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Questions about the BatchPCB service

Moderator: robacarp

#3912
(note: I'm in no way affiliated with this company, I just came across the google ad, and thought I'd pass on the info)

http://www.smtsolderpaste.com is giving away a free 250g jar of solder paste, plus a coupon for $25.00 off of your first order of 4 or more jars (500g) of solderpaste (at 40.00 each).

I've ordered my free jar of the lead free stuff..

On that note: any special caveats that I should watch out for?

I plan on using the syringe-and-solder-wick method of hand-assembly for my prototypes (which should be back from China any day now :-)

Am I totally screwed with trying to use a regular soldering iron instead of a hot-air unit? I'm going to eventually get a hot-air station, but it's not in the budget for this month...

Also, is the 8502 rework station just an 850B and soldering iron in the same box, or is there some advantage to the 8502's hot-air section over the 850B/850D? The reason that I'm asking is that I have a rather nice weller soldering iron already, and I don't really need the soldering iron section on the 8502 so I was thinking about getting the 850D (because who doesn't love a digital readout :-)

-- pryankster
By Vraz
#3930
I asked about the difference between the 8502 vs 850B+936. According to Sparky, the heating element for the iron in the 8502 is nicer than the 936 but the hot air sections of the 8502/850B are identical. Here is the link to the thread:

http://www.sparkfun.com/cgi-bin/phpbb/v ... .php?t=885
User avatar
By sparky
#4026
I'd love to hear how lead free solders and pastes work with the 85x units! The only difference is the higher melt temperatures which the units should be able to do. We've just never had to do lead free stuff.

I don't think our oven is supposed to be able to hit the higher temps, but it's worth a try.

On a quality note: my assembler mentioned the other day how he likes our Weller WES50 iron better than iron on the 8502. IMHO they are comparable, but the WES50 iron has the better tip.

-Nathan
By tmbg
#4041
when are you guys gonna be getting more of your air stations in? I'd love to have an 8502!
User avatar
By sparky
#4050
Hoping for April 15th.
By MGP
#4059
sparky wrote:I'd love to hear how lead free solders and pastes work with the 85x units! The only difference is the higher melt temperatures which the units should be able to do. We've just never had to do lead free stuff.

I don't think our oven is supposed to be able to hit the higher temps, but it's worth a try.

On a quality note: my assembler mentioned the other day how he likes our Weller WES50 iron better than iron on the 8502. IMHO they are comparable, but the WES50 iron has the better tip.
I've done some lead-free soldering with my Hakko 850B station and it worked OK. I had to crank the temperature up about 20% from what I'd normally use to get a nice clean flow on the joint. I don't care much for lead-free but I know some people must deal with it.

As far as the soldering stations -- I still use my good 'ol Weller EC2000 digital temp control soldering station. I've tried at least a half dozen other stations and still come back to the Weller. I've always liked Weller tips the best -- they last a long time and are inexpensive. I've even tried the really nice Metcal sodering stations and while they solder great, they eat tips ($$$) like candy.
By Pete-O
#4073
Are you kidding?!? I love Metcals! I used one for 5 years, replaced tips maybe 3 times.

But there's nothing wrong with Wellers. And you can't beat the price.

Pete
By BigRedBee
#4213
I'm doing all of my surface mount soldering using this free solderpaste a toaster oven. I put the solderpaste in place with a hobby syringe, stick the component on the board, and then pop'em in the oven for a few minutes. Works like a charm!!!
By rackley
#4217
A toaster oven? Wow, that's sweet...definitely lowers the cost barrier to doing SMD. What temp do you use? How easy is it compared to regular DIP soldering?

Ray
By MGP
#4219
Well that's the trick -- you need to use a "temperature profile" that preheats the board and components, rapidly ramps up the soldering temperature and holds it there for some time and then ramps the temperature back down under control so you don't thermal shock the board and components.

That's how the "pro" IR soldering systems do it and why we've been discussing controllers for our own homemade soldering toaster ovens.

There is a Yahoo discussion group that is setup for homemade SMD toaster ovens: Yahoo E-Z Bake Oven Group

As for your question about SMD soldering vs. through hole -- I much prefer building SMD boards now that I have a hot air tool and SMD oven. You can build lots smaller boards and I've found that working with paste is pretty easy and the boards go together fast (you often get to solder LOTS of leads at one time rather than one at a time).
By moorejl
#4253
Me too :)

I am using Kester R500 paste, a "free" EFD HPD dispense syringe and a $30 Betty Crocker toaster oven (cheapest one I could find). I was really in doubt that this would work, but honestly, reflowing is the easiest part. I set the oven to 450F, preheat the board on top of the oven for 10 minutes and bake for about 60-90 seconds and open the door soon after the solder melts.
By Pryankster
#4257
got my board back and (though they were wrong .. sigh), I hand soldered the smt parts on the board. It wasn't nearly has hard as I was expecting. I have a decent magnifier, a sharp point on my weller iron and a nice pair of stainless-steel tweezers.

For the passives (0805), a drop of solder on one pad, hold the part up to the pad, a quick touch with the iron on one side, and it's held in place to do the other side. easy-peasy.

For chips (TQFP so far), I just dropped a bunch of rosin on the pads, tacked two corners, and dragged a big blob of solder across the pins. I then used solder-wick to take off the excess and inspected under the magnifier. no bridges and no unconnected pins.


I'm still afraid of BGA's, though...
-- pryankster
By dhouston
#4267
I've managed to solder the CP2102 (MLP-28) using a toaster oven. The only caveat is to extend the pads out 0.010-0.015". If there is any bridging, that allows you to get the tip of an iron on the pad.
By wiml
#4284
I've reflowed some boards (just SOIC, nothing denser than that) using a small oil or alcohol lamp, the kind you might use in chemistry class. Hold the board well above the flame to preheat and bake out the moisture, then hold it just above the flame (at least a cm or so away from the flame tip or it'll get sooty) until the solder melts, then move it away to cool. A candle would probably do in a pinch. You might have to move the board around a little to get all the junctions heated properly, but it seems that the hot air rising from the flame flows around the board and heats it pretty well.

This is obviously a quick-and-dirty technique but it does work, at least for really small boards. :)