Make Dust Collection Ducting from MDF?

[Ole Anderson]

Kevin, welcome to the creek!

Wow, two grand worth of duct? Must be a huge shop with lots of drops. If I could attach an Excel spreadsheet, I would share pricing options (Ok I only was looking at snaplock). But I had a main run of 28' of 7", 10' of 6" drops, 30' of 5" drops, and 10' of 4" drops. 5 wyes, 9 large radii adjustable elbows and a couple of reducers and 3 blast gates (I already had several). Done in 2011. Oneida pricing, not including shipping, was nearly $694. I was able to get it locally from an HVAC supply house for just over $222. All 26 gauge or better. It helped considerably that my son got me his employee discount as he managed the HVAC place. But even double it and it still was not 25% of the cost 2 HP SDG.

As far as using the MDF, cutting all of that will make you wish you had your system up and running first. But of you are willing to fab a lot of 22.5 degree bends, wyes and then put a filler in the sharp corners to minimize cust catching areas, it could be done. Yes you will need more hp to overcome the extra losses you will get, but a 5 hp cyclone should get you there.

[Keith Outten]

You can't pull a vacuum on a sponge. Some people use MDF spoil boards on CNC Routers so they can pull a vacuum on sheets to hold them down to the table. I realize that a Vacuum system is a different animal than a vacuum hold down system but if you consider an entire collection pipe made from MDF you can expect the loss to be significant.

Another consideration is moisture. MDF absorbs moisture and swells. Running a lot of air through a system when the humidity is high will cause problems. I have to machine my spoil board again and again when the humidity is high in certain seasons...it will not stay flat.
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[Kevin Honkomp]

Wow, amazing response, thank you all. I get that it would be a pain to do the MDF and I’m still looking for alternatives. Like I said, I got a ton of it (literally more than a ton when I think about it) free so I’m always looking to use it. I’ve also moved it twice so I know how heavy it is. I’m about to retire and would have time to play with it. I’d use it just for the large runs and convert to PVC DWV (ASTM 2729) for 4” and under. That’s readily available here. My preference would be all PVC, but I need some 6” and the only distributor in my area that has it hates selling “consumers” and just avoids it by charging 4 to 6 times retail.
He’s also the only HVAC supplier in town.
The spikyfish link shows sort of what I was thinking, though his sweeps are much more elegant than what I had in mind. Nice job. Would be interesting to know how that worked out for him over time.
Also, I found KenCraft Company when searching this form and everyone had nice things to say about them. They have most of what I need in metal at reasonable prices, might be able to get the stuff they don’t have, and are working up a shipping quote. Thanks again for your thoughts.

Kevin