Finishing the finishing room

[Ole Anderson]

Keep in mind that finishing is the final touch on all of your hard work of building a WW project. I don't know what you have invested in all of your shop tools, but if you are willing to dedicate 144 sf of shop space for finishing, don't skimp on the final product. Seal the doors and filter your incoming air source. Invest in an explosion proof exhaust fan with a filter to protect it so you will be safe no matter what you spray. Make some racking for hanging doors and small parts and rig a small rotating table for finishing boxes (I just use a swivel shop stool when I rattle can a small project). A couple of low sawhorses and plywood works for larger projects and can be moved out of the way when you are done. Well, that is what I would do if I had the room for a dedicated assembly/finishing room. Easy to spend someone elses money isn't it?

[Michael W. Clark]

If you don't want to block the window, you could install the fan on a hinged board that swings over in front of it for use, then out of the way when not using it.

Be careful with "explosion proof" ratings on fans. Fans are usually rated for spark resistance (AMCA A, B, C). The level of spark resistance has to do with the materials of construction of the fan wheel and whether or not moving parts can come in contact with each other. The motors can be rated "explosion proof". A fan cannot contain an explosion such as a NEMA 7 electrical enclosure or an XP motor, it is open at both ends!

A lot of larger spray booths use an axial duct fan with the motor mounted outside the duct (belt driven). The fan would be AMCA rated. Probably more than your looking for, but just to give you some ideas.

I would stay with spraying WB or spray solvent based with the fan off and window open. Let it vent naturally. If you turn the fan back on after spraying solven, you could have a concentration of vapors and create a less than desirable situation.

Mike

[Larry Browning]

Keep in mind that finishing is the final touch on all of your hard work of building a WW project. I don't know what you have invested in all of your shop tools, but if you are willing to dedicate 144 sf of shop space for finishing, don't skimp on the final product. Seal the doors and filter your incoming air source. Invest in an explosion proof exhaust fan with a filter to protect it so you will be safe no matter what you spray. Make some racking for hanging doors and small parts and rig a small rotating table for finishing boxes (I just use a swivel shop stool when I rattle can a small project). A couple of low sawhorses and plywood works for larger projects and can be moved out of the way when you are done. Well, that is what I would do if I had the room for a dedicated assembly/finishing room. Easy to spend someone elses money isn't it?

Ole,
You also need to keep in mind that I am not completely unsatisfied with my current setup for finishing, which is actually nothing at all in terms of keeping the air clean. Maybe my standard are not as high as yours, or I just don't know what a good finish looks like, but I don't seem to have much trouble with contaminating the finish with over spray and settling dust.
I use a good dust mask and I have a couple of ambient air cleaners in the shop. I am just not willing to spend thousands of dollars on this. The cheaper the better. I don't think I am going to make things worse by doing this.
I would rather spend my time and money on drying racks, rotating tables, storage cabinets and stuff like that. If I can improve the air quality without breaking the bank, I am all over it. But, for now, it is going to be a very hard sell to convince me to install commercial quality Expl. Proof fans and filters.

BTW: I respect the ideas and recommendations of Howard Acheson. and will listen to what he has to say when it comes to finishing. If Howard says a 20" box fan will work, I will give it try. $20 sure beats $250 not to mention not having to cut a hole in the wall of my shop.

[bobby milam]

My finishing room is next to my back door. Most of what I do are small things so I don't get much in the way of fumes building up. Like you, just having a separate room to isolate most of the dust works for me. I am going to put a storm door on the back door and use a box fan to vent it out that way when I need it. Most of my finishing, I won't even need to worry about it. I'll just put a filter on it to keep the dust from outside, coming through the screen. Keep an eye out on Craigslist though. I see some good exhaust fans come on there once in awhile really cheap. If I find a deal on something I'll grab it but otherwise, I am using the money for the same things that you are talking about doing.

After just trying to finish in the garage all of last year, I am already enjoying having someplace that I don't have to sweep up wood chips and blow out everytime I try to stain something.

[Jim Neeley]

I started reading up on this a bit. I it seems the lower explosive limit (LEL) for methanol is about 5% by volume. The LEL for more volatile solvents is closer to 1%.
Your room is about 8500 gals in size. Theoretically, you would need to have 85 gals of solvent in the air for it to explode.
The problem is: That can't be right. Remember Richard Pryor. There is no way he had anywhere near that amount of solvent in the air. The bottom line is that some solvents layer. That's what got Pryor into trouble. In our case there is the gradient of mix coming from your gun. Yet, you don't seem to read about shellac explosions or fires.
I'd still be careful about spraying alcohol into a fan that wasn't explosion proof. It's probably even safer to spray shellac with the fan off, then turning it on to vent the room.

Here's a little assistance... the LEL for alcohol generall runs from 6-6.7% by volume however this is comparing the volume of air (a gas) with the volume of methanol vapor (again, a gas). With methanol, this is about a 500:1 ratio. This means 1 gallon of methanol, if evaporated, would create 500 gallons of 100% methanol vapor or 8,300 gallons of 5% vapor. This isn't a likely scenario BUT...

The whole room does not have to reach LEL for an explosion [explosion = rapidly burning fire that may or may not cause damage]; all that is required is for air/fuel of that concentration to meet an ignition source... the larger the volume, the larger the explosion.

Using a bit of unit conversion and stuff, what it means is that if 1 oz of methanol is vaporized and equally dispersed in 58 cu ft of air, that "cloud" will be at the lower explosive limit for methanol. Whether or not an explosion occurs depends whether or not an ignition source is available in the same place and at the same time as a vapor cloud whose density is between the LEL and upper explosive limit [UEL]. The UEL for methanol is 36%.

As part of my day job I specify combusible gas detectors but as a woodworker I spray shellac, urethane and pre-cat lacquer as well as waterbourne finishes.

To date I have done my spraying outside however I will be adding a spraying station to my shop, using an explosionproof fan I picked up on craigslist for $175. It is a 12" high velocity unit and I'll be spraying right in front of the fan.

Does this mean that if I'd sprayed in my shop without the fan I would have an explosion? Not necessarily, as the vapor would have to be between the LEL and UEL in vapor in contact with a source of combustion. I also cannot say that I would not have had an explosion. I know there are people out here who have "done it for years".

Here's where my OPINION kicks in: I do not believe that if I have run 100 red lights without getting a ticket (or worse), that in any way guarantees I will not get one if I do it again.

Like running red lights, spraying flammable products (such as shellac and lacquer) in the vacinity of an ignition source is risky behavior. My next thought goes back to a quote from on of Clint Eastwood's "Dirty Hairy" movies where he had his .44 magnum pointed in the face of a criminal and said "Do you feel lucky, punk? Well, do ya?"

This is just my $0.02... YMMV.

Jim

[Steve Milito]

Here's a little assistance... the LEL for alcohol generall runs from 6-6.7% by volume however this is comparing the volume of air (a gas) with the volume of methanol vapor (again, a gas). With methanol, this is about a 500:1 ratio. This means 1 gallon of methanol, if evaporated, would create 500 gallons of 100% methanol vapor or 8,300 gallons of 5% vapor. This isn't a likely scenario BUT...

The whole room does not have to reach LEL for an explosion [explosion = rapidly burning fire that may or may not cause damage]; all that is required is for air/fuel of that concentration to meet an ignition source... the larger the volume, the larger the explosion.

Thanks Jim. I knew I was missing something and thought it was something along those lines. I tried to find it on the WWW but I couldn't.

The shop I'm building has room for a small finishing room, along the order of 9000 gals. I've been planning to find a low spark fan with an explosion proof motor. A gal of shellac may seem like a lot, but I can easily imagine scenarios where 1 or 2 liters are sprayed in afternoon. That's not nearly enough of a safety margin for me. Especially when you considered that the higher the whole room concentration the more likely there are to be areas near the gun or exhaust that achieve LEL.

The same 500:1 ratio for solvent based finishes gets you to well below a liter of spray and I assume it's actually worse. That's clearly unacceptable to me if I were to spray lacquer.

Thank you.

[Larry Browning]

I would like to shift the focus of this thread away from ventilation an on to things like drying racks, rotating tables, and other features of a finishing room.

I really like what Matt has done with his drying rack. Has anyone got other drying rack ideas? I think I remember someone mentioning a nail board. How about a finishing table? Storage cabinets? Extra lighting? In my 12X12 room I have 2 8' T8 ceiling fixtures. Is that sufficient? I also have a couple of those portable halogen light on stands. Those seem to throw shadows pretty badly, I'm not sure how helpful those would be.

[Matt Meiser]

Forgot to mention: if I was making mine again (and I might, just for this reason) I would probably buy Fastcap Fastpipe for the supports.
http://www.fastcap.com/estore/pc/FastPipe-p44266.htm

52" pieces are $3--I figure I'd need 12 of those for my 24" long arms and and 8 for the 16" long arms for a total of $60, plus 5 packs of end caps for another $10. Probably not much more than I spent on EMT, caps that don't stay on great, and covering them with black poly pipe.

Those halogen lights will heat the room nicely.

[Larry Browning]

Those halogen lights will heat the room nicely.

Yeah I know. Those may not be the best for this application. But I could turn them on only when needed. I was just worried about them casting shadows too. Since I already have them, I guess I could see how they work. It wouldn't cost me anything.

[Larry Browning]

How about some ideas for a rotating table? What would be a good height? Maybe adjustable height? What about size? How to make it rotate?

[Steve Milito]

How about some ideas for a rotating table? What would be a good height? Maybe adjustable height? What about size? How to make it rotate?

Use a Lazy Susan Bearing. They come in many sizes and weight categories.

[Michael W. Clark]

Use a Lazy Susan Bearing. They come in many sizes and weight categories.

Ditto that. I have one with the screw on pyramids. At first I skimped on the number of pyramids and had to add more, it is definitely better for support. The lazy suzan bearing is good for lighter parts or components (small projects, doors, drawers, etc.). For larger projects, something more stable would be better or place small casters on the outside for additional support. Check out some of Charles Neil's site as well.

Personally, I would put the height around countertop height. I find it easier to stand on a step stool occasionally, versus stooping down and bending over all the time. You could make the table low and use risers or boxes, but then you have to store them. All comes down to what you plan to do. I am a hobbyiest and do a variety of things. Currently, my lazy susan gets setup on sawhorses for spraying outside.

Mike

[Larry Browning]

I had been thinking about a permanently mounted lazy suzan. But maybe a better idea is to just have a board with the LS mounted to the bottom. That way it could be removed and replaced with a nail board and other things. The saw horse idea rather than a table also seems good. That way they could be stored away when working with a tall bookcase.

[Matt Meiser]

I wouldn't do anything permanent.

[bobby milam]

I went with someones suggestion to me because it was easy and cheaper than buying the wood and building my own. I went to home depot and bought the slotted metal tracks and slotted brackets to just throw a board on. I wanted some tack strips for carpet installation to use on top of the board but they only sold them by the large box full so I will have to make my own. I am really limited for space so I can't have many shelves up or they'll really get in my way and I came across this.

http://www.centsationalgirl.com/2009...m-drying-rack/

I am thinking now that maybe I will make something similar to this and use slats instead of dowels so I can put tacks through the slats to get good drying on both sides. For me something like this might work well so I can fold them up out of the way when not in use. Not sure what size things you will be using your drying rack for. If I do it I'll probably put in some french cleats so I can have spares stored and switch between them and a shelf for other things as needed.

If you find a good source for the lazy susan, let me know. I need to get a couple.