Comments on: SparkFun stencil and solder paste class notes

By: komradebob

komradebob — Sat, 11 Dec 2010 05:41:28 +0000

I’ve had solder paste thicken up on me after a few months. I have had good luck ‘revitalizing’ it by mixing it with either a bit of isopropol alcohol (which dries out quickly on the pcb) or some liquid flux, which works great.

Now if I could get a good, cheap, easy way to cut stencils, I’d be thrilled.

By: ewertz

ewertz — Thu, 15 Oct 2009 19:42:57 +0000

@Billy – http://www.ohararp.com

By: Billy

Billy — Sun, 08 Mar 2009 10:56:06 +0000

Where do you get the stencils?

By: alexfox

alexfox — Wed, 18 Feb 2009 20:19:55 +0000

solder paste will easily last months in a not-hot environment (e.g. room temperature)

the reason the manufacturers have such stringent temperature requirements and expiration dates is because if a large batch of solder paste goes bad and ruins a large manufacturing run, someone is out of a lot of money!

for hobbiest purposes, don’t worry about keeping it cold or following the expiration date

By: Odin84gk

Odin84gk — Wed, 18 Feb 2009 20:00:57 +0000

@fartface
I agree that hand-soldering is preferable for 1 or 2 boards, but if you ever plan on trying your hand at 20+ circuit boards, a large stencil is the way to go.

By: macegr

macegr — Wed, 18 Feb 2009 19:55:26 +0000

@rob: Okay, you didn’t read the tutorial. They’re using a Pololu stencil (http://www.pololu.com/catalog/product/446) which is much cheaper. If you have access to a laser, you can make your own. And you can get 50g of solder paste for under $4 (http://www.dealextreme.com/details.dx/sku.4711). I have some and it works great.

By: arizonacharlie

arizonacharlie — Wed, 18 Feb 2009 18:31:16 +0000

really like this place, everyday a new invention

By: Rob

Rob — Wed, 18 Feb 2009 17:18:46 +0000

Solder stenciling is a great idea but has its drawbacks. You really don’t need a class for this if you have any experience soldering with paste. If not, buy some and learn. The problem with stenciling paste is that if you are only doing one or two chips at a time, why hassle with stenciling since a nice soldering iron will do the same? The stencils cost money ($99 I believe), the paste is expensive (~$50) and goes bad after a few months (even in the fridge). If you are doing a multiple part board stuff then by the time you hand place all the components you will find that the paste has dried out and does not reflow well or at all. The only way I consider using paste stencils is with a pick and place machine or if you have a big panel of boards with only a few parts on each. I’ve stuffed plenty of 100+ component boards with all 0402 and QFN parts using a soldering iron without trouble.

By: strider_mt2k

strider_mt2k — Wed, 18 Feb 2009 15:09:29 +0000

I should pick up a basics kit and start learning some SMD skills.
Hackaday you still rule.

By: fartface

fartface — Wed, 18 Feb 2009 14:48:19 +0000

Soldering surface mount parts is NOT bad if you have the right tools. Most guys are trying to half arse it with their radio shack special Club iron. you gotta get a good weller blade iron, micropencil and a set of hot tweesers. hot air reflow is good for stripping boards but I prefer a IR rework station. Snagged all I need for SMD work at Dayton Hamvention last year for nearly $100.00 total. also get a good soldering microscope. That helps a LOT when you start going to the ultra-tiny SMD components.

By: strider_mt2k

strider_mt2k — Wed, 18 Feb 2009 14:06:24 +0000

I am jealous of the folks in close proximity to these classes!

not only would it be awesome to learn new techniques, but to actively discuss them with humans in a face to face environment?

priceless!

The internet might be good for some things, but humans still have to interact on a personal level if we want to stay humans.

Don’t make me get the gom jabbar!!

By: Attrezzo

Attrezzo — Wed, 18 Feb 2009 13:22:14 +0000

@roboguy… ‘greed.

Learning is figuring out it exists and that you do it kinda like this… Doing it is just doing it.

That’s like saying a guy learned to drive a car hands on by reading the internet then just getting in and driving it.

Hands on is a class where the first day they put you in the car and say, “Drive and I’ll correct you when you screw up.”

By: Roboguy

Roboguy — Wed, 18 Feb 2009 12:28:13 +0000

I think the “trying it once” part is just doing it, not “learning hands on.”

All his “learning” was done by reading the websites.

By: dan

dan — Wed, 18 Feb 2009 08:28:02 +0000

‘i learned it by reading a few websites on the matter, and then trying it once…’

um, if that doesn’t count as hands-on, what does?

stuff like this makes me wish that i lived in america. you guys seem to have so many open-to-the-public classes, workshops and stuff available compared to over here in the UK. whatever people say about your country, at least people still have a desire to build things!

By: alexfox

alexfox — Wed, 18 Feb 2009 03:31:47 +0000

why exactly must you learn it hands-on?

i learned it by reading a few websites on the matter, and then trying it once…

thats all it takes; its not that difficult, especially compared to the alternative of soldering surface mount components by hand (although hot air rework isn’t bad)