Halloween tombstone foam paint ounces
Estimate craft or exterior paint ounces for foam Halloween tombstones from face area, coats, and stones — a graveyard prop planner for Prince William County yards.
paint_oz = stones × face_sqft × coats × oz_per_sqft × (1 + accent%)
When to use
Use this before buying gray base coats and black/white weathering for DIY foam insulation tombstones.
Foam is thirsty — craft acrylic often needs more ounces per square foot than smooth drywall. Start near 0.4–0.6 oz/ft² per coat for porous cut foam.
Accent % covers dry-brush highlights, letter fills, and moss dabs so you do not run out mid-weathering.
Cut foam stones you will fully paint.
Front face only; add sides into this average if you paint edges.
Usually 1–2 solid gray coats before weathering.
Porous foam often ~0.4–0.6 oz/ft²/coat.
Black wash, dry brush, moss green.
Worked example
Example defaults — 6 stones; 2.5 ft² face; 2 coats; 0.5 oz/ft²; 25% accent.
Compute: base = 6 × 2.5 × 2 × 0.5 = 15 oz; with accent 15 × 1.25 = 18.75 oz (~2.3 cups).
Buy an extra small black and white bottle for lettering even if base gray is covered.
Limits / assumptions
Units: face in square feet; paint in fluid ounces.
Assumptions: flat faces; same size stones; does not model spray-paint melt on polystyrene.
Not a substitute: manufacturer coverage charts for a specific paint brand or outdoor sealer coats.
Use foam-safe paints only. Ventilate when sealing outdoors; keep solvents and hot tools away from polystyrene foam.
FAQ
Front only or wrap edges?
If you paint sides and tops, fold that area into the average face figure or raise oz/ft² slightly.
Quart vs craft bottles?
16 oz ≈ one pint; many craft bottles are 2–8 oz — round up to whole bottles.
Sealer on top?
Clear matte outdoor sealer is extra — not included in the paint-oz total.
Already primed?
Drop coats to 1 if a heavy primer coat already covered the foam.