Model Boat Mayhem
Mess Deck: General Section => Other Hobbies and Interests => Topic started by: salty Nscaler on September 07, 2008, 08:38:57 am
-
Not willing to pay the price hobby shops are asking for a spray booth I came up with this little gem, its made from 1/2"BCX plywood and is 21"x24"x23 1/2" (16" to the filter)the force is a 6" in-line duct fan rated at 280 CFM both the light and fan are hard wired to a common light switch.Only thing left to do is get a 10" pine board and bore a 6" hole in it and install it in my shop window 8)
"With safety being the highest priority, we have no control over or cannot predict any loss or damage
following this post may incur, whatever they may be. This information does not necessarily reflect the views or policies of the
Model Boat Mayhem, it's owner or moderators or other forum members. They solely represent the personal opinion of the forum
member making the post. Model Boat Mayhem makes no representation concerning these opinions and does not guarantee the source,
originality, accuracy,completeness or reliability of any statement, information, data, finding, interpretation, advice, opinion, or view
represented."
-
Is your extractor protected? You may need to think about concentrated, inflammable fumes passing through it?
Stavros (Resident Paint Spraying Expert) may want to comment.
Roger in France.
-
Hi Roger, I guess I forgot about that part ! I am using a motor that is not insulated !!! I have used this type with no problem so far I think the key is making sure I do all my painting at one time and then let it run,where the problem is (as I think) is when one shuts off the unit and then turns it's back on that is when you may have an issues. 8)
-
It looks great, but how do you get your car inside it?
{-) {-)
Malc
-
My truck no longer fits in my shop I have my home layout in there and all the other projects that I am working on size wise I deal in N scale 1:160 so its way big I'm clearing a section of my shop to be the" shipyard" for when my tug kit gets here 8)
-
Excellent! I too refuse to pay shop prices and knocked my own spraying station up, for the sake of a couple of sheets of wood and some time with a drill I really don't see why any modeler would ever pay for such a thing!
Alex
-
Alex, Most of the one's I was looking at be it on-line or a shop or a catalog began base line at $299.95 then you have to buy "THERE " filters which adds up really fast, the filters I use cost $6.00 for a 3 pac.I place one in front as seen in the pic and a second one behind and then move them forward as I need to. 8)
Larry
-
Forgot the one thing this entire set up cost me $89.78 and about 10 hrs labor 8)
-
Salty Nscaler,
Could of done with that this morning. Varnished my boat and primed a stand for it. What a stink and took a while to come down from ceiling!!
Cheaper then booze though.
Ron.
-
Hi
I used a free cooker hood that was being throw away.
Boxed in and lead outside worth it weight in gold.
If using spray cans put a filter in front and be ready for
a shock at the amount of paint it collects.
Dave
-
All I can say is ARGH
IT IS AN ACCIDENT WAITING TO HAPPEN
It does not matter one bit that you have switched everything on before spraying,you have and by your own addmission are using and I quote I am using a motor that is not insulated!!!!!!!!!!!!!Not only that but I would hazard a guess that the light is not vapour proof as well.
IN MY PROFESSIONAL OPINION IT IS A TIME BOMB STOP USING IT BEFORE YOU GET SERIOUSLY HURT.
If for any reason it exploded and burnt you house down or shed well it's BY BY INSURANCE.
If anyone is planning to copy this well my advise to you is DON'T...............BUT if you do well buy a totally vapour/gas proof Fan and also a Proper Flame proof light they are available but expensive,but is your life worth it
Stavros
-
Well put Stavros,
I am an operator of grinding machines and it still amazes me just how many people buy a hand-grinder (bench-top grinder), and use them in totally the wrong way. Blunt wheels, heavy side-grinding, no guards, no eye-protection, hands too close, etc, etc.
Pity brains (including my own) do not come with automatic health warnings!!
Ron.
-
Hi
As A spraybooth engineer for my living, I can see why you should NOT use this. However if you like big BANGS then carry on. You need proper sealed to current standards motors, Flash Prof light fittings, Flash prof electrical switches. You then need proper dry extraction filters. the cardboard filters DO NOT meet the EPA standards. The ext duct need to go out through your roof and must be 3 meters above your roof. Your plastic fan will melt when the solvent fumes come into contact with it. I could go on but I'm not going to. IN SHORT DON'T USE IT.
-
Hey Everyone,I would like to thank Roger,Stavros and Martin for your input its all good guys 8)
-
Hi Dave, a few guys I know that model in N scale have built a rig like your chatting about most built a plywood box fitted it on top and used a different filter system and vented it also 8)
-
PLEASE oh PLEASE at least change the fan to a bifurcated type, this means placing the 'impeller' in the airstream BUT THE MOTOR OUTSIDE OF THE AIRSTREAM, either by 'Vee' belting the impeller to the motor, of (bifurcating) split the airstream to go around the motor on either side
>>:-(
-
The Regulations governing explosive atmospheres are here:
http://www.hse.gov.uk/fireandexplosion/atex.htm (http://www.hse.gov.uk/fireandexplosion/atex.htm)
The Regulations mainly relate to an Employer's obligations, but there is a PDF about halfway down the page which explains hazardous area zoning - It doesn't really matter whether an employer is involved or not, the same principles apply (to keep the user healthy/alive).
Cellulose dust in suspension in an enclosed air space like a spray booth will likely be classified as a Zone 1 area (I'd have to do the calcs to confirm) - the equipnent within that space would in that case either have to be intrinsically safe (insufficient power to generate a spark), or incapable of transmitting the volatile atmosphere to any apparatus within the hazardous atmosphere which might be an ignition source.
Open frame fan motors are CERTAINLY a no-no, as would be all uncertified lighting fittings and switches.
Malc
PS - Sorry I didn't pick up on this in an earler post - I hadn't imagined that anybody would construct anything so potentially dangerous...
(I spend most of my days at the moment doing hazardous area classification studies in the petro-chem industry - currently working on Ethanol blending on BP supply terminals across the UK).
-
Would 1 or 2 computer 80mm 12volt fan be a safer idea?
-
Hi Martin,I am using a 120 volt fan motor now that you said that I could take my old modem about and pull out the fans sounds like a good winter project I like I need more.To bad I didn't hook up with you guys when I lived in Scotland would have had tons of boats going back cross the pond 8)
Larry
-
I went to bed last night thinking about how this spray booth could be made safe for use without spending the sort of money on it that the correctly rated fans/lighting/switches would imply.
The solution isn't pretty. Mind you, neither is the present arrangement, but this would be a LOT safer to use:
1) Turn the whole box around so that what is presently the air intake filter effectively becomes the exhaust, venting the booth through the window.
2) Fit another smaller filter over the circular duct (now in the workshop).
3) Re-install the fan so that it pushes fresh air INTO the booth, rather than pulling spray particle-laden air through the fan.
4) Remove ALL electrics/lighting from inside the booth.
5) Make a cut-out in the roof (or side) of the booth and install a gasketted sheet of clear perspex/acrylic to form a window.
6) Mount the light fitting OUTSIDE the booth, shining it THROUGH the perspex window to illuminate the inside.
This way, the electrics are taken out of contact with volatile vapours within the cabinet, but it should still only be used with extreme care.
7) Don't try to hold me responsible if it all ends in tears.
Regards,
Malc
-
Hey Warspite, You know that would be a easy fix I could cut a new pc of ducting then open one side place the motor to the right and mount the fan inside the ducting.Knowing me being a pack rat I may have a fan motor laying around one of the sheds,living on a ranch in the boondocks you learn not to throw anything away thanks again! 8)
Larry
-
Salty
It occurs to me that your having quoted costs for this project in dollars that you are 'across the pond'? When I made my main post on this thread, I incorrectly assumed that you were in the UK and quoted a link to the UK Government Regulations. Please accept my apologies.
As I understand, the American Regulations for explosive atmospheres are pretty much the same as ours here in the UK, and it is VITAL that you separate the electrics from any contact with the vapor (spelled your way) created by spraying.
To give you an idea how dangerous volatile gases can be: (and this is hilarious):
My old boss, Dick Harrison, now long gone, bless him, had renovated his kitchen and moved the gas cooker from one side of the room to the other. He had run a copper gas pipe under the new floor with the end sticking up in the new position.
He tried to re-connect the cooker but found that the new gas pipe was too long, so he cut it off with a hacksaw. Copper filings went down the pipe as he cut it off and he wanted to remove these befiore making the final connection. He tried to blow the filings out by turning the gas on, but the flow rate wasn't high enough.
His next move was to use the vacuum cleaner - an Electrolux cylinder model. He put the hose nozzle over the end of the gas pipe and switched it on. The vacuum pulled the residual gas from the new copper pipe into the vacuum cleaner. As the gas hit the motor, it exploded and he was left holding the vacuum hose still connected to what was left of the plastic end cap of the Electrolux.
The remainder of the vacuum cleaner flew down his hallway and demolished his front door. The Electrolux cylinder tube was found in the street, with the ends peeled back like a banana.
(Can you see why we're all concerned for your safety)?
Malc
-
Malc, Hey your good not to worry about it.In the UK you run gas Thur copper ???? and he used a hacksaw instead of a pipe cutter sorry to hear that he passed. Over here we must run it thur black pipe?? now that is scary even to me but let me take this time to thank you and all for pointing out that this is not the best way to shoot paint 8)
Larry
-
Re this Spraybooth. DON'T DO IT. It's a Bomb that will go off. Buy one it is cheaper then your LIFE. I don't want to tell your WIFE you are dead :o :o
-
I have been reading this with interest and agree that this setup is very dodgy. There could be another way of creating a vacuum in a tube using some primitive and basic components without having any of the ignition sources in the airstream. I created a venturi effect using a vacuum cleaner set to blow rather than suck and the airflow was pretty fierce. I took a straight piece of pipe, one end of which was connected to the 'blow' pipe of the machine. Half way along the pipe, I cut a hole and fed another pipe into it at a very shallow angle so the whole thing looked rather like the letter'y'. As the air rushes down the long pipe, it creates a partial vacuum in the added angled pipe and this way, none of the fumes were in anyway in contact with the electrical potential for fire. It worked but I have no doubt it would not conform to any stringent safety rules found in this modern world.
The beauty of this system is that the source of air pressure (vacuum cleaner) could be remote from the area of work and also of exhausting fumes. The only hazard I could forsee at the time was the possibility of the cleaner motor blowing up and in a disaster scenario sending a giant ball of flame hurtling down the pipe at the exact moment I was spraying and at the exact moment the vapour concentration in the pipe was at the exact air /fuel ratio sufficient to cause some kind of backfire. For the amount of spraying I as a modeller ever got through I figured it was safe enough for my purposes. As an added precaution, I did earth the metal pipes to prevent static build up and possible electrical discharge as this can be a real hazard in high speed airflows.
I just know you chaps will condemn me to death for this one...Stavros, do your worst.
-
Sorry if I offend, I don't mean to, but it appears you aren't listening, even I can tell you this is madness.
The advise of everyone here is not to use it, PLEASE DON'T USE IT, you would probably be better off not using a box at all, and that's not adviseable either.
I was lucky, I was given a box, but it's well worth buying one.
Andy
-
Interesting. It never ocurred to me that a hobbyist would actually consider buying a special booth rather than knocking up a quick bit of plastic sheet as required. However I can see the attraction if only I had the room. Your set up looks ok to mee though not sure how I'd fit a 4 ft boat in there.
From picture 6 it looks like there is an arrow showing direction of air flow out the back of the box and down the duct. Surely it was never the intention to blow the fumes inwards into your face, so why bother with a filter? You are not producing industrial quantities of effluent. The whole idea is to whoooosh the fumes out. Unless you decided to point the spray straight at the motor the vapour concentration would be very low so not a problem even if it weren't a shaded pole induction motor see picture 4, - the kind that doesn't make sparks anyway. Vaccum cleaner motors are different because they need to go hell for leather and make a racket. All small domestic fans will be induction types but if you get a bit bigger as is being suggested they will also have starters that do produce a single spark one second after turn on.
If you are still put off you could mount the fan in the other side of your shed pointing IN - it would then get far more use ase a cooling fan on hot days, and provided the rest of the shed is airtight all the air will still go out through your box. I think RM suggests that.
Although American screw light bulbs can be made to produce sparks unlike nice safe British bayonets I would have gone with Reade Models suggestion of external light just 'cos it's cheaper to move one of my anglepoise lamps over temporarily. The older Fluorescent light starters also do produce a spark on turn on only.
Personnaly I spray outside but if there is no wind to clear the fumes have an 18 in centrifugal driven by a 1.5HP sealed motor - woodworker extraction type. I have to issue a tornado warning before turning that on !
-
I just know you chaps will condemn me to death for this one...Stavros, do your worst.
Stavros is busy on another thread so I'll do it...
Nobody will blame you for experimenting, and risk killing yourself - providing they are all a safe distance away! The important thing to understand is that gases/vapours and sparks from electrics/motors DO NOT MIX. Fans and vapours in combination are LETHAL.
Unless you've ever been mixed up in a real explosion, you can't begin to imagine how truly terrifying they are....
I've been involved in a few, in the early 70's I was on deck of the Liverpool ferry in Belfast harbour immediately opposite a large building that was blown up, got thrown back against the bulkhead when it went off in front of me. Another IRA bomb outside a cinema in Birmingham a year later - blew the windows out of my hotel bedroom. I'd wallked right past the bomb a short while earlier. I was working in Manchester on the Saturday morning that they blew up the Arndale Centre. In Feb this year we had a gas explosion in our caravan which caused major damage and scattered parts of the flue over a 150 yard radius.
My only interest in contributing to this thread is to try to get EVERYBODY who reads it to act responsibly, and be very careful. DON'T MESS WITH FUMES AND FANS The last thing that any of us want is to see is somebody badly injured - or worse.
Malc
-
Malc , from your last post do you come with a health warning, It seems that its not safe to be around you.. {-)
-
Me? Safe as houses...(said he, not wishing to tempt fate).
It's the ones that didn't make it that you needed to keep well away from {-) {-) {-)
Malc
-
Blimey Malc, you're in more danger going about your daily business than I have ever been whilst experimenting!
-
Since they didnt make it, there no point in keeping away from them - unless there decomposing gases are a danger ;)
Heres a point - most, if not all, paint extraction booths consist of a box with a plenum attached, covering the passage from the box to the plenum is a matt of filter media to entrap the larger particules of paint, most lighting is kept external and passes through the perspex windows (may need to be replaced over time to keep the illumination up to acceptable levels).
Now, connected to the plenum is a duct system, in which a Bifurcated flow fan is fitted, this ensures that the motor is not in the airstream, some in the past have used vee belted axials, where the impeller is on a shaft, which is pulley driven to the outside to the motor sited on the outside of the casing, the pulley arrangement is enclosed in a box with bearings to hold the impeller shaft.
It may not have occurred to anyone yet but this arrangement is used quite extensively in Model Boating.
A BOW THRUSTER ;D
Dont have the fan motor in the duct, make it a bow thruster and save the effort of building a bif or vee belt axial, for all our sanity
-
Hi Warspite
You are absolutely correct.
My earlier suggestion to Salty in America was based on the concept of pushing fresh air into the booth and not sucking volatile fumes through the fan, but a bifurcated fan system would do the same job providing the motor is sited well away from fumes in a non-hazardous area. Other electrics moved to a safe area outside the booth.
All this talk of 12V fans and screw-in light bulbs is a nonsense (no disrespect to previous contributors). Screw in light bulbs are just as perfectly capable of generating a spark as bayonet types - as is a 12V fan - just try shorting a 12V battery to see the sort of effects you can get...What is forgotten is that even a dangerous system can work well - until a fault develops. Good design caters for the fault situations as well as normal operation.
In industry, intrinsically safe circuits are mostly 24V DC (analogue 4-20mA or digital on/off), but the available power in the part of the circuit located in the hazardous area is limited with zener barriers (Google Pepperl+Fuchs) to the point where the circuit is incapable of generating a spark - it's handy actually, because if you're commissioning (as I often do) or maintaining instrumentation in these areas, you can quite happily do it 'live'. All of these circuits and the drawings for them are fully certified by the way, and nobody is allowed to work on them unless qualified and authorised to do so.
The first principle of locating electrical circuits in hazardous areas is DON'T - unless you really have to. Only then, firstly resort to intrinsically safe circuits before looking at other methods. If power is needed, flame proof/explosion proof/sand filled equipment is often specified. Explosion proof equipment is heavily built - not to withstand an explosion, but to allow large mating surfaces which prevent 'flame paths' of volatiles approaching the ignition sources inside.
Sorry to have bored you with this lot... I shouldn't bring work home.
Malc
-
So what do you think of the bow thruster idea, as long as the motor is quite a distance away to prevent leaking / localised gases from effecting the motor ;D ;D
-
I'll be installing one soon in my 54 inch long French harbour tug - thought I'd turbocharge the little blighter and see if I can get it to do wheelies. {-) {-) {-)
Malc
-
Unless you've ever been mixed up in a real explosion, you can't begin to imagine how truly terrifying they are....
I've been involved in a few, in the early 70's I was on deck of the Liverpool ferry in Belfast harbour immediately opposite a large building that was blown up, got thrown back against the bulkhead when it went off in front of me. Another IRA bomb outside a cinema in Birmingham a year later - blew the windows out of my hotel bedroom. I'd wallked right past the bomb a short while earlier. I was working in Manchester on the Saturday morning that they blew up the Arndale Centre. In Feb this year we had a gas explosion in our caravan which caused major damage and scattered parts of the flue over a 150 yard radius.
Malc Reade, the Kate Aide of model boating. :o
If you see him coming, run {-)
-
OK - that's you stuffed for the figures competition... {-) {-)
Malc
For the Tech-Heads amongst you:
http://www.pepperl-fuchs.co.uk/cps/rde/xbcr/great_britain/ATEX_Poster_ENG.pdf (http://www.pepperl-fuchs.co.uk/cps/rde/xbcr/great_britain/ATEX_Poster_ENG.pdf)
-
OK - that's you stuffed for the figures competition... {-) {-)
Malc
Hey I don't mind.
But Steamboatphil will be bricking it next show. {-) {-)
-
Good Morning All, sorry for the time lag be we are a few time zones apart.I have read all your input and I do thank you all I'm going to try and cover all bases in one shot.The fan motor is a in-line duct fan and will both blow and draw air depends on how you mount it,Yes I know the danger but I find it hard to think that ever person that models is using the proper type.I goggled " home made spray booths and found over 10,000 sites ans yes I know it does not make it right and all list warning about building them,it was not built for shooting paint on my first tug it is way to small I'll shoot that either outside or at my friends shop who is a welder and yes he's has a "real" spray booth.I like the thing about the bow thruster but I can't even find a RC boat club over here close to where I live so I'm sort of on my own, and yes I've been blown up myself happen in Edzell,Scotland 1985 I really didn't think I would have opened a can of worms here just wanted to share and yes my tug is ordered and now I'm waiting for it to get here 8)
Larry
-
Hi
I used a free cooker hood that was being throw away.
Boxed in and lead outside worth it weight in gold.
If using spray cans put a filter in front and be ready for
a shock at the amount of paint it collects.
Dave
That sounds an excellent idea!
-
As my main hobby is the building of guitars I can say that the finish of choice is still nitrocellulose lacquer. If you are spraying this stuff you most definitely need an explosion proof fan and spark arresting electrics. Without them you are on borrowed time. You may get away with an ordinary fan IF the motor is not in the path of the fumes and if you are using ordinary motors then you would need a squirrel cage blower so that the motor is far enough away from the fumes.
I am experimenting with some of the waterbourne finishes and they have come a long way towards replicating the nitro finish although the end result is not as hard as nitro. With this stuff you will get away with ordinary fans.
I have the added difficulty of maintaining humidity - which is a guitar builders worst emeny - plus maintaing temp at around 68 deg F. although this has more effect on finishing than building.
A dehumidifier works well with a properly insulated shed but the heating is still a problem particularly with regard to cost
-
When I built my spray booth I used a 12volt fan from a marine chandlers .
These bilge extractors are used to remove the volatile and explosive fumes generated by fuel or leaking gas cylinders from the bilges of small boats, the 12v supply is from sealed lead acid batteries which are always to hand. The fan is approx 4" diameter means you can use the ducting from a tumbler drier to pipe the flow outside.
My spray booth is collapsible to save space when not in use and the sides top and cover (to keep the dust off after finishing) are all made of perspex so no need for internal lighting. TAt the back of the spray booth, forming the front the plenum chamber is cooker hood material to act as a filter. But after using it for quite a while it is noticible that the pipework is discoloured by the spray. Evidently the filter material is not good enough but shows the extractor is working OK and as I really only use oil based paints the system must be working as I'm still here and haven't disappeared in a cloud of of smoke - yet!
Les Jones
-
Hi Les, Sounds like you have a great set up there, I was playing with the idea of Plexiglas but never follwed Thur on,I have been checking the both the duct and fan and have yet to find any paint spray on any surface and there is no paint resdue on the rear of the filter as of yet. 8)
Larry
-
Les,
Any chance of a pic of your spray booth?
Ian
-
Hi Ian,
I hope that the attached photos help.
The overall size of the box closed is 600mm x 470mm x 150. When open the booth is about 585mm wide x 520mm High and 500mm deep. The overall sizes were decided by the depth of the bench and storage space. It is made of 6mm MDF and 6mm Perspex. Most of the materials I had to hand and only bought the piano hinges. These had to be modified by drilling out the holes to suit the M4 countersunk bolts and then countersinking the piano hinge by hitting the bolt into the hole with a backing piece drilled and countersunk, this should be visible in one of the photos.
Other photos show:-
The box packed away for storage.
The fan, the “elbow” was made using some of the ducting; the photo inside the ducting shows the paint residue which means the filter media is not working that well. I think I’ll have to find some of the paper type material used in proper car spray booths.
The sequence of putting it together.
The front lid is in two pieces which fold back on top of the box when spraying.
At each side there is a butterfly bolt which screws into the Perspex and holds it all rigid
A short section of aluminium angle to hold the side in place, there are actually two pieces to sandwich the side the top when it is in place
The base of the right hand side Perspex has been lifted up by 6mm so that when it folds down it lies on top of the left hand side.
The top double hinge was necessary to make enough space in the box for the bits to fold into.
Its doing me very nicely at the moment the only thing is it’s never big enough to do the hulls of models so they still have to be done elsewhere either the garage or outside. One small thing that I did realise before I built this spray booth is that the larger the area behind the object being sprayed the higher the volume of air/spray you must extract, guideline figures can be found on the net. My Attwood fan seemed to be just about capable of the area I decided on.
I hope this helps.
Les
-
So my cardboard box with a plastic bag over it is ok then?
-
Hi Les,
You unit look the business any chance you could produce a plan of you unit for the rest of us to copy?? :-))
-
It's a brushless motor isn't it?
There shouldn't be any sparks...
:((