4'' Metal Blast Gates

The metal gates are much better than the plastic ones. The plastic ones get dust in the closed end where some people want to put a seal and will not close completely causing a really large vacuum loss. I started my dust collection system with pastic blast gates due to the price. I have since replaced all the pastic blast gates with metal ones and have not regretted it one bit. The small loss of vacuum can be overlooked if you have a big enough supply on the business end of the system.

I have a bunch of these - and the 2-1/2" ones - and am using them with the plastic bases. They work fine, though the open bottom does indeed represent a significant vacuum leak when the gate is open. Orienting the gate with the screw pushing the gate toward the vacuum-supply side does maintain a decent seal when closed, but when the gate is up, nothing fills the gap at the bottom of the gate. The gates do not sit deeply enough in the plastic bases for the bases to act as a seal. I agree with the others who say the flanges are too short. It was especially challenging to get these installed using hose clamps and bases when the hose was new and cold (not as pliable). I recommend using hose clamps to secure the hose to the flange and a separate zip tie to secure the gate to the base. I haven't tried to close off the bottoms of the gates yet - I only recently realized they were leaking there. A length of duct tape should do the trick, I would imagine. Other than that, they're sure sturdy and the gate seals well when oriented properly.

My use was to replace a plastic blast gate on a commercial air dryer at dog grooming operation. The plastic wore out broke and the metal gate was easy to adapt. It should last for many doggy groomings. Thanks

With the blast gate installed with the thumb screw facing away from the vacuum, the thumb screw and suction creates a good seal in the closed position. However in the open position, installed either way, there is a very significant gap around unit where the two sections are screwed together. There should be a gasket there! I would return the item, postage would seem to be a waste. I’ll insert some type of gasket with a thicker gate slide, this will create a much tighter seal, and make the item satisfactory to me. This item also has male connections, I would prefer female ends that would fit over the pipe. The unit is made solid, serviceable but in Taiwan. I would not recommend this item unless you intend to correct its leakage, or I might have received a bad one. I am still a very satisfied customer of Rockler.

The flanges on these as well as the 2 1/2" blast gates are not long enough to use the 4 inch hose clamps without some real squeezing by you. You almost need three hands but if the flange were a half inch longer, it would be so easy.