I Saved $49 in 30 Minutes (I did the math for you)
I needed a putty knife at work. No big deal, right? Wrong. Instead of burning an hour and $58, I sketched one on my tablet, traced it in Blender, and 30 minutes later I had a perfectly usable tool in my hand.
Total active effort: 7 minutes. The printer handled the rest (23 minutes of PETG stacking up while I went back to actual work).
Material cost: $0.17 in filament + a couple pennies of electricity. Rounded up: $0.20.
The Store Alternative
Nearest Home Depot: 5 miles away.
17 minutes each way + wondering + checkout time
= 40 minutes round-trip.
F-150 operating cost (IRS 2026 business rate):
$0.725/mile × 10 miles = $7.25.
Cheap plastic putty knife + tax: $1.05.
Subtotal before labor: $8.30.
The Expensive Part (Your Time)
As an engineer, my fully-loaded hourly rate is about $75.
- 40-minute store errand = $50 of company time
- 7 minutes modeling + loading the printer = $8.75
| Expense | Store Run | 3D Printed |
|---|---|---|
| Item Cost | $1.05 | $0.20 |
| Transportation | $7.25 | $0.00 |
| Labor (@ $75/hr) | $50.00 | $8.75 |
| TOTAL | $58.30 | $8.95 |
Net savings: $49.35 in under half an hour.
Maybe you don’t cost your company $75 per hour. I’m sure you’re not free. There are laws against that (unless you’re an intern for a politician…and then you don’t need to worry about money or putty knives. You’ll need a much bigger tool to shovel manure).
Sorry about that side-track. Where were we?
Is a 3D Printed Putty Knife Any Good?
Yes — for a plastic putty knife. It’s stiff, flexes exactly where it should, and spreads compound or adhesive just fine. I’ve used it for two weeks with zero issues. (Printed in PETG for durability.)
Skip the Modeling — Download My Ready-to-Print File
Want to save even more time? I uploaded the exact putty knife model I designed to Printables.
→ https://www.printables.com/model/1438845-putty-knife
Just hit download, slice it, and you’re printing in under 5 minutes total. No Blender required.
(I modeled it myself because I enjoy the process, but 99% of people should just grab this file.)
If you’re buying a $1 plastic tool you’ll use once a year? Just buy it. But for engineers, makers, remote workers, or anyone whose time is expensive? 3D printing turns “I need it now” into “I have it now — for pennies.”
Next time you’re about to jump in the truck for a $1 widget, run the numbers. You might be shocked how expensive that “quick trip” really is.
(And yes, I kept the printed knife. It lives in my toolbox now — proof that sometimes the best tool is the one you make in half an hour.)
Simmer3D 