By Martin Harris. Updated 2026-07-21.
Best Blast Gates for Dust Collection
A blast gate is the valve at each branch of your ductwork that closes off every machine except the one you're running, so your collector's full airflow goes where you need it instead of splitting across every open port in the shop. Each gate below was tested full-open, downstream of the same fixed reference collector and duct setup, not open air, so the CFM and static pressure figures here are directly comparable to each other under my standardized test protocol.
Top pick: 4 in. aluminum self-cleaning gate, for the lowest measured static pressure loss in this set and a self-cleaning slot that won't pack solid with fine sawdust over time.
| Product | Measured CFM | Static pressure | Price |
|---|---|---|---|
| 4 in. aluminum self-cleaning gate Top pick | 416 cfm | 0.08 in. w.c. | $35 |
| 4 in. automated gate | 411 cfm | 0.12 in. w.c. | $90 |
| 4 in. steel slide gate | 413 cfm | 0.11 in. w.c. | $25 |
| 4 in. ABS plastic gate | 408 cfm | 0.15 in. w.c. | $15 |
| 4 in. budget plastic gate | 395 cfm | 0.22 in. w.c. | $10 |
1. 4 in. aluminum self-cleaning gate Top pick
| Measured CFM | Static pressure |
|---|---|
| 416cfm | 0.08in. w.c. |
Full-open; minimal added resistance. At 0.08 in. w.c. full-open, this gate isn't where you'll find real airflow gains or losses in a system, it's a rounding error next to duct and hose losses.
Amazon
$35
Price last checked 2026-07-21.
2. 4 in. automated gate Best for automation
| Measured CFM | Static pressure |
|---|---|
| 411cfm | 0.12in. w.c. |
The actuator doesn't meaningfully affect full-open flow. At 0.12 in. w.c. full-open, this gate isn't where you'll find real airflow gains or losses in a system, it's a rounding error next to duct and hose losses.
Amazon
$90
Price last checked 2026-07-21.
3. 4 in. steel slide gate Best simple metal gate
| Measured CFM | Static pressure |
|---|---|
| 413cfm | 0.11in. w.c. |
Small slot and edge loss. At 0.11 in. w.c. full-open, this gate isn't where you'll find real airflow gains or losses in a system, it's a rounding error next to duct and hose losses.
Amazon
$25
Price last checked 2026-07-21.
4. 4 in. ABS plastic gate Best value
| Measured CFM | Static pressure |
|---|---|
| 408cfm | 0.15in. w.c. |
Slightly higher turbulence than metal. At 0.15 in. w.c. full-open, this gate isn't where you'll find real airflow gains or losses in a system, it's a rounding error next to duct and hose losses.
Amazon
$15
Price last checked 2026-07-21.
5. 4 in. budget plastic gate Cheapest option
| Measured CFM | Static pressure |
|---|---|
| 395cfm | 0.22in. w.c. |
A minor seal leak reduces usable branch flow. At 0.22 in. w.c. full-open, this gate isn't where you'll find real airflow gains or losses in a system, it's a rounding error next to duct and hose losses.
Amazon
$10
Price last checked 2026-07-21.
How to choose
Metal versus plastic comes down to durability more than airflow. A steel or aluminum gate will outlast a plastic one under daily slamming open and shut, and it won't crack in a cold shop the way a cheap ABS gate can. Self-cleaning gates use a shaped slot that lets debris slide past the blade edge instead of jamming it, worth the small premium if you're tired of fighting a stuck gate. Everything else here is preference: manual slide gates are cheap and reliable, automated gates open and close on their own when a tool's current-sensing switch fires, convenient if you're already running a remote or automatic switch setup.
Worth saying plainly: at this class, the static pressure loss across every gate in the table above is well under 0.25 in. w.c., full-open. That's a trivial number next to what a long hose run or an undersized duct will cost you. Gate choice barely moves the needle on airflow. Buy for durability, price, and whether you want automated switching, not for a fraction of an inch of water column you'll never notice at the tool.
FAQ
Do blast gates actually reduce airflow much?
Not meaningfully when full-open. The figures above put every gate in this set under 0.25 in. w.c. of loss, small compared to what a long hose run or a tight duct bend costs you.
Are self-cleaning blast gates worth the extra cost?
If your shop makes a lot of fine sawdust, yes. A standard slide gate can pack solid with fines over time and get hard to move, a self-cleaning slot design avoids that without costing you meaningful airflow.
How many blast gates do I need in my shop?
One per machine drop, generally. The idea is to close off every port except the one you're actively using so your collector's full airflow goes to that machine instead of leaking out three open gates down the line.