I picked up this project board from Tanner. The kit uses surface mount LEDs, and a lot of them (though the board was intended for THT).
Is this something I could use solder paste and a reflow oven to make?
If so, is there a syringe of paste at the makerspace?
Paste usually has a ~1 year shelf life and most need to be stored refrigerated, so I doubt we have any.
Not sure on the reflow oven either. A hot air gun would suffice in this case, though personally, I would still hand solder it.
We actually finally got some solder paste a few weeks ago. It should be with the spare solder on the shelf by the solder wick and alcohol. Look for the brand new paste in a syringe rather than any old junk that may not have been thrown out yet. I’m pretty sure it looks like this but don’t quote me.
That syringe plus the Aoyue hot air station (it’s usually on one of the two Mouser benches) should work great. As a starting point I’d suggest using 300*C, 100% air flow, no nozzle installed. Expect to need to turn the air flow down if you install a nozzle or else it’s easy to blow parts away. Nozzles are great for doing one part at a time but for a whole board it’s much faster without one. Nozzles are in the top of the black toolchest but we have a very limited selection.
There’s also a reflow oven on the motorized bench but I’d just use hot air instead unless you’ve played around with the oven (or want to) enough to get familiar with it. The fact that you can’t very well see inside to watch the solder reflow is problematic given that it doesn’t have repeatable temperature regulation.
1 Like
awesome, thanks for the advice on the air settings, too!
For a one-off with that number of LEDs I’d hand-solder with an iron.
I hate surface mount for one offs.
But if you have to; you need tiny beads in paste, and a toaster oven. Without a mask, brushing the solder paste on will be tedious. Next you have to place all those surface mounts onto the pads. Then you just stick it in the oven at 490’F, and when the solder melts, pull it out; watch closely.
This stuff is 63/37 which has no liquid state, so you can’t get a cold solder joint.
Next you get to solder all those LEDs.
Here’s an example of what the paste and hot air process looks like. I’m still looking for a better video but this one is already very good. Actually it’s nice for illustrating how forgiving the process is. The paste application is messy and the hot air gun is not intended for soldering but the end results are still great.
2 Likes
I know I am late to this party, but using solder paste on these LEDs will likely be high risk.
What will tend to happen is that the solder will wick towards the holes and either leave you with cold/dry joints or worse still cause the LEDs to tombstone.