Tools you need that aren’t in the cart

Most kitchens have all of these. If you don’t, a hardware-store run is under $20.

• 5-gallon bucket with lid. Dark color preferred — slows algae growth in the reservoir.
• Silicone sealant or plumber’s putty — for sealing the lid hole around the pump cable.
• Teflon tape — for the threaded pump outlet (3-4 turns, clockwise looking at the threads).
• Zip ties, lots. For tidying valve wires, securing tubing to the railing, and bundling the relay-to-solenoid runs.
• Marker or masking tape — label your valve wires V1 / V2 / V3 as you go. Future-you, troubleshooting at 11pm, will thank present-you.
• Paper towels — leak testing is wet. Have a roll within reach.

Soldering iron — do you need one?

Maybe. Here’s the decision tree:

If you’re going crimp-only (the recommended path for most people), you don’t need an iron at all. Page 07 walks the crimp-on quick-disconnect procedure: $25 ratcheting crimper, 100-pack of 0.187” fully-insulated female disconnects, done in an afternoon. The connection is removable, gas-tight, and survives years of vibration. If a solenoid dies, you pop the disconnect off and swap it.

If you’re going solder-only, or if you’re sealing connections inside an enclosure you’ll never open again, then yes — buy an iron. The catch: the spade tab on a 12V solenoid is a decent heat sink, and the plastic coil bobbin behind it deforms if you cook it too long. That rules out the cheapest unregulated $10 pencil iron. Spec is 40-60W, temperature-controlled, 380°C / 720°F set point, with a chisel tip at least 2.4mm wide.

Three picks at increasing budget:

• $15 unregulated 60W pencil iron — works for this project, but you’ll outgrow it the next time you try a fine-pitch joint. Floor of the budget.
• Pinecil V2 — $30. Rechargeable USB-C iron, fits in a jacket pocket, genuinely useful for fieldwork. I bought one because I solder things outside enough to make it worth the price; you don’t strictly need that.
• TS101 — $50. The other cult favorite. Slightly bigger, slightly more capable, same temperature-control quality.

If you already own a Hakko FX-888D or similar bench iron, you’re set. Don’t buy a second one.

Soldering iron

40-60W temperature-controlled iron, 380°C set, 2.4mm chisel tip. We solder 20 AWG stranded to 0.187” spade tabs and onto 5mm-pitch perfboard pads — both are forgiving but the spade tab is a heat sink, so don’t dawdle. Picks: Pinecil V2 ($30), TS101 ($50), Hakko FX-888D ($110). If you don’t already own one, the crimp path on page 07 skips needing one entirely.

The wire

20 AWG stranded silicone, multi-color pack. Spec is non-negotiable in three places:

• 20 AWG. The recommended spade-disconnect terminals (page 07) are stamped 22-18 AWG; 20 sits dead-center of that window and crimps perfectly every time. It also handles ~3A continuous, which is enough for the brass-bodied solenoid (the only one in the parts list that pulls more than ~800 mA); everything else is well under.
• Stranded, not solid. Solid wire (one thick rod) won’t deform under the crimp barrel and slowly works loose under vibration. Stranded grips properly. Solid wire belongs inside walls and on breadboards, never on crimp terminals.
• Silicone insulation, not PVC. Silicone stays soft in cold weather, tolerates 200°C+ at the iron, and won’t melt back if you graze it while soldering. PVC stiffens over time and shrinks if the iron tip touches it. Silicone costs ~50% more and is worth every penny.

Search “BNTECHGO 20 AWG silicone wire 6 colors” — six 25-foot spools for around $20. Use a consistent color code: red for +12V, black for ground, plus 4-5 zone colors so each solenoid run is visually distinct.