# SDR 35 Pipe & Schedule 40 Fittings



## fivecodys (Dec 2, 2013)

Hi guys,
I am in the process of modifying my DC system with a Super Dust Deputy and dedicated ductwork.
I have seen several folks using SDR35 for ducting.
Lowes and HD in this area do not carry this any longer.
My local Pipe shop has it but he warned me that SDR35 has an outside dia of 4.215 and standard SCh 40 PVC fittings are 4.50 inside dia so the fit would be very sloppy.
Has this been your experience?


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## Rayne (Mar 9, 2014)

If you have a local HVAC shop, check into using 28ga duct work. They are usually equal, if not cheaper, than PVC. Mine definitely was and even had 5" duct to maximize the opening from the SDD. The only connector that was difficult to find was a 5" Wye.


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## JBrow (Nov 18, 2015)

fivecodys,

Yes it is a sloppy fit. Seeking a landscape or plumbing supply house for SDR-35 fittings could make it easier and faster to install the pipe.

Metal pipe is also a good choice and as Rayne suggests, use 28 gauge minimum metal pipe. However, the 45 and 90 degree HVAC fitting could leak and add to the static pressure of the system. Here is a mail order company that offers 26 gauge pipe and long sweep smooth fittings.

https://www.kencraftcompany.com/product/26-gauge-snap-lock-pipe/

If committed to SDR-35 pipe and you cannot find SDR-35 fitting then I suppose the end of the SDR-35 pipe could be wrapped with some tape. My approach was to stretch the end of the SDR-35 pipe using a shop-made die and a heat gun. The stretching approach work well but will lengthen time needed to complete the dust collection piping system.


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## Mike_D_S (May 3, 2012)

The local guy I got my 5" metal duct from could order reverse crimped 5" wyes from his supplier for about $1 more than a standard 5" wye. Basically he told me that they form the wyes and then will bell or crimp the ends as required.

So if you talk to a local HVAC supply place, you can specifically ask them if he can get the Wyes correctly crimped for suction.

Using 45s with a small spacer is a good stand in for a long sweep 90. Get some good quality real foil duct tape and use that liberally to seal all the seams and you won't have any real trouble with leakage. Don't forget to seal the long seam for the snap lock straight pieces.

I found the price to go with metal duct from the HVAC guy to be within 20% of the 4" PVC pricing and got 5" duct instead.

Mike


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## Rayne (Mar 9, 2014)

> fivecodys,
> 
> Yes it is a sloppy fit. Seeking a landscape or plumbing supply house for SDR-35 fittings could make it easier and faster to install the pipe.
> 
> ...


I stand corrected. Mine are indeed 26 gauge. Just read the label as I was installing some conduit. lol. They won't collapse and there is no air leak if you tape them properly (which is a LOT on Wye's and elbows). So, 26 gauge was cheaper than PVC for me. Definitely worth looking into fivecodys.

Mike D. - my supplier didn't have the 5" wye's; I had to get them special ordered and were the most expensive part out of everything I had to use. That's awesome your local guy had some that could be recrimped for suction.


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## Mike_D_S (May 3, 2012)

Rayne,

Well to be fair I'm in Houston and the HVAC guys sheet metal supplier is in town as well. He basically told me that they form the wyes and then add the crimping as a separate step, so the upcharge was reasonable and I didn't have to pay shipping, though I did have to wait a week for them for them to place their next order of wyes.

Mike


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## wapakfred (Jul 29, 2011)

If you have the fittings and want pipe to fit them, then you'll be modifying the SDR35 in some manner (or use the heavier pipe). If you don't have the fittings and need to buy everything, look for ASTM D2729 at the box stores. They almost always have the 4", and some of them have 6".


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## fivecodys (Dec 2, 2013)

Thanks guys,
It looks like i will be going to metal.
I will be taking the old DC apart this weekend and mating it to the SDD for a wall mount set up.
Thank you Rayne for the link. Way better pricing that Oneida's web site.
Since my projected budget just got shot to pieces I may have to build my DC layout in sections and the budget permits. I will post some pics as I progress along.

Thank you all again for you time and comments.


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## Rayne (Mar 9, 2014)

> Thanks guys,
> It looks like i will be going to metal.
> I will be taking the old DC apart this weekend and mating it to the SDD for a wall mount set up.
> Thank you Rayne for the link. Way better pricing that Oneida s web site.
> ...


JBrow provided the link, so credit to him. I just checked my local HVAC company to see if they would sell to me (they were wholesalers of sorts), and they did. The link from JBrow is still a great price. Wish I found them for the wyes when I was building mine.


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