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Nitrogen to spray with?

31K views 106 replies 33 participants last post by  powerrodsmike 
#1 ·
Anyone noticed any diference using nitrogen to shoot their paint with? I can get a 230 bottle(biggest) for $16, so it's cheap enough if it makes a difference. I know I wouldn't have a water problem.
 
#52 ·
Is the nitrogen being used on the planes that fly higher? I mean, REALLY on all of them? What was the big difference when they weren't using it? For that matter, when were they just using air, when did it change?

Brian
 
#53 · (Edited)
It's a heat issue.
C/P
The reason airlines and race car crews fill their tires with nitrogen has absolutelly nothing to do with rate-of-loss or oxidation or even fuel economy. Nitrogen expands and contracts at a lesser rate with changes in temperature than atmospheric air. The process of separating the nitrogen out for the tanks used in this process removes the moisture content in normal air. It is the presence of moisture that causes the noticable increase in tire pressure with temperature increase. This is a BIG deal when you cruise at 200mph for 500 laps and you need all the traction you can get (meaning keeping the pressure as low as regulations allow).

It makes a big difference on airlines for massive planes coming into land where tire temperatures skyrocket rapidly. Again, keeping expansion down gives the pilots better traction, hence better control, during the rollout.
 

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#54 ·
milo said:
It's a heat issue.
Nitrogen expands and contracts at a lesser rate with changes in temperature than atmospheric air.

There would be NO change in internal tire pressure due to a decrease in atmospheric pressure. There would be a slight increase in the DIFFERENCE between internal and external pressure due to the fact that atmospheric pressure would be less at altitude, but even this would most likely be more than offset due to the drastic drop in temperature that occurs at higher altitudes. As far as using Nitrogen to control pressure on aircraft tires it very well could make a difference on landing with all that heat build-up and the point about the moisture content in regular compressed air makes a lot of sense.
 
#55 ·
Ok so I figure I should get this right since I started it with erroneous info, so I did a bit of research. Nitrogen offers the advantage of being dry, inert (does not support combustion), and does not damage the tire inner liner. It is also stable with temp change which is a big concern in aviation. Not in a cessna as that is not much different than a car, but in airliners, fast jets, heavy transport.

Here's a couple of links with good info.

http://www.getnitrogen.org/why/index.php

http://www.physlink.com/Education/askexperts/ae192.cfm


As for my comment about expansion at altitude I have no idea why I said that. Even though there is a difference in pressure at altitude the tires internal volume of gas will not change, regardless of the gas inside. The pressure differential would increase and the tire would 'grow' as altitude increases but it wouldn't matter what gas is inside as to how much growth you would have. Due to the construction of the tire it would probably be negligible.
 
#56 ·
Speede, There must be some big advantage to using Nitrogen, I have noticed that several outfits now offer Nitrogen tire inflation outfits that are quite spendy, don't know why someone who wanted to use it could not just use a tank of compressed Nitrogen and a regulator it would be a heck of a lot cheaper? :confused: Nitrogen (using a tank and regulator) is used on suspension struts on large off road haul trucks and the same equipment used to charge these could easily fill tires since it is just a simple regulator, hoses and fittings. Since these struts are partially filled with oil they would certainly diesel under load and shock if regular air was used so it is understandable why they use Nitrogen but I have never seen it used in the tires of these big rigs though, maybe it would be a good idea? The sales pitch for those tire filling rigs (I think even Harbor Freight has one!) claims substantially longer tire life and increased fuel mileage so maybe it is something that will soon become common.
 
#57 ·
We use it on tires, struts, hydraulic ressvoirs and accumulators. We use bottles but I know that when I was in the military we had a few nitrogen generators. Very expensive back then. As they are becoming more common the cost may become more business friendly but even with our volume we can't justify anything but bottles. Mind you our bottles are in a cart with a regulator/booster that is worth 5g's or so. If nitrogen is that much better for tires I would imagine trucking fleets would benefit from it's use. How long does a tire last before it gets chucked these days. I've never heard of a problem with inside tire wear (how many times can you recap a tire) so I would suspect the big gain is stable tire pressures which give better, more consistent gas mileage. On the stock car after just 25 laps our tires pressures can rise 15-20% using air.
 
#58 ·
Fundamentally, air, oxygen and nitrogen will all behave exactly the same, in terms of just how much pressure will change for each 10 degrees of temperature change. However, temperature alone is not the whole story. Ambient air contains moisture, which nitrogen does not. If moisture is there, it contributes to a greater change in pressure, simply because at lower temp, water condenses to become a liquid. A liquid form of water occupies very little volume and contributes only a negligible pressure to the tire. But at higher temp, water becomes a gas; water evaporates inside the tire as temperature rises. With ambient air, which contains about 20.9% oxygen, the oxygen permeates through the rubber of the tire, so some leaks out. With nitrogen, containing only a little residual oxygen, pressure changes due to oxygen loss are greatly reduced. So, on both counts, the race car guys are correct; nitrogen is more predictable - nitrogen is dry; it has no moisture to contribute extra pressure changes with temperature. And nitrogen permeates out much slower than oxygen, so pressure changes due to that leakage are almost eliminated, compared with ambient air.

The Paragraph above was taken from the link
http://www.getnitrogen.org/why/index.php.
Does anyone else see 'BS' written all over this paragraph?

As the link says all gases expand at the same rate so you will see the same increase in Pressure with a measured increase in temp. for air as Ni. (or for any mix of gases for that matter).

“But at higher temp, water becomes a gas; water evaporates inside the tire as temperature rises.”
If water becomes a gas then it behaves exactly as the other gases including Ni, they say that in the first sentence. With regards to moisture content in the tire can someone explain to me how water vapor that expands less than or the same as a gas can affect the total volume/pressure of a tire when it occupies less than 1% of the total gas in the tire. This reasoning has been mentioned a few times in this thread. If you believe this and want a gas that is dry and behaves exactly like Ni fill your tires up with the same air you spray paint with. No moisture, no problems.


“And nitrogen permeates out much slower than oxygen, so pressure changes due to that leakage are almost eliminated, compared with ambient air.”
How is the leakage of a few molecules of air going to affect a tire in a few hours of a race? (Even if this is true your talking about such a small amount of time difference it is probably incalculable).



Keep in mind this web site is put there by the people selling Ni. I think the Ni theory for road vehicles should be on the same shelf as the rest of the snake oil products that the auto industry seems to be saturated with.

I have yet to read a decent explanation as to why it is advantageous to use Ni in car tires.
 
#60 · (Edited)
Oh right the original post.

I have no clue. I have never sprayed a car. You're the expert - you should be telling us!

Sounds expensive though.

Edit - Brian -- You know I am serious about that. I am tired of being told by companies trying to sell their products what is true or false. It is up to people who know what they are talking about (like yourself) to debunk these myths and stop people wasting their hard earned cash on crap. Thank god for forums and the internet, if you look hard enough you will always find the truth. (Also thank you Jon for all your hard work on your powerTV detective work)
 
#61 ·
No, I am out of the paint business these days other than just at the shop kinda stuff. If I was still a rep I would be in the loop, but come to think of it, I can call a few people.

I'll do that tomorrow.

Brian
 
#62 ·
Most of the theories I see regarding Ni in tires focuses on the 'fact' that Oxygen leaks out of the tire faster than Ni. If you take a minute to think about this you can see how ridiculous this hypothesis is.

Lets say I fill my tire to 50 psi with regular air. If we round up figures and ignore trace gases to make calculation easier then the tire has 80% Ni and 20% Ox. Now if we are to believe the Ni companies the Ox. will leak first as it is a smaller molecule. When the pressure goes down to 40psi we can assume all the Ox. has leaked out and the tire now contains 100% Ni. We fill up again to the required 50psi and out of the replacement compressed air only 20% is Ox. Now out of the whole volume of the tire there is only 4% Ox and 96% Ni. It is only going to take one more fill up to put the level of Ox. below 1%. That is better than filling it up with pure Ni as that is only 99% pure!

Hey I have just realised I have my very own Ni generator (4 of them in fact)!! Better than paying more than $5000 for one.
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200331919_200331919
 
#63 ·
scrimshaw said:
Hey I have just realised I have my very own Ni generator (4 of them in fact)!! Better than paying more than $5000 for one.
Cool, if only the oxygen makes it through tires can we make respirator filters out of old tires too? :D

scrimshaw said:
Most of the theories I see regarding Ni in tires focuses on the 'fact' that Oxygen leaks out of the tire faster than Ni. If you take a minute to think about this you can see how ridiculous this hypothesis is.
I always heard that the main advantage to putting Ni in tires is the stability of pressure with temperature changes.

Speede5 attests to that fact in his post above.


Later, mikey
 
#64 ·
The 'theory' that Ni is more stable for a change in temp. is not true. Even the Ni companies don't say that. This is the first line of the paragraph that I got from their web site.

'Fundamentally, air, oxygen and nitrogen will all behave exactly the same, in terms of just how much pressure will change for each 10 degrees of temperature change.'

If you can remember anything about your old chemistry class :confused: this is one of the 'Gas Laws' which basically says all gases or mixture of gases expand/contract the same amount. (I had to look it up!!).
 
#65 ·
I have a friend who is using a nitrogen setup to spray at his shop. I have never tried it to see the pro and cons. He says it is great. He claims less trash,metallics lay out better,and no moisture. I really dunno. I may go run by and try it but I don't see my self changing over anytime soon unless my compressor starts making it own nitrogen. Tim
 
#66 ·
Yep, I called an old S-W rep friend of mine and he along with the S-W store salesmen both said the news of Nitrogen is going around the industry here (10 years after the Europeans of course) and we will be seeing more of it out there. Some shops are using it already. From what the S-W guys were saying they have only heard the news, no first hand testing yet. And, the pricing is just out of sight at this point only the high end shops are targeted. But it sounds like it is on the way!

Brian
 
#67 ·
scrimshaw said:
The 'theory' that Ni is more stable for a change in temp. is not true. Even the Ni companies don't say that. This is the first line of the paragraph that I got from their web site.

'Fundamentally, air, oxygen and nitrogen will all behave exactly the same, in terms of just how much pressure will change for each 10 degrees of temperature change.'

If you can remember anything about your old chemistry class :confused: this is one of the 'Gas Laws' which basically says all gases or mixture of gases expand/contract the same amount. (I had to look it up!!).

But the fact that Ni carries no water is the stated reason behind it's use.

nitrogen is dry; it has no moisture to contribute extra pressure changes with temperature.
I know at Poli-Form we had an Instafoam 500 foam gun that shot 2 part urethane foam for packaging ..The system required that a pair of 15 gallon tanks full of part a and part b foam be pressurized with nitrogen instead of shop air. The pressures were well within the range of any shop compressor.

.Using Ni from a 220 CF cylinder was mandatory as the chemicals that made up the foam would react with any amount of water (water was readily aabsorbed into the material as well), and make the mixing ratios at the head of the gun all weird. In part due to the water, and also the fact that each hose had a nichrome wire running through it to preheat the material...so any water in the lines there would react unfavorably as well.

For me, this is all academic. I won't put Ni in tires, or spray any paint with it..But the theory and application intrigues me.


Later, mikey
 
#69 ·
You are right but to be really correct Nitrogen is N subscript 2 the same as Oxygen which is O subscript 2 because they are both diatomic molecules which means they can't exist naturally as single atoms. But I didn't know how to type the subscript!! Suppose I could of written 'N2'.

Which is why I shortened it to 'Ni'.
 
#72 ·
Boy there is sure a lot of misconception on the internet about nitrogen. I really don't see a benefit to using it on the street in tires. Sounds like a gimic for people who here about racers using it so it must be good for them too. On this link http://www.nitrogendirect.com/N2Info.htm under aircraft/racecars i think is the best answer. aircraft and racecar brakes can easily get to the point where they are red hot, and the last thing you need is oxygen anywhere near that.

As for painting which is how this all got started, the only benefit I can see is the moisture control. The problem is nitrogen generators are cost prohibitive for even big paint shops. Bottles wouldn't last very long. I don't know, it's probably a good ides but so is a full professional downdraft paint booth and not many of us have those in their shops. Buy a couple of good airdryers/moisture filters and worry about more important tools.
 
#73 ·
Speede5 wrote --
As for painting which is how this all got started, the only benefit I can see is the moisture control. The problem is nitrogen generators are cost prohibitive for even big paint shops. Bottles wouldn't last very long. I don't know, it's probably a good ides but so is a full professional downdraft paint booth and not many of us have those in their shops. Buy a couple of good airdryers/moisture filters and worry about more important tools.
I was wondering the exact same thing myself. Wouldn't this

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200306679_200306679

accomplish the same thing as Nitrogen at a fraction of the price?
 
#74 · (Edited)
The filters or "separators" aren't perfect. The problem is compressed air has SOOOO much moisture in it. The filter has a LOT of work to get it out. First the air needs to be cooled, then ran thru the filter.

That is one of the questions I have, how much better could it be? Have you watched the video at the link I provided?

We are talking much more than a "filter", shooting with the nirtogen virtually eliminates static electricity!!!! The nitrogen is heated to the perfect temp. The atomization of the paint is controled by this process and not the as much the gun! They shoot the product with what looks like zero reduction! It looks like he is pouring paint right out of the can into the gun!

VERY interesting stuff.

Brian
 
#75 ·
Brian

I didn't watch the video, spraying paint is not something I do I leave that stuff to the experts.

I felt I must comment on something you said

The filters or "separators" aren't perfect. The problem is compressed air has SOOOO much moisture in it. The filter has a LOT of work to get it out. First the air needs to be cooled, then ran thru the filter.
The fact is compressed air is dryer than the ambient air that is being fed into the compressor. Anyone who has used a compressor should know this because the last thing he/she should do after shutting the compressor down is drain the water out of it and the filters/traps in the lines. This should tell you there is LESS water coming out of the compressor than going into it. Compressing air lowers it's dew point making it unable to hold the same amount of moisture.

The reason it is a problem in compressed air machinery is because it can't exist in the compressed air in as much of a quantity as the ambient air and therefore gets displaced as condensation in the tank, lines and tools and will get occasionally displaced and blown out with the compressed air thus ruining your paint job.

Having said that it does not remove ALL the moisture and I can certainly understand there is more reason to use Nitrogen on painting and other processes that are H2O intolerant but having done a bit more research on the tire issue I am convinced that it is another marketing scam to make us pay for something which we presently get for free!!.
 
#76 ·
MARTINSR said:
The filters or "separators" aren't perfect. The problem is compressed air has SOOOO much moisture in it. The filter has a LOT of work to get it out. First the air needs to be cooled, then ran thru the filter.

That is one of the questions I have, how much better could it be? Have you watched the video at the link I provided?

We are talking much more than a "filter", shooting with the nirtogen virtually eliminates static electricity!!!! The nitrogen is heated to the perfect temp. The atomization of the paint is controled by this process and not the as much the gun! They shoot the product with what looks like zero reduction! It looks like he is pouring paint right out of the can into the gun!

VERY interesting stuff.

Brian
That was an interesting video. Thats a lot more than just using compressed nitrogen from a bottle. That looks like something that would only be profitable for high volume manufacturing. I have to say again that anyone spraying as a hobby is best of sticking with air. If you can afford to play with nitrogen you should spend more money on tools and stuff.

But I would be interested in seeing it firsthand.
 
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