the actual batch in your bay, not just on a spec sheet. If you need a walkthrough or want to match your site’s setup, send a message through our contact form and mention White underbase without chalk. For related notes, browse Notes or review detailed systems before your next order lands.
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