Laser Engraver/Cutter - Questions and Decisions

[Jack Clague]

no way to flip it over, the only exit i have is that door, if i flip it over then the out flow is facing the wrong way

[Jack Clague]

Ahh shucks, I guess I'll have to see what PVC fittings I can get hold of, did it leak that bad? it seems pretty solid the one I have, its the semi rigid piping

EDIT: Tim is this the sort of stuff you were talking about, i can get this from the same supplier i got the extractor: https://www.carbatec.com.au/dust-con...r-pvc-2m-boxed

I didn't have any luck with that flexible metal piping. It leaked fumes and smoke. I converted to PVC piping.

[Gary Hair]

I don't mean front to back, I mean side to side - in the picture you posted, rotate it 180 degrees clockwise so that the inflow is pointing left instead off right. Yes, it will be upside down but it won't matter. I have two of them mounted the exact same way for the same reason. Just need to make a stand or adapt the one that came with it.

[Glen Monaghan]

Since you have the flex on the suction side, you really shouldn't have issues with fumes/smoke escaping back into the room from there (since it will have negative pressure inside), but PVC would be smoother and reduce friction losses and have essentially no infiltration of room air. Bends are a greater concern. You have to consider the air velocity, cfm, duct diameter, and radius of the bend versus duct diameter to determine specifics, but the turbulence caused by a 90 degree bend can cause losses in the bend that are equivalent to the losses in a straight piece of duct that are on the order of 20-40 feet. A 45 degree bend might cause a third as much loss as a 90 degree bend, so two 45s would be better than one 90, and a large radius bend (radius on the order of 2-3 times the duct diameter) is much better than a sharp radius bend (radius under about 0.75 times the duct diameter). A tight 180 degree bend like you have is about the worst layout you could have.

If you must position the blower to the right of the outlet as shown, you'd be much better off making a mount for the blower to hold it "upside down" so that the duct can enter straight from the left, eliminating that 180 bend entirely. The blower won't mind that orientation at all. Then, make that first 90 degree bend as large a radius (gradual) as you can. Remember that I said two 45 degree bends cause less loss than a 90, and that a large radius bend causes less loss than a small radius? Well apply that here by changing the layout of the longer run over to the blower... instead of having that 1st bend go straight down the wall into the 2nd 90 degree bend and then running horizontally along the floor over to the blower, turn the first (now large radius) 90 degree bend so the previously vertical leg instead goes diagonally down to the right, toward and gradually curving into the blower's inlet, basically eliminating the 2nd 90 degree bend.

[Tim Bateson]

That type of tubing will likely come with you engraver. I use a short run of that to my PVC pipe, then a short run to connect the PVC to the blower.

[Keith Winter]

I agree mine leaks also and when I get back home will change to pvc.

Be sure to ground it properly, I'm not an HVAC contractor but I've read that the reason metal is normally used is because it prevents sparks. I believe you can use PVC but you need to make sure the pvc is all grounded to be 100% safe. On a small run like your it may not matter, but depending on what you are cutting it may. I thought I'd mention it at least.

It's a pain to have to redo a system after it's done, so best to do it right the first time. I should know I've redone mine three times Glen has provided you some excellent advance above I'd try to incorporate as many of his suggestions as you can.

As for metal piping leaks:
The way to stop leaks with metal piping is to screw AND metal tape all joints AND elbows. Buy the extreme weather metal tape and you'll be golden, that stuff called "duct tape" is really quite awful for real duct work and comes loose easily in my experience. My system pushes around 4,000 cfm with rigid metal pipes and we have little to no leaks using this screw and tape method.

Edit: When I look at it again, Jack you have no joints in that layout just one solid piece of flex pipe so I'm not sure Tim or my suggestions even apply here.

[Jack Clague]

Thanks guys. I will check my local place tonight for PVC tubing and bends the might work and see about making up some legs for the unit to sit upside down on

[Gary Hair]

Thanks guys. I will check my local place tonight for PVC tubing and bends the might work and see about making up some legs for the unit to sit upside down on

Just realized what country you are in... it's already upside down, you need to turn it rightside up!

[Phil Vernon]

Hi Jack,
Sorry not having been on for a while.
I am in Melbourne and have worked for 2 of the 3 multi-nationals you mentioned.
My advice would be to not sign just yet but go to the Visual Impact exhibition this week at Jeffs Shed, Thursday, Friday and Saturday. They will all be there http://www.viie.com.au/melbourneexhibition2015
You will be in a good bargaining position..the 3 main players all have their strength and weaknesses.
Happy to talk to you about it.
Regards,
Phil.

[Jack Clague]

Just realized what country you are in... it's already upside down, you need to turn it rightside up!

Haha

For convenience and also to clear some floor space I have thought that maybe the below might be a better solution, sorry for my sucky drawing abilities but how about this? (I do not intend to use the door and want it barred as its a security risk)

Capture.JPG

The idea is to mount the extractor on one of the "barring" braces I am putting on the door using the supplied hanging clips, on the photos above you can see the holes in the base that the hooks fit into, this will have the inflow facing the machine and if i measure it right I can get it in the exact same height line as well, the output will then be facing the floor and will turn a casual 90deg into an exit duct through the door.

Thoughts?

[Jack Clague]

Hi Jack,
Sorry not having been on for a while.
I am in Melbourne and have worked for 2 of the 3 multi-nationals you mentioned.
My advice would be to not sign just yet but go to the Visual Impact exhibition this week at Jeffs Shed, Thursday, Friday and Saturday. They will all be there http://www.viie.com.au/melbourneexhibition2015
You will be in a good bargaining position..the 3 main players all have their strength and weaknesses.
Happy to talk to you about it.
Regards,
Phil.

Hi Phil,

Thanks mate, I intend to visit that exhibition, I am taking Friday off work to go, I have though already signed for my machine.

I did allot of prodding and poking with the top 3 runners here in AU and I think the overall deal I got was pretty good.

Are you going?

Jack

[Gary Hair]

Haha

For convenience and also to clear some floor space I have thought that maybe the below might be a better solution, sorry for my sucky drawing abilities but how about this? (I do not intend to use the door and want it barred as its a security risk)

Capture.JPG

The idea is to mount the extractor on one of the "barring" braces I am putting on the door using the supplied hanging clips, on the photos above you can see the holes in the base that the hooks fit into, this will have the inflow facing the machine and if i measure it right I can get it in the exact same height line as well, the output will then be facing the floor and will turn a casual 90deg into an exit duct through the door.

Thoughts?

I think the door will vibrate off its hinges and drive you crazy in the mean time. I would probably leave it on the ground with rubber feet instead.

Is there any way you could put it outside and run the duct through the door? That would eliminate a lot of noise if you could.

[Jack Clague]

Hi Gary,

The Brace will not be touching the door, the brace is being securely fixed to the two supporting wood braces either side of the door and will be heavy duty timber, do you think this will still cause some issues?

I could place another brace at the lower part of the machine as well so instead of it "hanging" there is will be essentially bolted to the wall?

I think the door will vibrate off its hinges and drive you crazy in the mean time. I would probably leave it on the ground with rubber feet instead.

[Phil Vernon]

Are you going?

Jack

Hi Jack,
I hadn't really decided actually.
Got a mate down in Hoppers Crossing owns an Engraving Business that I'm gonna call to see when he's going.
I may be able to get off from work early to go on Friday, will run it pass the boss who is overseas atm.
Will pm you my mobile number.
I live NE Melbourne in the Diamond Valley...yourself?

Cheers,
Phil.

[Jack Clague]

Taylors Hill, NW, yer chuck me your number I'll give you a text so you have mine, would be great to keep in touch