Britbike forum Forums British Motorcycle specific Brands Vincent forum 1950 Black Shadow: Total Rebuild

Does having one out of the three count?...

I should add that my previous post only listed the cost of the "equipment" needed to paint, not the expendables. Like having an excellent grease gun; you also need the grease.

Obviously, paint is required in order to paint, but also cleaners, strippers, solvents, gloves, overalls, sand paper, tack cloth, etc.

I keep my house in order
Take account of all my whims
I bathe my hope, I test my traps
Preparing to begin...

Without wishing to increase your expenses any further, I was wondering if it would be worth adding a pressure gauge inside the booth.

In theory, the gauge should show some pressure differential between the outside and inside and therefore give some idea of how well the booth is sealed.

You could get pressure readings with the exhaust blocked off and then with the filters in place, this would then give you an idea of a) how well the booth is sealed, b) how much pressure is lost through the air filter. It might also be useful to get an idea of when the exhaust filter is becoming blocked.

There probably isn't much pressure differential so it might need an accurate gauge to take measurements.

I have built simple manometers for measuring differental pressures., that would do.
An off the shelf one is easily hidden in the budget.

RadonAway 50018 Easy Read Manometer, Red
https://www.amazon.com/RadonAway-50...2159-2603105?pd_rd_i=B071GPLK8P&th=1

The simple answer is 'no'. The more complicated answer is:

I have a suitable manometer, and installing it would be easy, but the information it would supply wouldn't serve any purpose. If the shed were made of thick-enough steel to withstand the pressure, and had no leaks whatever, the fan would increase the pressure inside the shed until a steady state pressure was reached. That would happen when the flow of air leaking backwards through the fan blades due to the high pressure equaled the flow of air being pumped by the fan blades. If a hole were then punched in the booth the steady state pressure would be lower due to that leakage path. However, knowing that the pressure was "too low" wouldn't help locate the hole. In contrast, the desert sun shining on the closed booth let me detect and eliminate even the tiniest pinholes everywhere in the walls and roof.

Clean rooms use manometers, but for a somewhat different reason. Most of the air is recirculated through the filters because otherwise there would be a huge load on the air conditioners if they had to deal with a constant flow of outside air, and the very expensive HEPA filters would need replacing much more often as well. However, a smaller fraction of "makeup air" from the outside has to be introduced to make up for leakage. Some of that leakage is deliberate to ensure a constant supply of fresh air to keep the workers from breathing 100% CO2 by the end of the day. Anyway, because of the makeup air, and because the pressure drop across the filters increases as they slowly get clogged (typically, having a lifetime of years), manometers are used to adjust the fraction of makeup air and to monitor the filters to know when they need replacing.

I still have to wire the light, add a few paving stones in front of the door, and duct-tape the roof seams, but the paint booth is 99% done at this point. So, I paused to make what I hope is a comprehensive list of all the consumables needed, cross off the ones I already have, and order the rest.

In general, all five of the following might be sprayed on a given item: sealer, primer, primer-surfacer, top color coat, and clear coat, some of which also require thinners, reducers, retarders, fish-eye eliminators, and activators. However, leaving aside all of those for now, as well as the necessary transfers and gold leaf, the following disposable items are required for painting the Vincent:

Disposable paint cups (if using such a system, as I am with the 3M PPS2.0)
Paint filter cones
Paint gun spray cleaner
Cleaner/degreaser
Lint free cloths
Tack cloths
Automotive-grade masking tape
Guide coat spray paint
Bondo®, if needed (which I don't believe will be for the Vincent)
Abrasive papers from 120 grit through 2000 grit with appropriate sanding blocks
Scotchbrite®-type pads
Nitrile gloves
Tyvek® overalls
Tyvek® hoods
Disposable shoe covers
Polishing paste with appropriate application pads

As an aside, the air in the paint booth will be filtered to eliminate particles down to ~1 µm, but the external filter cones for the paint are 200 µm as are the internal ones in the PPS2.0 cups. The final paint layer itself will be no more than 50 µm.

Aside about the value of information.

Before I retired, I had to spend the time to prepare lectures and show up in class whether or not the students showed any interest, because I was paid to show up. But, I also had a measure of whether that time was appreciated in the form of student evaluations all of them filled out at the end of the semester.

NYBSAGUY and I know how much of our time and effort went into writing 'The Motorcycle, Design, Art, Desire', but we also know that effort is appreciated because it is measured by the number of people who spent ~$50 each to buy the book, and the fact sales have been such that it will be reprinted in the fall. In the same way I know the effort that went into researching and writing my 'The Gold Star Buyer's Companion' is appreciated.

However, although I know how much time and effort went into, say, yesterday's comprehensive post detailing the items needed to build a professional paint booth, the only measure I have of interest in that information is the thread received ~1000 views since yesterday, although possibly 998 of them from bots, but just two people took the time to click their mouse on 'like.' Not spend $50 or $75, just click a button.

I'd love to be a fly-on-the-wall when Madame MMan is doing the monthly household accounts.

"Professor Honey, what's a MERV air filter? Seems very pricey. Do you think the housekeeping staff is overdoing it on the cleaning products?"

MMan-- i read all of your posts as I consider them interesting and well written.
However I do not click "like" buttons as I think they are somewhat infantile---so in my case at least the number of "like" buttons clicked is absolutely no guide to interest on the part of the reader.
Of course I may be the only guy with those characteristics---in fact I probably am-- as I have found many times over the course of my life.
But as I say to my wife--- that just means the other guys have got it wrong!

It's not nearly as interesting as you might think. After decades of this, what passes without comment as a perfectly normal expense in this household would raise red flags just about anywhere else. It also totally befuddles the Amazon algorithm that makes purchasing recommendations.

I agree, but it's the only thing I have to judge by. My Ariel thread has had nearly 1.5M views as of today, but I'd be amazed if more than 1% of those were made by actual people, as opposed to bots. Without feedback, infantile or not, it can feel like I'm talking to myself in an empty room.

I've probably written about this before, so stop me if you've heard it... I've given a lot of talks in my lifetime, so I'm pretty good at "reading" an audience. I can tell when something I thought might be interesting falls on deaf ears, in which case I move on, when something I thought was mundane gets a positive reaction, in which case I might add more details that I otherwise wouldn't have, etc. Britbike is more like "speaking" to an audience than it is writing for a book. The most welcome feedback comes in the form of subsequent posts that offer additions, corrections, suggestions, or even digressions, but 'likes' at least tell me the room isn't empty.

The devil made me do it...

Looking back at the "likes" that I've added, your observation seems spot on

I remember when you were painting the Ariel, you used dry paper, as opposed to wet & dry.

Which type of paper will you be using for the Vincent? I can recommend wet & dry as you get a much smoother finish, especially with the finer grades.

Might also be worth adding a roll of masking paper in case you have any large areas that don't need spraying.

Regarding the Bots, you can see which ones are in use and which posts they are looking at the "Who's Online Now" box on the left hand sidebar, you will see a list like the one below.

I believe Bots read each post equally without favoring one over another, but not really sure.

It is possible to disable Bot access so maybe thats something for Morgan.

Where do you even get Bots?

I want a Bot that, when she wakes up in the morning, my wife has had 1m 'likes' overnight.

Just the list you posted shows that can't be the case. Of those 18, 5 (28%) show them "reading" my threads, and I'm not responsible for anything close to 28% of the threads or posts on Britbike. There must be some threshold number of views that triggers frequent return visits.

That was my first experience into the world of Bondo and decent paint, albeit using rattle cans, and as the following quote from one of the last of the Ariel paint posts indicates, I wasn't trying to do better than the paint on the rest of the bike: "I assume something like 3M "ultrafine" compound would make the paint even shinier, but shinier would be out of place on the Ariel,..." Also, I was doing an in situ repair with the bike on a lift so wet paper would have made a mess that I didn't want to deal with. However, I'm upping my game with the Vincent, with the goal of nothing less than perfect paint. I'm reasonably confident I can reach that goal.

To digress with a story I've probably written before, when I was in high school I was going to make my own 6" telescope. Books describing how to do that advised that, because of the experience gained, first grinding a 4" mirror and then grinding the 6" mirror would be faster than going straight for the 6" (a 4" has ~3½× less material to remove). The Ariel mudguard was my 4" mirror.

I should say that even once everything is fully functional, I won't be starting with the Vincent. I have nearly a dozen BSA fuel tanks, a number of oil tanks, forks, several frames, etc. with which to hone my skills before I attack the Vincent. Not that I expect to need to paint all those BSA parts before I'm ready.

I spent some time yesterday familiarizing myself with the three knobs on my DeVilbiss spray gun, and where each should be nominally set. Also, the gun I selected came with 1.2 mm and 1.4 mm nozzles, and a needle that works with both of them, which my earlier research showed will cover just about any paint I might use. However, different nozzles and needles are available for this gun in sizes up to 2.5 mm (i.e. area ~4.3× larger than 1.2 mm), which must be for people who want to spray molasses in winter.

DeVilbiss wants the resistance to earth from the gun to be less than 1 MΩ to dissipate electrostatic charge due to flow through the gun. Unfortunately, as can be seen, the 15 ft. hose I intend to use inside the booth has a resistance greater than 1 GΩ over a length of just an inch, so I'll have to devise a ground strap.



I also worked on other details of the compressed air system. I'll bring air to the spray booth at whatever pressure the compressor delivers, i.e. starting at 120 psi and dropping from there as it can't keep up with the 10.8 cfm demand of the gun. Since pressure regulators only regulate accurately over a limited range of input pressure, the next photograph shows a second regulator I'll have inside the booth.



The deVilbiss recommendation for the gun is 22 psi so I'll probably set this regulator at something like 30 psi to allow for a range of adjustment outside that recommendation. This regulator incorporates moisture and particle filters, but also shown in the photograph is a disposable moisture/oil filter. In any case, the 30 psi this regulator will supply will go next to another regulator/gauge at the gun itself, so the gun's regulator always will deal with a constant input pressure. I'll set that regulator to the recommended 22 psi until/if I determine another pressure produces better results.

Although the regulator and moisture filter in the above photograph are specified to flow high cfm, the number of quick-connect fittings in the line possibly could reduce flow to less than the required 10.8 cfm for the gun when the pressure at the compressor drops significantly. I'll do a test of that and, if it's a problem, I might have to replace the quick connects with high flow versions.

Details like the above take time to sort out, but it's much better to do now rather than discover there's a problem only after I'm encased in Tyvek® in a 100 ℉ booth with a pint of expensive epoxy paint rapidly hardening in the gun.

Looks like you've been very busy, and with your commendable attention to detail, I'm fairly sure professional results will soon be forthcoming.

Regarding the Bots, these are generally employed by search engines so that content can be easily found by indexing material on this site. What algorithms are used I guess is dependent on the company that deployed them and we are totally dependent on Morgan to ensure that any malicious ones are blocked.

I can imagine that any thread which exceeds a certain number of posts might attract more attention from a Bot than a thread with little activity, so it then becomes a kind of self-fulfilling prophecy as each read by a Bot adds to the count.

Down with the Bots !

What you see in the following photograph are two 25 ft. sections of ⅜" air hose, with one end connected to the compressor and other end to a male/female pair of quick connects to simulate the inlet to the paint booth, followed by the pressure regulator, water/oil filter, 15 ft. air hose, ball valve to regulate air flow, and finally an air flow gauge.



As a reminder, the paint gun's specifications list 10.8 cfm at 22 psi.

I started with the ballast tank at the full 120 psi, and opened the valve far enough to get a flow of 11 cfm. After 1¾ minutes the pressure in the tank had dropped to 80 psi, at which point the compressor kicked on. After a total of 6 minutes the pressure only had dropped a further 10 psi to 70 psi. During the test I had to increase the setting on the pressure regulator to ~60 psi to maintain the 11 cfm with the valve fully open. It was still flowing 11 cfm when I ended the measurement since I can't imagine ever needing to paint for a full 6 minutes without interruption.

Anyway, despite the total of eight pair of male/female quick-connect fittings, 65 feet of ⅜" air hose, a regulator, and a water/oil filter, the compressed air system passed this initial test, although not with a lot of cfm to spare.

For a better test, I attached the gun's pressure regulator and the gun itself to the outlet of the air flow gauge, which required making an adapter because my supply of quick connects is running low and I only could find a few with larger ½" NPT inlets.



With the trigger fully depressed and the regulator fully open (or closed, depending on how you look at it), it only reached a flow of 6 cfm.



From previous tests I know the ⅜" air hose isn't limiting the flow, which points a finger at the restriction of the many quick connects in the line and, in particular, the last one. But, it's too soon to jump to any conclusions just yet. First, I need to test the flow of the individual components, after which I'll jump to unfounded conclusions.

First things first, I measured the flow at the end of the two 25-ft. hoses, which also included four pair of connectors. Surprisingly, it was only 11 cfm. Then, as shown in the next photograph, I removed the pair of connectors on the output of the air flow meter and the flow pegged the gauge at over 20 cfm.



Hmm. The final male connector is like all the others, but the female has a larger thread, which is why I had to make an adapter. I would have thought the larger ½" NPT fitting, vs. the ⅜" of all the others, implied its internals provided a great flow, but obviously not.

OK, the gloves are off now. Or, at least the outlet connectors are off. So, thanks to the many quick connects on all the components I can test the flow of them individually.

25+25 ft. air hoses > 20 cfm
25+25+15 ft. air hoses > 20 cfm
25+25+15 ft. air hoses + water/oil filter > 20 cfm
25+25+15 ft. air hoses + regulator/filter > 20 cfm
25+25+15 ft. air hoses + water/oil filter + regulator/filter = 11 cfm

Hmm. Somehow, in a way to be determined, the water/oil filter is interacting with the regulator to reduce the air flow. I put the outlet connectors back on and measured 11 cfm again. I then put the gun and its regulator on again, adjusted the pressure with the trigger fully depressed to be 22 psi, and the air flow was just 6 cfm, not the 10.8 cfm listed in the service manual. Hmm, again.

Looking at the DeVilbiss specifications, it lists the single pair of values of 10.8 cfm and 22 psi, so I have to wonder how much (if any) the fluid nozzle might affect the air flow requirement. I currently have the smallest one in the gun, and the largest one has an area 4.3× larger, so could that explain the difference in air flow between what is listed and what I measured? That is, does the DeVilbiss manual list the worst-case flow rather than the a flow that applies for all fluid nozzles? More measurements should get to the bottom of this.

Meanwhile, even though I unsealed the water/oil filter earlier in the day and it only was used for maybe 15 minutes, the pink color shows it's already saturated with moisture.



However, I wasn't careful about always having it after the regulator/filter in the line, and one time I tested its flow alone. Still, I'll have to see if a better way is needed of filtering the moisture from the air line.

Sorting out the details continues.

A careful re-reading of the product literature for the air regulator/filter shows it removes particles down to 5 µm but doesn't list a specification for water removal. So, in the interest of keeping the paint from drowning, I have a moisture separator in my McMaster-Carr shopping cart that also removes particles to 3 µm and reduces oil to 5 ppm. However, placing the order awaits today's measurements.

It's interesting what actually reading product literature reveals. Yesterday I wrote that "Somehow, in a way to be determined, the water/oil filter is interacting with the regulator to reduce the air flow." The mystery of that 'somehow' was solved by reading the specifications, which says the disposable filter flows a maximum of 20 cfm @ 100 psi. When I tested it alone in the line, the full compressor pressure of 100+ psi was on the inlet and 0 psi was on the output (nb. these pressures are psig, so atmospheric pressure is '0'), which is why it pegged the flow gauge at over 20 cfm. However, when placed in line with the regulator, 100 psi was on the inlet, but only ~60 psi (the setting of the regulator) was on the outlet, so the flow rate should have been ~60/100×20 cfm = 12 cfm. I measured 11 cfm. Mystery solved.

These disposable filters are intended for air tools, where the full compressor pressure will be on one side of them, but very little pressure on the other side when the trigger of the tool is depressed. Unfortunately, this means I can't use one as a final moisture filter for the paint gun. Even more unfortunately, desiccant filters with high flow rates cost serious money. However, knowing the actual flow rate of my spray gun in the configuration I will use it (i.e. is it 6 cfm, or is it the 10.8 cfm listed by deVilbiss?) can save a lot.

If I have the regulator set at 60 psi, the pressure drop across the filter when the gun is operated will be 60–22= 38 psi. In that case, 6 cfm @ 22 psi is equivalent to 16 cfm at the 100 psi where most of the desiccant filters are rated, while 10.8 cfm is equivalent to 28 cfm @ 100 psi. A particular type of desiccant filter in the McMaster-Carr catalog that meets the former specification is $827 while for the latter it's $1333. In either case it's not cheap, but $500 less not-cheap for the lower flow rate.

Unfortunately, the decision is more complicated. A much less expensive filter, $259, that meets the 6 cfm flow rate is listed, but it requires a $103 replacement desiccant cartridge when the original becomes saturated, whereas the desiccant in the $827 filter can be rejuvenated by heating. What I don't know is how long either would last before becoming saturated, or if the cartridge in the less expensive filter could be rejuvenated even though that possibility isn't mentioned. The desiccant is held in what appears to be a plastic cylinder that likely couldn't withstand the ~250 ℉ needed to restore silica gel, assuming it is silica gel, but it might or might not be possible to slice the cartridge open and reuse it. Also, if the 10.8 cfm @ 22 psi turns out to be correct, a more expensive, $386, version of the less expensive filter would be required. However, possibly the issue is moot, since maybe the cartridge would last "forever" under the conditions I'll use it.

Decisions, decisions. More measurements are underway to help me make less-uninformed decisions.

p.s. to eliminate as many variables as possible, a few minutes ago I connected the flow meter with the output quick-connect fittings directly to the 25+25 ft. air hose and measured a flow of 11 cfm with the input pressure somewhat above 100 psi. I then connected the spray gun and adjusted its regulator for a pressure of 22 psi with the trigger fully depressed. The flow was just under 5 cfm.

Although I'll want to find a more free-flowing female connector for the output of the air flow gauge, the 11 cfm limitation of the present one doesn't affect the 5 cfm that I measured. However, more work is needed to reconcile my measurement with the 10.8 cfm of the deVilbiss manual.

One way of removing moisture without having to buy costly consumables is a system of multiple drops in your air line with drain valves at the bottom. Pictures, as always, are a better way to explain so a quick google turned up one of many you-tube videos of such an arrangement.

It wont remove all of the water but it might give you more life in your desiccant filters.

youtube.com/watch?v=41qdZI5doLQ

John

This is now mounted to my shop wall next to the compressor. The instructions for the dryer recommend that there be lots of line between the compressor and desiccant (I’d have to look it up, but it does qualify as a lot) If the desiccant gets too hot it will start to disintegrate and travel down the lines. The copper tube prevents that. This is overkill for the amount I use the compressor and don’t get much water out of the first tap.

9A02AD3E-35B2-40DB-A001-E895E32BE900 by First Last, on Flickr


9981926F-BA0C-4558-AC9B-263FB73DBAF6 by First Last, on Flickr

Great minds... I (re)"discovered" such systems last night when I started trying to find information on the expected lifetime of desiccants in air lines.

I remember you showed that setup some time ago. I also remember I made some snotty remark about you needing it only because you lived in the wet Northwest, whereas I lived in the dry desert.



A 10 ft. section of ¾" pipe has a volume of 212 cu.in. = 0.123 cu.ft., which means at a flow rate of 5 cfm the air will spend 1.5 sec. in the pipe. Or, 3 seconds to go up to the top of a loop and then back down. The question is, is 3 seconds long enough to cool the air to the ambient temperature of the pipe (which, in summer, won't be much cooler than it started at)?

The next photograph is a view looking up in the closet for my compressor, showing an uninterrupted space extending at least 15 ft. upwards.



Conveniently, ¾" galvanized pipe is available in 10 ft. sections, which can be carried in my pickup. And, thanks to the construction of the closet, it would be relatively easy to install as many 10 ft. loops of pipe as I wanted. From measurements I made at the end of the 50+ ft. of ¾" air line in the garage I know that even 60 ft. of pipe would provide negligible resistance. Although, at $34 per section, it would be nice not to install more loops than necessary.

Ideally, there would be an on-line calculator I could use, but thus far I've only found sites that unreasonably expect me to plug numbers into formulas and calculate the answer manually using BTUs and degrees Rankin. Meanwhile, I've ordered the moisture separator and desiccator from McMaster-Carr, so add another $400 to my previous figure for the cost of the paint booth. And probably another $100 for galvanized pipe and fittings before I'm done with the air.

TP TOOLS

I found this useful when setting up my dryer loop.

Probably too late and your not interested in it anyway......but IMO if you're looking for that perfect paint job, using expensive equipment and materials. Galvanized pipe might not be the best choice???

Gordon

Not too late, and I am interested. What's the issue with galvanized pipe for this application?

Ah, I've now read your attachment that recommends black iron rather than galvanized, to avoid the possibility of flaking. That makes sense. Unfortunately, it doesn't save a lot of money, but it is 6% cheaper than galvanized. Thanks for that information. I still need to calculate the length required for it to cool the flowing air to ambient before I buy pipe of any kind.

I have to be honest.....I used galvanized for my dryer loop because I already had most of it and I'm not doing any painting.....just blasting. So if I'm half way through a task and something clogs up (that hasn't happened yet....fingers crossed) I'm not out some expensive paint and stopped halfway through a paint job.

I can sweat copper......but just didn't have a warm fuzzy feeling about it with the pressure blasting takes.

So not really apples to apples to what you're trying to accomplish

Gordon

I've now refreshed my memory on what I was told years ago, when the building that held my lab was being built, that black iron was a legal requirement for many sprinkler systems because one time somewhere a flake from galvanized pipe caused a problem. I also was told at that time that, because of the black pipe, whenever a sprinkler system is activated the rusty water that comes out basically ruins everything as it puts out the fire.

From what I've just read, standing water in a galvanized pipe is bad for the coating, but as long as it remains dry it's fine. In the cooling loop(s) the pipe will remain dry all the time since condensed moisture will fall to the bottom of the loops where the valve(s) will release it. If any flakes came off the inside of the pipes they would have to be small enough to make it through two filters (5 µm and 3 µm), plus the desiccator, before they could reach the gun. But, since there won't be any standing water, there wouldn't be any rusty water issues with black pipe, either. It sounds like either would be fine for this application, although galvanized pipe seems "cleaner" than black iron.

I still haven't found an on-line calculator, and I remain reluctant to manually calculate how many furlongs/BTH of black iron I need for every degree Rankin of temperature drop but, for what it's worth, one site lists typical air flow speeds in an HVAC system, with values ~10 ft/sec. for heat exchanger coils. That's to be compared with the ~10 ft/1.5 sec. that a flow of 5 cfm will give. If that site is correct, the slightly slower flow through a 10 ft. section of each leg of a pipe when painting would be fine for complete heat transfer, indicting a single loop would be sufficient.

As long as the drain cocks are left open when not in use, either should work well in a low humidity environment.

The drain cocks may need a length of clear hose below them and a gauze filter of some sort to keep the unwelcome visitors out. It's mud wasps here, but probably scorpions there.