Lost items in multiblocks are gone forever.
Also, the forestry soldering iron does not help you. you need the GT soldering iron with at last 10.000EU and some soldering material in your inventory.
Soldering materials are tin, lead or soldering alloy in ingot, rod or fine wire form.
Edit: No making stuff cheaper/easier. It works fine without cheating. Making a Soldering Iron works fine with LV machines. The alternative would be to feed the EBF with 5-6 Amp instead of 4 directly. One second of too little steam and material is lost even without any maintainance issues.
My personal favorite for LV EBF. 3 Energy hatches <- 8x cable <-9x battery buffer with 8 batteries <- steam turbines.