Polishing needles

[8_Ball_Customz]

I have seen people mention this several times but no real technique. What exactly does this consist of and what is the procedure?

[learn_it]

It is a fairly simple procedure. You need a fine cutting or rubbing compound and a soft rag or lint-free towel. Simply put a dab of the compound on the towel and spin the end of the needle over and over.

The compound smooths out and refines any factory/milling edges on the needle and gives it a very smooth surface that will reduce wind turbulence and give you a better line.

Now, this being said... it is possible to ruin your needle if you are too aggressive. You DO NOT want to go nuts and change the shape/taper of the needle as that will cause another whole series of problems. The best way to avoid this is to do the procedure by hand (dont stick the needle in a drill or dremel) and use FINE polish.

[Jeroen - CDM]

They say it takes the quality and perscision of the needle away.... (at least with a wetstone...tuning it)

'factory made is the best you'll get...' Offcourse if the tip is bent...ya have no choise..

[redanner]

Diana said it all except I use toothpaste! You will not find a finer polishing compound as toothpaste! Its really hard to be aggressive with toothpaste! I also use deer leather hide as the polishing rag the rough soft side! The other side is smooth & soft also! I just wash the toothpaste off when I'm done!

[colourshift]

I use 2500 grit sandpaper to remove any machining burrs on the needle, dragging while twisting the needle, in the direction away from the point (so you're not catching the needle tip against the paper) Then I use Maas metal polish and a paper towel to gently polish the needle.

[SmittyDidIt]

Just to add...I've seen a tip on using a drill for this...this is the way I do it now. Same method, only put the needle into the chuck of the drill, support the end of the needle in the other hand and then as you slowly turn the needle( you don't need high speeds) I gently move the tip into the buffing compound. If you try it I definately have to stress that you have to support the tip with your other hand or you will more than likely bend the needle. I've also used this method for straightening out bent tips.

(Disclaimer- this tip is not my own creation but instead was found while surfing thru different forums)

[redanner]

Just to add...I've seen a tip on using a drill for this...this is the way I do it now. Same method, only put the needle into the chuck of the drill, support the end of the needle in the other hand and then as you slowly turn the needle( you don't need high speeds) I gently move the tip into the buffing compound. If you try it I definately have to stress that you have to support the tip with your other hand or you will more than likely bend the needle. I've also used this method for straightening out bent tips.

(Disclaimer- this tip is not my own creation but instead was found while surfing thru different forums)

Great tip SmittyDidIt but one problem I like speed and the friction from the needle would burn my hand! You know how to tell if the needle has a micro hook on it? Stab your finger with it! If it bleeds you have a hook if you don't bleed then your not human!

[Shiva]

Just to add...I've seen a tip on using a drill for this...this is the way I do it now. Same method, only put the needle into the chuck of the drill, support the end of the needle in the other hand and then as you slowly turn the needle( you don't need high speeds) I gently move the tip into the buffing compound. If you try it I definately have to stress that you have to support the tip with your other hand or you will more than likely bend the needle. I've also used this method for straightening out bent tips.

(Disclaimer- this tip is not my own creation but instead was found while surfing thru different forums)

I got some very fine (Meguires?) polishing compound from Walmart, and use a slow speed cordless drill as well.
paper towel, with the compound on the towel.. geltly press into a fold of the towel and turn on drill
my NEW tips immediately turned the polishing compound black.
once they were polished, fresh compound and a repeat gave no new black stuff on the compound.

[draggin81]

I use some wet 2500 grit sand paper to smooth things out and round the edges off (where the needle starts its taper).
Then polish with Mothers Polish, 10,000grit sanding gel (eastwood), then 0.5um diamond paste (got it from a supplier through ebay).
The diamond paste is THE finest polish you will find. Period.

Also, you don't needle to polish the needle from end to end. Just polish from where it meets the back of the paint cup on forward. If you're not sure, then just polish the front half.
You'll have to re-polish it once in a while, maybe every few weeks at the most. Oh yeah, DO NOT use a drill or dremel tool. Especially not for your first try. Thats just asking for a useless needle.

[8_Ball_Customz]

Thanks to everybody for the response. I have fixed and polished a bunch of needle tonight and even tried a custom taper. I know I know but I just wanted to see how it does. LOL

[fontgeek]

If you are polishing to remove the machining marks as Diana wrote originally, then you should only be polishing your needle ONCE.
Using a drill, dremel, etc., makes it way to easy to remove too much material and change the shape of the taper in the needle, and even the finest polish is still removing material, whether it be by hand or by machine.

When you change that taper, and then push that needle into the nozzle, you are probably damaging the nozzle and making the needle so that it no longer seats smoothly or properly. The original taper on the needle is designed to interact smoothly with the nozzle, when you alter one half, you scew up the very performance you paid the big bucks for.

Instead of butchering your airbrushes, try practicing. That polished needle will at best help you keep your brush a little cleaner, since the needle only keeps the paint from entering the nozzle cap, it doesn't have control on the paint as it is blown out of the brush, that happens in the nozzle cap, where the paint and air are mixed and sprayed out of the airbrush.

There seems to be a misnomer that the air and paint pass through the fluid nozzle, and that the needle is going to cause all these turbulents. They don't. If they did, you couldn't open the valve for the air without opening it for the paint too, and you would have that air pushing back through the paint passage all the time. The needle and nozzle control the paint volume that you can spray, the only part of the needle that interacts with the air is that little tiny bit of the tip. If it is clean and straight, then it will perform.

For the polishes you are using, can you use a magnifying glass or loupe and see the abrasives?

With that same loupe or magnifying glass, can you look at your needle and see those pits or ridges at the tip?

If you can see the abrasives, but can't see the pits and ridges, then it means that your "polish" is going to be cutting bigger ridges than you are trying to take out.

If you have to "polish" your needle more than the first time, then you are not taking care of your brush, those ridges, bends, etc. are from not getting your brush clean, or from banging up the tip of the needle.

Do you want your brush to perform at it's peak, and last?
Keep it thoroughly cleaned, and protect the tip of the needle from damage, the polishing most of you are talking about does alot more damage than good.

[SmittyDidIt]

Just to point out one thing on my comment in this thread...is that when I use a drill, I am using a very slow speed on my drill and using the drill also helps to keep a consistent polish as you go over the taper of the needle. Based on what I've learned in my background (machining) it is always easier to turn a smooth surface without the risk of creating flats on the curved surface. Flats are created if you don't turn the needle as you are trying to polish and assuming you may be using a too rough of a sandpaper. For me I'm comfortable with doing it this way, for others its just a suggestion.

Also just to drop this in on what Fontgeek has said, the airbrush is all based on a venturi principle, so if ya wonder what that is, check Wikipedia and that'll explain how it works for those that don't understand the principle.

[egneg]

Forget the drills and liquid polishes. Get some crocus cloth (commonly used by machinists) and tape it to a flat surface such as glass. Now take a very good look at the taper that is on the needle as you don't want to change it even slightly. Use your finger on the taper to keep it in contact with the crocus cloth and rotate the needle by hand. Do not try to push the needle forward or back just rotate it. Use a machinists loop (75X) or something with high magnifying power to inspect the needle.

[fontgeek]

egneg, that's good advice.
What kind of abrasive rating does crocus cloth have, and where can we get crocus cloth?
Is it sold under some other name?
I'd love to find a 75x magnifyer, my strongest is a 12x.

[redanner]

Thanks for the tip egneg! I copied it and saved it as a word document! You may think I'm crazy But I sometimes use what is called Rock Wool it is nothing more than insulation that is blown into the attic! After I clean the needle I use the Rock wool dry and it cleans any tarnish or pigment stains off the needle with no effort! Don't ask me why because I don't what that stuff is made of!

[Shiva]

crocus cloth WAY too coarse..
used that in machine shop.. if the needle is THAT bad, throw it away cause touching it to the cloth just destroyed it, IMO.
I got waterproof sand paper down to 4,000 grit, and ONLY IF the tip was serious and I had no other handy to replace it with would I start there.
15,000 grit polishing cloth is SO fine, that you cannot tell its actually cutting.
as for a 75x magnifier? everyone has them.. go to a GOOD toy store and get a kids microscope set.. usually get 100 or 200x in them easy.

IMO.. and NOT having dug into the 'needle production finishing' from the factory, I am 'guessing these are probably machine fine ground. this will most likely leave 'some' rough edges, just due to the grit of the grinder..

take a piece of a table top, spread inch gravel on it level, and carefully blow some smoke with a fan low down and close to the gravel top-sideways.. notice the turbulance over it..

lay a piece of 80 grit wood workers sand paper down and repeat.. LESS disruption in the flow pattern.

this 'polishing' that everyone is getting bent outa shape over is nothing more (WITH THE PROPER grit/substance/technique) than knocking off the 'high spots' that are left by the production finishing. this does decrease the weird air currents that would be thrown up by the air passing over a 'boulder'...
and it SHOULD NOT if PROPERLY done, cut ENOUGH to make the needle no longer fit the tip. we are talking MICRO fractions.
assuming you had the tools to measure before and after, take 400 grit wet or dry paper and measure a small piece of steel across a dimension.. wet the sand paper and rub this piece on the sand paper for 5 minutes and REMEASURE.. depending on hardness etc, you might see some 'thousands' removed.. IIRR the average hair is .005 to .007 thousands. if you EVER take that much off a needle- its ruined. UNLESS you got GOOD measuring tools AND the knowledge of what shape you want.
taking the Mothers or Meguires or similar polish, you could possible taking off something akin to the 'hundreds of thousants range..
.0000x range. think dividing a hair into 500 parts for starters OR LESS.


the IDEA is air flow, directed and SMOOTH.. not directed and wild, which I could see happening if the tip was not totally as slick as possible.,
I cannot see the factory devoting the time and extra machineing necessary to produce a 'mirror finish' on something as cheap to make as an air brush needle

[fontgeek]

Shiva, your math is nice, bu† when you put your needle in a drill or dremel, you are spinning at a fairly high rate, and if you take each revolution as a pass over the sandpaper, then your own math says that they are going to be taking a good bit more material off the needle.

Keep in mind that when you push down to get air, and then pull the trigger back to let the paint out, that you are pulling the needle out of the path of the air, and that if you have the trigger pulled back only slightly, that only the very tip of the needle remains in the path of the air.

Shy of a hooked or bent end on the needle that makes the paint hang up, or damages the nozzle, the polishing only effects how the paint might flow over the needle and through the nozzle.

If you are trully going after the machining marks from the factory, then you should only have to fight this battle once per needle. If you have to do it more than once, then you are adding the rings or damage to the needle yourself. If you got rid of those machining marks when you first polished the needle, then there shouldn't be any left for you to polish off on any more polishing sessions.

[Shiva]

1200 grit sandpaper had a 'grit' that is .00026 inch.
I am using something that is over 10 times finer. 15,000 grit.. you cannot take off a lot of material with that, plus the low speed drill used is probably in the 600 rpm or less range.. plus we are not talking minutes of polishing, but seconds.
I did mine under 10 seconds and probably closer to 5.
turn on, with the needle in the fold of paper with polish in place-count 5.. polish is black and I am done.

to prove this doesnt make a big diff, put the AB tip assembled underwater and push DOWN on the air, leave needle fully closed in tip, do this before and after.. see if you get air leaks.. and YES, is a 1 shot deal as far as polishing.

[egneg]

As with sandpaper crocus cloth also comes in different grades - I guess I should have mentioned this in the original post. I use the finest grade. The type I have has a surface that is almost as smooth as paper. It wears very quickly and that is why the needle is not moved. Just turn it a few times and as the cloth wears a away it gets smoother and you are left with a truly tapered and highly polished needle.

[draggin81]

Since there are particles in the paint we spray over the tip of our needle, there is wear and tear.
It may not seem like it, but all paint has solids in it, which act the same as "grit". Eventually, these solids will score the needle and, eventually, the nozzle.
Nozzles are typically made of huch harder alloys, so they are pretty wear-resistant. Needle are made of stainless steel, which by it's nature, is a soft metal. It is also porous, which traps paint particles in it's micro-pores. No matter what cleaning methods you use, these things happen. It's simple physics.
So, since you are essentially spraying grit over your needle everytime you paint, your needle will eventually need to be re-polished to maintain optimum performance. And, eventually, your nozzle will need to be replaced as well. Any time you have anything moving, wear and tear is going to happen.
Polishing the "stalk" of your trigger, the back lever, the spring holder and needle chuck, and the edges around the trigger slot can yield a smoother handling airbrush, too.
As for using custom shapes, I say go for it. It's your needle, and your money. Give it a try. I have piles of "hits" and "misses" from expirimenting with needle shapes.
First off, no factory anywhere matches thier tips and needles when putting together and airbrush to ensure optimum fit (Microns HEADS are matched, wich simply means there nozzles are centered in the air cap hole). For them to do so would be fiscally impossible. They just try to make everything as identical as possible so things fit close. There are tolerances in every manufacturing process, though.
At first, I tried making the taper os the needle as long as possible, having a sharp a point as possible. Eventually, though, I found that s lightly convex shape works best for me. It allows that "right now" response, and fits my style.
It might not work for everyone, but it works for me. Like I said, it's your needles, your money, and your airbrush. Understand that you probably will ruin more than a few needles, and most likely a couple nozzles. What you won't do is damage your airbrush beyond repair (just don't pull a bent needle back through the body).
I can send you a few pics of some needle shapes that I use if youd like. Just IM me.

--oh yeah, I still advise against using drills or dremels, but if you have training as a machinist you know what your doing. If you dont, doing it by hand is probably a much safer bet. Especially if you accidentally bump the needle on something while the drill is going and bend the needle. Now you have a really, really sharp propeller in your hands, and it could very well hit something painful before you get your finger off the trigger,

[redanner]

This is for any person new to airbrushing! I agree with both opinions in this thread! There is nothing wrong experimenting honing or polishing needles if thats your desire! The only time I have worked my needles is when I've had a micro-hook at the very tip or the needle is bent! I would suggest any body new to this art form to always run water through a new or used airbrush you have just bought! This is to see if it sprays! If the used airbrush has damaged or altered parts I would replace them immediately! Then I would practice with what you have to see how its suppose to work from the factory for a period of time! After you are satisfied with the experience of the factory airbrush's performance then only would I consider altering an airbrush if it does not perform well or the way you think it should! If you do alter it with any advise from the ABT Forum and screw it up and need to replace parts that will be your decision and doings nobody else’s!

"I am he as you are me and we are all together" --The Beatles

[Frog]

I polish my needles when new. I dont polish again after that as I see no need. They are already smooth.
I would NOT recomend a newbie to polish there needles until they have the experience to KNOW if it made any difference (good or bad ) because until they have good control hiw can they know.
If a newbie polishes there needle and screws it up they are not going to know and will have a harder time learning.

[ARTSPRAYJ4J]

if in daubt do without

all my needles are polished i have also retapered some, i use a drill and a traditional oilstone ,others dont touch thier needles

there are at least two schools of thought about this subject and each is as valid as the other ,what i will say is needles wont break the bank so buy a spare just in case you are not happy with the results obtained by polishing

polishing increases paint flow for a faster more responsive airbrush especialy at lower air pressure when fine detailing it also helps with tip dry problems

for general airbrushing the benifits are negligable

the choice is yours

paul