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amateur SMT soldering question
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author amateur SMT soldering question
Just a little poll, for you, dear wigglers.

For those of you who build modules with SMT components (but do not have a reflow oven): do you hand solder, hotplate reflow, or toaster oven reflow?

I am dying to try my hand at some DIY Mutable boards but, seeing just how freaking tiny those components are I was hoping y'all might have some recommendations on technique.
lately i have been hand soldering the chips (with a puddle of flux) and using hot air for the passives.

(Also recommended in Mutable Instruments construction guide)
hand solder, soldered 100's of modules that way.
I use a frying pan (hotplate) reflow method and touch up by hand afterwards. I have some magnifying glasses and a microscope to help check for bridges on really tiny ICs
Hand solder some ICs but reflow mostly in oven.
paste and hot air gun, touch up by hand after. Can purchase a chinese air gun for ~20 quid
Did a 0805 SMD based module with iron and thin solder. No extra flux. It works. smile

I am currently practicing using the hot air gun (858D) on those cheap test boards but will try the module (NLC flanger) any day now...
Thanks for the input, everyone. I suppose I should just get a few practice boards and figure out what works best for me.
spacedumpster wrote:
Thanks for the input, everyone. I suppose I should just get a few practice boards and figure out what works best for me.

Just beware of some practice boards on eBay- my initial attempts with them were poor as the boards were rubbish! Get some decent quality plated or at least tinned types or you’ll get put off the whole enterprise!
I use the same iron and solder that I use for through hole. I haven't done any 0603 but e.g. the DAC on an Ornament and Crime was very doable this way.

I do not (yet?) prefer surface mount to through-hole. Clipping leads is relaxing.
I find 0603 barely doable with iron... eek!
A magnifier and lots of practice might helo I guess.

And yes, the practice boards help me overcome the SMD fear. Useful things those.
Hand. No problem down to 0805, but 0603 is getting fiddly.

I'll also note that boards designed for humans to SMD are somewhat different to those assuming a pick/place and oven is doing all the work...
hand. (have not tryed sonething smaller than 0603)
0603 and 0.5mm pitch chips are pretty easy by hand with the right tip and technique. I recommmend paste for smd electrolytic caps.
Recently built a pile of Mutables (0603 passives and 0.5mm pitch QFPs) using:
*Solder paste dispenser with very fine tips (27 to 31).
*Cheap ass Chinese hot air gun (set to 300c and lowest air flow).
*Strong magnification and illumination.
*Lead-free no-clean-flux paste

No matter what method you use, the most important trick is limiting the amount of paste you apply. Trying to clear excess solder from fine pitch pins is no fun. The drag soldering shown in so many youtubes gave me fits. When using hot air on passives, if you get both sides flowing, the parts just pop into place with no cajoling.

The second most important trick is keeping your tweezers clean of solder flux, which makes them sticky and troublesome.

When hand soldering fine pitch chips, I use the iron to tack solder two opposing anchor pins and set proper registration. All the remaining pins are done with hot air. I hold the hot air unit directly over the board so it blows straight down. This minimizes tombstones and creep.

Even though I use no-clean flux, I clean it anyway so I can get a good inspection under magnification.
I've done many of them with the techniques from that eevblog video. Get some good tweezers and some good reading glasses or these - hangeable/dp/B01H8808H6/ - and you'll be ready for anything.
Solder the chips first, then the small stuff. Solder the tall parts last.

Use a flux pen to coat the pads before you place the part. Use a small chisel tip on the iron set to 315C, or 600F and load a bit of solder on one side of the tip. While holding the part with tweezers touch the iron to the board, or the pin with the solder load toward the board. Just enough solder should wick from the iron to the board.

This method works well down to 0603, and works best with HASL finish on the board. ENIG or OSP finish, like what thonk ships in some of their kits is a little harder to get the solder to flow onto.

Practice makes perfect!
Ask and you shall receive! Thanks for all the tips everyone. This is why i love this forum, loads of different answers, all of them helpful. I am so much an amateur that I did not even realize the components came in different sizes. Sooo here's hoping the bits I ordered from mouser aren't too teeny tiny. seriously, i just don't get it
Hand, using a cheap Antex 15W iron. For me, the key is lots of flux and especially lots of magnification. A really good loupe makes all the difference.
Everything by hand, here.

I have a temperature-controlled solder-station, and I usually have it set to the highest temperature (400C).

I use the same tip I've used for years to do through-hole stuff. I'd use a finer one, but the current one seems to have welded itself onto the iron, and I can't get it off.

For passives, I add solder to one pad, then reheat the solder and slide the component into the remelted solder using tweezers, then solder the other end. This works for me with 0805 and 0603.

I don't tend to use flux for passives.

With SOIC ICs, I pre-load a pad, then slide the IC into place, as with passives. I then straighten the chip, if necessary by gently nudging it, then solder the opposite pin. I'll then do the remaining pins one-by-one.

Sometimes I use a little flux from a pen-type flux-dispenser.

For finer-pitch ICs, I use the drag-solder technique. I'll pre-load a pad (or several, if they're really tiny), reheat and slide the IC into place. It might take a few attempts to get it into place. Then I'll solder some pins at the opposite corner. Finally, I'll drag-solder all the pins, and remove the excess with fine solder-braid. Sometimes, I find that some pins aren't properly soldered when I test the module, and I have to do another drag-solder pass.

I use lots of flux to do fine-pitch ICs.

I just finished my first SMD yesterday (Grayscale Binary)
All hand soldered

must haves:
-a pair of small tweezers
-magnifying glass
Hand solder with a WES51D and the 0.010 tip and the thinnest solder I have. For passives, I put a "bubble" of solder on one pad, reheat
the pad with the iron and slide the passive into place, then solder the other side.

For ICs, solder bubble on one pad, reheat and place the chip, flex it till the pads line up, solder the opposite corner. Double check
the alignment. Then solder one at a time, fix overblobs with thin solder-wick braid.

The air wand comes out only for removing parts or repairs; I have pulled a 44-pin TSOP without any damage and reinstalled it this
way (hot air for removal, opposite corner single soldering for replacement).

I've never mastered drag soldering.
- Bill
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