I've bought recently this UV lamp to cure my SLA prints:

But I seem not to be able to get the job done. I got some leftover supports and wanted to throw them in the trash, so I put the lamp onto them, at less than 10 cm, over a cardboard box with foil paper in the walls, and accidentally forgot about it. After 5 hours I remembered, got back, and the resin was still sticky and not cured. Not to say that I should do this for both sides, so I don't think it's a good solution.

I tried another one, this time with the lamp in my hands, and put the lamp over the piece less than 3 cm away. I spent 3 rounds of 5 minutes (that's 15 min) with the lamp pointing directly at it (less than 3 cm away) and it was still not cured, either.

So I'm asking: am I doing something wrong? May my UV lamp be defective? Or is it normal to take so much time? Can you recommend any UV lamp that gets the job done and doesn't take forever?

I already have an Elegoo Mercury curing machine, but it hasn't enough room for big prints, that's why I want to get a lamp that I can use and adjust for bigger prints.


If the SLA Resin is not curing under the lamp after several hours, it is likely the lamp is not emitting the correct wavelength of UV light to properly cure your resin. Typical SLA resins cure at between 350-410 nm light. The listing you post does list the lamp as emitting 405 nm light, which would be in range. However, because of the failures you are encountering, it is likely that the lamp is not emitting any UV light at all and is possibly fake.

SLA parts can typically be left out in direct sunlight for a while to cure, as an alternative without requiring a curing machine or lamp. Finding a lamp on Amazon (or similar retailer) that has a lot of positive reviews (such as this listing) will yield better results as unfortunately UV emitting products are often targets for fakes, as it is impossible to discern if something is producing UV light or not by the naked eye.

It is also feasible to make your own curing lamp (or box) with genuine UV emitting LED's purchased from reputable parts retailers such as DigiKey and Mouser, but please take safety precautions when working with UV emitters, as the eye cannot regulate the intake of UV light and can cause permanent eye damage!

It may be possible to test if your lamp is producing an appreciable amount of UV light with any bright white object, such as a piece of printer paper, and seeing if it fluoresces. Though this test may not be very accurate.

  • $\begingroup$ He could buy some uranium marbles to check UV lamps. Uranium glass often glows green under UV light, it's very nice. $\endgroup$
    – FarO
    Jul 9 at 16:16

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