solder paste got “hard“

Flashlight Modding and DIY Parts
1

hey guys!

i was very short on time lately for my modding projects.
yesterday I lost my job, so… :wink:

i wanted to reflow a MT-G2 for the first time and opened the solder paste , but it was “hard“
i think i bought and opened it 2 month ago.
it was like very wet sand then - now its mildly moist sand.

question:
which fluid does it need to get it more wet again ?
or is it for the bin?

thx
Martin

2

Did you keep it refrigerated?
You can recover it to some extent by adding liquid flux.

3

It has a short shelf life about 6 months. Keeping it tightly stored in the refrigerator helps

4

There is even a video on rejuvenating solder paste by SparkFun https://www.youtube.com/watch?v=TCyki2frm3Q :bigsmile:

5

I've gotten some extra life from a tub by adding some flux:

https://www.fasttech.com/products/0/10002129/1153800-amt-amtech-professional-soldering-flux-10ml

...but it tends to be so cheap, and I use so much, that I just order another tub when it starts getting a little firm. I don't keep mine refrigerated like you are supposed to. And I usually stir it up with a toothpick whenever I use it, which seems to help.

6

Sorry to hear about the job, at least you have some time for projects now…

7

I just watched the video.
And I have to say that the soldier paste I got from FastTech is in worse shape than the most dry example. No wonder I had a little trouble using it. I intended in ordering from Mountain but they were out of stock at the time.

8

Ebay: Kester 959T or Kester 951 flux 959T would give better wetting (stronger flux action), 951T gives a cleaner appearance, less residue.
kester.com 959T
kester.com 951

9

Martin, I hope that you are not on a downward sprial that your flashaholism (you know sometimes one needs to hit bottom before they get help) :slight_smile: is now costing you employment (part joke and part sorry to hear you may need to cut back for a bit) :slight_smile:

10

thanks guys for the solder tips and kind words!

therapy:
i reflowed a xp-g2 on a noctigon, put it in a 1405 with a slightly pushed stockdriver (2,3 A tail) and got 52 kLux @3m (=468 kcd right?)
(due to heat values are falling fast - measurements taken after about 15 secs…)

i feel better already :wink:

pic taken with huawei P8 / ISO 800 / 1sec

11

How did you “slightly push” stock driver? I have the same flashlight but don’t have driver that can handle 2s input and is kicking at least 3A!!
Would you consider adding some pics of the driver?
Thanks

12

i added a R100 to the sense resistor which got me 2,2 A tailcap (did not take emitter amps)
then another R100 and poof goes a XM-L2 :frowning:

then I desoldered the second resistor and voila!
2,2A again on a xml and 2,3 with the xp-g2 :beer:

if i find some time i make a small modding thread if you are interested.
the emitter seems off center (can’t get a crisp image) and needs a bit readjustment i am afraid

13

Man, I can’t wait for n10sivern’s test of the light I sent him that I measured at 470kcd with a collar. I get the feeling all my candela measurements are going to get a free 20% bump on their output. (I think my meter is off about 20% from what you guys are getting for equivalent lights)

Sorry to hear about the job. Hopefully something new and better comes along.

14

I had a picture or driver somewhere….

15

exact that one !
just last night i unsoldered mine to make the required picture :smiley:

16

Where did you add resistors?
I think I poked R120 with tweezers making a short circuit and observing light output but nothing happened so I come to conclusion that R120 is not sense resistor!
Also tried “pencil” trick on the capacitor in top left corner, to see if it will make this driver 1 mode only, you never know if this trick might work, but on this driver it did not, unfortunately…

17

the R120 is the right one

i think a too low value does not work!
1 added R100 made the push
a second killed the LED….

back to one works fine

Edith added the modthread

18

BTW. I keep my solder paste refrigerated, I think it is sitting in the fridge almost a year and it works just fine, I take a small portion that I will use with a toothpick and return rest into cooler. As the part that I am going to use warms up it becomes a bit softer, then I dab a toothpick, preheat the MCPCB and when I get close to hot MCPCB, paste becomes very liquid, sticks to pads right away (if the MCPCB is coold or just not preheated it doesnt want to stick to solder pads)…