4" hose to PVC connection won't fit.

[Matthew Sherman]

I am in the process of building a thien separator. I am using a 5" metal connector for the center hole in the lid. The elbow is what I am having the trouble with. From some searching it sound like the thin wall S&D pipe should accept 4" flex hose. I bought the 4"x10' flex hose Menards sells, but it seems a little small. The inner diameter seems too small to fit over the S&D fittings outside. The hose is too big to fit in the female end of S&D fittings. Then regular DWV PVC the hose a bit loose in the female ends for these connections. Should I order some 10' sections from Rockler or the PSI? This is driving me crazy because there is a video showing PSI hose slipping over a S&D fitting with little problem. :eek:

[Ib Rikhof]

When building my dust collector system this is how I solved the problem. Most of the system is 5 inch pvc well casing which I reduced to 4 inch near each machine. I used 5" to 4" reducers and came out of the 4" end with about two inches of the heavier (sch 40) pipe. I then cut a short (approx. 5 inch) piece of the thin wall pipe. I set this piece on the band saw and slit it parallel to the axis. I then slid one edge of the slit inside the other and put it inside of the sch. 40 pipe. This enabled me to measure how much oversize the thin walled pipe was above just fitting tightly inside the sch. 40 pipe. Then back to the band saw for another cut parallel to the first. This cut produced a strip about 1/2" wide. Using pvc cement I then glued the cut edges together reinforced by the strip inside the pipe along the cut. This piece is then glued inside the 4" sch 40 pipe with enough sticking out to slip the hose over and tighten with a 4" pipe strap. Hope you can follow my explanation and that it helps. --- Ib

[Bruce Wrenn]

Lowes stocks a fitting that transitions 4" sch 20 to 3" sch 40. The 4" end slips over 4" sch 20, and 4" hoses fit over the 3" end. The 3" end has a molded stop inside, which I remove by using a 1/2" flush trim router bit.

[Steven Wayne]

When building my dust collector system this is how I solved the problem. Most of the system is 5 inch pvc well casing which I reduced to 4 inch near each machine. I used 5" to 4" reducers and came out of the 4" end with about two inches of the heavier (sch 40) pipe. I then cut a short (approx. 5 inch) piece of the thin wall pipe. I set this piece on the band saw and slit it parallel to the axis. I then slid one edge of the slit inside the other and put it inside of the sch. 40 pipe. This enabled me to measure how much oversize the thin walled pipe was above just fitting tightly inside the sch. 40 pipe. Then back to the band saw for another cut parallel to the first. This cut produced a strip about 1/2" wide. Using pvc cement I then glued the cut edges together reinforced by the strip inside the pipe along the cut. This piece is then glued inside the 4" sch 40 pipe with enough sticking out to slip the hose over and tighten with a 4" pipe strap. Hope you can follow my explanation and that it helps. --- Ib

Do you have a photo?

[Tom Rausenberg]

In setting up my DC system, I had to shrink some PVC fittings slightly also. I did it with heat. Put one or two hose clamps over the end, and heat with a heat gun as you tighten the clamps. It worked for me.

[Matt Meiser]

I just buy the black plastic 4" quick connect fittings which fit into a 4" S&D coupling perfectly, or if not, I wrap a wrap or 2 of electrical tape around them. The Woodcraft ones thread into the hose so you don't even need a clamp.

[Jim O'Dell]

I've had no problem getting the 4" flex over the 4" S&D pipe. Tight fit, but it works just fine. I've not tried to put flex inside the female fittings. Jim.

[Thom Porterfield]

True, Matt, the flared end of the Woodcraft Q/D fitting slides into the styrene S&D fitting, but it's wobbly. The tape you suggest would no doubt rectify that. But what if you want to go to one of the other standard ABS dust fittings, say to attach a blast gate at the end of a run of S&D pipe? I'd like to use as little spiral hose as possible.

[Randy Henry]

Thom, I built my own blast gates using 4"S&D straight couplings on both sides of the blast gate. On the top side, the pipe slides right into the coupling, and on the bottom side coupling, I use a flex hose plastic spice coupling. It slides into the S&D coupling perfectly, without having to use any tape to snug it up, but I do use foil tape on the outside to keep it in place. The exposed end of the hose coupling gets the flex hose and clamp. On my PM 15HH planer, I came off the dust chute hood with a 45 deg, street el. The el part slid over the factory 4" fitting perfectly after I heated it up slightly. From there, I started to the piping with that 4" splice coupling that fit into the female end of the el, then connected the hose to the exposed end.

[Tom Hargrove]

I use 4" metal vent connectors (less than 6" long, crimped on both ends) from the HVAC section at Menards. They fit nicely inside the female side of a 4" PVC fitting, and if necessary can be held in place with a short sheet metal screw. My 4" hose (which came from Rockler) slides easily over the outside of the metal fitting and is held in place with a hose clamp.

[Thom Porterfield]

I did discover that the 4" flange sold by Woodcrafters (for use as an outlet on a machine, I guess, at least that's what I bought it for) fits into S&D pipe. It's a struggle, but it goes in.

But for the most part, the wide range of ABS dust collection fittings available from Woodcrafters or Rockler or the like won't go into--or over--S&D pipe, and they rattle around inside S&D fittings.

Research continues. (But it sure seems to me that someone before me has had this same exact hassle and has discovered a solution, one which I will gleefully steal, should I happen across it.)