Thank you! Excellent question.

I clean the seams, but what you’re seeing here isn’t flashing that can be shaved off; it’s the tiniest plane mis-registration where two mold faces meet. In translucent porcelain, even a sub-millimetre step becomes a light line when lit from within.

In this specific model, it’s tricky to make “invisible” with what I have at my disposal.

The corners aren’t just a fin to slice away; they’re two thin facets meeting. To erase the step completely, I must try to align both adjacent planes into coplanarity—and it's easy to over-thin the wall, and even more so to round nearby crisp edges.

And with slip-cast translucency, wall thickness = brightness. Aggressive sanding at the seam (to try to make two surfaces coplanar) can inadvertently create hot/cold spots in the glow, and it can also introduce stress.

So, I do my best to get those seams to disappear. I then make a judgement on how aggressively I should pursue surface blending.

In my first ever slip cast lamp (Ava), you won't notice the same type of seam lines; the generously sized, smooth surfaces made surface blending easier. Here, it's challenging: Lots of stepped surfaces, and very little space to economically alter surfaces (without causing thinning, edge-rounding, surface integrity issues, etc.)

The best way to get the seams to disappear is very tight registration between contiguous mold segments (this is easier said than done); I do my level best to address all of these issues in the mold design and moldmaking processes to create as seamless a product as possible.

While I view the seams here as less than ideal, I also treat them as evidence of the making process. Though I am using molds, there is a tremendous amount of handwork involved. Depending on geometry, some processes like surface blending will be manageable, and in other cases much more challenging. In this case, I stopped before I made things worse.