DIY Studio Build — Egg Crate Spill Grid

Egg Crate Spill Grid
Build Guide

40 × 33 cm softbox · 2 placemats · foam board frame · velcro corner attachment

Materials
2× Black vinyl placemats 12" × 18" (30.5 × 45.7 cm) · must be vinyl not fabric
1× Foam board (leftover) any offcuts ≥ 40 cm long · 4–5 cm wide
4× Velcro squares one per corner · hook + loop
— Hot glue + craft knife + ruler ruler, cutting mat helpful
Grid specs
Cell depth ratio
Your strips are 5 cm deep (the width of the strip = the depth of each cell). At ~5–6 cm wide cells, the depth:width ratio is close to 1:1, giving roughly a 45° light cutoff — standard for studio spill grids.
Softbox face 40 × 33 cm
Strip width 5 cm = cell depth
Row strips 6 strips × 40 cm — trimmed from 45.7 cm
Col strips 6 strips × 33 cm — trimmed from 45.7 cm
Outer boundary Foam board frame on all 4 sides
Cell width 5.71 cm (40 ÷ 7)
Cell height 4.71 cm (33 ÷ 7)
Slot intervals Row: 5.5 cm · 3.5 cm margin each end  |  Col: 4.5 cm · 3 cm margin each end
Attachment Velcro squares at 4 corners of foam board frame
Step 1 — Cut strips from placemats

Cut plan — both placemats identical · 6 strips per mat

PLACEMAT 1 (and 2 — same cuts) · 30.5 cm wide × 45.7 cm long strip 1 strip 2 strip 3 strip 4 strip 5 strip 6 5 cm 45.7 cm = strip length 30.5 cm (6 × 5 cm + 0.5 cm sliver) 0.5 cm sliver discard Per mat: 6 strips × 2 mats = 12 strips 45.7 × 5 cm each Mat 1 → trim to 40 cm → ROW STRIPS ×6 Mat 2 → trim to 33 cm → COL STRIPS ×6

From each placemat — cut 6 strips

Mark lines along the 30.5 cm dimension at: 5 · 10 · 15 · 20 · 25 cm
Cut along the 45.7 cm length → 6 strips of 45.7 × 5 cm per mat
0.5 cm sliver remains at edge of each mat — discard
⚠ Vinyl only — fabric placemats will fray at every cut edge

Trim strips to length

6 strips from Mat 1 → trim to 40 cm → ROW STRIPS · 5.7 cm offcut each
6 strips from Mat 2 → trim to 33 cm → COL STRIPS · 12.7 cm offcut each
Keep all offcuts — useful for foam board frame extensions if needed
Step 2 — Cut slots

Strip anatomy — slot direction, depth, position

ROW STRIP ×6 — 40 cm · slots from BOTTOM · 6 slots · 5.5 cm intervals 3.5 3.5 2.5 cm 40 cm · ▼ BOTTOM EDGE COL STRIP ×6 — 33 cm · slots from TOP · 6 slots · 4.5 cm intervals 3 3 33 cm · ▲ TOP EDGE slots meet at midpoint · each 2.5 cm deep row is longer 40 vs 33

Slot position map — mark before cutting · scale 8px/cm

ROW STRIP — 6 slots · 5.5 cm intervals · 3.5 cm margin each end · cut from BOTTOM 0 3.5 9 14.5 20 25.5 31 40 3.5 3.5 COL STRIP — 6 slots · 4.5 cm intervals · 3 cm margin each end · cut from TOP 0 3 7.5 12 16.5 21 25.5 33 3 3

Row strips ×6 — 6 slots, cut from BOTTOM

Mark from left end (cm): 3.5 · 9 · 14.5 · 20 · 25.5 · 31
5.5 cm between each slot · 3.5 cm margin at each end · evenly spaced ✓
Slot depth: 2.5 cm · Slot width: your mat thickness (measure first)

Col strips ×6 — 6 slots, cut from TOP

Mark from top end (cm): 3 · 7.5 · 12 · 16.5 · 21 · 25.5
4.5 cm between each slot · 3 cm margin at each end · evenly spaced ✓
Slot depth: 2.5 cm · Slot width: same as row slots
Step 3 — Interlock the grid

Assembly sequence

A — lay 6 row strips parallel · slots facing UP · ~5 cm apart ~5 cm → B — slide col strips down through slots · left to right next glue dot ×36 C — finished grid face · 7 cols × 7 rows · ~5.7 × 4.7 cm cells 40 cm (7 cols) 33 cm (7 rows) ■ velcro corner ■ foam board border — row strip — col strip
1
Lay row strips flat Place all 6 row strips parallel on a flat surface, slots facing UP, spaced ~5 cm apart. Use a scrap piece of foam board as a 5 cm spacer.
2
Slide column strips through Hold a col strip vertically, slots facing DOWN. Press down through all 6 row strip slots at once. Work left to right — 6 col strips total.
Widen slots slightly with a craft knife if too tight. Don't force.
3
Square and lock Lay flat. Check corners with a square. Add a dot of hot glue at every intersection on the back face — 36 intersections total (6×6). Let cool fully before moving.
Step 4 — Foam board frame

Frame construction — top view

LONG A — 40 cm LONG B — 40 cm SHORT A — 33 cm SHORT B — 33 cm GRID SITS HERE 40 × 33 cm ● hot glue corners ■ velcro square (hook side) one per corner 40 cm outer width

Frame cuts — from foam board offcuts

2× strips at 40 cm × 4–5 cm wide → LONG sides (top + bottom)
2× strips at 33 cm × 4–5 cm wide → SHORT sides (left + right)
Long strips span full width · short strips fit between them
Strip width (4–5 cm) just needs to be consistent on all 4 sides
4
Assemble the frame Hot glue the 4 foam board strips into a rectangle around the finished grid. Long strips on top and bottom, short strips between them on the sides. The grid sits flush inside the frame.
5
Attach velcro at corners Cut 4 short velcro strips (~5–7 cm each). Stick hook-side to the back face of the foam board frame at each corner, extending slightly past the corner edge so they can latch onto the softbox diffusion frame. Stick corresponding loop-side pieces to the corners of the softbox diffusion frame. The grid latches on and peels off with a firm pull.
6
Mount to softbox Press grid onto softbox front face, velcro side in. Peel off to remove — no tools needed.
Studio Build Guide · Egg Crate Spill Grid · 2 placemats · 40 × 33 cm · 7×7 cells · velcro corner mount