The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: attwood on February 23, 2014, 04:53:31 PM

Title: dust collection on a lt 40
Post by: attwood on February 23, 2014, 04:53:31 PM
hey guys im new to the site but not new to sawmilling  I have finally got a building up to keep my mill under  the building is 40x60 with one 20x40 bay enclosed to set up my molder and planer in and also for a wood working shop  my question is that I have a 5hp dust blower that pulls 4900cfm im wanting to have it hooked up to my molder as well as my mill but have shutoffs where I can use one at a time  will this size blower handle the sawdust coming out of the mill and about how far will it carry it  im needing close to 50 feet to get it away from my building  thanks for any help and advise
Title: Re: dust collection on a lt 40
Post by: Magicman on February 23, 2014, 05:52:28 PM
I can not offer any dust suggestions but Welcome to the Forestry Forum, attwood.   :)
Title: Re: dust collection on a lt 40
Post by: millwright on February 23, 2014, 06:31:25 PM
I have a blower with 2hp that I use for the sawmill and planer, it will easily blow over 70 ft.
Title: Re: dust collection on a lt 40
Post by: attwood on February 23, 2014, 07:24:27 PM
what type of pipe did you use  I was thinking pvc but have heard of having to ground it so it will not make static electricity and cause fire
Title: Re: dust collection on a lt 40
Post by: Larry on February 23, 2014, 07:36:13 PM
I've used and use PVC without grounding in my shop.  Planed 1000's of feet of dry lumber.  Ran piles of dry sawdust from industrial sanders through it. 

But I think if your a commercial operation your going to need metallic pipe to meet code, and make the insurance man happy.

You can read about different ways to ground PVC with wire inside, wrapped around the outside, and various other schemes.  I'm not convinced there effective.  If you want a ground and positive protection buy metallic pipe.

Welcome to the forum attwood. :)

Title: Re: dust collection on a lt 40
Post by: Chuck White on February 23, 2014, 09:25:29 PM
Welcome to the Forestry Forum, Attwood!
Title: Re: dust collection on a lt 40
Post by: pineywoods on February 23, 2014, 09:33:22 PM
Welcome atwood. I use 6 inch metal stove pipe, available at your local hardware store. 2 hp blower and about 40 ft of pipe and flex hose. Three elbows in the pipe. Works fine. Where in south ark ?
Title: Re: dust collection on a lt 40
Post by: attwood on February 23, 2014, 09:49:09 PM
im in rison  small town about 60 miles south of little rock
Title: Re: dust collection on a lt 40
Post by: Brucer on February 24, 2014, 12:50:05 AM
Quote from: attwood on February 23, 2014, 04:53:31 PM
...  I have a 5hp dust blower that pulls 4900cfm ...

Not enough information. What pressure does it produce when its moving 4900 CFM. The pressure is usually expressed as "inches water gauge", or "WG. Your blower will only move 4900 CFM when it has enough pressure to overcome the resistance in your ducts.

To move sawdust through a duct, you will need to have a duct velocity of 20 to 23 m/s, or 4000 to 4500 feet per minute. With a 4900 CFM blower that means a 14" duct will do the job. Probably not very practical though. Your motor might also trip out.

If you installed a 5" duct, you would only need 600 CFM or so. The smaller diameter duct will also need more pressure to push the air through than a 14" duct. The longer the duct and the more bends in it, the more pressure required.

If your fan is belt driven, you can slow it down (never speed it up). That will help if you are moving too much air.
Title: Re: dust collection on a lt 40
Post by: attwood on February 24, 2014, 05:13:05 PM
im not sure on the pressure  its the bigger blower that woodmaster sells
Title: Re: dust collection on a lt 40
Post by: pineywoods on March 07, 2014, 09:56:59 AM
Attwood tell us about the woodworking shop. Is your molder 4 sided? You are about an hour drive from me. Would be nice to have a 4 sided one local. I sent you a pm, but don't think you can reply until you have a few more posts..
Title: Re: dust collection on a lt 40
Post by: attwood on March 09, 2014, 09:16:35 PM
well the shop is a 40x60x12  I enclosed the first 20 foot bay and that part is on a slab  the other 40x40 is open with a gravel floor  got the woodmizer under that part with plenty of room left to stack lumber under  the molder I have is a woodmaster 718 with the two router attachments to do the 3 sides at once  got plans to get another planer so I can leave the routers all hooked to the woodmaster   im about to start running a lot of 1x8 pine to make v joint t&g paneling for my house   so far all the lumber ive used on my house has been cut on our mill  once im done with my house I hope to have a side line sawmill service and also maybe offer the t&g and lod siding  may even cut some ties
Title: Re: dust collection on a lt 40
Post by: pineywoods on March 09, 2014, 10:43:49 PM
Sounds like a real nice setup. Inside a building with a gravel floor, you sure will need a sawdust blower system. After lots of trial and error, I finally came up with a system on my lt40 that works well. One 2 ft long section of flex hose, the rest is 6 inch hardware store stove pipe.


 (https://forestryforum.com/gallery/albums/userpics/14000/sawdust1.jpg) 

 (https://forestryforum.com/gallery/albums/userpics/14000/1037/sawdust.jpg)

You are welcome to come look. I'm a couple of hours south of you just across the state line.

Title: Re: dust collection on a lt 40
Post by: YellowHammer on March 11, 2014, 11:34:03 PM
I use a 2 hp blower and have no trouble with sawdust from my Lt40.  A little flex hose to a straight pipe to take slack out, then to a ball swivel to allow rotation to protect the flex hose, and finally to 6 inch metallic stove pipe.  I'm running dust about 50 feet, then blowing into a 3 yard dump trailer.
It works fine, no complaints. 
YH


 (https://forestryforum.com/gallery/albums/userpics/21488/image%7E37.jpg)