The cut sheets
1 sheet. 1220 × 2440 mm, 18 mm plywood. Total cut path 34.7 m.
Machine time for the whole unit: about 1.3 h best, 2.3 h typical, 5.2 h slow. Based on reported 120 W-class diode speeds, multiple passes at 18 mm. One timed scrap cut will replace this.
A commercial CO2 flatbed is about 1.1 h in the sourced case. That number is an assumption, not a cut on this machine.
Sheet 1 carries a fit-test coupon: cut it first and try the tab in the slot before you cut the rest. Hover or tap a part below to light it in the model.
Build stages
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1
Cut the sheet about 231 min (3 h 51 min)
Run the fit-test coupon (slot = tab + 0.1 mm), then cut 1 sheet from the DXF (CUT layer): 35 m of path, 68 drainage slots. Inside-out order, air assist on. If the ply is exterior/marine grade, expect the phenolic glue lines to char more: slow down and test a scrap.
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2
Remove char and sand about 40 min
Brush char from every edge, 120 then 180 grit; ease the shelf edges. Sand the drainage slots with a folded strip of paper.
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3
Dry fit about 12 min
Lay SIDE-L flat, push the 3 SHELF boards and the two rails into its slots, add SIDE-R. Check each shelf tab ends flush with the outside face and the stair profile lines up. No glue.
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4
Pre-finish about 60 min (1 h)
Seal every face and edge now: 3 coats of spar urethane or exterior poly (wet pots, spills). Mask tabs and slots so the glue still bonds. Seal the drainage slot edges well; they take the water.
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5
Glue-up (Titebond III, water-resistant) about 25 min
Glue the 3 shelf tabs and the two rail tabs into SIDE-L, then fit SIDE-R and clamp across the width. Wipe squeeze-out at once; check square by measuring both diagonals.
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6
Screws as clamps about 12 min
10 #8 screws (3.0 mm pilots pre-cut): #8 x 1-1/2 in through the side faces into the shelf edges, between the tabs. Use coated or stainless screws if it will live outdoors.
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7
Anti-tip anchor about 10 min
Fit the anti-tip strap through one of the two 6 mm holes in RAIL-TOP into a wall stud. Heavy pots on the top tier raise the tipping risk, so keep the heaviest pots on the bottom tier.
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8
Final coat, cure, pack about 30 min
Last coat on the top faces, 24 h cure, 15 kg pot load test on each shelf, felt/rubber pads on the 4 feet, flat-pack in one box (about 720 x 820 x 80 mm).
About 7 h for all 8 stages.
Materials and hardware
18 mm (3/4 in) birch or Baltic-birch plywood, 4 x 8 ft (1220 x 2440 mm) x 1; use exterior-grade ply for a patio stand. Thickness 18 mm. 1 sheet.
Glue: Titebond III, about 3 oz.
Finish: spar urethane or exterior poly, 3 coats (about $14).
| Hardware | Qty | Each | Line |
|---|---|---|---|
| #8 x 1-1/2 in wood screws (coated/stainless) from model | 10 | $0.10 | $1.00 |
| Anti-tip furniture strap kit mandatory above 900 mm; recommended always | 1 | $6.00 | $6.00 |
| Wood plugs / filler | 1 | $2.00 | $2.00 |
| Felt/rubber foot pads | 4 | $0.40 | $1.60 |
| Hardware total | $10.60 |
Screws counted from the model: #8 x 1-1/2 in × 10.
Profit estimate
Estimates and assumptions. Every dollar figure on this page is a planning estimate, not a quote and not a promise. Sheet price, hardware, fees, labor, and machine wear are assumptions. Machine time is based on reported 120 W-class diode speeds, multiple passes at 18 mm. One timed scrap cut will replace this.
Diode machine time
These three columns are the same unit at the mid selling price. Best, typical, and slow are the diode estimates. Based on reported 120 W-class diode speeds, multiple passes at 18 mm. One timed scrap cut will replace this.
| Best | Typical | Slow | |
|---|---|---|---|
| Machine time | 1.27 h | 2.28 h | 5.2 h |
| Cost per unit | $126.76 | $128.48 | $133.44 |
| Gross margin | $38.24 | $36.52 | $31.56 |
| Gross margin % | 23.2% | 22.1% | 19.1% |
| Net after fees and labor | -$28.26 | -$29.98 | -$34.94 |
| Gross profit per machine hour | $30.11 | $16.02 | $6.07 |
| Net profit per machine hour | -$22.25 | -$13.15 | -$6.72 |
Commercial laser (assumptions)
These columns are assumptions, not a cut on this machine. ASSUMPTION. Sourced case: 300-600 W CO2 flatbed, single pass at ~600 mm/min (vendor 480-720), 60 m/min rapids, 5 min/sheet, $8/h operating cost. What-if cases: a machine 10x / 20x faster than the diode mid cut+travel time (not sourced for 18 mm ply).
| Commercial CO2 (assumption) | What-if 10× (assumption) | What-if 20× (assumption) | |
|---|---|---|---|
| Machine time | 1.05 h | 0.29 h | 0.19 h |
| Cost per unit | $133.00 | $126.92 | $126.12 |
| Gross margin | $32.00 | $38.08 | $38.88 |
| Gross margin % | 19.4% | 23.1% | 23.6% |
| Net after fees and labor | -$34.50 | -$28.42 | -$27.62 |
| Gross profit per machine hour | $30.48 | $131.31 | $204.63 |
| Net profit per machine hour | -$32.86 | -$98.00 | -$145.37 |
Selling price, at the typical diode time
| Low price | Mid price | High price | |
|---|---|---|---|
| Selling price | $95.00 | $165.00 | $250.00 |
| Cost per unit | $128.48 | $128.48 | $128.48 |
| Gross margin | -$33.48 | $36.52 | $121.52 |
| Gross margin % | -35.2% | 22.1% | 48.6% |
| Net after fees and labor | -$92.98 | -$29.98 | $46.52 |
| Machine hours | 2.28 h | 2.28 h | 2.28 h |
| Gross profit per machine hour | -$14.68 | $16.02 | $53.30 |
| Net profit per machine hour | -$40.78 | -$13.15 | $20.40 |
ESTIMATE: 2.3 h (low-speed case 5.2 h, best case 1.3 h) of machine time per unit for 35 m of cut path in 1 sheet(s) on a 120 W diode, 18 mm plywood. Machine time, not material, is still the limit on profit per hour, but a single test cut on scrap will replace this range with a real number.
All dollar figures are planning ESTIMATES / ASSUMPTIONS, not quotes, not guaranteed. Sheet prices: 4x8 ft 18 mm birch plywood $70-110, basic plywood $55-75 (assumption). Machine time uses a sourced RANGE for a 120 W diode on 18 mm ply (low 120 / typical 300 / high 600 mm/min effective, i.e. after multiple passes; taken from reported speeds for a 120 W-class diode); ACMER publishes no 18 mm ply feed rate, so none of it is measured on this machine. Machine wear/electricity $1.70 per machine-hour (assumption). Labor valued at $25/h for the "after labor" line only. Marketplace fees 10% (assumption, e.g. Etsy-style).
Where the price band came from: My estimate: Etsy/Amazon plywood plant stands run about $30-$110 for small units (a survey of similar pieces, third-party estimates); a window- or wall-fitted 3-tier unit with slatted shelves, finished, is priced above that. Low = 2-tier unfinished, high = 4-tier finished and sized to order.
Try your own numbers
Change the sheet cost, hardware, selling price, labor rate, or machine time. Finish ($14.00) and packaging ($10.00) stay put. Machine wear follows the machine-time choice: $1.70 per hour on the diode estimates, $8.00 per hour on the commercial assumptions. Fees stay at 10% of the selling price. Labor uses the planned 2 h at the rate you type.
Still an estimate. Based on reported 120 W-class diode speeds, multiple passes at 18 mm. One timed scrap cut will replace this. The commercial rows are assumptions, not a cut on this machine.
Parameters
These are the knobs for a custom order. The model on this page uses the defaults. Stay inside the limits.
| Parameter | Default | Limits |
|---|---|---|
| Width | 700 | 400-900 mm |
| Height | 800 | 500-1100 mm (anchor above 900) |
| Depth | 400 | 250-500 mm |
| Tiers | 3 | 2-4 (>= 200 mm clear between shelves) |
| Step back each tier | 100 | 60-140 mm (top tier >= 150 deep) |
| Thickness | 18 | 17.5-19 mm |
| Slot clearance | 0.1 | 0.0-0.2 mm |
| Plinth height | 90 | 90-150 mm (0 = floor standing) |
| Slatted shelves | 1 | 0 or 1 |
Safety notes
- Anchor to a wall stud with the anti-tip strap (ASTM F3096 style); mandatory above 900 mm, recommended on every unit.
- Rated target 15 kg per shelf (UNVERIFIED - load test a shelf before selling). Wet soil is heavy: 5 L of damp potting mix is about 4 kg.
- Not a children's product (no CPSIA testing). Not a climbing aid.
- Outdoor use needs exterior-grade ply plus a UV-rated finish; indoor-grade birch ply swells and delaminates when wet.
Unverified / to test
- Machine time is an estimate (120 W diode on 18 mm ply, sourced range, not measured on this machine); cut time and profit/hour depend on it.
- Shelf load rating and deflection untested; the deflection line in checks.txt is a hand calculation with an assumed ply modulus.
- Exterior/marine ply (phenolic glue) cut quality on the diode laser is unverified.
- The cost model charges one whole 4x8 sheet but this design fills only 34% of it (offcut not credited). Nesting 2 stands per sheet (area allows it; not nested here) would cut mid cost to about $83 and lift mid gross margin from 22% to about 49%. As modeled, the low price band is below cost.
- Price band is my estimate, not a market quote.
Downloads
Meadowlark Models. Numbers on this page are estimates. Machine time is based on reported 120 W-class diode speeds. One timed scrap cut will replace it.