What am I doing wrong - Spraying Exterior Latex

[John TenEyck]

Woah, why is the paint drying "all throughout the gun"? That should only happen if you disassemble the gun and don't clean it. Waterborne products are about the easiest thing to clean. Dump out the cup, flush water and/or soapy water through the cup and gun, then disassemble and clean out what remains inside the gun with warm soapy water. Reassemble and blow some air through it. It takes 5 or 10 minutes, start to finish.

I clean off the air cap and tip of the needle after each spray session, but only clean the gun at the end of the day. There's no need to unless you are spraying something that's catalyzed with a short pot life or the finish has something in it that settles out very quickly.

John

[Alan Lightstone]

Really more paint all inside the gun, not drying, though there were some dried spots.

I've been cleaning out the gun, and air cap after every spraying. Then spraying water through it. Takes more than 5-10 minutes.

Haven't tried hot water and soap. I'll try that next.

Using 3M PPS system, so the cups fortunately a non-issue.

[John TenEyck]

I clean my gun only at the end of the day. If you open the needle wide open water will flush out most of the paint inside the gun before you disassemble it. I wasn't kidding when I said it's a 5 - 10 minute job. Remove the nozzle and needle, flush the internals again, brush out the internals with soapy water and flush, clean the inside of the nozzle with a brush and soapy water and flush, wipe the needle clean, and reassemble.

If it's taking a lot longer there must be something unique about your gun.

John

[Jim Becker]

Alan, I rinsed and reused the PPS cup liners, too. I've had the tool for something like three years and am only on my third cup with the previous one still usable.

[John TenEyck]

Same here. The liners and lids last a really long time with waterbornes. When I clean the gun at the end of the day, but plan to spray the same stuff the next day, I remove the PPS cup from the gun and put a plug in the lid. There's no need to clean it out between uses, although I do remove the lid and stir the contents the next day before spraying to make sure everything is well mixed.

John

[Alan Lightstone]

I clean my gun only at the end of the day. If you open the needle wide open water will flush out most of the paint inside the gun before you disassemble it. I wasn't kidding when I said it's a 5 - 10 minute job. Remove the nozzle and needle, flush the internals again, brush out the internals with soapy water and flush, clean the inside of the nozzle with a brush and soapy water and flush, wipe the needle clean, and reassemble.

If it's taking a lot longer there must be something unique about your gun.

John

I only use waterborne finishes and that very occasionally occasionally includes "house paint" type products. I use hot water right from the tap in the kitchen sink and have never had an issue with cleaning my gun(s). Should something actually be dried, a solvent cleaner can be used, but I try to avoid that by cleaning immediately once the job is done.

OK guys. Feeling pretty dumb right about now. I'm so used to spraying solvent based finishes, I never thought of just running hot water from the sink in the gun. The opening up the tip wide open trick works great too. I'm sure this is all old news to both of you, but it was eye-opening for me. And thanks so much for the suggestions. Worked great when I tried it this evening. Much quicker and cleaner.

I have been reusing the PPS cup for this latex job and capping it, but otherwise have gone through a number of them when spraying lacquer.

I did change the filter cap on the PPS cup the next morning. Is that even necessary?

[Allan Speers]

John:

Can I add both Floetrol and up to 10% water to thin it, or is it a total amount of dilution limit?

The Floetrol TDS states that you can add up to 8oz of Floetrol to a quart of latex paint (which seems like a huge amount). I added 50 ml, which is a drop in the bucket (about 1.7 oz) compared to that.

No recommendation from me, but realize that Floetrol is not used to thin the paint, but rather to help slow drying time.

Someone else mentioned heat from the turbine might be causing your paint to dry quickly. That was an issue for me when spraying thick multispec. I added a 5' whip hose, and immediately noticed a small improvement, so you might consider that. (It makes it much easier to work, as well.)

And one more HUGE improvement for spraying latex is to get an HVCLP adaptor. This turns your suction cup into a sort of semi-pressurized pot, and then lets you use the gun's original air control to beter dial-in the spray quality. You can get one from these guys, for around $60 delivered, IIRC
AMERICAN TURBINE LLC 1-877-748-4857 (They are the US distributor.)
I added this to my 4-stage turbine system, and the difference was not subtle. HIGHLY recommended.

[Alan Lightstone]

No recommendation from me, but realize that Floetrol is not used to thin the paint, but rather to help slow drying time.

Someone else mentioned heat from the turbine might be causing your paint to dry quickly. That was an issue for me when spraying thick multispec. I added a 5' whip hose, and immediately noticed a small improvement, so you might consider that. (It makes it much easier to work, as well.)

And one more HUGE improvement for spraying latex is to get an HVCLP adaptor. This turns your suction cup into a sort of semi-pressurized pot, and then lets you use the gun's original air control to beter dial-in the spray quality. You can get one from these guys, for around $60 delivered, IIRC
AMERICAN TURBINE LLC 1-877-748-4857 (They are the US distributor.)
I added this to my 4-stage turbine system, and the difference was not subtle. HIGHLY recommended.

As it turns out, helping to slow the drying time seems to have helped the most. So I've been using 50ml Floetrol per quart, and no added water which seems to work ok. Certainly not as nice as spraying lacquer, but I'm getting the job done.

Never heard of a HVCLP adapter. I looked on YouTube, and saw it, but I almost always use full air supply pressure from the flexible hose whip (which I do have) when spraying, and not sure how this would help in my case. I may be missing something here.

I used the 3M PPS cup system, so it is under pressure anyway. Does this eliminate the utility of that HVCLP adapter?

Oh, and thanks again, guys, for the tips regarding cleaning the gun with hot water running through the gun. Works much better than my previous approach. It does take about 5 min per cleaning, so a huge improvement.

[Ken Krawford]

Interesting comment about cleaning the gun with hot water. When using latex based paints I've always used cold water thinking that hot water would cause the paint to congeal. I'll have to give hot a try.
As an aside, I just replaced my very old 4 stage Graco HVLP system with the Fuji Mini-Mite 4 and a T-70 gun. I tear the gun down immediately after each use but find I have to work much harder to get this brand new gun clean compared to my old Graco one.

[Alan Lightstone]

Interesting comment about cleaning the gun with hot water. When using latex based paints I've always used cold water thinking that hot water would cause the paint to congeal. I'll have to give hot a try.
As an aside, I just replaced my very old 4 stage Graco HVLP system with the Fuji Mini-Mite 4 and a T-70 gun. I tear the gun down immediately after each use but find I have to work much harder to get this brand new gun clean compared to my old Graco one.

I find it harder to clean than my old Fuji GPS gun too.

[Jim Becker]

Interesting comment about cleaning the gun with hot water. When using latex based paints I've always used cold water thinking that hot water would cause the paint to congeal. I'll have to give hot a try.
As an aside, I just replaced my very old 4 stage Graco HVLP system with the Fuji Mini-Mite 4 and a T-70 gun. I tear the gun down immediately after each use but find I have to work much harder to get this brand new gun clean compared to my old Graco one.

Heating things up seems to help any partially drying paint to peel off. I can clean my gun in about five minutes and that includes waiting for the water to get hot.

[Ken Krawford]

I just did a cleanup with hot water and it worked very well. The cup had been sitting for several days about 1/4 full with paint and dried paint on the sides. Hot water and a fairly coarse Scotchbrite pad and it's like new. Thanks for the tip.

[Rich Engelhardt]

Scrub things with some sudsy ammonia along with the heated water & things should go even a little better.

[Alan Lightstone]

Scrub things with some sudsy ammonia along with the heated water & things should go even a little better.

I read that denatured alcohol is good for cleaning dried latex paint. Anyone use that on their guns?

[Jim Becker]

I read that denatured alcohol is good for cleaning dried latex paint. Anyone use that on their guns?

I use acetone when I need a deep clean of anything that's been used for "latex" paint including getting any gunk out of brushes. I do not believe that DNA is going to do anything, although it's nice as a final rinse.