Thursday, February 19, 2015

What can I use to flush my "A" side hose?

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My Side Cartridge Broke

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Flushing the "A" Side hose. How many gallons of fluid do I need to flush it out?

I get asked this all the time, so I thought I would play around and tell you how to figure that out.

A 3/8" hose.
Remember Math class and saying "when will I ever need to know - πR²  (Pi x Radius Squared)?"  Well look at yourself now.

3/8" = .375" diameter. the radius is 1/2 of that.  .1875
.1875 x .1875 x 3.14
Thats .110 cubic inches of space inside the 3/8" hose per inch of hose.

50' of hose is 600 inches.

600 x .110 = 66 cubic inches in a 50' hose.

1 gallon has 231 cubic inches.

If you have 200' of hose, you have 66 x 4 = 264 cubic inches. 1.14 gallons to fill the hose. (add a little for the fittings at each end of each hose)

Fluid is by passing as soon as I turn on the fluid

ANSWER:  The majority of the time, this is from the side seal (the little steel thingy that rides on the mix chamber - known as assembly18C) not sealing on the chamber surface.

Check your gun PRIOR to connecting the fluid manifold to the gun. Take your gun and hook up only the air hose and turn the air valve on to allow air to flow to the gun. If a check valve (assembly # 26)  pops out, you have a problem with that side cartridge (assembly # 18.) If the "A" check pops out, replace the "A" cartridge assembly or if the "B" check pops out, replace the "B" side cartridge.

The check pops out  due to air bypassing the side seal/chamber surface, flowing through the cartridge and into the check valve port and this causes the check valve to pop out. Checking the gun with air supply only will save you a fortune in time, seals and frustration.

You can also try flipping the "A" and "B" cartridges if you have not run any fluid through them. Switch the "A" and "B" sides. If the problem is in the side seal, the problem will move to the other side of the gun. If the problem remains on the same side after switching/replacing the side cartridges, you could have issues with the front end body (assembly #11) being worn out or scratched.

Dangers of Compressed Air

Atmospheric air typically contains 2 million dirt particles per cubic ft. Of that, 80% of these particles are less than 2 microns in size and are too small to be captured by the compressor intake filter and will pass directly into the compressed air

A small 100 SCFM compressor and refrigeration dryer combination, operating for 4,000 hours in typical climatic conditions can produce approximately 2,200 gallons (8,328 liters) of liquid condensate per year.

Bacteria and viruses will also be drawn into the compressed air system through the compressor intake and warm, moist air provides an ideal environment for the growth of micro-organisms. Along with this, compressors contain oil to lubricate the piston as it strokes to compress the air. This oil is carried over into the compressed air system and mixes with water vapor in the air to form an aerosol. The water/oil mix is very acidic, causing damage to the compressed tank by creating rust particles.

This is why you can't use your air compressor as a fresh air supply without special filters designed to remove oil, water, vapors and particulates from rust. All of this runs down the supply hose and into your equipment and gun.

Coming out of the air compressor should be a pre-filter and should be sized 2x larger than the output fitting. If your compressor has a 1/2" fitting, you need a 1" coalescing filter. This filter will remove larger particles of solids and fluids. As the air cools, more water will fall out of the air. That's what a refrigerated dryer is for. It chills the air and causes water vapors to drop out, but it only works on vapors, not fluids. Ideally, your dryer should be as far from the compressor as possible to allow the air to cool some prior to entering the dryer. At the inlet of the dryer, a .5 micron filter is required to remove solid contaminates. After the dryer is when you can plumb the Breathing air panel for your supplied air masks. Supplying the supply air system with as air that is clean and dry will allow the system to work better and longer. See this link for the panel:

We also recommend the LM-100 or the SPF Depot DD-10 inline air dryer at the inlet to your transfer pump and drum mixer motor to increase the life of the seals.

This panel meets all OSHA standards for the breathing air required at your job site.

For more breathing safety products, click here.

Spray Foam Gun Chambers Resurfaced on Sandpaper

Everyone cleans their chambers on sandpaper and it does do a good job at removing small scratch marks.

Over time, the chamber will become "cupped" from sanding in a circular pattern and "inclined" from pushing hard on the front end were the scratch marks are.

In our shop, we resurface worn chamber surfaces to new condition. Its not uncommon to have to remove over .0005" to get to a flat surface. Here is a link to a picture in our site to show an example of a chamber that has both characteristics.

To properly sand, we use 600 grit to get it done fast and finish it with 1200 grit. You can get both of these grits from Harbor Freight at a very reasonable price. Push or pull the chamber in a straight line only while holding even pressure in the middle of the chamber and make sure you have a clean flat surface for the sand paper to sit on. Do not rub in a circle - that will "cup" it and pushing to hard on the front part will slope it.

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Are you Boiling Spray Foam Parts in Anti-Freeze? Stop.

Some manufacturers love it when you boil your parts in antifreeze to clean them. As for me, it drives me nuts, but - go ahead and order new parts after you ruin yours.

You know why all radiators aren't made from aluminum? Corrosion. Some are and you better use the coolant they recommend, or change the fluid every two years.

As you boil antifreeze, acids begin to form from the chemicals you boiling off the fluid. The fluid also becomes electrolytic. The hard coat anodize coating, our PTFE top coat and our nickel plate handles are all plated by electrolysis. What you end up doing is stripping the plating off the surface. Then IONS are created in the fluid and this starts to eat the aluminum parts as causes pitting. On thin wall parts, it will eat a hole through the part. (why they don't make aluminum radiators.) Add to that, the boiling temperature for coolant is 370º. That's not as hot as we anneal aluminum parts at or heat treat, but it is getting close. Hope you don't just dunk them in cold water to cool them off.

Over time, all the anodized coating will be stripped off. That coating is .0001 thick. Applied to the ID of a port it is a difference of .0002. Now you start to bypass fluids. For foamers, we notice it over time, but if you spray polyurea coatings - you're spraying at 1500-3000psi. With that huge increase in pressure, your leaks will be noticed much faster than foamers that just use 1100psi.

Need to see a customers gun we just cleaned and rebuilt because it was by passing too much?  Click here.

Check out our Foam & Polyurea Solvents for a safe/effective clean

Issue: Slow Spray Gun Response When Trigger Pulled

ANSWER: The problem is the muffler/Exhaust port on the bottom of the gun handle. On the bottom of the handle is a hex head bolt with a 1/8" hole in the center. That's the breather/filter - assembly # 22. Remove the part and your speed should be normal. I left mine out, but you can push a nail through the small screen. As foam and grease collect on the screen, the exhaust leaving is slowed down causing the shift force to work against itself. Many factory people will claim you have to have that to prevent foam from entering the gun handle. I say - If you have that much foam blowing in the air, you have far bigger issues to address.

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