Soldering Wishlists

[thathardwareguy]

Hey everyone... I'm new here so hopefully I put this in the right place.

I've somehow gotten into the position where I'm looking at upgrading 10 university soldering stations (shared by ~100 students, >70% haven't soldered before). They're an absolute mess right now, but we don't have a ton of money to fix them up. We do have about 12 Weller WR2's and 6-8 WES51 units. (As well as a 5 of the cheap sparkfun stations, non-hakko). I've got a few years experience soldering, and I've looked through Dave's first tutorial for tool recommendations, here's what I've compiled.

Most of the work is through hole, so I'd like to keep 8 stations for that, and 2 for surface mount work. We don't have the resources to do 10 stations for both.

For all the stations, I'm thinking

• Some sort of Tool Organizer
• Good Flush Cutters
• Flat Needle Nose Pliers
• #2 and #5 Solder Wick
• Flux Pen or 2 (non 'No Clean')
• Acetone/Isopropyl
• Brushes

Various wire sizes, strippers (the wire kind), and maybe things like dental picks would be available but not left out for general use, we have a system to handle that already in place.

For the Through Hole Stations, in addition,

• Weller WR2 (Soldering/Desoldering Irons)
• Medium and Large Chisel Tips
• 0.4mm and 1mm Solder
• Jeweler's Loupe or Handheld Magnifying Glass

For the Surface Mount Stations,

• Weller WR2 (Soldering Iron/Hot Air Wand)
• Fine and Medium Chisel Tips
• Very Fine Conical Tip (we stock Schmart Boards...)
• 0.4mm Solder
• Non-Locking Tweezers
• Stereo Microscope

What I'm not sure about...

• Are round nose pliers useful? Locking Tweezers?
• How about wicking tips?
• Weller Hot Air Wands... I've only ever used the larger style, are they equivalent?
• There's about 8 WES51's left unused, what could we do with them?
• Most of the PCBs are immersion tin finished, so I'm looking for mildly active fluxes, is that alright? They're generally newly finished PCBs.
• I have a tool organizer from Omni, it's plastic and has slots to hold often used tools, is there something similar out there you can just buy of the shelf?
• What am I missing?

So, what would you do in this situation? Anything's welcome.. Brands, tools, wish lists, general advice, ridicule, etc.

[Ian.M]

In addition to the WR2 at each station, put large chisel bits in all the WES51 units, (and as many of the Sparkfun unit as needed to make up numbers) and use them for heavy through hole work as expecting average students to swap bits will only lead to trouble (equipment damage and burn injuries). By the time they get into SMD work, hopefully you'll have taught them to respect good equipment, and as the WR2 has auto haqndpiece detection, you could issue the SMD hot air tools, fine bits etc. as a kit they sign out they can use at any WR2 equipped station.

RMA or even R liquid rosin flux should be fine - buy in bulk and decant into dropper or brush bottles or refillable pens.  You may want some good quality gel flux for the SMD kits, though personally I've always found it more of a PITA than its worth due to the extra cleanup needed for gel fluxes. 

Don't forget effective fume extraction or filtering for each station - you have a duty of care to minimise the risk of colophony allergy induced asthma.

Tip tinner cleaner should be available at each station. A retractable fibergass brush for cleaning dirty/oxidised pads and terminals would also be useful.

Good tools will get beat to death or grow legs and walk away.  Basic pressed steel lap joint side cutters and needle nose pliers should be standard at each station but the good, precision box jointed ones should be issued on a signout basis and cutters checked for damage by closing them on a cigarette paper.

Rather than using off-the-shelf organisers, if you can CNC cut plywood or heavy foamed plastic sheet in-house, make tool boards/trays with a place for each tool, so missing tools can be seen at a glance.

[nanofrog]

For all the stations, I'm thinking

• Some sort of Tool Organizer
• Flat Needle Nose Pliers
• Flux Pen or 2 (non 'No Clean')

Various wire sizes, strippers (the wire kind), and maybe things like dental picks would be available but not left out for general use, we have a system to handle that already in place.

• Organizer: I like IanM's idea of a tool board so you can do a quick accounting of all the tools per station. Otherwise, stuff will vanish.
• Needle Nose Pliers: Best to get a pair with teeth IMHO.
• Flux Pen: I'd recommend using some form of refillable dispenser, and refill as needed with MG Chemicals 835 (type = RA; comes in 1L cans). If you purchase 1 gallon containers, a hazardous materials fee is added; so if you go this route, you're cheaper to buy an entire case, which contains 4 - 1gallon jugs (i.e. Kester 1544, which is RA; 186 is RMA).

I'd also limit how expensive you go on the hand tools due to abuse. This doesn't mean you have to buy cheap crap, but balancing decent performance with an acceptable cost will pose challenges IMHO. For example, you could use Piergiacomi or Xuron for cutters (stamped steel types). Hakko rebrands the Piergiacomi's for ~$5 each. Xuron's a little more IIRC, but they should still be ~$10 or so.

Pliers is a bit of a challenge, as the stamped steel ones aren't what you want IME.

Also, are you limited to purchasing from companies that will accept Purchase Orders?
And what's your budget per plier & cutter?

^ would further help with making recommendations. 

For the Through Hole Stations, in addition,

• 0.4mm and 1mm Solder

You don't need to go this thin (even .020"/.56mm is pushing it for general purpose IMHO). I'd recommend Kester 44, 66 core in .032"/.81mm (3.3% of RA flux by weight) as it will give them a lot of control for PTH, and is also usable for SMD (i.e. 0805; even 0603 with some practice). If you're set on thinner, go for .025"/.63mm. Please note the smaller the diameter, the higher the price.

For the Surface Mount Stations,

• Very Fine Conical Tip (we stock Schmart Boards...)

Why not teach them to drag solder instead with either a 3mm Hoof/Bevel or a dedicated shape for drag soldering (Weller calls the shape Gull Wing)?

FWIW, I've Schmart boards as well, and this method works well. If you're set on point-to-point however, you can still use a chisel (not sure how small of a pitch you're using to make a size recommendation).

Also, I'm with IanM on not allowing students to change tips (make them aware of sizing the tip to the joint though). Should lower injury, and save you a lot of aggravation regarding inventory.

What I'm not sure about...

• Are round nose pliers useful? Locking Tweezers?
• How about wicking tips?
• Weller Hot Air Wands... I've only ever used the larger style, are they equivalent?
• There's about 8 WES51's left unused, what could we do with them?
• Most of the PCBs are immersion tin finished, so I'm looking for mildly active fluxes, is that alright? They're generally newly finished PCBs.

• Round Nose Pliers: They're useful for bending leads without nicking them (so are other profiles, such as snipe nose, needle nose, flat nose, ... with smooth jaws <no serrations/teeth>). But I presume you don't have to comply with Milspec standards, so it's not that important.
• Wicking Tips: Can you elaborate please?
• Weller Hot Air Wands: If you mean the HAP200 (Hot Air Pencil, 200W), then NO. They're no where near as powerful, and are only meant for small devices on say dual layer. But if the latter is all you'll be having them do, then they'll be fine.
• Remaining Weller WES Stations: If you've the physical space (incl. tables, chairs & power), I'd put them out to reduce the student : station ratio. This way they get more time on it to learn how to properly produce joints, based on your comment most of it will be PTH.
• Flux Activity: I recommended RA above for cleaning off any oxidation that may have occurred on the component legs in particular (presume the boards will be relatively new, but the components may be much older). And like R and RMA, Kester's RA can be left on the boards (doesn't cause corrosion). Same for MG Chemicals' 835 RA flux. 

[thathardwareguy]

Thanks for the advice

I hadn't considered refillable flux pens/bottles, probably a better option in the long run.

We can definitely roll our own organizers in house, probably some laser cut hardboard material would work well, we can CNC plywood but it's a lot slower.

Not really limited in who we can buy from, but we don't have a set budget right now. $15-20 for cutters and pliers seems pretty reasonable.

Most of the surface mount we've been doing now is 0603's and 1.0-0.5mm pitch QFP/SOIC packages, which was why I included the small solder. Perhaps .032" out on the bench and we'll keep some smaller (0.25" or 0.02") in the back for the tiny stuff. I had forgotten about those tip tinning containers entirely..

What I called a 'wicking tip' (what I believe Dave called it in a video) looks to be the Weller gull wing tip (flat surface with a dimple to hold solder). I'd love to teach them to drag solder and, well, just solder properly in general. We've got a class that we teach but the curriculum is in serious need of refinement. One of the higher ups here thought it would be a brilliant idea to teach the intro to soldering course online as a powerpoint (yeah, go figure) and have students come in a take a 'test' to receive credit. The test involves three through hole components, removing a jumper, and a single 0805 resistor. It's been frustrating so I guess I've kind of given up on teaching anything...

As for the hot air, I was indeed referring to the HAP200 (well it's an HAP1 but it's similar), mostly for removal of passives/small ICs from 2 layer 1oz PCBs, so I think it's worth a shot, instead of adding a whole separate unit to the station. We're supposed to have a decent reflow oven in soon for paste work so I expect demand for hot air to go down then.

Fume Extraction is definitely something we need to look at, but the multiuser systems for this type of application are just plain expensive, we'll definitely mention that upstream...

[nanofrog]

I hadn't considered refillable flux pens/bottles, probably a better option in the long run.

It's cheaper, and you can customize the dispensing method (I prefer a Bonkote BON-102 refillable brush pen, but the genuine article runs ~$15 per). There's also nail polish bottles, brush bottles, needle bottles, and refillable pens (i.e. CW7000). You can even dip a small, inexpensive artist paint brush into a tiny container of flux as needed (20 pack or something similar that works out to ~$0.25 or so each). Spot plates work wonderfully for holding a small amount of flux (preferably ceramic/porcelain).

We can definitely roll our own organizers in house, probably some laser cut hardboard material would work well, we can CNC plywood but it's a lot slower.

A shadow board would be perfect for quick inventory of the tools per station (tool outline in a contrasting color from the board's background color). 

Not really limited in who we can buy from, but we don't have a set budget right now. $15-20 for cutters and pliers seems pretty reasonable.

I'd suggest going for the stamped steel Piergiacomi versions (Hakko would be an alternate source), and put the difference towards the pliers (say Schmitz if you have access to a university PayPal account for your dept.). I bought directly from them with no issues whatsoever. Cost per plier ran me ~$28 (including the currency exchange fee and shipping). 

Most of the surface mount we've been doing now is 0603's and 1.0-0.5mm pitch QFP/SOIC packages, which was why I included the small solder. Perhaps .032" out on the bench and we'll keep some smaller (0.25" or 0.02") in the back for the tiny stuff. I had forgotten about those tip tinning containers entirely.

This would be fine IMHO. I'd only keep .020" as the smallest diameter spool, though .032" should be sufficient for these packages, particularly if drag soldering IC's (gull wing is the ideal tip for this, though a 3.0mm hoof/bevel will do as well)..

Fume Extraction is definitely something we need to look at, but the multiuser systems for this type of application are just plain expensive, we'll definitely mention that upstream...

Not going to be cheap to do it right, unless you've windows that can open (simply aim fans outside an open window if possible, or use a squirrel fan & inexpensive duct work to vent it outside).

[Ian.M]

For the flux pens, if you bulk buy liquid flux and refillable pain pens/markers you should be able to get the unit price well under $2 without compromising usability.
If you use dropper or internal brush bottles, you should make up weighted close-fitting bases for them to minimise the risk of spills to reduce colophony exposure. 

Drag soldering is easy enough with a plain chisel or screwdriver style bit.  You only need a special drag bit if you need to do large ICs in one pass per side, but even that is possible with practice without the special bit if you add an appropriate amount of extra solder at intervals along the row of pins before the final flux and drag.  As its desirable to minimise bit changing except with the iron fully cold under the instructor's direction, IMHO specialist bits should be avoided.

I suspect the powerpoint is not fit for purpose, unless it includes really good videos, and plenty of practice time and materials are provided. Can you get the higher ups to audit the powerpoint course and test (I'm assuming they don't know much about soldering),  or do a trial with two randomly selected groups, and a questionnaire for initial experience level,  comparing traditional hands-on instruction and the powerpoint?

Low powered hot air is fairly useless without a board preheater.

[nctnico]

I'd go for Ersa soldering irons and tips. In my experience Weller is crap because the tips wear out so fast and nothing is more annoying than a tip which won't wet properly. JBC is slightly better but the tips from Ersa are the best I have used so far.

Flush cutters are also a waste of money because they go bad real quick no matter how much you spend. Better get the smallest (125mm) side cutters from Knipex. Those are much more resillient.

[KL27x]

^There are "flush" cutters that aren't quite flush. They leave a flush cut, but the jaws have a tiny bit of overlap/shearing action. They work quite well. Last pair I have ever bought. They only cost like $10.00. Xuron, I think.

Hemostats come in handy, sometimes.

Refillable flux pens sound like a good idea. Have tried. Not impressed. The tips wear out and or clog up, anyway (and even soaking the tip in acetone may not revive it!). And refilling them with sticky flux is a bit of a chore. I mean, if you are going to use a syringe to fill it... why not just dispense the flux from the syringe?

[Ian.M]

As long as you don't pay the premium for a branded refillable flux pen, it can be cost-effective.  Refillable paint pens and spare nibs for them are fairly cheap, so even if you only get one fill out of a nib because of careless users, its still cheaper than pre-filled flux pens.  Get a dispensing pump for the can or bottle of flux and fill the pens directly without messing with syringes.  You do need to make sure the flux is alcohol based and the pens (and pump) are compatable with alcohol based paints/stains. 

[Monkeh]

^There are "flush" cutters that aren't quite flush. They leave a flush cut, but the jaws have a tiny bit of overlap/shearing action. They work quite well. Last pair I have ever bought. They only cost like $10.00. Xuron, I think.

Yep, Xuron shear cutters. Near flush cut, very sharp, and last well, but cheap.

[macboy]

There are so many options for flux dispensing. Pens work fine until the tip gets all shaggy or clogged. And of course flux costs about 100 times as much per volume in pen format than in >= 1 L bottles.

As an alternative, consider brushing it on with a nail-polish style bottle. You can buy the empty bottles with the brush cap on ebay/etc for around $1 each. Also consider disposable brushes, search ebay/etc for "disposable dental applicator". They have a small tip just right for precision application of flux, and cost literally pennies each, usually sold in packs of 100 to 400 for a few dollars. The risk with either of these is the need for an open bottle to dip the brush tip into, this is a spill waiting to happen.

I had tried a syringe with a fine blunt needle tip for liquid flux, and I did not like it. Difficult to control and the tip clogged often. Probably much better for paste flux than for liquid. I have also used dropper bottles, like the kind used for eye drops (in fact, I used recycled eye dropper bottles). These work well enough but I find that one drop is almost always far too much flux. It just necessitates extra cleanup work & supplies.

Consider buying your solder wick in 50 or 100 foot rolls, it is a fraction of the cost per foot as those little 3 foot spools. You can always refill the small spools from a large one, I do that at home.

I personally don't find 0.015" solder to be too fine for SMD, but I certainly wouldn't want to use it for through hole work. I also have some 0.010" that I occasionally use.

[stmdude]

Good tools will get beat to death or grow legs and walk away.

This, a million times this. The average life-time of a precision side-cutter _at work_ is about 5 minutes before some moron tries to cut FR4 or hardened steel with them.

Have you got anything like a vice or similar thing to hold the PCBs?

Also, instructions..  Printed instructions at each station, reminding them what the nice cutters are for, when to clean the tips, to put everything back in order, turn things off when done, etc.

I assume these stations will be "assembly" stations?  If so, maybe the WES51s could be setup as small re-work stations ?

[KL27x]

I had tried a syringe with a fine blunt needle tip for liquid flux, and I did not like it. Difficult to control and the tip clogged often.

Yeah, my friends business, they all use squeeze bottles with long steel needles. Worthless, IMO.

I use a syringe with a tapered plastic needle with the tip cut down. So it's probably 8-12 gauge, I guess. I dunno. I cut the tip until it looks right. Just big enough to run a piece of thick jute twine through it. Wax and trim the tip of the twine to get it to a point, so you can thread it through. It should be a tight squeeze. Knot the end to trap the twine in the back of the tip. Then trim the business end almost flush with the tip, extending just a tiny bit. E viola. You have a brush tip. This kind of tip prevents the all or nothing (intermittent squirts across the room or clogs) you get with a fine needle. And you can customize the size for your need. You can lay out a lot or a little flux without any danger of uncontrollable squirts. The brush tip is just right for dotting all the pads in a SOT 23 footprint or a passive with just a swipe and/or laying down flux over a row of pads. Much smaller than a flux pen tip.

I would use a refillable flux pen if it worked better. The syringe with brush tip works a lot better for me. I don't use it to save money. I stopped reusing the syringes, even. I just fill a bunch at a time, and when a syringe runs out, I swap the tip onto a new syringe and throw the old one out. I store the syringe tip-down with no cap, using a bit of brass tube for a stand. It doesn't clog or drip or evaporate. It's just ready to go.

Consider buying your solder wick in 50 or 100 foot rolls, it is a fraction of the cost per foot as those little 3 foot spools. You can always refill the small spools from a large one, I do that at home.

Yeah, the little 5 ft bobbin has got to be the best dispenser there is. I refilled mine a while back, and figured out it holds at least 12 feet of 100mil Chemwick. That's a lot of wick.

If you're going to buy a 50 foot roll of braid, be sure to use a ton of it every day.... Or seal the roll in an air tight container. Wrap it in several layers of plastic wrap. This will keep it good, longer. The flux will dry out, making it less active. And/or the copper will oxidize over time and the flux will get partially used up, leaving copper salts in place of the flux.