paint booth ducting

[paintdaddy]

I got a pre fab paint booth installed in my new shop finally but still need to run the duct work.The sales rep recomended running it straight up through the roof but the directions say one bend is possible with the standard motor that comes with the booth.I would like to go out the side of the building.My question is if I made a 90 degree turn will it cause too much turbulence in the pipe or do I need to use a 45?

 

[Darren M.]

If you don't get your answer here you might want to try it at www.autobody101.com. (Not to push you away, just to give you another venue.)
IF, you do find your answer at another location do me a favor and update this thread. I'd be interested in the answer or simply a link to where you question was answered.
Good luck.

 

[bmwpower]

I consider one bend to be equal to 90 degrees.

 

[Uncle Buck]

I look at a lot of paint booths throughout the our state, and I do not think one 90deg bend should be a big deal.

 

[JayB]

Can you go through a side wall? I helped my buddy with this. http://gallery.intlwaters.com/thumbnails.php?album=208
Core bit went through it like butter.

 

[paintdaddy]

Yep,thats what I want to do is go throught the outside wall that is directly behind it.Jay I see you guys used a 90 in the one you built.From all the advice Ive gotten here and on the other site I think thats what Im going to do.The other advice I was getting ,I think was over analyzed,if ya know what I mean.I was told it would cause a backdraft or whatever you want to call it directly in the 90 bend,thanks for all of your help.

 

[danski0224]

Just be aware that the effective length of an elbow made for spiral pipe is going to be much shorter than the same fitting made for traditional pipe. Spiral duct elbows can also be had with short or long radius throats, depending on size (diameter).

The vent instructions may also state the minimum length of straight ducting that must be connected to the booth before the elbow.

 

[Darren M.]

Couldn't you add a fan at the top/end of the duct to induce negative pressure effectively PULLING the air out? That coupled with positive flow of your initial fan should over come any back drafting.... wouldn't it???

<---- NOT a fluid dynamics expert, nor did I stay at a Holiday Inn Express last night.

 

[paintdaddy]

Couldn't you add a fan at the top/end of the duct to induce negative pressure effectively PULLING the air out? That coupled with positive flow of your initial fan should over come any back drafting.... wouldn't it???

<---- NOT a fluid dynamics expert, nor did I stay at a Holiday Inn Express last night.

I thought of that also .I think Im going to run with what Ive got and if I have problems,Ill add a fan at the end of the duct.

 

[ChevyRestorer/C3]

In my job we run Vacume lines 2"- 3" to printing presses as Well as high pressure compressed air. The press manufactures state that it is better to use two 45 degree elbows as opposed to one 90 degree elbow. Their train of thought is that there is less restriction when making the turns with this setup which yields less pressure drop (only on the vacume side). I would think that this theory would apply to your set up as being less restrictive as to use one 90 turn. Just something to think about.

 

[car-nut]

You will not have a problem running a 90 degree bend. For the best possible performance from your fan as far as air flow is concerned you should go straight with NO bends. It is said in the autobody /painting world that any bend will cut down on your fans efficiancy, about 30% reduction in air flow. I have been a painter for 10 years and have sprayed in alot of booths. I was the painter at a Chevy dealership that had a 90% bend in the ducting. It worked fine. If you were planning on doing high production painting you might want to rethink it. But if you are spraying only one car a day or less you will have no problems at all.
Good luck, I hope I was somewhat helpfull

 

[paintdaddy]

You will not have a problem running a 90 degree bend. For the best possible performance from your fan as far as air flow is concerned you should go straight with NO bends. It is said in the autobody /painting world that any bend will cut down on your fans efficiancy, about 30% reduction in air flow. I have been a painter for 10 years and have sprayed in alot of booths. I was the painter at a Chevy dealership that had a 90% bend in the ducting. It worked fine. If you were planning on doing high production painting you might want to rethink it. But if you are spraying only one car a day or less you will have no problems at all.
Good luck, I hope I was somewhat helpfull

Thanks guys,Idont plan on doing any production work so I think this will be good also.I have worked in alot of booths also but for some reason never cared about the duct work until now,thanks again.