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rkhanso
07-15-2010, 12:11 PM
I got in on the Strobe group buy (http://doityourselfchristmas.com/forums/showthread.php?t=11802) that just ended. I made one of the DIY hot air guns from the Radio Shack de-soldering iron.
Here's a link to the idea: CLICK HERE (http://www.engadget.com/2006/03/07/how-to-make-a-surface-mount-soldering-iron/) -- but I didn't keep the bulb on, just put the hose over the air tube on the iron.

Question: to build 160 of those Strobe boards, anyone have an idea how much solder paste in the syringe I'd need to get? I've seen 7g tubes, 35g tubes and 100g tubes.

LINK (http://www.janelonline.com/SearchResults.asp?searching=Y&sort=13&search=solder%20syringe&show=80&page=1)
LINK (http://cgi.ebay.com/New-Wahl-Silver-Bearing-Solder-Paste-7-1-Grams-Syringe-/270596972271?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3f00d61eef)

Can someone with some experience give a little advice? I'd hate to run out 1/2 way through putting those boards together.

budude
07-15-2010, 01:46 PM
I got in on the Strobe group buy (http://doityourselfchristmas.com/forums/showthread.php?t=11802) that just ended. I made one of the DIY hot air guns from the Radio Shack de-soldering iron.
Here's a link to the idea: CLICK HERE (http://www.engadget.com/2006/03/07/how-to-make-a-surface-mount-soldering-iron/) -- but I didn't keep the bulb on, just put the hose over the air tube on the iron.

Question: to build 160 of those Strobe boards, anyone have an idea how much solder paste in the syringe I'd need to get? I've seen 7g tubes, 35g tubes and 100g tubes.

LINK (http://www.janelonline.com/SearchResults.asp?searching=Y&sort=13&search=solder%20syringe&show=80&page=1)
LINK (http://cgi.ebay.com/New-Wahl-Silver-Bearing-Solder-Paste-7-1-Grams-Syringe-/270596972271?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3f00d61eef)

Can someone with some experience give a little advice? I'd hate to run out 1/2 way through putting those boards together.

I'd be interested to see how that works for you. I have one of those desoldering guns already and bought a fish pump (you should have seen the look from my wife on *that* purchase!!! :rolleyes:) a couple months ago but haven't hacked it together yet.

rkhanso
07-15-2010, 06:04 PM
and bought a fish pump (you should have seen the look from my wife on *that* purchase!!! :rolleyes:) a couple months ago but haven't hacked it together yet.
I can imagine. A look only a wife can give - and I've seen it many times.

Have you fired up your iron with the air pump attached and on? It seems to get hot enough, but the airflow is lower than I thought. I realize you don't want a lot of air flow - so the tiny parts don't blow away, but I'm wondering if I need to get a little bigger pump. I guess trial and error is the best experience.

I guess the 'real' method of soldering SMD in an oven, or whatever, has a specific temperature rampup/down procedure to follow. Going hand-held without any idea what temps we're at - are there any guidelines that we should follow to get a proper solder?

Another question about that solder paste. I saw some syringes for sale on eBay that had an 'expiration date' on the tube. Does this stuff get old after a while? I would just spring for the 100g tube, but if I'll end up throwing most of it away after this short PCB/Strobe project, would rather save the money and get just enough for the job.

james70818
07-15-2010, 06:47 PM
Another question about that solder paste. I saw some syringes for sale on eBay that had an 'expiration date' on the tube. Does this stuff get old after a while? I would just spring for the 100g tube, but if I'll end up throwing most of it away after this short PCB/Strobe project, would rather save the money and get just enough for the job.

I really don't think it goes bad. More of a way to help rotate stock. I purchased 2 1lb rolls for $9.99 shipped that had a self proclaimed expiration date on it. They work fine. I also have some real old stuff that is 20+ years old and it works well too. Now this is all flux core stuff not paste. Maybe the paste could dry out over time?

aussiephil
07-15-2010, 07:36 PM
Another question about that solder paste. I saw some syringes for sale on eBay that had an 'expiration date' on the tube. Does this stuff get old after a while? I would just spring for the 100g tube, but if I'll end up throwing most of it away after this short PCB/Strobe project, would rather save the money and get just enough for the job.

Hi

Yes - it does age. It dries out, it goes hard, becomes impossible to use in syringe. For just using with hand soldering you can just mix it with some solder flux and continue on.
However, if you use it with an Oven (or griddle) then it shouldn't be mixed.

What i do with the fresh paste i use with stencils, that is excess at the time, is to put it back into another syringe and use it for hand solder projects.

Not sure yet just how much the strobe boards will use. Personally i would just by the 35g tube, 100g would be truly excessive. The current 35g syringe i have, has done quite a few thousand pads for the controllers. It will go a suprisingly long way.

Cheers
Aussiephil