I found it somewhere, perhaps items.xml, and saw it was deprecated. That means that we can't currently create stainless steel blocks. I had built a heavy-duty base in A17 using those blocks and exported it to a POI. I still use it. I hope they're not removing those.
The good news is that I can ALWAYS install an older version of the game (thanks, Pimps!) and pull the code if needed.
Thank you for your help!
I'm pretty sure that you could never actually craft stainless steel blocks. You could only
upgrade from steel to stainless steel.
If that's what you want to do, you have to re-add the ability to upgrade from steel to stainless steel.
You would add something along these lines into the "steelMaster" block:
<property class="UpgradeBlock">
<property name="ToBlock" value="stainlessSteelMaster"/>
<property name="Item" value="resourceSteelPolish"/>
<property name="ItemCount" value="1"/>
<property name="UpgradeHitCount" value="4"/>
</property>
Unfortunately, you'll have to add additional code to every steel block shape, so they upgrade to the correct stainless steel block shape. You only have to specify the stainless steel block, not the rest (they inherit). For example, in the "steelRamp" block, insert this:
<property class="UpgradeBlock">
<property name="ToBlock" value="stainlessSteelRamp" />
</property>
Hope that helps.
EDIT: Of course, you also have to add in some way to get stainless steel polish in the first place. I'm pretty sure that it was only available from higher-level trader loot in past alphas. If you want to do that now, I believe you would add the steel polish to the "modAllT5SecretStash" trader item group in traders.xml.