First impression procon boy ps-270 Mr. Hobby GSI Creos

Ahh..... not even worth wasting my $5 then. Thanks.

Do you have some good o-ring replacement that you can recommend or sell?
Ok, you’ve received some great advice / info here so how about you head over to the intro section and give us a little insight about you ?
Where you call home, what gear you have, what got you started, where you want to head.... etc :)
 
Well, that's actually something weve been working on together. I selected the material and manufacturer. They must be custom manufactured as they aren't available in the material and size..
Rings for different areas of the brushes will start to come available pretty soon here.
That sounds very cool. I’m always a little paranoid about ruining O rings. Nice job tracking down a supplier.


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So here's another update. I had my GSI up for sale the last week or so, just wasn't feeling it. So I remembered what I think @Robbyrockett2 said about changing to HP-B+ internals and I remembered I had a KopyKake airbrush a friend gave me. It was patterned after the HP-B. So I stole the needle seal out of it.
The needle had way too much taper to it, so I used a chinese .3mm Micron replacement needle. I ordered a bunch of the .2 and .3 needles before there was the Sharpenair. Also some might not know, but this allows you to run a needle that has a smaller diameter. I truly believe in the thin needles. So I got it all polished and prepped and man this thing is a BEAST.
The only complaint I have now, and it's pretty minor, is it takes more effort to depress the trigger than a Micron. It's not a spring thing, it has to do with PSI pushing against the mechanism, which must be larger than the microns.

So the test below isn't just about lines and how thin they are but good taper when closing the trigger, but that the paint starts where you want it to. I've seen plenty of airbrushes that were a crapshoot when the paint would start.
20181028_212220.jpg 20181028_212255.jpg
 
This I suspect was actually a problem with your 289's needle that I don't think would be there on a new factory needle.
Reason being, the taper angle from the factory between the 1.2 and 1.4 shafts are actually the same or extremely close originally.
I have both setups and both work the same, but I have to be more careful of how I work on the 1.4 shaft.

And in fact I believe it is a minor issue in the design of the sharpenair as well, the geometry of it would make a different angle on different shaft sizes. It favors the smaller shaft size.

I'll have to make some drawings to explain my thoughts and show what i mean so give me a little while.

Either way, a 1.2 shaft will tend to end up with a sharper angle when repaired or polished unless the repairer is extremely concious of this issue. So for that it may be a good choice anyhow.
 
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Ok so first. Here's a 1.2 and 1.4 shaft with the same taper.

IMG_20181029_183046.jpg

The portion of needle in the nozzle and protruding from it is identical and should perform identical provided the same taper angle.
The angle of course meets the outside of the needle on the 1.4 much further back and should appear to be a longer taper.


Also note, your Chinese .2 and .3 needles are likely identical to one another.

The minor issue ( one of two) on the sharpenair. Is a bit harder to explain but I'll give it a shot ince you've had a chance to see this.
 
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This I suspect was actually a problem with your 289's needle that I don't think would be there on a new factory needle.

I don't believe so. A needle designed for a .3mm nozzle is different than a .2mm nozzle's needle. I was using a .3mm needle in a .18 nozzle. Now a GSI 270's needle may have helped a bunch, but the other benefit is the 1.2mm needle takes up less real estate in the paint channel and nozzle itself. IMO, and that of Dave @ coast, having more room available for flow effects the ability of the paint to flow and react to venturi demands.
grex_xref_nozzle_kit_parts.jpg
 
Normally yes, they use a different angle. Chinese tend to be identical.

Angle on a .2 hp-b needle w 1.2 shaft and a .2 270 needle w 1.4 shaft is the same and both perform the same in the 270. Shaft diameter being the only difference .
Paint flow requirements of a fine line being nowhere close to pushing the limits of what can move through the channel regardless of shaft size.

.3 in a .18?
I thought you were talking about the 289 with a Chinese .3 needle?
 
Normally yes, they use a different angle. Chinese tend to be identical.

Angle on a .2 hp-b needle w 1.2 shaft and a .2 270 needle w 1.4 shaft is the same and both perform the same in the 270. Shaft diameter being the only difference .

.3 in a .18?
I thought you were talking about the 289 with a Chinese .3 needle?

I was using my standard 289 needle with the .18 nozzle setup. It fit and would work not too bad, but it was touchy. So I put the Kopykake stuff in, including it's needle and it was so far out the nozzle it was laughable. So I tried the .3mm Chinese micron one and it looked alot better. Looking at the .2 and .3 ones I ordered I think you are right, they are the same. But the KopyKake most definitely is not.
 
I was using my standard 289 needle with the .18 nozzle setup. It fit and would work not too bad, but it was touchy. So I put the Kopykake stuff in, including it's needle and it was so far out the nozzle it was laughable. So I tried the .3mm Chinese micron one and it looked alot better. Looking at the .2 and .3 ones I ordered I think you are right, they are the same. But the KopyKake most definitely is not.
Ah ok, this makes a lot more sense lol.
As the 289 needle would be likely to actually use a more blunt angle appropriate for a .3

Why not throw the .18 needle in there?


I'm guessing you're also talking not just .18 nozzle but whole head assembly?
 
Ah ok, this makes a lot more sense lol.
As the 289 needle would be likely to actually use a more blunt angle appropriate for a .3

Why not throw the .18 needle in there?


I'm guessing you're also talking not just .18 nozzle but whole head assembly?

Yeah I put that 770 head back on it. It's a keeper for sure now. I wouldn't recommend this method over say a complete 770, but it allowed me to use parts and pieces just sitting around.
 
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