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View Full Version : Exhaust hood for Shenhui SH-G1290



Andrei Georgescu
03-22-2014, 8:51 AM
Hi

I want to build an exhaust hood for my laser engraver. My plan is to weld a hood frame, mount some light panels on it and anchor it to the ceiling above the work surface. In it's center it will have a fan, then the hose will take the smoke and gasses right into the main exhaust system of the building.
My guess is the hood should be able to slide up and down so it won't bother me when I'll be arranging the materials on the work surface.
I would appreciate any opinions about how safe this system you think it might be. The factory build hood will be removed for my system to work.
Also, (please try not to laugh) are protective glasses a must while operating the machine?
I would like to minimize the risks for any accidents while using it.
I will post photos of it when I'm done and if it turns out to be a good idea maybe this thread will be useful someday.

Scott Shepherd
03-22-2014, 10:43 AM
If I understand what you are trying to do correctly, I think you'd be making a mistake trying to draw the smoke up. Right now the smoke is pulled across the top of the work area and out the back of the machine, I'm assuming. If you put the fan on the top hood, it would pull the smoke up, which would contaminate your lens and mirror within minutes of running. The smoke needs to go out, over the top of the work, parallel to the table. If you pull it up, I think you're asking for trouble. Just my opinion.

Rodne Gold
03-22-2014, 10:58 AM
Just plumb in the hose from your blower before building anything. Protective glasses only needed if you lasering with the lid up - which you should not do!!!!

Andrei Georgescu
03-22-2014, 1:26 PM
I didn't mount the exhaust yet and I think I've used the laser for about two hours just testing it. That thing you said with the smoke going up and contaminating the lens and mirror sounds reasonable. I expected the laser head blower to keep it away from the lens but the mirror would be exposed anyway.
Yep, I've been using it with the lid up :o. I was more afraid of something catching fire but now that I think about it my eyes are probably more expensive than the machine.

I know a guy who mounted the hose right on the lid of his machine (I think it's a Trotec 60/ 90 cm) and he said it's more efficient than mounting it in the back. Do all of you use the standard exhaust system?

Kev Williams
03-22-2014, 2:19 PM
Every day I watch my laser's lenses get buried in smoke and flames and sparks and every other product of the laser combustion process regardless of the exhaust. JMO but I don't think sucking the exhaust up instead of sideways is going to make much difference to the lens...

Scott Shepherd
03-22-2014, 3:17 PM
Might not change anything on those types of machines, but I'd bet my paycheck that you'll ruin a lens if you suck the smoke up on a western machine. Leave your exhaust off and see how long it lasts. The smokes going to go up with the exhaust off, and when it goes up, it cakes on the lens. Don't ask me how I know.

George M. Perzel
03-23-2014, 1:46 PM
Andrei;
I also have a big Shenhui and augmented the rear exhaust (blower is located outside about 6 feet from rear-center of machine) with three computer fans mounted on the front blowing towards the rear-clears a lot of smoke fast. They are powered by a 12 volt/110vac converter. See pic below:
Best Regards,
George
Laserartshttp://www.sawmillcreek.org/asset.php?fid=225187&uid=2842&d=1341246085http://www.sawmillcreek.org/asset.php?fid=225186&uid=2842&d=1341246083

Andrei Georgescu
03-24-2014, 3:20 AM
Can't see the pictures but I pictured the setup from your description. I will definitely give it a try myself. Thanks George!

Andrei Georgescu
03-24-2014, 2:15 PM
I cleaned the lens and mirrors today. The lens had one surprisingly big flake of ash inside and I can't figure out how it might have got there. The rest was clean. I have also mounted the standard exhaust system which seems to work well enough. I find that turbine too noisy though and somebody told me it will get noisier.
With those computer fans it should be perfect. My guess is they can be mounted on the inside of the hood. This setup should be cheaper then making an exhaust hood. It will be my first try.