8oz jar, 7cm diameter, soy container wax, CD10 wick, 8 percent fragrance oil. First burn ran three and a half hours and the melt pool reached about 5cm across, leaving a ring of hard wax on the glass. Second burn was worse. Do I go up a wick size, or is something else wrong, because the flame is already about 2cm tall and flickering?
Test with the fragrance you actually sell. Different oils behave completely differently at the same load - vanilla heavy ones are notorious for needing a size up over something citrus. A wick that is perfect in one scent tunnels in another.
Can confirm. Same wax, same jar, same wick: one scent burns clean and the other hangs up every time.
Ambient temperature matters more than people expect. Testing in a 16C room in winter and a 24C room in summer gives you two different verdicts on the same wick.
Confirm your jar is genuinely 7cm at the widest and not tapering. Straight sided and tapered jars need different wicks at the same nominal size.
Burn tests need at least two full burns with a complete cool between. One evening of testing tells you almost nothing.
@cure_rack_cody · 5mo ago · 4 replies
Go up, but test properly, and fix the flame separately because it is a different signal.
A CD10 in a 7cm jar at 8 percent fragrance is under-wicked. Fragrance oil raises the effective melt point and a heavily scented soy needs more heat than the wick chart implies - the charts assume unscented wax and nobody makes unscented candles. I would burn CD12 and CD14 side by side rather than stepping up one at a time.
The 2cm flickering flame is separate. Tall and dancing usually means the wick is too long, not too big. Trim to 5mm before every burn including the first. A long wick burns tall, sooty and hot at the top while still not throwing heat outward, which is precisely the picture you have.
One more thing: three and a half hours should have reached the glass. Once a memory ring is set that jar will tunnel forever. Do your testing on fresh pours, not on that one.
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@probe_to_ground · 5mo ago
I have been trimming to about a centimetre. Dropping to 5mm on the next test set.
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@annualfee_amy · 5mo ago
Test three wick sizes in identical jars on the same day and burn them side by side. Guessing one at a time cost me two months.
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@cure_rack_cody · 5mo ago
Five millimetres every single burn, and let burn one go the full distance to the glass. Those two habits fix more candles than wick changes do.
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