Lasers for print post-cure and for bonding separate parts with resin

I’ve been using my budget curing jar design for post-curing prints with excellent results. But there have been a few instances where a print failed, or I busted something pulling off the supports, where the failure was repairable. But holding two pieces of printed resin together with the joint wetted with some uncured resin, inside the jar, for the many minutes it takes to get the resin to “set” (the LEDs in total are only 24W so the amount of light reaching the bonding area is quite low), was proving to be too “challenging”.

I went looking for higher wattage alternatives to the SMD LED strip. Thought about adding an additional string of LEDs to just increase overall wattage. But then I came across this on and decided the price was low enough to give it a try.

Now, I’ve bought from Banggood before and quality control can be a little hit or miss. I wanted two of these that worked, so I ordered three. Of course, one didn’t work and I’m arguing with Banggood about replacing it, now. But the two that did work worked great.

250mW output. Advertised as “405nm” (though the label on the laser itself says 400-450nm). The laser has excellent brightness and as you can see from the picture below, it casts a beam that’s about 3/4" in diameter vs. the typical pin point you get from a laser pointer. Very easy to “paint” the area you want to cure, even if you’ve been drinking a bit before you start. And based on my testing of a few randomly spilled drops of resin the output frequency seems to be pretty close to what the FL resin wants. A 1/4" diameter droplet of resin cured solid in about 5 seconds.

Also worth noting… The resin gets hot when it cures. I guess that shouldn’t have been surprising to me (chemistry, hello?). But it was, as I discovered when I smeared a little resin with my fingertip and then thought “hmmm, wonder what resin cured to human skin feels like?” (yeah, not my best idea. You do remember I mentioned drinking, above?). No serious burns, not even blistered. But it did hurt. Do not try this experiment yourself! :grin:

Anyway, for someone looking to buy a small laser pointer to aid in post cure and resin bonding tasks, I would highly recommend one of these units as an optimal choice. You need to do a little fabrication to power them, so soldering skills are probably also required, but well worth the effort. They’re designed to be powered off a single Lithium battery cell, so any power supply that outputs 3.5 to 4.0V would work (how I’m doing it, though in the picture below it’s being powered by one of the spare batteries for my IPVD3 Vape device). There is a regulator/driver board so I’d wager it’d take 5V without failing if that was all you had available.


When something breaks I use Bondit with the builtin UV light. Cures almost instantly.

Not as practical with a large surface area needing bonding. But yeah, Bondit is basically the same idea as the resin the printer uses. Should work as good.

Great idea, Nice sized beam, thanks.

I had bought a cheap LED UV torch to do this, but it doesn’t seem to cure anything. It mustn’t be the correct frequency.

I just ordered one now, and have my UV safety glasses on standby for when it arrives.


It’s BONDIC not BONDIT my bad!!

but you know what I meant.

Yeah. Bondo, Bondic, Bondit, it’s all just stuff that sticks other stuff together. I knew what you meant even though I didn’t pick up on the error either.

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