HVLP spray gun cleaning and lubrication

[Frank Martin]

I am using a Fuji gravity HVLP gun spraying waterborne finishes. For lubrication after cleaning, is the oil used something special or is it same thing as the more commonly available air tool lubricant? I don't have access to spray gun lubricant locally and would need to mail order if it is indeed something special.

Thanks!

[Daniel Berlin]

I am using a Fuji gravity HVLP gun spraying waterborne finishes. For lubrication after cleaning, is the oil used something special or is it same thing as the more commonly available air tool lubricant? I don't have access to spray gun lubricant locally and would need to mail order if it is indeed something special.

Thanks!
Are you lubricating it because some manual specifically says to?
You shouldn't need to lubricate a spray gun after cleaning, and especially not with oil. This would be very bad for the gun, and could later cause fisheyes depending how much oil you used.
Every few years, make sure the grease on the various packing nuts is still good. If you are hobbyist, you will likely never need to do this part either.

Just to be sure, I went through all the fuji manuals they have on the website (IE the pre-2003, 2003-2009, and 2009+), and none say you should lubricate the gun. The only reference to lubrication i could fine is in in the pre-2003 manual, where it says if the trigger mechanism is sluggish, to lubricate the trigger pin.
That's it ;)

[Henry Ambrose]

I lube my HVLP with a little bit of PG2000, Boeshield or similar, inside and out. A tiny, thin coat of Boeshield especially makes the gun exterior easier to clean. I think most any light oil will work. Do not use silicone of any kind.

[Frank Martin]

Daniel,

I saw this in Jeff Jewitt's video on spraying that comes with his book (wonderful book and video by the way) where he suggests lubricating the needle after cleaning. Sounds like this is definitely not needed after each cleaning. I am just curious how often I may need to do this. At least for now, sounds like I should not worry about the lubricant just yet.





Are you lubricating it because some manual specifically says to?
You shouldn't need to lubricate a spray gun after cleaning, and especially not with oil. This would be very bad for the gun, and could later cause fisheyes depending how much oil you used.
Every few years, make sure the grease on the various packing nuts is still good. If you are hobbyist, you will likely never need to do this part either.

Just to be sure, I went through all the fuji manuals they have on the website (IE the pre-2003, 2003-2009, and 2009+), and none say you should lubricate the gun. The only reference to lubrication i could fine is in in the pre-2003 manual, where it says if the trigger mechanism is sluggish, to lubricate the trigger pin.
That's it ;)

[Daniel Berlin]

I thought you meant lubricate it like you do the rest of your air tools (IE insert oil into some passage :P)

So, in regular usage, particularly for waterborne the rate at which the needle will need lubrication is "not very often", because a lot of waterborne finishes don't contain anything that is really going to dissolve the existing lubricant. Solvents definitely will dissolve it. You will definitely wipe it off if you remove the needle and clean it :)

In your gun, it looks like only a very small part of the needle is actually exposed to the fluid, so if you are using waterbornes and cleaning right after, i doubt you'd even need to clean any part of the needle but the tip with any regularity (IE i bet you could clean off the tip and whatever is exposed once you remove the aircap)

In any case, if you want to remove the needle and clean it with each cleaning, and then lube it, you don't technically need "spray gun lube", but you do need a lubricant that has no silicon or petroleum distillates, because they can contaminate the finish if you are using waterborne. The easiest thing to find that meets these criteria is in fact, "spray gun lube" :)
I have a local harbor freight, and they sell 10 buck cleaning kits that include a little thing of spray gun lube that lasts many months/years.



Daniel,

I saw this in Jeff Jewitt's video on spraying that comes with his book (wonderful book and video by the way) where he suggests lubricating the needle after cleaning. Sounds like this is definitely not needed after each cleaning. I am just curious how often I may need to do this. At least for now, sounds like I should not worry about the lubricant just yet.

[Daniel Berlin]

I lube my HVLP with a little bit of PG2000, Boeshield or similar, inside and out. A tiny, thin coat of Boeshield especially makes the gun exterior easier to clean. I think most any light oil will work. Do not use silicone of any kind.

Using boeshield on the *inside* is a bad idea unless you are spraying oil based stuff. Boeshield uses petroleum distillates which will not, in general, get along well with water based finishes.
Of course, once all the solvents dissolve, the film it leaves is unlikely to be an issue, but i don't like to take chances.

[Sam Hamory]

I would never put any oil or certainly not silicone anywhere near a finishing gun. Mineral oil is the only lubricant I use. (Baby oil) Use it on the needle every 3rd time you clean and on all the threaded parts. It's never caused me a problem and it's prevented many.

[Henry Ambrose]

Using boeshield on the *inside* is a bad idea unless you are spraying oil based stuff. Boeshield uses petroleum distillates which will not, in general, get along well with water based finishes.
Of course, once all the solvents dissolve, the film it leaves is unlikely to be an issue, but i don't like to take chances.

It has not been a problem in my experience.

[Daniel Berlin]

It has not been a problem in my experience.

Okay, so you haven't had problems, so let me ask the other question: What exactly is the point?
1. Guns that are used for waterborne finishes have stainless steel fluid passages. I can understand spraying boeshield on the outside (though it's usually anodized aluminum), but what exactly is spraying it on the inside meant to accomplish?
2. Boeshield is basically dissolved paraffin wax. Assuming there is a good reason to spray stuff on the inside of the gun, why would you spray wax?

[Henry Ambrose]

Daniel,
Even stainless is not impervious to corrosion and a little lubrication does no harm on most any moving part, especially if it keeps other material like paint out of the joint or fit. I don't spray the inside of the gun, just put a tiny drop on the moving parts and then a drop or two blown through the gun. Putting a tiny drop on any threaded parts helps when its time to take the gun apart. On the outside I just wipe a little bit of Boeshield on all surfaces. When the solvent evaporates, a very thin film of wax remains - so little its barely noticeable. The wax film does not hurt in handling the gun and it really helps on clean up, 'cause the over-spray is stuck to the wax and not to bare clean metal.

For clean up I use whatever is the appropriate solvent and then hot soapy water followed by plain hot water, then let it sit out to dry. When I put it back together, I use a little bit of lube as described above. Next time I spray all I have to do is fill it and hook it up, knowing that the gun is totally clean and functional.

[Daniel Berlin]

Daniel,
Even stainless is not impervious to corrosion and a little lubrication does no harm on most any moving part, especially if it keeps other material like paint out of the joint or fit. I don't spray the inside of the gun,

Above you said "I lube my HVLP with a little bit of PG2000, Boeshield or similar, inside and out."
The "inside" part is what i was questioning. The rest I understand just fine :)