upgrading soldering equipment

hello,

in the (near) future i would like to buy/make some new stuff to simplify and accelerate the soldering part of my projects, i am writing here for advice

for now i am doing everything (and i am quite satisfied) with my hakko 936 plus cheap solder wire

what i would like to have is:

  1. soldering oven
    there are countless of diy project which start from cheap oven or even toaster but i quite doubt them works well, especially without a lot of work of calibration. do you have different experience?

buy a cheap product on the net: i just discovered that them aren’t so expensive, for example this and maybe there are even cheaper or second hand stuff

  1. solder paste
    i already bought some of this stuff but i found it quite un-usable since it has a huge viscosity (almost a solid in my opinion) and i am unable to put it where i want in a simple way
    to solve this i think i will make a dispenser with a stepper motor: example maybe an attiny85 will do the work, there is also a air version but i don’t like it at all
    then the only problem would be how to refill it, any ideas? or i would need to buy small soldering paste tube

which is your experience about?

What type components do you work with? Through hole or smd? How big are the projects, as in what is the parts count?

Have you tried using Liquid Soldering Flux.
(something like this https://www.amazon.com/Kester-959T-Soldering-Bottle-Clean/dp/B01N11M60P/ref=sr_1_3?ie=UTF8&qid=1520731931&sr=8-3&keywords=liquid+flux+soldering )

If doing SMD, solder the 2 corners to position the part and then put the Flux down and drag a ball of solider over all the pins and there will be little or no bridging. If you do get bridging use some solder wick and then more flux and reheat with solder iron.

Not sure how you would use solder paste without some kind of applicator.

Are you where power is 220v 50Hz ?

Show us some of the work you have done and expecting to do.

Huge amount of stuff on YouTube.

Most SMD soldering done with stencils to apply solder paste to PCBs.

You might want to watch this:

I do a bunch of one-off boards, using from just an ic to 30 or so components. Ordering boards and stencils for playing around would tend to get expensive.

I have a temp controlled solder station and a hot air rework station to assemble my projects, and I just picked up a 4 slice toaster oven that I'm not sure if I'm going to make it into a reflow oven or make my lunch with.
As for solder paste, I just use an xacto knife to put a small dab on the pad. It might take a minute, but it works just fine. A little paste goes a long way.

I am based in europe, italy so 50Hz with 220V
I would use it mainly for SMD stuff, I use 0805 parts and AVR and STM32 MCU (these have a smaller pitch compared to AVR and i have difficulties to properly solder them) for now i m around the 10 SMD parts but now i am projecting a development board for a 64 pin STM32 that would have something like 30-40 things on it

examples of some little projects:

(yes, i like to do development boards :-[ )

tinman13kup i feel myself in your situation since my projects consist usually of a few boards, usually one for me and one/two for some friends, for this reason i didn't consider the possibility to buy stencils
and also, like you, i am not very ready to go for the DIY way modifying a toast oven. I am also happy that i am not the only one who put the solder paste with the xacto knife, but i will solve this with the stepper dispenser

larryd:
Most SMD soldering done with stencils to apply solder paste to PCBs.

You might want to watch this:

- YouTube

interesting video, i didn't saw it all but i would do if i will buy that rework station, this T-962 seems to work good for a hobbist

1steve:
Have you tried using Liquid Soldering Flux.
(something like this https://www.amazon.com/Kester-959T-Soldering-Bottle-Clean/dp/B01N11M60P/ref=sr_1_3?ie=UTF8&qid=1520731931&sr=8-3&keywords=liquid+flux+soldering )

If doing SMD, solder the 2 corners to position the part and then put the Flux down and drag a ball of solider over all the pins and there will be little or no bridging. If you do get bridging use some solder wick and then more flux and reheat with solder iron.

Not sure how you would use solder paste without some kind of applicator.

is this just a normal flux or has it something special?

anyway i use a quite old (i think it has more then 10 years, not kidding) flux and it still works good

Keep in mind, temp means a lot when it comes to solder paste. My little electronics room is tucked in the corner of the basement, and since I keep the thermostat low to begin with, that room tends to stay in the 60F range. At that temp, the paste doesn't like to stick well, and it is difficult to get a small dab for a 0402, If I warm it up a little (I'd guess 75F) it becomes much more workable. The paste I have is in a syringe, albeit a quite large tip for small parts. I tried a small syringe, but it won't work. The material is too think, and if you heat it the flux is all you get.

For some of the small pitched ic's with no leads and center pads, I will put a bit of paste on them and use the rework gun to melt it. That lets me see if there are any bridging issues. Then I just flux the ic and reflow the solder.

For a few boards like that, with just a few components, suggest you stay with hand soldering (w/ w/o solder paste).
For small SMD PCBs, I use a HAKKO FX888D soldering iron with pointed curved tip.

C.jpg

If you haven’t seen these, they might be of some interest to your.

http://forum.arduino.cc/index.php?topic=445951.msg3627000#msg3627000

http://forum.arduino.cc/index.php?topic=445951.msg3636667#msg3636667

http://forum.arduino.cc/index.php?topic=445951.msg3642288#msg3642288

Oh what the heck, take 20 minutes and review all 476 posts (with a glass of Italian wine) :wink:
http://forum.arduino.cc/index.php?topic=445951.0

larryd picture
Good solution, I am doing in different way.
Holding PCB in hand and pressing soldered component by finger nails, less possibility that component will move from right spot.

Larry to hold the smd in place i usually use tweezers for 0805 components and a cotton-swab for ic but I liked the idea of a smd hold-down, i though about it but never made one. I will see what i have around in the garage, thanks!

with just a few components, suggest you stay with hand soldering

yes you are right, 30-40 components are not many, i should stay with hand soldering

my desire to move to a different soldering method is not because i am lazy but because i am not enough precise :frowning: when i play with AVR like the m328 which has a pin-to-pin distance of 0.8mm i doesn't have any problem with hand-soldering but i am not enough good with components which have a distance of 0.5mm like the stm32's mcu. This is quite frustrating to solder and desolder a component twice of three times. this is the main reason why i would like to move to a new soldering method

this is something i didn't realized before but i think that this is my main problem: the placing of the ic in the perfect position
how do you do it? just with a microscope and tweezers? sometimes i lost even 5 minutes to put it in the right place and it isn't never 100% perfect

Tom, thank you for the suggeation about the warm-up of the solder paste, next time i will do it!

I use the solder paste that the OP mentioned, and a converted toaster oven (ControLeo2 control module and toaster oven mod kit, on the recommended toaster oven). Works great as long as I use stencils to apply the solder paste - I was never able to find solder paste that worked well from a syringe; I tried several.

I use tweezers and good lighting to place the parts; I have not found part placement to be problematic when there's a nice even layer of solder paste from a stencil - I suspect your difficulty is partly because when solder paste is dispensed manually, you don't get an even layer of it.

"....is this just a normal flux or has it something special?

anyway i use a quite old (i think it has more then 10 years, not kidding) flux and it still works good...."

Yes, just normal "Liquid" solder flux. Need to be "Liquid" not paste solder flux. Position the part (tack corners.) and then run a pool of Liquid Flux over the pins/pads, then solder.

Look at post #24, 28, 34, ....................

You can find interesting methods how to do that on youtube.

1steve:
"....is this just a normal flux or has it something special?

anyway i use a quite old (i think it has more then 10 years, not kidding) flux and it still works good...."

Yes, just normal "Liquid" solder flux. Need to be "Liquid" not paste solder flux. Position the part (tack corners.) and then run a pool of Liquid Flux over the pins/pads, then solder.

In my link I used a lot of soldering paste , that is the secret , the paste kind is not important I am using plumbers soldering paste is much cheaper for long time.
For cleaning toothbrush and kitchen liquid soap , rinsing with water, drying with paper towel, blowing the water from under components.

this is something i didn’t realized before but i think that this is my main problem: the placing of the ic in the perfect position. how do you do it? just with a microscope and tweezers? sometimes i lost even 5 minutes to put it in the right place and it isn’t never 100% perfect

I use a stereo microscope for fine pitch soldering and alignment.
A head magnifier @ X2 or X3 works too.

I use to solder tack an I.C. corner with solder . . .

However, for hand soldering, I now:

  • liquid flux the pads, let dry so it becomes sticky.
  • with tweezers, position I.C. perfectly on pads, place magnetic hold down at I.C. center. (I updated the hold down with a 3/4" magnet, the SS rod is a 2mm bicycle spoke). Position the chip with the left hand :wink: and place the hold down with the right. ~ 5 seconds per I.C. using microscope.
  • with 63/37 .02" solder with iron curved tip @400°C (quickly)

E.jpg

Two points:

  • If you try the magnet hold down sitting on a 403 SS surface you will not go back to the way you do things now.
  • If you get a chance to solder using a stereo microscope you will be astounded how good you can solder.

Urge you to go thru the 400+ posts as linked to see other hints.

Along with tweezers, I use a vacuum SMD pickup tool mentioned in the links. It is made using an air pump.

https://forum.arduino.cc/index.php?topic=445951.msg3159122#msg3159122

VacuumPickUpTool.jpg

larryd:

  • If you get a chance to solder using a stereo microscope you will be astounded how good you can solder.

+1 to this. I am a mediocre solderer at best. My brother used to make hearing aids and taught me some basics. But until I got a stereo microscope I was lost with the small stuff.
Now, I can make it work. Not pretty, but working.

DrAzzy:
I use the solder paste that the OP mentioned, and a converted toaster oven (ControLeo2 control module and toaster oven mod kit, on the recommended toaster oven). Works great as long as I use stencils to apply the solder paste - I was never able to find solder paste that worked well from a syringe; I tried several.

I use tweezers and good lighting to place the parts; I have not found part placement to be problematic when there's a nice even layer of solder paste from a stencil - I suspect your difficulty is partly because when solder paste is dispensed manually, you don't get an even layer of it.

This is (almost) my exact process as well.. except I do NOT have a controller on my toaster oven.

I use my vinyl cutter to make my own solder paste mask/stencils.
out source to whatever Chinese PCB fab house to get my PCB's made
solder paste from ebay (China) ... couple bucks USD.

I suppose I could try and use my laser cutter for stencils as well? (never gave it a shot as of yet)

There is a thread where we go over all the techniques here: (mind give you some alternate solutions on what you wanna do)

From pcbway.com, when you order your PCB, a metal stencil costs only ~ $15.

I have a stereo microscope with a camera, but have yet to try it soldering. There seems to be a learning curve, as X,Y- no problems, but Z seems to be lacking. I was pulling a couple DIP chips from a pcb I was wanting to scrap and ended up splitting an adjoining ic, exposing the actual chip. I only have a 90x scope, but it sure is interesting even at that level of magnification. It makes soldering 0201s look like a walk in the park.

the paste kind is not important I am using plumbers soldering paste is much cheaper for long time.

I wouldn't suggest plumbers on anything unless you want the green rot. Use rosin core solder and flux, or formulas specific to electronics