Slot car track boarders R3 inside & R4 insdie

These are 1/32 scale inside curve boarders for Scalextric (and others) slot car track. They are loosely based on the old classic Scalextric piano key boarders. These more closely resemble rumble strips around full scale race tracks.

They are hollow and require supports. I use a "grid" at 10% infill and leave the supports intact.

The first two pictures are two R3 boarders, the 3rd is the R4 boarder.

Edit: Just added lead-in lead-out pieces. They have a rounded end so the beginning a