Green tech cards require PCB solder.
PCB solder can only be made in a foundry (or its upgrades) which requires a crucible to make.
Crucible is unlocked by Adv. material processing 2, a blue tech, which including itself requires 41 techs researched using green tech cards. Blue tech cards also need PCB solder.
Colony research is not an option, the Depot is locked behind Radar, also a blue tech.

Unless I'm missing something obvious we seem to be at an impasse. Occam's razor would suggest green tech cards are intended to use regular solder? Which while also limited to foundries in factory terms can be crafted by the player.

fixed

That was fast, thank you, chewing through green tech now, Unfortunately got another one, Steel appears at every option to be also gated behind crucibles, The regular (crushed manganese) recipe can only be made in a foundry, the 248 recipe can be made in a metal caster but requires molten iron from an arc furnace which needs invar plates which can only be made in a foundry. Steel gates pumpjacks which prevents you getting to blue tech cards.

I'm wondering if the crucible isn't the issue, it's required for foundries which are a red tech and all it's ingredients are red tech at worst, yet it is only unlocked by a blue tech and I'm also just now realising it itself can only be made in a foundry, which itself needs a crucible as part of its recipe.

I'm thinking the crucible unlock should be with the foundry tech and should be hand or at least regular furnace craftable, maybe with an advanced version for more advanced foundries?

fixed

Another quick fix, thank you kindly, steel and oil flowing, the hunt for mineral water begins.