Badger 3155
6/2011
Badger makes a model 3155 airbrush which is like a 155 with a finer needle and a different trigger mechanism.
These three parts will also fit the in the 155.
Needle P/N 51-081DT
Tip P/N 41-003
Regulator P/N 41-033
The tip and regulator also fit the model 175 brush, but it uses fine needle part no. 41-006.
I was able to get all three parts for about $15.
Here is the difference in the two needles:
At the top is the regular 155 needle and the bottom is the fine 3155 needle. Note that they both have a double taper, but on the fine needle it is a tiny section right at the tip. The main taper is steeper on the fine needle but continues to a much smaller diameter. The fine regulator and tip have smaller openings to match the needle. The output opening of the fine tip has an inside diameter of about 0.020" or 0.51mm whereas the normal tip measures about 0.030" or 0.76mm.
I found that I could actually produce fairly fine lines with this set-up, even with pressure set as low as 10psi, which surprised me.
Above is a sample done on paper towel using Floquil flat black thinned 1:2 paint to thinner. I also noticed that, with this needle, I had to stay farther back to produce the same width of spray pattern. Apparently the cone of the spray is much narrower. Also, there is no sudden change when the trigger reaches half way as there is with the regular needle. You can't blast out as much paint either, but I was able to cover fairly large areas with no problem. On the negative side, the needle appears more fragile. With the 155 head assembly, there is no protection for the needle. My guess is that this is why they put the small secondary taper on the end. It makes the needle a little shorter and tougher, and they probably found that it had little or no effect on spray quality.
One note: The main shaft of the fine needle was not as smooth as the original and didn't move as freely though the needle bearing. However, this was easily fixed with some light buffing with very fine abrasive paper used wet.
So, if you have a 155 and you don't like the way the trigger sensitivity changes at mid position, this is a low cost solution. I still feel more comfortable with the regular needle, probably because that's the one I'm used to, and it does everything I need. But, it's nice to know that I have the option for doing really fine work if I want it.