Beams and reinforced plates neither produce scrap when crafting, nor contributes to scrap production when used in a recipe.
Affected recipes: Copper/bronze capped beam, iron/steel/chromed beam, bronze/iron/steel/chromed reinforced plates.
This is basically all beams except wooden beam, and all reinforced plates.
Heavy copper cable has the same problem.

For copper beam, it's most visible in steam derrick recipe:
(I'm still having the old default of producing 10% scrap, instead of current default of 5%)
8 steam pipe + 12 copper capped beam + 12 tin plate + 4 copper piston -> 1 steam derrick + 1 tin scrap
This recipe certainly has scrap enabled, but the copper capped beam doesn't show up in scraps.
For heavy copper cable, it's most visible on radar:
1 Large iron frame + 1 Iron core EM coil + 16 iron plate + 1 heavy copper cable -> 1 radar + 1.5 iron scrap

This seems to explain the heat exchanger / turbines / hull sections / solar assembly / empty high pressure canister missing scrap problem.
Centrifuge is currently fine, all 3 of its input materials produce scrap when crafting, so it shouldn't produce scrap. Fixing the beams & reinforced plates should fix the rest.

I wonder whether this is an oversight or a delibrate design choice.

Is your observation related to this entry in the changelog? ↓

Version: 1.0.1
Date: 24. 06. 2024
Bugfixes:
- Alloying recipes no longer produce scrap.

Yes you're right, at the moment there's an exception for recipes producing beams and reinforced plates to make them not produce scrap. And they don't produce scrap when they're ingredients. I added the exceptions because from the ingredients it seemed unrealistic. Like the reinforced plates are made from 2 plates + rivets and looking at the pictures I guess it's supposed to just be 2 plates riveted together, which wouldn't really produce scrap. Same thinking for the beams and the heavy copper cable.

The code for excluding it is pretty simple and I could easily add a setting to change it, like the setting for gears. Will probably add that in next update.
https://github.com/StephenBarnes/ProductionScrapForIndustrialRevolution3/blob/main/code/constants/excluded-recipes.lua#L12

I guess it's about balancing some priorities: scrap production should be realistic, consistent, not too annoying, but also not unbalance IR3's recipes by too much.

Is your observation related to this entry in the changelog?

No, that change was removing scrap from the recipes for brass/steel ingots in alloying furnaces.

Thank you for your response. I was also curious about this, and I agree that the current implementation is logical.

Additionally, thank you for creating this mod. I really appreciate IR3's unique take on the game, especially with your mod and the added complexity of "realistic" scrap production.

Yes you're right, at the moment there's an exception for recipes producing beams and reinforced plates to make them not produce scrap. And they don't produce scrap when they're ingredients. I added the exceptions because from the ingredients it seemed unrealistic. Like the reinforced plates are made from 2 plates + rivets and looking at the pictures I guess it's supposed to just be 2 plates riveted together, which wouldn't really produce scrap. Same thinking for the beams and the heavy copper cable.

The code for excluding it is pretty simple and I could easily add a setting to change it, like the setting for gears. Will probably add that in next update.
https://github.com/StephenBarnes/ProductionScrapForIndustrialRevolution3/blob/main/code/constants/excluded-recipes.lua#L12

I guess it's about balancing some priorities: scrap production should be realistic, consistent, not too annoying, but also not unbalance IR3's recipes by too much.

I think the beams and reinf plates recipes should not produce scraps when crafting them, and instead produce scrap when they are consumed in another recipe. Just like iron plates in a recipe creates scrap in the output, reinforced iron plates should also behave that way. Each reinforced plate should count as 2.5 ingots when calculating scrap, and metal beam is 3.5. Copper/bronze capped beams return both wood and metal scrap.

I think, when crafting the reinforced plates, it's just riveting the two plates together, so no scrap in the process. However, this process only creates standardized general shape reinforced plates, so when crafting these reinforced plates into final products (like scatter bots), they need to be further cut into shapes, which creates scrap in the process.

Ok, I think the analogy to normal plates makes sense. I added options in the new version to make beams and reinforced plates generate scrap, turned on by default. It adds scrap to more recipes so it should make the mod harder. If any of you have used this mod for a while let me know if I should change any defaults for better balancing