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Gasoline Permeation and PVC

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34K views 44 replies 16 participants last post by  CaptainMidnight85  
#1 ·
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You guessed it ...manifolds...

Anyone have experience and dataabout the affects of using PVC and gasoline together?

Not wanting to have this turn into Chem 101, but personal experiences and knowledge aquired is the aim.
 
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#27 ·
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I agree wholly Kit.

Real Life Knowledge of PVC based material outside of the standard Plumbing PVC/CPVC product line is limited to the uses for which those pieces are used for and by the people that use them. Talking toa Plumber about this topic gains little to no ground as many have found out.

Fortunately core bulk material can bespecified and purchased in small batch quantities for the experimenter. Engineered Plastics are the future in intake applications as the current use shows. Nylons (Nylon-6 (6.6 specifically) are preferred), Polystyrenes, Polypropolynes, Polyvinyl Chloride (and its derivetives), Acrylonitrile Butadiene Styrene, Acryllics in general, PMMA (Poly(methyl methacrylate) and its derivetives; alsoknown as Plexiglass... the list goes on.

Thermoplastics... that is where its at. That is my focus.

And the initial focus of this thread is in support of the Single Carburetor thread.

PVC formulated for the application is a suitable material for use in that application and is favorable on many levels for the individual willing to understand and work the material. Store-bought plumbing products are sufficient for off-the-shelf use in this application based on my experiments and tests.

Please feel free, everyone, to add your experience in the use of PVC as a designed intake manifold for use on your Goldwing.

Honda will eventually use them on future bikes.
 
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#28 ·
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Uh.......Oh......I am a hockeyoligist by trade. :clapper::clapper::clapper::cheeky1::cheeky1::cheeky1:

PVC for an intake manifold. Well how hot does it get at the intake area?? This is a consideration.

A newly manufactured PVC pipe or fitting or molded flat section of the material is very tough when new. You can beat it with a sledge hammer and it will simply dent, you can run over it with the D9 Cat track and it will simply egg shape a bit.

Give it six months of exposure to sun, heat, and it will shatter like glass. Use the same hammer and it will shatter. Run over it with the tractor and it will crack into thousands of sections.

It would have to be formulated to withstand heat, and also UV protection additives added. The gray electricians PVC which does have some U.V protection mixed in would be the closest thing on the market to withstand the sun. As for age and getting brittle it all does that.

I would suspect that even if one used solid sheet, and machined a intake manifold out of it it would be great for a time, then just crack.

Kit
 
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#29 ·
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Laughing is goood for the soul... :smiler:

UV degradation is a non issue once the off-the-shelf-fittings-bin PVC GL1000 manifold is coated with UV resistant paint; Krylon is a inexpensive example. But YES, a committed formulation of co-polymers would be beneficial in batch use to prevent UV degradation.

Note the millions of Vinyl Windows and Doors that are in service on many homes and businesses that are actually made of unplasticised PVC, or PVC-U, not Vinyl as most purchasers assume. PVC nonetheless. A very durable material when engineered to be one.

Off-the-shelf-fittings-bin PVC plumbing products are capable of sustained 160 degree temperature exposure with no detrimental harm. Higher temperatures are tolerable for durational exposure. I don't see these temperatures sustained at any point in the manifolds working area.

As for strength or toughness of the shelf items, I have not experienced an issue relevant to worry. I expecta failure-point though, as I will have to create one.

I forsee no incursion by a tracked vehicle, a hammer or even a hard head that would crack, break or otherwise prevent itsreliable use.

I've been wrong before though... once.
 
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#30 ·
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CaptainMidnight85 wrote:
Laughing is goood for the soul... :smiler:

UV degradation is a non issue once the off-the-shelf-fittings-bin PVC GL1000 manifold is coated with UV resistant paint; Krylon is a inexpensive example. But YES, a committed formulation of co-polymers would be beneficial in batch use to prevent UV degradation.

Note the millions of Vinyl Windows and Doors that are in service on many homes and businesses that are actually made of unplasticised PVC, or PVC-U, not Vinyl as most purchasers assume. PVC nonetheless. A very durable material when engineered to be one.

Off-the-shelf-fittings-bin PVC plumbing products are capable of sustained 160 degree temperature exposure with no detrimental harm. Higher temperatures are tolerable for durational exposure. I don't see these temperatures sustained at any point in the manifolds working area.

As for strength or toughness of the shelf items, I have not experienced an issue relevant to worry. I expecta failure-point though, as I will have to create one.

I forsee no incursion by a tracked vehicle, a hammer or even a hard head that would crack, break or otherwise prevent itsreliable use.

I've been wrong before though... once.
So are you one of those engineer guys. :smiler: I met an old friend yesterday, he is an engineer, and one heck of a nice guy.

I simply have to tell you PVC in real world use will not work. That is why the automobile industry uses a nylon thermoplastic.

Other than running over it with a tractor out working in the field , I have built more than several homes. I am quite aware of PVC and its uses, from windows to exterior trim. To whatever.

However PVC is not conducive to heat, it does get brittle, works fine in a window that just sits there with no vibration or stress.

PVC has a great expansion and contraction rate too. About 22 inches per 100 feet if you are looking at say 3 inch pipe. This is quite significant, not so much so with a short section, but still way beyond other materials. Expansion and contraction creates leaks, in the automotive world.

It is not strong in lesser amounts or in less mass units that would be realized in the formation of a inflow fitting for the carb. It will crack at the mounting sooner or later, it will be impossible to keep a secure and tight seal, too much expansion and contraction.

And........if the motor ever does overheat, just one time, best have some gorilla tape along, to tape the carb up to the engine to get home with. Maybe one of those windex bottles would work, fill that with gas and spay a bit into the opening just enough to run it home. :)

The thermoplastic nylon used for auto applications is tuff, withstands extreme heat, does not expand or contract, and for the most part is satisfactory, but starting to also develop problems in the cracking department from the vibration and what little expansion and contraction that material does have.

What about an aluminum manifold?? Design it and cut it out with CNC milling. What cannot be programmed to that , cut ahead of time on a lathe, punch the holes on a drill press and then turn the laser loose on it and there you go.

I can run the machine but do not have a clue how to write a program for something like this, but should be simple for some one who does this all the time.

Plastic is good under many conditions. but take that material and put it to use under stress, vibration, heat, or where it may have to hold a thread and it will fail. It will crack, break, and in some way not be satisfactory. Even the GM repair shops are finding this out, as any shop you go to there on the trash cart will be a plastic manifold or two.

GM once had a all plastic motor , even tested it. They placed metal alloy sleeves in the cylinders, and bushings and sleeves in the heads, and at the crank ends, and all points of wear and contact.

It never survived due to heat, expansion and contraction.


Keep trying though that is what the mother of invention is all about, I just think quite frankly that a block of hardwood would do better than PVC under this application.

Kit

Edit: There are a great many uses of plastics in the automotive and motorcycle engine applications in use already today, spacers, air boxes, and so on, even gaskets. But they are all some type of thermoplastic. Generally nylon or poly thermoplastic of some kind. Not PVC.
 
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#31 ·
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What do you think would happen if the bike should have a backfire thru the carb?
 
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#32 ·
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Kit Carson wrote:
CaptainMidnight85 wrote:
Laughing is goood for the soul... :smiler:

I've been wrong before though... once.
So are you one of those engineer guys. :smiler: I met an old friend yesterday, he is an engineer, and one heck of a nice guy.

I simply have to tell you PVC in real world use will not work. That is why the automobile industry uses a nylon thermoplastic.

Other than running over it with a tractor out working in the field , I have built more than several homes. I am quite aware of PVC and its uses, from windows to exterior trim. To whatever.

However PVC is not conducive to heat, it does get brittle, works fine in a window that just sits there with no vibration or stress.

PVC has a great expansion and contraction rate too. About 22 inches per 100 feet if you are looking at say 3 inch pipe. This is quite significant, not so much so with a short section, but still way beyond other materials. Expansion and contraction creates leaks, in the automotive world.

It is not strong in lesser amounts or in less mass units that would be realized in the formation of a inflow fitting for the carb. It will crack at the mounting sooner or later, it will be impossible to keep a secure and tight seal, too much expansion and contraction.

And........if the motor ever does overheat, just one time, best have some gorilla tape along, to tape the carb up to the engine to get home with. Maybe one of those windex bottles would work, fill that with gas and spay a bit into the opening just enough to run it home. :)

The thermoplastic nylon used for auto applications is tuff, withstands extreme heat, does not expand or contract, and for the most part is satisfactory, but starting to also develop problems in the cracking department from the vibration and what little expansion and contraction that material does have.

What about an aluminum manifold?? Design it and cut it out with CNC milling. What cannot be programmed to that , cut ahead of time on a lathe, punch the holes on a drill press and then turn the laser loose on it and there you go.

I can run the machine but do not have a clue how to write a program for something like this, but should be simple for some one who does this all the time.

Plastic is good under many conditions. but take that material and put it to use under stress, vibration, heat, or where it may have to hold a thread and it will fail. It will crack, break, and in some way not be satisfactory. Even the GM repair shops are finding this out, as any shop you go to there on the trash cart will be a plastic manifold or two.

GM once had a all plastic motor , even tested it. They placed metal alloy sleeves in the cylinders, and bushings and sleeves in the heads, and at the crank ends, and all points of wear and contact.

It never survived due to heat, expansion and contraction.


Keep trying though that is what the mother of invention is all about, I just think quite frankly that a block of hardwood would do better than PVC under this application.

Kit

Edit: There are a great many uses of plastics in the automotive and motorcycle engine applications in use already today, spacers, air boxes, and so on, even gaskets. But they are all some type of thermoplastic. Generally nylon or poly thermoplastic of some kind. Not PVC.
I take it you have a Engineer Guy joke or two?... I've heard most of them already. :tongue:

Well.... barring the low temperatures of my locale, my testing has been successful.

My current manifold is working flawlessly as designed. Simply put, it does work.

I don't discount your hands-on field work with the material by any stretch. In fact, I am welcomed to know that many here have some experience with the common uses of it. Many who have used it for utilities service are, and will be skeptical of its use on my motorcycle. I've found that the more skeptical some allow themselves (kids, primarily thus far) the more gloat I accrue, 'specially when I ride away and return in short order with my own questions.

I gave the window and door examples as just that though; examples... to show that UV radiation is of little concern if designed to withstand it. PVC-U IMO would not be the choice solution for a manifold due to its overall toughness. It is not rigid enough for my liking but would work just the same.

Expansion and contraction are a non-issuedue toits small size and comparative mass. I believe your information is flawed as I have not experienced any measurable amount of deformation in its size characteristicswhile in its working environment. Granted, my testing with the inclusion of heat and time have been limited thus far to my garage in the South Dakota winter. I have heated the garage to the point of sweating myself more than once and found it a futile effort. I tried though. More testing to follow of course.

The position of the manifold negates any overheating situation. I am working with the intake; centralized above the engine and in free flowing air. There is simply not enough heat generated.

Aluminum is great although the purpose for the PVC construction route is for those that wish a simple do-it-yourself route to acquire a inexpensive, reliable and easily constructed manifold consistent with the nature of the single carburetor thread.

PVC is a Thermoplastic.

My further experiments with blended thermoplastics are ongoing.

Real-World experience in this matter is of great importance as you've stated. I am fortunate to be able to dedicate the time necessary to acquire it. Once I've completed all of my tests I will post pictured results as I've previously stated. I believe many-a-GL'er will benefit from my pioneering efforts in this often ridiculed road.

I appreciate your debate. It is fruitful one.

:clapper:
 
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#33 ·
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Big Cahuna wrote:
What do you think would happen if the bike should have a backfire thru the carb?
Nothing.... essentially.

I can induce the controlled detonation characteristics of a backfire, but as of yet have not tried. I have thought about it though.

The effects ofa backfire that give me the small amount of concern I have are limited to that of sonic shock and nothing more. A manifold properly constructed and mounted should have no issue with the known tuning issue mishaps available. There are variables though, and physics drive that car.

IMO, anyone contemplating, then attempting this manifold route should expectbackfire(s) upon the bikes first starting attempts. I thought I detected a subtle detonation on mine when first started but nothing significant in its affect. I had a properly tuned carburetor that was previously running the bike.

The amount of time it would take for a fire to start and then be extinguished is sufficient for any *normal person to deal with.

*Some would say that anyone using a manifold designed from PVC is not normal to begin with. All I can say is be prepared as you normally would for such a event whether using a manifold made from PVC or any other material.

Putting my bike in a intentional state of detune to induce the effects is something I would rather bypass. But... in all fairness to my testing... it will have to happen sooner or later. The personal shame I sacrificially put myself through...
 
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#34 ·
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Well if it works then you have done a service to others who would like to accomplish this with everyday backyard tools and materials.

Good luck with your endeavors, and I hope it does work. PVC is readily available, not hard to come by and if certain fittings and standard forms will work into the design that would work well.

Consider CPVC though it you do get into cracks or heat problems. CPVC is much more sturdy and flexible and just plain tuff. Not brittle and tempered to withstand heat, and even if heat is not present, the temper of the plastic is what makes it strong.

That in large bushings such that can be shaped and fitted are available, maybe not at the local store, but any large supply house can get them and they do not cost a whole lot.

You could take a large 2 by 3 or 3 by 4 bushing and make just about anything like that out of it.

Nylon and advanced poly thermoplastics are not available commonly to all. There might be some supply house that sells it in molded blocks, do not know.

Anyways Good luck.

I will save the engineer joke till one day in person, much more fun that way. :cheeky1::cheeky1:

Kit
 
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#35 ·
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...a shameless bump indeed!
 
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#38 ·
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I was thinking as I read this post, how about extra heavy PVC? Did a google search and found this site. The one thing that looks bad is they say the highest temp for use with PVC pipe is 140 degrees f. I would think where it would be used would be hotter then that. Might not be the best choice for the manifold.,http://www.harvel.com/tech-specs-pvc-pipe-80.asp
 
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#39 ·
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Big Cahuna wrote:
I was thinking...
BC, PVC comes in many different formulas, and can be formulated in many different ways. It is a plastic whose properties con be tailored. Standard s40 plumbingPVC piecesare sufficient to use as manifolds for our bikes.
Crayola Crayons and their 64 colors could be given as a example of the many different types of "PVC", but 64 is a fraction of the true number of possibilities.

Manycharacteristics of s40 PVC are comparable to the characteristics of a standard grade ABS mix, such as that used in my Vetter fairing. Type 1 schedule 40 PVC is stronger than standard black ABS plastic in all respects, but comparable. My plastic ABS Vetter Vindicator is still going strong after 30+ plus years.Granted, it has not been sprayed with gasoline for 75K miles and it is not made of PVC but I suspect it would still be functional if it were. There is more than oneGL out there that has successfully proven this for more than a few years that I am aware of. Quite possibly more.

:byebye:
 
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#41 ·
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PVC tubing,

I had to buy all types of materials and I needed to get familiar many types of products plastics are one area. What I know could fill a thimbleful, I don't claim to be an expert, or even some to look to for answers. Just someone who has spent a little time with it.

Well, I can see why you picked PVC, it has good chemical resistance, so your good there.

There are different types of PVC,

type I Good corrosion/chemical resistance lower impact vibration resistance used as an electrical Insulator, or fluid transfer pipe, water, air

type II same as type I but has a high impact resistance as well, higher tensile strength so you no longer have a material that can easily crack, due to vibration or temp as type-II is good for -50 to +140F deg.

CPVC is a high temp version of PVC operating temp +0F to + 200F used as chemical Processing & metal finishing, it is fairly tough a higher hardness than Type-I

My experience using the type 1 PVC tubing, putting in water pipes, The cement makes an air tight seal melting the two pieces into one.

I used type-1 pipe to run air lines in my shop and I run 130-PSI compressed air to run air tools all the time.

Westgl
 
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#42 ·
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CaptainMidnight85 wrote:
Big Cahuna wrote:
I was thinking...
BC, PVC comes in many different formulas, and can be formulated in many different ways. It is a plastic whose properties con be tailored. Standard s40 plumbingPVC piecesare sufficient to use as manifolds for our bikes.
Crayola Crayons and their 64 colors could be given as a example of the many different types of "PVC", but 64 is a fraction of the true number of possibilities.

Manycharacteristics of s40 PVC are comparable to the characteristics of a standard grade ABS mix, such as that used in my Vetter fairing. Type 1 schedule 40 PVC is stronger than standard black ABS plastic in all respects, but comparable. My plastic ABS Vetter Vindicator is still going strong after 30+ plus years.Granted, it has not been sprayed with gasoline for 75K miles and it is not made of PVC but I suspect it would still be functional if it were. There is more than oneGL out there that has successfully proven this for more than a few years that I am aware of. Quite possibly more.

:byebye:
The point of my post was where it actually states the recommended temp rating for schd 80 pvc, which is twice the wall thickness as schd 40, is only 140 degrees. And being the location of where on a wing it will be used should get to that temp or above. longevity would be my biggest concern from vibration. It was already posted that pvc tends to get brittle when exposed to sunlight, so by exposing it to heat as well would hasten its lifespan. I'm sure it would work for a while, but I would have more faith in the manifold if it was made from copper and sweated together. As far as the Vetter fairing, I'm sure the actual abs plastic has a coating of paint or resin like a fiberglas boat has. Where the pvc is just exposed to the air, sun, gas, ozone, and all the naysayers that say it won't work.,,
 
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#43 ·
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westgl wrote:
PVC tubing,

I had to buy all types of materials and I needed to get familiar many types of products plastics are one area. What I know could fill a thimbleful, I don't claim to be an expert, or even some to look to for answers. Just someone who has spent a little time with it.

Well, I can see why you picked PVC, it has good chemical resistance, so your good there.

There are different types of PVC,

type I Good corrosion/chemical resistance lower impact vibration resistance used as an electrical Insulator, or fluid transfer pipe, water, air

type II same as type I but has a high impact resistance as well, higher tensile strength so you no longer have a material that can easily crack, due to vibration or temp as type-II is good for -50 to +140F deg.

CPVC is a high temp version of PVC operating temp +0F to + 200F used as chemical Processing & metal finishing, it is fairly tough a higher hardness than Type-I

My experience using the type 1 PVC tubing, putting in water pipes, The cement makes an air tight seal melting the two pieces into one.

I used type-1 pipe to run air lines in my shop and I run 130-PSI compressed air to run air tools all the time.

Westgl




Do not use PVC piping for air lines. They will burst eventually. And when they do, it's like a bomb going off. Hopefully it happens at night when no one is in the shop.



Check on the garagejournal.com forums. Lots of discussion on the subject.



They may work for you a long time..but I would not risk it after looking into the topic. Black iron is about the best choice. Copper isfine as well.
 
#44 ·
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Not an argument from me BC, just a factual debate...

Schedule 40/80 PVC are both Type-1Classes of PVC.
Type-1 service ratings are not generic, but are specific for the polymers used.
Type-1 PVC (allplumbing PVC available) is defined with ASTM standards and UL listed for itsintended service. Everyone, everywhereuses the same composition because of this for PVC sold in this Country. Other Countries may have different, additional or supplemental standards, but all rely on the ASTM standards for comparison. Additionally, there are ANSI and NSF ratings, but I'm trying to keep it short.

ASTM Type-1 PVCstandardizes schedule 40/80 PVC with:
a melting point of 360°F
a continuous service ambient air temperature rating of *160°F@ 264psi (*temperature rating goes up with less pressure)
a deflection temperature of *154°F@ 264psi
a Rockwell hardness of 112

Chlorinated PVC (CPVC) has different properties (as noted by Kit above) with:
a melting point of 395°F
a continuous service ambient air temperature rating of *200°F @ 264psi
a deflection temperature of *224°F @ 264psi
a Rockwell hardness of 117

AllSchedule 40/80can be had in Type-2 ratings which would increase its thermal properties, rigidity and strength.

Those are just base figures for base calculations for a given design using base products.As I've said, PVC comes in many different formulas. Those that work with it know. Corzan®, for example, is a high grade proprietary PVC mix. It comes in standard plumbing fittings configurations and its ratings are significantly higher than either Type 1/2. A continuous service ambient air temp rating of280°F is base for that product for example.

Don't misunderstand the pricing of high-end PVC compositions.
The suggested retail price of a Corzan® 2" elbow is over $100... A manifold of any kind made from the stuff would be exoticby anyones standard.
Other mixes have even higher ratings and costs. High temps and plastics don't come cheap.

As I've noted; manifolds from Type-1 schedule40 PVC plumbing fittings are certainly in use and have been for some time.The 140° rating is a code-derived safety rating and should benoted, yes. I've tested using it, and it held-up. I had to test it 'cause others are using it. I had to know for myself.
I am using schedule 80 CPVC for my duals though. It is not that much more expensive. The availability of CPVC is the same as PVC and I've gravitated towards that. That is the process of experimentation and my anal, common sense conclusion since the threads start. For a few bucks more, you get more temperature. I applaud some fellas for having run PVC for years with no ill results. It makes my choices easier. No area of contact on my bike sees the plastic exceeding the temperature limits of Type-1 PVC thermal ratings. I realize you are suspicious, but it is true. Other Forums have members that have proven results and we here shall have the same.

For the curious, a couple of these CPVC set-ups (minus a few+ visual pieces and lots of shaping) and your dual-carb set-up is a day away for about $130. A single-carbset-up is about half the cost plus a hair. Going the Clear route would be slightly more expensive and it would take an artistic hand to look perfect... Schedule 40 is ridiculously inexpensive. Coating (or painting) the end result is additional in recommendation, cost and labor and could be made to give it a unique look. But hey, its plastic... Make it known as such. The real-deal pics on my bike will have to wait for another day.
 

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#45 ·
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Sorry Tom2, you posted while I was writing mine up... Not meaning to step over your post. :byebye:
 
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