Airless Sprayer Material Hose Length

Aug 28, 2009 11 Replies

Seems most of the painting I do requires a gallon of paint or less, but I still what to use my airless.



I'm thinking of making a simple gallon hopper to replace the pickup tube, and buying a shorter material hose to save material. I think a 15' hose would be fine for most of my purposes. But when I mentioned this to a spray equipment guy, he insisted I would need to keep at least 25' for dampening the power pulses from my pump, or it greatly shorten the life of my diaphragm. My airless is a diaphragm type CH 3/4 hp, .44 GPM.



Does anyone else have any actual experience with shorter material hoses? I understand his reasoning, but I just can't see why the relief valve in the pump would not be adequate for dampening the power pulses.


By my estimation, 10' of 1/4" hose has .03 gallon in it. Not worth taking a chance.

Karl

We have a parking lot striper which is supposed to have a 50' coil of hose between the pump and the gun. One of the guys thought that was BS so he replaced the 50' coil with a short whip. You could see the repeating variation in the width of the stripes. Put the 50' hose back on and the visible oscillation was gone.

Granted it's only about 3 ounces of material lost, but it adds 95 square surface inches to the clean up task, almost doubling it. I think I could reduce clean up time and save a good bit of wash down solvent as well.

Any idea what the whip length was, or the GPM or HP of the sprayer?

It's an old Titan portable with IIRC a 4 HP gas engine. The whip was not more than three feet long. Line striping is very sensitive to pressure variations.

How about switching to HVLP and just washing the cup out? More appropriate for many smaller jobs anyway.

I have a Binks (18 I think?) 2 QT pressure cup system, but my needs call more for deposit rate the finish quality. I plan to switch to a 1 gal hopper, straight to the pump, with a short hose. Most of the time I will be shooting things that are not water soluble, so clean up time and minimizing wash down solvents are the priority.

Primary uses are painting machinery, equipment and fixtures with oil based paints.

You can lay down more than enough material to paint trucks with an HVLP system, with higher transfer efficiency. On the other issue, I still like oil too, but the new waterborne finishes have come a long way.

I'll keep the HVLP in mind, wouldn't mind having one anyway. What water based finishes do you recommend?

We've had good results in boiler rooms, etc., with Sherwin Williams pre-catalyzed water-based epoxy. The color and gloss holdout beats alkyd. For pure abrasion resistance, alkyd is still better in some applications. The biggest improvement I've seen is in clear floor finishes. The best waterborne hybrid wood floor finishes now outperform the oil-based in most respects. The oil-based finishes are now being formulated with less solvents and the waterborne finishes are being refined as VOC regulations get more stringent. The storage requirements for solvent based finishes are a PITA, and even though home shops may not need to comply, it's something to consider from a fire safety angle.

You could eliminate the big coil of hose with a pulsation chamber or an accumulator of some sort - Pressure vessel with a bag or bladder inside, and a pre-charge on the air side of the bladder roughly equal to your operating pressure.

They use them all the time in hydraulic systems, and that's what a paint sprayer is. And you can add an orifice on the outlet to give a regulation action, allowing the short hose to the spray head to be a final pulse filter.

*IF* you can find a chamber that is easier to clean the paint out of than the 25-foot hose coil was... That's when KISS kicks back in.

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