# Weller WDC Solder Containment Pocket

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At least on e-commerce platforms, there seems to be some confusion about how the Weller Dry Cleaner (WDC) unit is supposed to be used, but the tub isn't just for misplaced brass wool bundles.

In fact, you're supposed to slap your solder iron against the high temperature elastomer rim to flick away residual solder, oxides and flux residue from your solder tip. That alone plus fresh solder may be enough to keep the tip clean and operational, but it also lets one get much more life out of the brass wool.


What has been a source of endless annoyance is any accumulation of solder particulate accumulating in soldering iron stands and in any jar or tub used for solder collection...
waiting for it to be knocked over or shaken during transport, spilling the fines.

To contain the mess - and when it comes to leaded solder, the toxic contamination - I've come up with the following way to build a means to capcture fines produced into an item that's already on the desk. All in all, it's just a metal cup or pan with solid wax in it that provides three functions:
- it lets hot droplets melt into the surface
- it can be heated to present a fresh wax surface
- any fine particulate and dust collecting on the surface in a cold state is wetted and gobbled up during the melting cycle.

Ideally, a longer pan should extend underneath an opening in the brass wool holder, in which the fine cold scrapings sift towards the bottom of over time, and could be allowed to escape into the wax pan as well. Such a re-design in heat-resistant plastic though is easily outside the scope of this project. Perhaps there are fun high temperature filaments out there that allow 3D printing the next generation of holders (Ultem, Tullomer?)...

## Wax Getter

In homage to the [metal films evaporated onto the inside of vacuum tubes](https://en.wikipedia.org/wiki/Getter), one can think of the solder particle catcher presented here as an analogy to reactive getters that would catch and hold on to residual gas molecules:


All it really needs is some stearic acid or blend with paraffin wax to catch hot droplets.

In a second step, the idea is expanded to making a catch tray that can be heated, and so wets or embeds solder particles of all sizes, especially when they were cold upon hitting the surface.

## The Build

The initial idea was to machine somethign out of a billet of aluminium, adding 5° draft angles by choosing a conical endmill (the height is 20 mm):


As it turned out though, the inner walls of the WDC pocket aren't exactly straight to begin with. Add to that the need for CNC machining, and this is no longer a simple part to make. The lack of easy ways to do the workholding should already have been discouraging enough.

A much more cost-aware and hand crafts - friendly approach however is to make it be sheet metal.

- AlMg3 or similar sheet stock used for [deep drawing](https://journalmt.com/artkey/mft-202003-0014_the-research-of-the-different-properties-and-production-parameters-having-influence-on-deep-drawing-sheets-made.php) is recommended
- 0.5 .. 1.0 mm thickness
- make the rear wall straight, but the front wall lean forward so the upper rim makes full contact with the pocket
- One of the corner folds (needed to make it hold liquids) can be opened up and formed by pushing a steel dowel pin into it, then massaging he metal around it. This feature will hold the soldering iron, allowing it to double as a tub heater for resetting the solder containment pocket:



And there we have it, reset and ready for more work:


## Conclusions

I now own three of these Weller WDC units, with one just using the bare tub and a piece of paper inside. After using this system for the 3rd year, I can say with confidence that it has proven itself.

I wish all my soldering iron holders had at least a wax pan underneath that could help contain any particles, especially where others cannot be kept from using Pb containin solders.


Finally, there's also a [video on twitter](https://twitter.com/MisterHW/status/1642198250051588097) of it in action.

And so you're not thinking I'm making this all up, this is still the first wax fill, gradually turning an amber "spent flux" color as it dissolves the residue sticking to the solder:


Perhaps I should have calculated the volume expansion over time to see whether there's leftover wax when the fill level reaches the 15mm mark.

### Timeline

- 2023-02 first experiments
- 2023-04 solder containment pocket built from sheet metal
- 2025-11 release of this write-up