Solder and Soldering Irons

thanks for the tip about kitchen sponges, I always wondered how I destroyed my old soldering iron so badly.. I'll start using the copper wool ball thing I have instead now

 

I've been using the same cellulose sponge for 30 years now. It doesn't seem to degrade....

 

Oh man, i just did some toaster oven reflow!

 

hey how is the folsom amp coming? hope you didn't have to oven reflow it

 

Thats next in line after I finish this other headphone amp with a bazillion SMD components. I wouldn't reflow the Folsom considering how many electrolytics it uses.

 

Soldering Iron, Non-Electrical Use...

Some time back I bought a very low-wattage soldering iron with a flat screwdriver-shaped bit for "welding" plastic.
I have a microfibre car brush (like one of those California brushes, I think, but not waxed). All those things seem to have a generic plastic body, over which the the fabric-backed brush is fitted, and a hole for a tubular handle. My handle hole split.

Used the iron to weld the split, and used plastic cable tie as "welding rod" to add material. I've embedded hot staples to strengthen glue repairs on plastic items before, and was wondering how to reinforce my weld. I melted a length of copper solder wick into the built-up plastic around the diameter of the tube. Seems to me that this is a simple and easy way to give some strength to a thin area of load-bearing plastic.

 

Heh...melting plastics with solder irons. This reminds me when I ruined some cheap soldering iron (all in one type) by turning good quality VHS tapes into bad quality SVHS tapes. I still have that "hole burner" which I now use to refill my laser printer toner cartridges.

 

Cellulose sponges can be found pretty much anywhere, like the ones by Scotch. Used those for years when soldering, but always hated them because they never seem to "clean" the tip. Like everyone says, after you use brass, you don't back. Little decrease in tip temperature and more importantly, excess solder actually makes it off the tip and onto the brass wool. Brass wool can actually scrub burnt flux off a tip which never seems to happen with sponges. With sponges, I had to keep adding new flux to burn off the old flux and starts a nice cycle of flux on, flux off.

For some reason, I follow Mr. Carlson (Mr. Carlson's Lab on Youtube) and bought a can of lacquer thinner. No idea if it is better than Acetone. Definitely unhealthy for polystyrene like acetone. Just as expensive as paint thinner or acetone. I stopped using cotton swabs and cotton balls for cleaning flux because they tear, leaving cotton fiber everywhere. If I have to retouch, then that fiber burns. Isopropyl leaves more residue than the lacquer thinner, though (or it takes more isopropyl to clean the same amount of residue as acetone or thinner).

I buy these types of things to clean small areas: https://smile.amazon.com/s/ref=nb_sb_noss?url=search-alias=aps&field-keywords=foam+cleaning+swab

I have an ESD mat, which unfortunately is not heat resistant... So I added one of these https://www.banggood.com/35x25cm-He...p-1112869.html?rmmds=myorder&cur_warehouse=CN on top when I need to solder.

They have fancier versions with magnetic sections to hold small things in place, like screws. The pad is spongier than a baking pad so if you drop something, it has a chance of NOT bouncing away or at least not as far.

 

I removed just about all the plastic from the tip, but the soldering iron is certainly not clean any longer. Doesn't matter: bought it for this job specifically. Have another for electrics.

 

Heh, I remember doing something turning my 3.5" floppies from low density to high density by punching that hole in the corner...

 

I've found to clean a board, using a small brush works well. You could probably use a toothbrush, I have a small brush but I forgot where I got it from lol. I cut the bristles down so they are about 3/8" long, and then put a little alcohol (or solvent of your choice) in a cup. Unlike qtips or any paper product, brush doesn't leave behind anything, except maybe a few bristles that come loose, and they are easy to remove.
The other trick is to get a napkin or something like that, and then right after you scrub the board with the brush, dab with the napkin, so soak up the alcohol and flux. Then gets the flux residue off the board. I was doing this yesterday and the napkin was turning brown, good sign that its working.

For solder, a LONG time ago I bought a spool of silver, multi core ersin solder from Mcmaster carr. They don't advertise it as ersin, but it is, at least it used to be. Its way more expensive than it used to be, around $100 for a spool now, but a spool has lasted a long long time.

My iron now is a cheapo from hobbyking. For the money, it works really well, temp controlled iron
https://hobbyking.com/en_us/soldering-station-with-adjustable-heat-range-us-warehouse.html
$27 with shipping, but it can be cheaper when its on sale.
Then you really need to buy more tips, they sell sets of 10 cheap for these hakko clones.

Had a better iron for many years, but I broke it by trying to use a broken tip to do something quick, and then I got solder in the temp sensing element and now it won't turn off. But the hobbyking works fine, does that I need.

Randy

 

These are annoying to solder



That's a grain of rice for scale.

 

Worse than MELF stuff?

 

Oh my god! I'm just praying that it is, at least, Basmati!

 

I have an easier time with MELF components, but I haven't had to deal with parts this small either. Plus the leads are along an axis of symmetry and it doesn't spin around while Im trying to secure one of the legs down.

The grain is pretty big actually.

 

Good tweezers and some type of magnification help me a lot working with small parts. I have the headband type that has different lenses so you can vary the magnification. At work we have lights with built in magnifiers, but they are not cheap, really nice though.
Also a fine tip and fine solder helps. Getting an few tips is important, so you have the right tip for whatever you're doing.

Another tool I picked up a some point is a simple one, basically a sharp metal point. Mine has a wooden handle, but it looks like these would work
https://www.amazon.com/Pittsburgh-1816-Harbor-Freight-Tools/dp/B018A1X1VA

I use it when I'm checking for opens and shorts on surface mount parts, especially IC's. The probes that come with meters are too fat tipped, you need a very fine tip to hit an IC lead without shorting. Connect this to a meter with a clip lead, and probe away. Whenever I solder a SM IC, I check for shorts between every adjacent pin. And if I'm not sure, I check to make sure there is not an open between the pin and the pad.

Did anyone say to always buy extra resistors and caps? I think I've only done as small as 0805, but even they are pretty small, its it very easy to lose them.

 

So what's a good station/set everyone here uses?
I want to buy one for strictly soldering caps.

Any solders stations that can heat up fast & have a digital read out on the actual temperature?

 

Hakko FX888D - fast ramp up and well made for less than $100 on Amazon. Annoying interface that I've grown to like (set up to 5 temperatures or use the not well thought out manual system to change temps).
TS100 with a good power supply - may have even better thermal capacity than the Hakko with even faster ramp times IF you have a good power supply feeding it. Prices vary, but around $70? I don't own one, but I would really like to test one out. The bundles seem to be a crap shoot for the power supply.

Tons of Chinese knockoffs of old Hakko or Weller designs in the $50 range.

If you want some peace of mind that the iron is somewhere near the expected temp, you should get something like a fake Hakko tester: https://www.banggood.com/DANIU-FG-1...-Tester-0-700-p-952899.html?cur_warehouse=USA

Even my genuine Hakko FX888D was off by -30 C from the displayed 300 C. After calibrating it (1 point calibration?! Guess there is a reason for the <$100 price tag).

 

A little tip for soldering on PCBs at least for SMD components. Standard procedure is to tin one of the pads with solder and then move the component into place while your iron is still touching the pad. I have found that its best to avoid a pad connected to a ground or a similar large copper plane initially because the copper absorbs a lot of the heat. Choose a pad with a thin trace when securing the component and then solder the rest. YMMV

As far as reflow oven soldering goes use waaaaaay less paste then you think you need. I used far too much on a QFN chip and it started slipping during reflow. Of course a stencil takes care of this

 

Speaking of tweezers, we recently discovered Hozan heavy duty tweezers. You can get them on Amazon. They're super high quality and the only tweezers I've seen with a pressure rating on the different styles. Compared to some Swiss brands, they're reasonably inexpensive.
http://www.hozan.co.jp/E/catalog/Tweezers/_Heavy-duty.html

Those are just the heavy duty series; they make a bunch of other types.