I have an older Kremlin system and we have been using it for only spraying pigmented CV and a different pump for our clear CV.

We are fighting with the gun plugging up frequently, usually during the primer coat. This pump will sit for a week or more at a time before our next painted job sometimes.

So after every session we flush with thinner, I would like to think pretty well but I'm not the one who does it.... We also check the gun filter.

What can I do here? Is it gunk in the lines? Pump? Is there something else than thinner I can use to flush the system with? We rarely ever have this issue with the pump we use for clear.

Thanks

Pump type?
Gun type?
Do you leave the thinner in the gun?
Tip size?
Can you get gun wash?
What is on the gun filter?
Do you use pickup tube filter?
Do you disassemble the gun to clean?

More info needed to diagnose

-It's a Kremlin 20:25 pump.
-Gun is an older Graco don't know what type.
-I leave thinner in the lines when not in use.
-I don't use pickup tube filter... This pump had a massive tube/hose for 55 gal drum so I remodeled it to use a smaller tube that I can stick in a Gal can.
-We do not strip the gun down often to clean... I do have an Ultra sonic machine and we will run everything through that every so often but not enough. Honestly I get a little frustrated with the way the gun gets left by my spray guy. Of course he would clean it well if I allowed him a couple of hours to do it every once in a while.
-What should I be looking for in gun wash? I have some Quick Strip "Naked Gun" that we use to when doing a thorough cleaning. I have never pumped it through the whole system, Is that okay to do? Is there something else that can be pumped?
If so what do you use to flush that out so there won't be a problem with the CV?
-We have been using a 511-515 tip

I have no training in finishing and have been stumbling through this for 11 year trying different things. I was told not to use a pump for pigmented because it would wear the piston/packings out, but I had this old setup around from the days of spraying precat and I though why not give it a shot. I took it all apart and cleaned it. Now there is no way I want to go back to a cup gun even with our recent struggles.

I treat my Kremlin 14-10 nonchalantly and because of that I have issues that crop up. I leave pigmented in the lines overnight if I'm using it the next morning so I don't lose 10-12 oz of paint or primer by doing a full restart.

So the thing that can happen is the nylon cup that is the piston can get full of dried pigment that falls out of solution.

You take the pickup line off the pump and take the check ball valve out and see if there is something on it that might stop it from sealing properly. Clean it with a brush, thinner and compressed air.

Then unscrew the cylinder and take it off the unit. Check it for dried paint and remove anything that shouldn't be there.

Then you deal with the piston cup. There is a nut on the bottom that needs to be unscrewed. You'll need another wrench to hold the piston arm from spinning. Be careful when you are taking this apart because there is a little 1/8" check ball that can fall out and get lost. Pull the nut and the nylon cup off straight down being mindful of the check ball. Remove the cup from the nut, if it's jam packed it might not just slip off. Clean everything off. Check the hole where the nut attached to the piston rod and make sure it's clean.

Reverse the process and put things together. Use some mineral oil on the piston walls to lube it up along with the nylon cup and the black O ring at the threads. The O ring will likely be swollen and might be hard to get back into place because it will be oversized from the swelling. I was able to get another from my local hardware store. I brought a caliper to check the thickness of the ring and the size was pretty close. Save the old O ring as it will shrink back to size after the thinner evaporates. Or you can let it sit overnight and dry out and shrink instead of buying a new one.

After you put things together again run thinner through it to wash out the mineral oil.

On the gun check to see that the screen on the bottom of the gun is clean. I've had mine for 13 years and it's still the original. You can buy them for about $5 each, but you'll have to buy 5 or 10 of them, sucks, but it is what it is.

Do you use a screened O ring at the tip. Usually people use the white hard O ring, I use a black screened O ring. This prevents anything from getting into the tip and clogging it.

I haven't filtered finish into a cup in a decade. I don't have a pickup screen in use. I have the screen at the bottom of the gun and I use a screened O ring at the spray tip. I don't have any issues that I didn't cause myself from lack luster cleaning practices. But I can get the pump and gun back in working condition pretty quick.

SteveL
I have a very similar setup as you. 2 different pumps for clear and pigmented finish. I also will leave the finish in the system overnight if I will be spraying the next day.
I found that the pigments in the primer will settle to the bottom of the can overnight and partially clog the pickup tube. If I shake the tube really well and use it to stir the finish it will decrease the amount of solids that try to go up the tube at startup.
When spraying white primer I will drop a small block of wood into the can of finish and place the tube on it so it is not resting on the bottom of the can where the solids are settling.
Hope this helps.

Get accrastrip. It is something you can put in the gun overnight and it keeps the gun and lines clean. Just flush out in the morning with thinner and fill with paint and you’re good to go. We’ve been using it for years and it solved the problem of clogging for us.

Accrastrip is made by US Polychem. If you google it you can find a distributor. It was originally recommended to us by our Kremlin distributor.

The liner of the fluid hoses eventually starts breaking down. We have 1 Kremlin and 3 CA Technologies pumps. When we start having issues with the tips plugging up all the time, we start checking specifically for debris in the inline filters that looks similar to the hose liner material (black, usually). If we see anything resembling that, we change the fluid hose.

They aren't particularly cheap, so we don't do it willy-nilly, but it usually ends up being the culprit.

We spray conversion varnish and always always cycle fresh thinner through them at the end of the day. They are used daily.

So I have some Accrastrip coming. What is the best way to go about useing this stuff?
-Are you guys just using it every so often or every time you spray?
-How do you go from this stuff which is water based back to CV? Do you just flush with thinner, if so how much before you are safe?
-How many times do you use the same accrastrip? what do you filter it with?
Thanks

We reduce it with water 50/50 and it is ready to use. At the end of the day we pump out the finish and fill the lines with this solution overnight. In the morning we pump it out and fill the line with clean lacquer thinner and let it recirculate through the lines for a few cycles of the pump. After that we just fill the line with finish and start finishing for the day. You can clean your guns and just about any of your finishing equipment with this solution, however don’t soak anything with seals in it for too long as they will swell. After cleaning any equipment or parts we just rinse them with clean lacquer thinner. I’ve found you can keep using the solution over and over by just pouring off after the residue settles to the bottom.