Budget UV Cure Box (Jar?)


Since I learned so much from this forum, I’d like to make contribution to this community.
Here’s the way I made my own version of UV box, little budget and only few parts needed.
First, get these parts ready, 12V/2A power supply, 5m LED string, 1pc of transparent glass and stainless box.
Here’s the picture.

And then pave the 5m long LED string onto side walls, since this is a 25x25x25 cm cubic box, the LED string should pave 4 rows on each wall. Plug in, it’s beautifully lighted.
I just broke the glass before right before taking picture, otherwise you’ll see the prints should be like floating in the air(middle line).


Where did you get the polished stainless steel box and how much did it cost? I can’t imagine that being under $100. The picture of the Eiffel Tower glowing is pretty cool :wink:


The stainless box costs me slightly under $100. Actually, I have a factory customized for me. But I think you can find similar items, box or jar from culinary equipment store, a lot of cooking goods are made by stainless. You can also try ebay for used ones. But let me know if you just want 6 pieces of stainless sheet, I can check with factory to see if they can do it for you.

The Eiffel Tower is my 3rd print for testing purpose, it turned out a very successful print. 100 microns for 3+ hours. Will try flexible resin soon.


I have no data to base my opinion on, but I don’t think you want a mirror reflective surface. I gave this some thought when selecting components for my method. I think a surface with a low specularity is going to do a better job of scattering the light and so provide more uniform coverage. Crinkled foil scatters the light randomly. A highly reflective surface doesn’t and you might get “hot” and “cold” spots… Probably doesn’t matter, but I consciously chose the foil approach vs. a mirrored surface.


I will got with the foil, the led just arrived and now I need to find a bi jar.


Great design and nice supplier hookup for the LEDs! I just ordered all the supplies so hopefully I’ll be rapid curing next week. Thanks for the tip!


I’ve learned that curing the Flexible resin is best done underwater. This curing “jar” will work great for this process too, as well as the more traditional “dry” cure method. The acrylic jar will hold water just fine, and all the electronics are on the outside where they’ll stay nice and dry.


How do you know water UV curing is better? What did you measure or observe to come to that conclusion?

I’ve found that prints will fully cure on their own given enough time. The only thing the initial cure is needed for in most cases it to prevent warping and finger prints. In fact, that’s one thing I don’t like about SLA prints is that as they fully cure they can get very brittle and easy to break.


I haven’t had a need to use the water method, but FormLabs is very clear on this subject. The flexible resin interacts with oxygen in a way that can limit full curing. FormLabs says to cure underwater if the prints remain tacky.

Prints are never fully cured when they come off the printer. Prints will always continue to cure so long as there’s UV light present. There’s lots of UV in the everyday ambient environment, so any print will “cure out” over time if left to its own. And yes, as the print cures-through, it becomes more brittle (though this does not apply to the FL flexible resin, it stays flexible).

In my experience, it is better to fully cure the print before attempting to separate it from the supports, so waiting for an “ambient” cure is not an option. The purpose of the curing jar is to accelerate that cure so I can shorten my design cycle (significantly) and still be working with fully-cured parts.


I have some flexible resin but haven’t printed with it yet. I haven’t seen where Formlabs says to cure it under water. Can you post a link?



Not without searching, which I don’t have time for right now. But I bet someone from FL would be happy to point you at the pertinent documentation. It’s on the site somewhere, and I don’t remember having to work hard to discover the reference.

That being said, my first print with FL Flexible came out just fine with normal preparation. Surface was dry and tack-free after about 30 minutes under the LEDs in “clean air”. In fact I was surprised, since I also expected it to be black in color when cured, and it’s more a light translucent grey, not black at all.


@Tony_Shulthise, a suggestion about curing underwater is on the Flexible Resin user guide here. I have personally found that curing underwater works great, its become my go-to method for all flexible parts.



Thanks guys!


Hi Tony, simply to share a short video, FL flexible resin works well. I did leave in it in water under the sun for like 20min. Flexible resin is an amazing material.
Check the link here:


Finished building my box today. I added 2 AA battery holders (1.5V each battery, 8 batteries total) in serial to power the setup. Works well and it’s portable as well as having a handy on/off switch.



Alas, if you used the LEDs I used (or ones like 'em), we’re talking 24W, or 2A at 12V. Your 8 AAs in series will give you 12V, but at 2A the capacity of those cells is going to be good for maybe 30 minutes of run time at most. Unless you use something like an Energizer Lithium battery. Lithium will give you closer to 1:15 of run time. Based on my experience with how much time is required to cure-out a print, you’re going to be putting new batteries in the battery holder every time you go to cure a print. Maybe more than once per print. And the LEDs will get dimmer as the batteries discharge (their voltage when “used up” is about 1V/cell), so the cure time will be extended as a result. You really want a DC power supply. A 12V/2A wall wart ought to be fairly easy to get a hold of, that’s really what you want. Actually, 3A would be better (so you have some operating margin and the power supply isn’t running flat-out all the time).


I thought about that after using it a few times (holding up OK so far). My wife’s thought is to get rechargeables, but I didn’t really arrange the casing to allow easy access to the batteries. I’ll think on solutions, but with me using water, I’d rather stay away from wall sockets.


I see a lot of great ideas for curing boxes here, but I notice no-one is mentioning Aluminium as the reflective part… Polished alu can reflect up to 90% of UV light while stainless steel only manages to reflect somewhere around 60%. I’d suggest building an aluminium box rather than a stainless steel box. It’s probably even cheaper as well…


Alex: My jar is wrapped with Aluminum Foil!

Marcus: Recharging is going to be a real PITA. If you’re going to go that way, get yourself a AGM battery (motorcycle battery). Something like that will give you 10AH of capacity, which would run the LEDs for many hours before there was any risk of meaningful dimming. But a wall wart power supply should be perfectly safe. The part that’s touching 120V is remote from the part that’s filled with water. You could always make the cable from the wart to your LEDs longer if you were really worried. I bet you have electrical outlets near sinks in your house that are closer than the typical 4’ you get with a wall power adapter…


True, but the outlets near water are the GFI-style :slight_smile: