poor quality 90 degree fittings for dust collection

I'd take it back. If you read up a little, 90 deg bends are not really optimal anyway, you may be better off just using tubing to make the largest bend you can afford in your space (or hook a couple 45's together). Ideally, the tubing would be straight for the highest possible flow rate - every bend you add lessens your cfm.

I looked at the commercial fittings and was similarly underwhelmed. 4" light sewer pipe is much higher quality.

"Bob Davis" wrote in news:Z7MXb.4675$ snipped-for-privacy@newsread1.news.pas.earthlink.net:

Use standard borg plastic pipe fittings. Its cheeper. Now the sizes are a little off for the connectors but I watched a show on TV where a guy did custom pipe work with a heat gun. Aparently with a little bit of heat you can stretch, shrink, bend and shape PVC just about anyway you want. He took a piece of 2 inch and warmed it up and made a 2 - 4 reducer by using a broom stick handle to slowly encrease the size of the pipe till it fit in a 4 inch fitting.

If he can do this the slight 1/4 inch change needed to get standard 4 inch PVC to fit into duct collector ports should be a sinch.

Sometime I think it is a plot. Dust collector and shop vacumn fittings are intentially made just a little bit different from standard PVC so you cant use the cheep high volume stuff.

Now I caution you that I haven't tried this yet but I am going to. After all a couple of dollars worth of PVC should provide you with plenty of stuff to practice with. And if it doesn't work out then all you wasted is a little time.

You might consider doing that in a well ventilated place. See toxic fumes warning at

"David Merrill" wrote in news:foOXb.187845$U%

bookmark this one.

I have read up and done extensive calculations. There is a balance between ideal flow conditions and making things fit in the shop. A 90 degree ell doesn't add that much drop. Its almost academic. What is really surprising (but not if you think about it) is the drop associated with flexible dust collection hose. A 2 foot length of flex hose has twice the drop of a single

Bob

But you shouldn't really be using 90's anyway. Mainly because it is a potential clog point. You should be using two 45's to round out the corner.

Roy

Good point, Roy.

Bob Davis

If you're using regular DC fittings, they are already "high flow" design. If you're using 4" PVC, (2) 45's work better, or find a local plumbing supply(NOT a BORG) and get high flow 90's(wouldn't know this, but SIL is commercial plumber, and our code calls for high flow 90's in sewer lines).

I couldn't stand it. I happened to have a heat gun that I've used for years for heat shrink tubing (electronics wiring). I wondered if it would enough output. I needed a 4" x 4" square nozzel that adapts to 4" S&S pipe. So I took a 4"x4" fence post and put a 10 degree taper cut on four sides to make a jig. Then I took a scrap of pipe and began heating it. I could tell when it "went rubbery" and slipped it over the end of my wooden jig. Voila! I had a perfect nozzle ready to hook up to my dust collection piping.

Bob

"Bob Davis" wrote in news:jcr_b.5185$ snipped-for-privacy@newsread2.news.pas.earthlink.net:

Cool! Sometimes all it takes is to do it!