Britbike forum

Classic British SparesKlempf British PartsBaxter CycleThe Bonneville ShopLowbrow CustomsGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supplyJob Cycle

Upgrade your membership to Premium Membership or Gold Membership or even Benefactor


New Sponsor post
Triumph 650/750 High-Output Alternator Kit
by The Bonneville Shop - 01/13/23 11:29 pm
New FAQ post
Missing edit button
by wrench136 - 05/30/22 2:57 pm
News & Announcements
Premium members! 🌟
by Morgan aka admin - 01/31/23 2:14 pm
Buy BritBike staff a coffee ☕️ or pint 🍺
by Morgan aka admin - 01/15/23 9:29 am
Benefactor ✅
by Morgan aka admin - 01/08/23 8:38 pm
Gold members! ⭐️ ⭐️ ⭐️
by Morgan aka admin - 01/03/23 6:30 pm
How to guides - Technical articles
British Fasteners Specs
by Morgan aka admin - 01/03/23 1:29 pm
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Member Spotlight
TR6Ray
TR6Ray
Illinois, USA
Posts: 2,675
Joined: May 2010
Top Posters(30 Days)
Lannis 77
DavidP 74
Top Likes Received (30 Days)
Kev. 36
DavidP 25
Newest Members
BSA A65 rebuild, Dan Haggard, Padsdad, sam keller, Raz
12,386 Registered Users
Forum Statistics
Forums35
Topics76,525
Posts783,968
Members12,386
Most Online204
Jul 10th, 2022
Random Gallery photo
Photo posting tutorial

Previous Thread
Next Thread
Print Thread
Page 24 of 58 1 2 22 23 24 25 26 57 58
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by quinten
I know it's just a shed , but i looks like if you don't care , which is different than you don't know any better
It's outside the snake-proof fence that surrounds 80% of our property so it's in no-man's land where no one but me (and 10,000 Britbike subscribers...) ever will see it. Typically, I only go back there a few times a year, to check the inlet filter on the water harvesting tank or to get some fencing wire my wife needs for a gardening project. The shed is only a means to an end, i.e. being able to paint my Vincent so I can get back to restoring it (plus other bikes in the future). Time spent making it look professional for the customer is time wasted because, as you suspect, the customer doesn't care. All that matters to the customer is that it's functional, which means what's important is being able to seal it well, and install an appropriate system for flowing dust-free air across the parts being sprayed.

Originally Posted by quinten
is the floor area larger the the shed footprint ?
Yes, the plywood is 6'3'×8' while the shed is supposedly 6'2"×7'11". I say supposedly, because it's centered on the plywood and just from the last photograph alone it's clear there's several inches of exposed plywood outside the edge of the shed. The actual dimensions to the farthest edges of the Al base are 6'1"×7'7", so 5" shorter than the following drawing shows.

[Linked Image]

However, what matters for me are the inside dimensions, and the ones claimed come within about an inch of what I measured them to be.

[Linked Image]

Originally Posted by quinten
If your gravel allows for longer pegs to be driven this will aid against uplift
It's always a crap shoot when driving stakes into the ground around here, because sometimes they'll go as deep as wanted, but other times they'll encounter a large rock before they're deep enough. One of my stakes hit such a rock with ~1" left to go. That's the reason I mentioned a few more stakes at 45°. I'll cut some rebar longer than needed, pound it in as far as it will go, and if I hit a rock early I'll cut it off near the plywood and pound in another.

As can be seen, I've made some progress with my part-time work on it today, despite working alone.

[Linked Image]

Already it's together enough that I can tell it is an excellent size for what I have planned for it, and that I will be able to completely seal all the seams with caulk (although, how I will sealing the doors is still an, ahem, open question).

I made progress despite some holes not being aligned correctly (not the worst example, since part of this hole is actually visible).

[Linked Image]

Also, I've encountered a few holes that were pre-stripped, conveniently saving me the effort to do that myself. And, the reason for the sagging bar across the top of one of the above photos is they compensated for the stripped holes in some places by not remembering to any drill holes in others, like that bar.

[Linked Image]

When encountering something like this, odds are it means I have the wrong part, or I installed it backwards or upside down. But, no such luck in this case, since there aren't holes anywhere in that bar.

I'll have to drill the holes myself, which won't be as easy as it might sound since they need to be in the correct locations in order that all the panels properly fit together with each other. If I drilled each hole just a few mm from where it should be, by the time I worked my way across four side panels the last one would not mesh with the corner panel.

1 member likes this: NYBSAGUY
Support your #1 Vincent Forum
Joined: Nov 2016
Posts: 427
Likes: 201
Britbike forum member
Offline
Britbike forum member
Joined: Nov 2016
Posts: 427
Likes: 201
You need a lot of clamps. Just hand clamps, but plenty of them. A few clamps will be your second, third, fourth helpers all in one. They can can hold things while you drill, and everything else besides.

1 member likes this: gunner
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by NYBSAGUY
You need a lot of clamps.
I have lots of clamps, but it turned out to be easier than I feared to drill the holes where they needed to be without any assistance. So, the holes are drilled and the panels are attached.

[Linked Image]

Thanks to the wide-angle lens on my iPhone I didn't have to step into the worst of rattlesnake country to take the photograph. I hadn't realized until I stepped back to take the photograph that the grey of the shed is in keeping with the color scheme established by the water harvesting tank, so the wildlife won't be subject to clashing colors that they might find offensive.

I quit for the day and took the photograph when I got to the door jambs and, again, found no holes where holes need to be. Or, where I think holes need to be. Careful consultation of the inscrutable pictograms at the beginning of the day tomorrow may reveal important information I overlooked. But, at this point the basic first floor structure is together and it feels sturdy enough as-is to withstand a reasonable breeze tonight, of which there isn't supposed to be any, so what remains are the doors and attic.

2 members like this: gunner, NYBSAGUY
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
With construction of the shed slowly nearing completion, I've been spending more time thinking about air flow. Ideally, one entire wall of the shed would be the inlet for filtered air, and the entire opposite wall would be the filtered outlet. What I need to devise is the minimum acceptable approximation of that flow, requiring the least possible complexity for the ducting.

I hope to use a fan I already have.

[Linked Image]

Obviously, if this fan were a few feet away from a part and aimed directly at it, the air flow would be more than sufficient.

The open area of the fan's outlet is 20.5 in.2, which is equivalent to a pipe of diameter 5.1". Conveniently, a stock piece of A/C ducting fits snugly over the rectangular outlet of that fan, exhausting it into a 6"-diameter pipe so this ducting adds no resistance to the air flow.

[Linked Image]

Another stock piece of A/C ducting with an 8"-dia. inlet holds 10"×10" filters, which are available in all grades of filtration up to HEPA, so an 8"-to-6" reducer would mate it to the fan.

[Linked Image]

With an area of 100 in.2 I wouldn't expect the filter to represent too much resistance to air flow from the fan, but that has to be checked. The main question, though, is if air from the fan that is inlet at one side of the shed through a single 10"×10" filter, and outlet at the other side through another 10"×10" filter has sufficient velocity over a wide enough area to carry the spray away.

[Linked Image]

[Linked Image]

Clearly, flow could be split to a second inlet filter at some distance, to be determined, from the first, or "wings" added at the filter to direct part of the flow upwards and downwards, or a more complex diffuser constructed, or a more powerful fan used at the inlet or outlet. But, no matter what, experiments are needed in order to know what the air flow will be before cutting any metal from the shed. Luckily, I have the technology to conduct those experiments.

[Linked Image]

A 1 mph breeze (5280 ft/60 min. ≈ 1.5 ft/sec.) seems like it would be sufficient to carry the mist away, but that will be easy to confirm with a spritz of paint from a rattle can after I map the air flow distribution. Stay tuned.

p.s. HVAC people can jump in to point out that I don't know what I'm doing. But, we already know that...

Joined: Mar 2019
Posts: 1,470
Likes: 426
Member
Offline
Member
Joined: Mar 2019
Posts: 1,470
Likes: 426
Quote
and outlet at the other side through another 10"×10" filter
A question from another non-HVAC type.
What is the point of filtering the outlet?
In my mind that filter would clog up in pretty short order.
How about a 90 elbow around which is tied a large burlap bag?


1970 T120R - 'Anton'
1970 Commando - 'Bruno'
1967 T120R - 'Caesar'
1972 Commando - 'Big Red'
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by Hugh Jörgen
What is the point of filtering the outlet?
Even if I didn't plan to have the outlet aimed directly at the back wall of the garage I would filter it. For one thing, it will keep scorpions and snakes from coming in while I am working. I'll cap the inlet and outlet at times when I'm not painting, but there only will be a positive pressure inside the shed when the fan is on and doors sealed, so the outlet filter also will be useful during transition times when I'm firing up the shed prior to starting to paint. I bought fairly coarse filters for the outlet so they shouldn't clog very fast.

Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by Gordon Gray
Shouldn't you NOT be listening to painters about proper air flow in a spray booth?
I welcome input from anyone who has relevant advice to offer on any aspect of this. That said, in my half-vast experience most painters have experience using spray booths, not designing them.

Joined: Feb 2019
Posts: 1,367
Likes: 489
Britbike forum member
Offline
Britbike forum member
Joined: Feb 2019
Posts: 1,367
Likes: 489
Originally Posted by Magnetoman
With construction of the shed slowly nearing completion, I've been spending more time thinking about air flow.......
You've probably already thought of convection effects, ie hot desert sun heating the building resulting in hot air inside that wants to rise, but just in case, maybe locate the inlets lower and the outlets higher so as not to be fighting the natural convection forces.

But the other effect to consider is the cooling effect of the spray gun discharge, both the expanding air and the evaporating solvents. But it's probably not a factor. I have a feeling your hot desert sun will overpower that one.

Joined: Aug 2001
Posts: 6,176
Likes: 301
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 6,176
Likes: 301
I grew up in a village that had two paint booths withing a mile or so, one was a small car size booth with a 1 foot extractor, the other was a truck/coach builder with several 2 foot fans, on the outside walls of the booths it was obvious what colour had been just painted, you better keep plenty spare filters. I never got inside the big shed, but the smaller one I kicked around in , it stank strongly of thinners and the walls were mostly red lead runs.



Years later working in underground chambers which had stuff to be painted I got very used to dealing with LEV, Local Exhaust Ventillation If you mix paint in that wee shed without a forced clean air helmet on and good LEV you will suffer. fans and filters can be too small, but never too big.
A good number of the painters who turned up for pipelines and other tight squeeze jobs seemed to have just come from jail, I think you are way too overqualified to paint.
Just a qualifier, I am not a good painter, but had lots of fumes to avoid, the pipeline guys had air fed helmets with portable oxygen re breathers if the helmets were dropped.
In my working time the only contractor I had to get an ambulance for was a painter.
You might want to enlarge the intake louverage to avoid still pockets.Snakes permitting.

Last edited by gavin eisler; 04/04/22 10:33 pm. Reason: Qualifier

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
1 member likes this: NYBSAGUY
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by gavin eisler
If you mix paint in that wee shed without a forced clean air helmet on and good LEV you will suffer.
Maybe you missed it, but I bought a force-air respirator for this escapade.

[Linked Image]

Originally Posted by gavin eisler
A good number of the painters who turned up for pipelines and other tight squeeze jobs seemed to have just come from jail, I think you are way too overqualified to paint.
Are you suggesting I need to spend some time in jail before I'll be qualified to start painting? I've had a couple of speeding tickets, and was detained for an hour by the Saudi police -- does that count?

I'm sure I wrote the following somewhere before, and at the risk of offending someone, but a few decades ago when I was looking for a painter for the Vincent my then-technician said there was a sweet spot with painters, after they'd had enough experience to be good at the job, but before the fumes destroyed their brain cells.

Joking aside, keep in mind that I'll use the booth infrequently, maybe an hour at a time when I do, and always with protective gear. I know I'll be better protected from paint fumes than the majority of people reading this who regularly use rattle cans to paint something or other.

Originally Posted by Stuart Kirk
ie hot desert sun heating the building resulting in hot air inside that wants to rise.
Given the small size of the shed I'm not sure hot air will rise, because during the day the entire inside will be so hot that I expect convection currents to keep everywhere inside at a constant, very high, temperature. During the summer I'll paint at night, after the temperature has dropped enough that the walls of the shed have stopped glowing.

Further progress on the shed today resulted in the roof being mostly attached.

[Linked Image]

I was able to install those panels from the inside by standing on a small step-stool, but I'll have to bring a taller ladder to the construction side to install the final two panels on each side from the outside. There are other pieces yet to install so it's not as close to being finished as it might appear. Also, I have fewer than half the screws holding the panels in place so the remainder still have to be installed. However, that should go faster since I can use my electric drill for most of them.

Joined: Sep 2004
Posts: 2,092
Likes: 329
Britbike forum member
Offline
Britbike forum member
Joined: Sep 2004
Posts: 2,092
Likes: 329
I was speaking to my brother about this who is in HVAC sales for offices rather than spray booths and his thoughts were as follows:-
- you need to determine the CFM capacity of the inlet fan and match it with the room size. If you wanted the air changed every minute, then a fan with 100 CFM would be about right, given the size of your booth.
- you might want to create positive air pressure in the booth, rather than negative, so that dust isn't sucked in through every crack but blown out. This may mean sealing up cracks to stop air from escaping and also ensuring the outlet has a smaller capacity.
- on the outlet side a secondary fan is generally used and would be a smaller capacity than the inlet to encourage positive pressure.
- commercial spray booths often use a top to bottom airflow with outlet vent grills on the floor and inlets on the ceiling. This obviously won't work with your booth but perhaps you could try some kind of cross-flow where the air enters at the top and exits at the bottom on the other side.
- as mentioned careful positioning of the vents is key to preventing contamination of the parts.

Last edited by gunner; 04/05/22 7:12 am.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
1 member likes this: Gordon Gray
Joined: Sep 2013
Posts: 4,019
Likes: 329
Britbike forum member
Offline
Britbike forum member
Joined: Sep 2013
Posts: 4,019
Likes: 329
reasons for a Paint Tardis ?

1. Provide a sterile enough environment to keep dust particulates
out of the wet paint as it cures .
2 control humidity .
3. somewhat contain overspray
4 .. ?

Two strategies ;

A . Create a vacuum with an exhaust fan
... might collapse the shed , or encourage every hole to pull in unfiltered air .
... so one goal with this method is to introduce large filtered holes and eliminate smaller holes .
( a singe large filter hole Might introduce structural failures in the shed , not originally accounted for )

B . you could pressurize the inside of the shed with filtered air and introduce a main controled exit
( somewhere above ambient pressure ) ... sounds the more expensive route ,
But this would eliminate the need to seal every pinhole .


with either strategy , a top to bottom air Exchange will probably naturally
allow particulates , dust and overspray , to settle
onto the floor below the painting zone .

air Exchange velocity , might be an issue ?

1 member likes this: Gordon Gray
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by Gordon Gray
I'd have a hard time believing someone like Don Hutchinson wouldn't have an opinion on how a spray booth should be set up.
He might well have excellent advice. But, at this point I know the overall aspects of what is needed so it's down to figuring out the best way to accomplish the details within the limitations of how I plan to do it. I'm not dismissing the idea that there very likely are people who know how to do exactly what I want to do. But, while spending time contacting people to ask if they have useful information could pay off in some cases, it is unlikely to in most. So, overall, I don't think it would be a good use of time at this point in the process. That's not to say additional advice isn't quite welcome.

Originally Posted by gunner
HVAC sales for offices ... If you wanted the air changed every minute, then a fan with 100 CFM would be about right, given the size of your booth.
The requirements for a spray booth are a bit different than they are for an office. Since I have a separate supplied-air breathing apparatus, in principle most of the air doesn't need to be changed as it does in an office to keep all the workers happy. Also, while sitting in a breeze from an A/C unit would be annoying for an office worker, a breeze in the vicinity of the parts being sprayed is exactly what I need. That said, the volume of the shed is 266 cu.ft. and the capacity of the fan is 600 cfm so, on average, the entire volume of air would be changed every 30 seconds. This will be useful in summer evenings when I need to eliminate the super-heated daytime air to make it tolerable. While the total air flow from the fan seems adequate, the reason for my experiments is to develop an air-flow system that results in the necessary breeze of filtered air across the parts.

Originally Posted by gunner
commercial spray booths often use a top to bottom airflow
Top-to-bottom is common, but commercial units also are made with top-to-side and side-to-side since not all sites have the ability to dig a trench underneath for the exhaust..

Originally Posted by quinten
pressurize the inside of the shed with filtered air ... would eliminate the need to seal every pinhole
Having a positive pressure has been my intention from the start, for the same reason a positive pressure is used in a clean room. The reason for sealing it as well as possible isn't because the fan wouldn't be able to keep up with the leaks, it's that the shed will sit unused for months at a time, during which time dust can enter through any hole or gap that I didn't seal. For example, if left unsealed, dust could enter through gaps between the overlapping corrugated ceiling panels. When I agitated the shed in closing the door after painting, there's the very real risk of that dust breaking loose and falling on the wet paint. That's why I need to seal every pinhole.

Originally Posted by quinten
air Exchange velocity , might be an issue ?
Even if there were pinholes, essentially all the air that is forced in by the fan will leave through the filtered outlet. That means near the inlet and outlet there will be a breeze. But, air won't take a straight-line path from inlet to outlet so I have to determine if that breeze will be strong enough, or possibly too strong, in the middle.

On the construction front, the manufacturer's dimensioned drawings leave out the effect on height due to the roof supports. The center support reduces the height to 5'11½" from the drawing's 6'5", which is fine for me, but the two supports in the middle of the roof panels reduce the height in those locations to 5'6".

[Linked Image]

So, after bumping my head, I'll have to stoop if I need to be in those parts of the shed. That still leaves a bump-free, stoop-free area of 21 sq.ft. in the center of the shed.

1 member likes this: NYBSAGUY
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by Gordon Gray
We all know you have a plan
Yes, and so did Custer...

But, don't get ahead of the syllabus. First the equipment (gun, filters, spray booth, etc.), then the paint, then the painting. Of course, this could be where the professor says in response to a question "we'll discuss that later," and then later says in response to that same question "we discussed that earlier"...

As can be seen, the roof is now complete.

[Linked Image]

The photograph also gives you a glimpse of the no-man's land that is Rattlesnake Gulch. Finer snake-breeding habitat would be difficult to find anywhere.

I'm running short of additional pieces to screw on, so it shouldn't be much longer before the basic, uncaulked, un-air'd, shed is complete. I'll try to get that done by the end of tomorrow, but then will have to take unpaid leave from this unpaid job for unpaid work on another for a few days. That will give me time to ponder the mess I've gotten myself into.

1 member likes this: NYBSAGUY
Joined: Oct 2017
Posts: 720
Likes: 250
Britbike forum member
Offline
Britbike forum member
Joined: Oct 2017
Posts: 720
Likes: 250
Well done MM. Before you started on this I had already planned some sort of spray booth in my own future and had done some reading about air flow and filtration etc. I will therefore be watching with interest when you get to the next part of the "booth" which (after caulking) I guess will be fitting it out.

Originally Posted by Magnetoman
but then will have to take unpaid leave from this unpaid job for unpaid work on another for a few days.
Reading this is almost like we are living parallel lives.

John

Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
I hadn't realized I left a volume of my bespoke shop manual open on the desk my granddaughter uses, so it caught me by surprise when I walked into the office yesterday and she said "Are you going to paint your Vincent red or blue"?[*] It took me a moment to realize where that information came from. Her computer was sitting on the manual that I had left open to the section on painting. Interestingly, to me at least, is the page it was open to mentions the "Chinese Red" Vincents, but not the blue, so she had to have read more than just the open page.

[*]A small number of Rapides came from the factory in "Chinese Red," and there's some indication there might have been a few blue ones, although none are shown in the factory records.

2 members like this: NYBSAGUY, George Kaplan
Joined: Feb 2019
Posts: 1,367
Likes: 489
Britbike forum member
Offline
Britbike forum member
Joined: Feb 2019
Posts: 1,367
Likes: 489
Originally Posted by Magnetoman
.......The photograph also gives you a glimpse of the no-man's land that is Rattlesnake Gulch. Finer snake-breeding habitat would be difficult to find anywhere.....
This suggestion may come under the heading of "with friends like there, you don't need enemies" but, your local rattlers do like eating rodents. You could easily make their habitat even finer by simply supplying a little rodent food here and there. Far away from your new spray booth of course.

Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by Stuart Kirk
You could easily make their habitat even finer by simply supplying a little rodent food
One reason it's such great rattlesnake habitat is it's also great packrat habitat, without which there would be nothing to eat our car wiring.

The design of the air flow in a spray booth has much in common with that of a clean room, although with a few significant differences. Because a clean room has to be kept at a constant temperature, the air has to be chilled, and because the expensive HEPA filters would clog too soon if outside air was supplied, the cleaned air is recirculated, as shown in the figure.

[Linked Image]

If the air weren't recirculated, the air conditioning requirements would be massive. The clean room in my lab was large enough that in order to maintain "laminar flow," i.e. without turbulence that otherwise could stir up dust, additional return air plenums, noted with red arrows in the next photograph, dropped down along the center of the length of the room.

[Linked Image]

Because of the design of a clean room, the entire volume of the room experiences an imperceptible breeze of clean air that picks up any fine particles and filters them out before the air returned to do it all over again.

Sadly for me, the clean air entering my spray booth won't be chilled, and because I'll use a less expensive, but still not cheap, inlet filter, the air doesn't have to be recirculated. However, those aren't significant differences. The significant difference is that for a paint booth, relatively high flow is needed in the vicinity of the parts, while flow in the rest of the shed is largely irrelevant. Luckily, motorcycle parts are fairly small so that air flow is needed only over a small volume.

Based on the length of the Girdraulic forks and the width of the RFM (rear frame member) I'll be looking for "significant" air velocity in a swept area ~28"×12", and over as large a length as possible, but ideally at least 4 ft. These are the values I'll use when experimenting with different inlet and outlet configurations.

The only two purposes of the moving air are, to remove mist from the vicinity of the parts so it can't settle on them and affect the finish, and to keep a cloud of spray from obscuring visibility. The 70% efficiency figure for HVLP guns is for large panels, like car fenders, where all the spray that leaves the gun hits the part, and 30% bounces off. However, spraying a motorcycle frame isn't the same, since much of the spray will simply go past on either side of the tubes. The same is the case for nearly all other motorcycle parts. In principle, a very high air velocity could gather all that excess paint before it hit the back wall of the spray booth and take it to the outlet. However, using just the 30% figure, if a quart of paint were sprayed, and if 30% of it ended up at the outlet, that would mean nearly a pint of paint to clog the filter. So, I conclude from this that an excessively high air velocity is not desirable.

I want the air flow such that as much as possible of the overspray makes it as far as the back wall, where I'll hang a plastic sheet, while still providing visibility. So, what velocity is needed? I'm glad you asked, because my first experiment provides the answer.

There's a gentle breeze today, varying between 0 and ~5 mph as measured on the instrument I showed in a recent post.

[Linked Image]

Spraying paint sideways into the breeze, 2 mph was sufficient to bend the "beam" of paint by 90° before it had traveled 1 ft. Even 1 mph, the minimum the instrument reads, would carry much of the overspray into the filter. I think this will prove to be good news since the velocity at the output of the fan, and hence at the output of the 10"×10" filter, will be much higher than 1 mph, possibly permitting a few simple louvers at a single filter to direct the flow slight upwards and downwards as well as straight to result in the desired swept area ~28" high ×12" deep. However, as any good scientific paper ends, further experiments are needed.

Joined: Mar 2019
Posts: 1,470
Likes: 426
Member
Offline
Member
Joined: Mar 2019
Posts: 1,470
Likes: 426
Originally Posted by Magnetoman
However, as any good scientific paper ends, further experiments are needed.
However, as any good scientific paper grant application ends, further experiments are needed.


1970 T120R - 'Anton'
1970 Commando - 'Bruno'
1967 T120R - 'Caesar'
1972 Commando - 'Big Red'
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
Originally Posted by Hugh Jörgen
Originally Posted by Magnetoman
However, as any good scientific paper ends, further experiments are needed.
However, as any good scientific paper grant application ends, further experiments are needed.
Not to pick nits, but a grant application should begin with a convincing explanation of why further experiments are needed, with the body of the application containing convincing evidence that the person writing it is precisely the person who is able to do those experiments. Of course, best if the experiments already have been done, but not published, so the person writing the proposal knows they are doable. Already having the data takes the stress off writing subsequent progress reports.

3 members like this: George Kaplan, Shane in Oz, Hugh Jörgen
Joined: Feb 2008
Posts: 6,336
Likes: 626
Britbike forum member
Offline
Britbike forum member
Joined: Feb 2008
Posts: 6,336
Likes: 626
Reminds me of the experimental classes at university in UK.
We would write the objectives and the methodology, then report the results, analyse the results and draw the conclusions.
Then if we had time we would do the experiment!

1 member likes this: George Kaplan
Joined: Aug 2020
Posts: 31
Likes: 7
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2020
Posts: 31
Likes: 7
I now fully realise why I prefer brush painting, (although some of the principals apply).


1961 BSA Super Rocket
1953 BSA BB GS
1939 Rudge Ulster
1951 Bailey Rudge
1969 Indian Velo
1979 Moto Morini Camel
Modern Ducati thing
1 member likes this: Hugh Jörgen
Joined: May 2019
Posts: 1,391
Likes: 576
Britbike forum member
Offline
Britbike forum member
Joined: May 2019
Posts: 1,391
Likes: 576
Amen to that……
Haven’t quite caught up on my reading yet. Wondering what you have in the way of buffing and polishing gear. I don’t want to be that guy (it comes naturally) , but you’ll need to wet sand and polish the tank for sure. Even if by some miracle you don’t end up with a Myzus persicae doing the funky chicken (top and centre in your wet paint) you’ll still have to deal with orange peel. That’s just the way it is.

Joined: Nov 2011
Posts: 8,721
Likes: 1123
Britbike forum member
OP Online Content
Britbike forum member
Joined: Nov 2011
Posts: 8,721
Likes: 1123
We're back from a short trip to attend a wedding in the Midwest. If we don't come down with covid it will be a miracle, but there was no choice but to attend. The bride looked every bit a Disney Princess. I'm not saying this because she's related, but because she is a Disney Princess, playing the characters of Ariel

[img]https://www.google.com/url?sa=i&url=https%3A%2F%2Fprincess.disney.com%2Fariel&psig=AOvVaw16I3fE9GjGH1ku0lep1PCD&ust=1649693853928000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCICLiNfyifcCFQAAAAAdAAAAABAE[/img]

and Rapunzel

[img]https://lumiere-a.akamaihd.net/v1/images/pp_princess_rapunzel_static_mobile_20694_0171d854.jpeg?region=0%2C0%2C640%2C480[/img]

at Disney World. If actors were hired to play the ideal couple for a stock photo, they wouldn't have been more photogenic.

Originally Posted by Rudge00
I now fully realise why I prefer brush painting,
I can't say your conclusion is wrong...

Originally Posted by Cyborg
Wondering what you have in the way of buffing and polishing gear ... you’ll still have to deal with orange peel.
I'll start with this to begin the smoothing process.

[Linked Image]

If the 1 h.p. isn't enough, I'll have to upgrade to a larger pre-polisher. However, once the peaks are down to size, I have air-powered orbital sanders and polishers, with wet/dry paper up to 3000 grit, to finish the job.

A lengthy series of posts in my Ariel thread shows the equipment I used when I repainted the rear mudguard after fixing a dent in it.

Joined: Mar 2005
Posts: 10,851
Likes: 280
Britbike forum member
Offline
Britbike forum member
Joined: Mar 2005
Posts: 10,851
Likes: 280
MM Please move the steady rest up close to the face of the stone. Mr Cunningham, my 6th grade shop teacher, would turn in his grave. As it is set it is a perfect distance to take the thumb off up to the first joint.
Your friend!

1 member likes this: Magnetoman
Page 24 of 58 1 2 22 23 24 25 26 57 58

Moderated by  John Healy 

Link Copied to Clipboard
British Cycle SupplyMorries PlaceKlempf British PartsBSA Unit SinglesPodtronicVintage MagazineBritBike SponsorBritish Tools & FastenersBritBike Sponsor






© 1996-2023 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5