In-line Desiccant Filter Affect on Air Pressure

cmfisher4

Promoted Users
I've been shooting primer (epoxy and 2K) on my Spitfire project for a while now and I've only recently did a test run on an old panel that I took from bare metal through bc/cc. I'm learning still, of course, but it seems to be going okay.
I've always used an in-line dessicant filter between the gun regulator and the gun. I have moisture problems if I don't use one and I don't really have any other options unless I spend a bunch of money, which I'd rather not do.
I was messing around a bit today and decided to see what would happen if I took the filter off. I've always painted my epoxy at about 26# at the gun (compressor is about 110#) based on what I've read and the tech manual. With the desiccant filter off, at 26# the gun puts out A LOT more air at that pressure and it is loud (almost hurts my ears). If I leave the regulator set like that, but then put on the filter, regulator pressure bumps up to about 45# and the noise and air flow is about the same. If I then turn the regulator down to 26#, where I've been painting, air flow is drastically reduced as well as the noise.
This obviously has to affect how the paint will come out of the gun. This opens up a whole can of worms for me. I have never painted without the filter. So this leads me to believe that I've had my gun set up really wrong for a while now and have been getting lucky (or screwed, but I don't know it yet). I don't know what testing would look like at 26# without the filter, but I'm going to do that soon before I move forward with any more painting. I probably don't really understand the relationship between air pressure and fluid flow, either.
My question is which gun behavior seems proper: lots of air flow and lots of noise, or something less. I know it's hard without being there, but I'm trying to get a feel. Or should I just do some testing runs and see what happens?
 
You are correct. Your pressure gauge needs to be at the gun, after your filter, and measured with the gun trigger pulled. That is the only way you will know what you have.

I purchased a regulator/gauge from Amazon that is a true diaphragm regulator for a pretty reasonable price. I will see if I can find the listing.

John

PS, Here is what I purchased when I bought the new Iwata LPH400 gun.

https://www.amazon.com/gp/product/B0073NVA2Y/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
 
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yeah, I think this is why Barry recommends wall regulator settings, but things happen where clean are is more important when you have trouble. I even got some cheap couplers that seem to knock the air down on my grinders. Everything takes a toll.
 
I swapped the position of the regulator and the filter. Huge difference in gun behavior. I didn't lay too much paint down, but thankfully it seems like I don't have to change my technique (what there is of it). Paint lays down much smoother and consistently, too. Oh why didn't I figure this out before?!

Thanks, all.
 
Upon the recommendations of others, I bought both of these listed below:

https://www.amazon.com/Motor-Guard-...ocphy=9021536&hvtargid=pla-489471992847&psc=1

https://www.amazon.com/Motor-Guard-...coding=UTF8&psc=1&refRID=5KY00ENSY5TNNE8MDJRC

I am informed the DD1008 will flow better than the Harbor Freight stuff. Listed the link from this forum below:

http://www.spiuserforum.com/index.php?threads/dessicant-dryer-systems.6518/

Would be interested to see what you find out and are doing differently in the future.
 
Hi Chris. Thanks for all of the links. Turns out, I'm the guy that told you the Motor-Guard ones flow better, but that was before I figured out I had it all wrong on this thread. I didn't re-try them after I figured out how I was messing stuff up, so that may be bum dope!
Otherwise, I do have the M-60 filter. It's hard to prove a negative, but I've never had a problem with particulate in my painting. That, along with the in-line desiccant filters and I don't have any moisture problems, either.

Thanks,
Chris
 
As an update, Chris (and everyone else), I tested the HF today and I could not get my regulator to get air pressure above about 15psi. So, while it's a better number than I was getting before, I would not consider it adequate for painting. For $8 (use a 20% coupon and get it for about $6.50) it may be worth trying out to see if you get better results, but I stick with my original "not recommended".

Chris
 
Those little des. filters restrict. I have 2 of these, 1 before & aft motorguard. 1st one loads with water, keeps motorguard dry. 2nd one stays bone dry. 1 before motorguard's all u need, scrap little des. dryer. Try it.

IMG_2587.jpg
 
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