Thread: We all have to start somewhere

Guess who would be the first to answer a post like that to day?
Regards

Originally Posted by A Duke

Guess who would be the first to answer a post like that to day?
Regards

Jee, I dunno, Who?

Originally Posted by A Duke

Guess who would be the first to answer a post like that to day?
Regards

BobL ... that's who! And thank goodness for that.
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Bob, talking about starting somewhere ... I just had a wild unsupported idea whilst reading Jonno's thread.

Imagine a 6" line through the workshop from machines with good ports/hoods. Instead of a cyclone or a 3 HP dusty, imagine the line splits at a wye after which we have two short 5" or 6" lines each running to a generic 2 HP dusty (single bag machines, nominally rated at 1,200 CFM, and perhaps optimised as per your thread on generic dustys).

If that would work, it would be a very cheap ducted system in terms of set up costs, given that we can buy 2 HP dustys for about $300.00 each. Of course, running costs need to be considered. That set up would still be be cheaper to run than a good cyclone, but probably a bit more than a 3 HP dusty. A good cyclone is about $2,250. A 3 HP dusty is about $1,300. Two generic 2 HP dustys would be about $600. That's a big difference in capital costs, and it seems that it's the capital costs that most hobbyists struggle with. One would also need to consider power requirements.

If this approach would work, a hobbyist could buy one 2 HP system initially and use a short flexy to connect to machines. When he could afford to spend some more, he could add another 2 HP dusty and some 6" ducting.

So ... is this actually a wild idea unsupported by theory ... or does it sound potentially feasible?

. . . .So ... is this actually a wild idea unsupported by theory ... or does it sound potentially feasible?

My back of the envelope analysis of DC systems goes like this

In most cases the #1 problem is insufficient flow at source
- this is cause by the
* DC and ducting not delivering the air flow
* machine ports not enabling the air flow.
* filters blocking up
The next biggest problem seems to be leaks
Then comes filter efficiency

Tandem DCs will help with flow but locating any pressurised component of a DC system inside a shed is asking for problems not to mention the noise.

The other issue is power - which is probably why 2HP DCs are popular, but running two 2HP DCs plus a 3HP machine at the same time is going to need a bit more than a 10A GPO.

Two DCs in series will also provide less flow than two in parallel, but running things in parallel is more expensive and not that easy either as the machines can end up fighting each other rather than dragging more air through a pipe.

Heh. I LOVE seeing stuff like that. I'm a klepto for personal history (as well as junk) and really enjoy those moments when I find something from the days of yore that I'd forgotten about. It can make you appreciate (or regret) where you are and what you're doing now.

It's not wood related, but recently I was able to convert a bunch of old video camera tapes to digital and put together a snippets video of the history of my music playing from not long after I started until almost the end. From stuggling on the basics to gigging around regularly and teaching.

If anyone's up for a laugh: Go to Woah - A Personal Music Progression - YouTube


In fits of boredom I'll also visit The Wayback Machine to look back at some of my earlier websites and see how my style and coding changed over the years.

I can still remember my earliest posts here so, but that wasn't all that long ago. A lot has changed.

A lot hasn't either

Question from a newbie to dust collection.
i have a 2HP dust extractor fan/motor/housing without the volute and bags. Initially I was going to make a complete unit by spare parts.(harder than I initially thought)
i have been reading posts on DC for about a week now. I am NOW looking to clean up the dangerous dust (unseen particles) instead of the dirty dust (sawdust over every flat surface in the shed)
sorry I digress, my question.
I was planning to set up each machine with multiple collector hoses back to a single outlet. the outlet would be the same size at each machine and i would move the DC (motor part) between machines. the DC would have a short (suction) flex to connect to the TS/Router/sander/etc then via another short (delivery)flex would be connected to the main line which would run outside into the volute and collection part.
All the systems and descriptions show setups as long suction lines and virtually no delivery line.
Is there a reason they are done this way? My understanding is that a DC will push the dust a lot better than pulling. I.E. better performance.
cheers

Originally Posted by Wrongwayfirst

. . . . .Is there a reason they are done this way? My understanding is that a DC will push the dust a lot better than pulling. I.E. better performance.
cheers

There is no difference between the push and the pull for small DCs, they generate a small pressure gradient and the air carrying the dust moves according to the size of the duct. The main reason for not using push is that this places the ducting under pressure so that all the joints and the blast gates have to be completely air tight otherwise dust will leak out into the shed. This is a lot harder than it seems.

Besides being a PITA, continually moving a DC and connecting and disconnecting ducting is an additional source of leaks. I have worked in several workshops where this was the modus operandi, and the obvious happened. Operators get lazy, so if the DC is connected to one machine and an operator just needs to perform a short operation with another, they think ," I won't bother to move the DC as this operation will not make a lot of dust". Well these short operations add very quickly and the shed becomes completely contaminated. Even in fully ducted systems some users forget, or are too lazy to open the blast gates to a machine because ".....this operation will not make a lot of dust". That's probably why the Corrimal men's shed set theirs up so the right gates open when any machine is switched on.

Another worthwhile reason to have the motor and impeller outside is to reduce noise.

From what I can see a generic 2HP system, even when modified, will struggle to get close to the desired 1000 cfm at source unless it is used alongside a machine with a very short piece of flexy and the bag is replaced with a pleated filter. To remain effective this set up will need to be constantly monitored for leaks - the only way to be assured of no leaks is to use a particle counter and test it every time it is moved - ie PITA.

Thanks, I figured there had to be a reason. Back to the drawing board. Great to have an experienced ear before spending money in all the wrong places.
cheers