ANOTHER exhaust question

[Chad Fitzgerald]

I know this has been beat to death but im asking again anyway.

My new shop is close to being done, ready to install the ductwork for the laser exhaust.
Im using the red HF dust collector, been using it for a long time now and it does great.
exhaust will be place at the outside wall, end of the run.

Using 4" pvc pipe

Going through the office wall, up to a 10' ceiling, then either

90 degree turn, then 16' through the outside wall (I know this would be best as far as air pull, but it will be close to the front porch so noise and smell may be an issue with the wind blowing the wrong direction)
or
90 degree turn, then 46' through the back outside wall (this would be best for noise and smell as there is nothing back there, 100 acres of woods and crop land)

My notes in the ( ) is what I am trying to decide which is most important.
Question is, is the extra 30' going to make a small, big, huge difference in extraction from the laser, which in the end is the most important consideration.
If it were your shop, wouold the difference in extration outway the benefits of noise/smell/comfort or the other way around.

Appreciate all opinions, and facts.
Thanks Chad

[David Somers]

Morning Chad!

Where does your family spend most of its time while you are working on the laser? That might be the place to avoid?
Or if in summer the front windows are all open to keep the house cool? The back might be better?

Or....why not put in both ducts and then you can swap as appropriate? You wouldn't be talking about a big expense to do that. Put a gate in the lines and then if the family is chilling on the front porch you can go out back, and vice versa. Easy enough with the walls open.

He says cavalierly! <grin>

Dave

[Dan Wilhelm]

Is there any danger to ducting with PVC? I thought most laser companies recommended sheet metal ductwork because of the possibility that hot embers could make their way into the duct.

[Kevin Gregerson]

I know this has been beat to death but im asking again anyway.

My new shop is close to being done, ready to install the ductwork for the laser exhaust.
Im using the red HF dust collector, been using it for a long time now and it does great.
exhaust will be place at the outside wall, end of the run.

Using 4" pvc pipe

Going through the office wall, up to a 10' ceiling, then either

90 degree turn, then 16' through the outside wall (I know this would be best as far as air pull, but it will be close to the front porch so noise and smell may be an issue with the wind blowing the wrong direction)
or
90 degree turn, then 46' through the back outside wall (this would be best for noise and smell as there is nothing back there, 100 acres of woods and crop land)

My notes in the ( ) is what I am trying to decide which is most important.
Question is, is the extra 30' going to make a small, big, huge difference in extraction from the laser, which in the end is the most important consideration.
If it were your shop, wouold the difference in extration outway the benefits of noise/smell/comfort or the other way around.

Appreciate all opinions, and facts.
Thanks Chad
The biggest worry with something that long other than correct exhaust sizing is the gunk pieces that accumulate in the pipe over time eventually creating a fire hazard from the hot items coming out of the laser. As for pressure, you should have a minimum of 6 inches at the machine. With that much distance it's likely that you need to start with something in the realm of 9-12 inches static pressure on the exhaust. Plus, I'd add in a filter box of some sort for the larger bits and pieces that get into the exhaust tube that you can clean out from time to time to keep away the long term fire hazard.

[Kevin Gregerson]

As a heads up a filter box should have a similar view to this. http://www.bofa.co.uk/cm/dynamic/large/23012014102642.pdf

If you want to build your own and need a lead on the filters I can point you in the right direction as well. They don't cost much for what they do.

[Chad Fitzgerald]

Family on the porch: porch is on the new shop, not the house. covered porch is there more to dress up the shop, customers to sit on if they please(country setting) and for me to drink coffe in the morning and beer in the afternoon.

PVC: been using it for 4 years now, no problems. currently running about 15' to the out wall, plenty of suction.

So I guess I am asking if that extra 30' is going to make a huge difference??? If it is I will run it out the side and deal with it, if not i will go the extra length.

Chad

[Kevin Gregerson]

Family on the porch: porch is on the new shop, not the house. covered porch is there more to dress up the shop, customers to sit on if they please(country setting) and for me to drink coffe in the morning and beer in the afternoon.

PVC: been using it for 4 years now, no problems. currently running about 15' to the out wall, plenty of suction.

So I guess I am asking if that extra 30' is going to make a huge difference??? If it is I will run it out the side and deal with it, if not i will go the extra length.

Chad

It's a two fold thing. 30 feet plus the 90 degree angle are hurting the static pressure and increasing risk of buildup in your pipe. Shorter from a safety standpoint is the way to go. Less to clean and simpler. Though, to quiet things down you can put a larger pipe on the exhaust side of your blower and pipe that away from the house.

[Eric Claiborne]

as a side note, the green dc from harbour freight is only half as loud....even caught it on sale at the same price as the red one.

[Bob McGinn]

If you run the laser much in the winter consider the number of complete inside air exchanges you are doing every hour (stated differently, Heating the great outdoors) it will begin to make economic sense why some many have elected to build or buy contained inside scrubber/filter systems.

[Rich Harman]

as a side note, the green dc from harbour freight is only half as loud....even caught it on sale at the same price as the red one.

I've been using that one for a while now, much quieter than what I was using before. It is actually gray though...

[Kevin Gregerson]

If you run the laser much in the winter consider the number of complete inside air exchanges you are doing every hour (stated differently, Heating the great outdoors) it will begin to make economic sense why some many have elected to build or buy contained inside scrubber/filter systems.

Even easier, just run a line from the outside into the laser machine and just put holes on the bottom of the machine to feed in the air from the outside.

[Glen Monaghan]

Even easier, just run a line from the outside into the laser machine and just put holes on the bottom of the machine to feed in the air from the outside.

Hmmm, not around here... In the winter you'd be pulling 0 degree, 0% humidity air straight into the laser, and in the summer it'd be 95 degree, 95% humidty air. Neither bodes well for the internals.