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Downsize PVC to fit blast gates

Shrink PVC pipe for your ductwork needs

Downsize PVC to fit blast gates

Downsize PVC to fit blast gates

When I installed a central ductwork system for my dust collector, I used 4" PVC pipe instead of steel and saved 75 percent on the cost. But the inside diameter of the 4" PVC is 1/8" too large for blast gates designed for steel ducts. My dad and I solved that problem by shrinking the PVC pipe slightly with a propane torch.

To soften the PVC for the joints, we slipped a hose clamp over the pipe and carefully heated the pipe until it softened. With the pipe end soft, he slipped the fitting into the pipe, slid the hose clamp up near the end, and tightened it to snug-up the softened PVC end. Once the pipe cooled and hardened, we removed the hose clamp to use for the next joint.

Finally, I secured the blast gate to the pipe with a sheet metal screw. With no tape, glue, or steel, and only a single hose clamp, it's a clean, simple way to build an inexpensive but effective collection system.

--Scott Perry, Tinley Park, Ill.


Comments (6)
Dave6911 wrote:

I used your idea to join 2 slightly mismatched PVC pipes..Put the smaller one in the oversized one,heated the larger one with a heat gun ,screwed the hose clamp down.Repeated this by moving the clamp down about 3/4" each time, till I had had about 2" shrunk.The fit is as tight as any factory fit.. Thanks..

4/5/2013 08:56:04 PM Report Abuse
seaminer wrote:

I used silicone to glue the blast gates and joints together. That way at a later date if I need to move pipe around it comes apart and can be re-glued easy enough.

9/22/2012 12:19:35 PM Report Abuse
robertheinroth wrote:

Addition note on (green)PVC Sewer Pipe. If use use green sewer pipe the indisde diameter is a greater fit but you must attach it to the gate w/ 4 screws drilled and tapped.

11/14/2011 10:44:21 PM Report Abuse
JamesinKS wrote:

Just be careful with flame around PVC. Burning PVC releases hydrochloric acid. Kind of hard on the lungs and eyes. Skin too.

10/31/2011 09:24:33 PM Report Abuse
woodwelder2 wrote:

Great idea. I am upgrading my shop and need a way to produce a junction from opposing directions. One little recommendation that I found out when I installed my dust collection system. If possible, use the clear plastic piping. If you have a clog, you instantly know where it is and can unstop it. Thanks again for the idea. Mitch

10/2/2011 07:51:31 PM Report Abuse
Toolhound wrote:

Gorilla Glue works great, too. It expands, filling the gap around the blast gate and locks everything together securely.

6/8/2011 11:30:13 AM Report Abuse

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