paint sprayer tip sizing and paint thinning

[ycgoat]

I bought a used Graco MagnumX5 airless sprayer thinking I would be able to initially spray some old metal cabinets with an industrial coating like DTM, and eventually primer and maybe seal old car and truck sheet metal. The sprayer has a maximum 515 tip. My neighbor gave me a slightly used DTM primer I tried to use on one of the older cabinets but the tip clogged almost instantly. I was hoping to buy some DTM for this project but it's recommended tip size is .017 - .021. I have ordered a new tip (315) Assuming the used sprayer isn't trashed can I thin the DTM for the .015 tip?

 

[Jehannum]

I've tried this with higher solids base coats before (specifically, I tried to spray a metallic base coat with a 1.4mm tip when I should have been using 1.8 to 2.1).

When I tried to go the route you're going, I ran into issues with the size of the solids, rather than the viscosity of the fluid.

That may or may not be an issue with your primer, but I'd definitely try it out on something you don't care about first before running down the rabbit hole of trying to smash that square peg into the round hole.

 

[ycgoat]

Just an FYI; The primer was an Alkyd marine coating, but the DTM I am looking to get is a water based. I am reading that I use a funnel to check the viscosity but that seems awfully vague. Is there a screen or funnel for different tip sizes? Thinking on paper, If I am understanding what I am seeing on line; the .015" tip is equivalent to 381 microns, so if I thin the paints with a 190 or 200 micron screen that should ensure the paint is thin enough to spray in my set up (assuming I did buy a POS)

 

[K13]

You use a viscosity cup to check viscosity.

 

[signcrafter]

If its clogging the tip the pump is most likely good. Try putting some water in a pail and spraying that and play around with that to see if pump is working good. Make sure you strain your paint, that makes a huge difference to avoid clogs when spraying. I dont usually thin anything when spraying airless. Use the correct tip and strain and it doesnt plug unless using crappy paint. Sherwin William's industrial has some good dtm but it's pretty pricey. But I can tell you I've sprayed it using a fine finish tip and it didnt plug at all.

 

[ycgoat]

If its clogging the tip the pump is most likely good. Try putting some water in a pail and spraying that and play around with that to see if pump is working good. Make sure you strain your paint, that makes a huge difference to avoid clogs when spraying. I dont usually thin anything when spraying airless. Use the correct tip and strain and it does'nt plug unless using crappy paint. Sherwin William's industrial has some good dtm but it's pretty pricey. But I can tell you I've sprayed it using a fine finish tip and it did'nt plug at all.

Thanks for the input, and I did not strain it. The primer also seemed very thick.

 

[The Cobbler]

there should also be a filter screen in the pump unit, and one in the spray gun . might check to see if they are there & in good condition .

 

[ycgoat]

I replaced the intake tubes, flushed out the paint thinner with water, then pumped out the water and added some pump armor. It’s a good thing to, I got a little paint out while doing it. I found the manual online and it shows a filter in the handle and a small screen in the pump with a spring and ball. While flushing it seemed to have good pressure, so I guess I need to get a viscosity cup and use fresh paint.

Yes sign crafter a gallon of the Sherman Williams DTM was listed on line as $130. I have not bought any yet