You can customize ic2's recipe configs by copying the one you want from the jar's assets/ic2/config to your config dir and adding the new recipes. There is a fairly extensive description on top of the file.
shouldn't it be "railcraft"? The command "/ic2 currentItem" should show the proper entry for whatever you are holding.
This post seems related to my problem:
I can't turn Nether Quarz and Certus Quarz from Applied Energistics 2 into dusts in the macerator.
I think it worked back then.
Is it supposed to not do that? And more importantly: how can I add the recipe quarz->dust ?
So I know now that I have to copy the macerator.ini file from the IC2.jar and put it in a folder in the config and add the recipe to the file. Like
minecraft:coal@1 = ic2:dust#coal
for making coal dust from charcoal.
But under what path can I find macerator.ini in the jar? I clicked through all folders that seem to make sense but I havn't found it.
ic2.jar: assets/ic2/config/macerator.ini
Move it to .minecraft/config/ic2
As for adding machine recipes, instructions are given in each .ini file on how to add your own.
As for why it worked back then, AE2 added its own macerator/crusher recipes when other mods are detected. However, this was with a unofficial AE2 port for 1.11.2 (Llamagistics). I looked in the llamagistics jar and found some custom recipes folders where all these recipes could be altered, including macerator recipes, if IC2 was loaded.
Right now I'm looking in the ae2 jar for 1.12.2 and I couldn't find any crusher recipes involving the macerator. So you'll have to add that to the macerator.ini yourself.
Ok, thank you.
That explains why I was unsuccessfully looking for that file. I can't see the assets folder.
So I've opened the ic2.jar via an online decompiler, as seen in the attachment, but theres no assets folder. Where do I have to look?
No no no, directly after opening the ic2 jar, you should go to the assets folder, not ic2.
I've used 7zip to open the jar.
This is great, thank you.
With 7Zip I see it too. The compiler didn't show the assets folder.
I was able to add the charcoal to coal dust recipe that I copied to validate the method. Works.
But now I need to find out the ID of certus quarz, certus quarz dust and nether quarz dust.
I tried the following so far but didn't work:
minecraft:quarz = appliedenergistics2:nether_quarz_dust
minecraft:quartz = appliedenergistics2:dust#nether_quartz
minecraft:quartz = appliedenergistics2:#4772/3
How can i find out the ID's?
Just installed ic2 and ae2 for 1.12.2 to see it for myself.
Press F3+H to enable the advanced tooltips when hovering over items.
Hovering over nether quartz shows that the ID is minecraft:quartz
and the AE2 quartz dust is appliedenergistics2:material. However, this item has a metadata ID of 3 (as seen by the 4308/3, or 4772/3 in your case. So you would have to add @3 to the end of appliedenergistics2:material.
So, according to the recipe format for the macerator recipes, the recipe code would look like this (on a new line, without ; in front of it, because that disables it):
minecraft:quartz = appliedenergistics2:material@3
I added this to a empty line at the bottom of my macerator.ini, saved, then reloaded minecraft to check if it worked. It did.
Ahh ok now I understand it. I enabled advanced tooltips already and I was trying things like appliedenergistics2:material#certusQuartzDust
With and without underscores. Also tried dustCertusQuartz etc.
with @3 it works for me too. Already implemented the recipe for normal quartz which would be
appliedenergistics2:material@0 = appliedenergistics2:material@2
if someone wants to add it too.
thanks again and sorry for the inconvenience.
EDIT: imagine all the customization possibilities now that I understand the whole system. 
no but for real i dug through the appliedenergistics jar aswell and found all the recipe files. I really learned a tiny bit about modding or atleast about how these things are arranged and how they work in the progress. thanks for that too!
