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Topic: Soldering iron (Read 8109 times) previous topic - next topic

Paul_KD7HB

"Balling" solder is a sure sign there is no flux. Use flux pen or buy small bottle of flux and use a small brush.

Paul

TomGeorge

#31
Mar 26, 2015, 11:39 am Last Edit: Mar 26, 2015, 11:42 am by TomGeorge
Hi,

jboyton;
You have an adjustable iron, I haven't seen anyone ask what temperature you have it set on?
Looks like you could be a little too hot.

What solder are you using?

Tom.... :)
Everything runs on smoke, let the smoke out, it stops running....

jboyton

The iron has an adjustment screw but no temperature scale, so I have no idea what the temperature is. I have been trying to adjust it to where it heats quickly but not too hot. That seems to depend on the situation (tip size, what I'm soldering).

Solder is Kester 60/40 tin/lead rosin core 0.031".

polymorph

You don't want to solder each lead separately for an SMD IC. And a tiny tip is -not- always a good thing, as the heat can't travel quickly enough to a very thin tip, and solder will pull away from a very thin tip.

Search for "drag soldering". Have lots of flux on hand, I prefer No Clean liquid.

https://www.youtube.com/watch?v=wUyetZ5RtPs

http://www.eevblog.com/2013/03/04/eevblog-434-smd-thermal-pad-drag-soldering-tutorial/

Steve Greenfield AE7HD
Drawing Schematics: tinyurl.com/23mo9pf - tinyurl.com/o97ysyx - https://tinyurl.com/Technote8
Multitasking: forum.arduino.cc/index.php?topic=223286.0
gammon.com.au/blink - gammon.com.au/serial - gammon.com.au/interrupts

jboyton

Thanks for that. I had actually watched a video about drag soldering before trying the second time but wasn't sure how to apply it since the IC I was soldering has no pins, only flat pads:



I wasn't sure that dragging made any sense since there would be nothing exposed to drag across except for the traces on the board.

Paul_KD7HB

At my plant, we would only solder that kind of a device using solder paste and a reflow oven.

Paul

jboyton

Ha ha, understood. But I don't have a plant, only a meager set of tools. I would happily spend $10 or $20 on a shield with this device but nobody makes one yet. So I have a working part now but I'm not terribly confident that it is soldered in a way that will stand the test of time. Maybe a little vibration and it will go kaput? I don't know of a way to ascertain the quality of the solder joints, so we'll see.

CrossRoads

#37
Mar 27, 2015, 06:09 am Last Edit: Mar 27, 2015, 06:09 am by CrossRoads
Time to invest in a a hot air rework station.  Surface mount is not going away.
http://www.mpja.com/Rework-Station-Hot-Air-for-SMD-Replacement/productinfo/16121%20TL/
I bought several nozzles too for the size chips I deal with the most so that all get heated at once.

Bunch at Amazon too.
http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=hot%20air%20rework
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

polymorph

Yeah, hot air or reflow for that chip.

Lots of people doing solder paste and reflow using toaster ovens and even fry pans.

Frying pan reflow

It is amazing watching the solder melt and the parts pull to the middle of the pads.

Toaster oven transformed into a solder reflow oven
Steve Greenfield AE7HD
Drawing Schematics: tinyurl.com/23mo9pf - tinyurl.com/o97ysyx - https://tinyurl.com/Technote8
Multitasking: forum.arduino.cc/index.php?topic=223286.0
gammon.com.au/blink - gammon.com.au/serial - gammon.com.au/interrupts

CrossRoads

Don't need much transforming to turn toaster oven into reflow oven.
I have an old Sears Kenmore toaster oven with 4 elements.
I use a thermocouple probe that came with my DMM to monitor the temps:
http://www.extech.com/instruments/categories.asp?catid=48
(we have 2 meters - an older EX330, and a 2nd that we just got that is similar but has simpler controls, both on sale when we bought them, ~$35 I think)
Ramp up to 125C-150C, hold for 90 seconds,
Ramp up to 183C-215C, hold for 90 seconds,
cool down.
Have done it enough that I know about where to crank the dial to get pretty close, and use the meter to monitor and not exceed the temps.
4 elements ensures the temperature ramp up rates can be met.
Only had 1 problem reflowing, did a batch of cards and had several near the edge, which did not get as warm as the middle, so some cards had to be reflowed. So now we stick with smaller batches and stay away from the sides of the oven.
It is neat watching the paste liquefy and turn shiny near the end of the 90 seconds at the higher temperature.
(I have all the parts to make an automatic controller - just don't seem to have time to assemble them and do some programming)
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

polymorph

Yes, you absolutely can control a toaster oven manually with a temperature probe and a digital timer.
Steve Greenfield AE7HD
Drawing Schematics: tinyurl.com/23mo9pf - tinyurl.com/o97ysyx - https://tinyurl.com/Technote8
Multitasking: forum.arduino.cc/index.php?topic=223286.0
gammon.com.au/blink - gammon.com.au/serial - gammon.com.au/interrupts

jboyton

A toaster oven?? Now you're talking my language.

CrossRoads

Yep. Look for a 1500W oven, that will generate the desired temperature ramp rates.
I got a larger one on sale at Target too, haven't tried yet as the old (20+ years) smaller Sears Kenmore unit is still working well.

See the ramp rates and temperatures here.
I use Kester EP256 solder.
http://www.kester.com/download/EP256%20Data%20Sheet.pdf
These guys have a good price for a syringe of solder, with includes some small needles for dispensing. I also bought some 22 gage plastic needles that the tip can be enlarged like on a caulk gun for squeezing out larger quantities for stencil use on a whole board.
http://www.cmlsupply.com/kester-ep256-lead-solder-paste-63-37-syringe-dispenser/
http://www.cmlsupply.com/dispensing-needle-22ga-tapered-tip-blue-pk-50/



Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

jboyton

Would a regular kitchen oven work okay? Or would it be too difficult to control the temperature?

How the heck did that guy with the frying pan do it?

CrossRoads

Quote
Would a regular kitchen oven work okay?
Only if you're trying to poison yourself!
I only use this old toaster oven for solder reflow, not food preparation anymore.
Large ovens will take too long to heat up
125C is 257F
200C is 392F.  My gas oven takes more than several minutes to get that hot - with reflow, the whole warmup, reflow, cool down cycle is only 5-6 minutes.

Frying pan, clothes iron upside down, takes some experimenting to find the rights temps & times.
I've seen videos with toasted fiberglass too! If one is getting hot enough to burn the PCB material, that can't be good for the ICs.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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