How To Clean A HVLP Spray Gun

How to Disassemble, Clean and Reassemble an Apollo A7700 HVLP Paint Spray Gun

Like any other piece of equipment, HVLP paint spray guns can last a very long time with proper care and maintenance. Between coats of the same liquid, it is fine to leave the coating in the gun for a few hours. When switching colors or the type of coating (e.g., primer to base coat), it not necessary to completely disassemble, but it is advisable to remove and clean the tips, needles and nozzles to insure optimal results.

It is best practice to disassemble and thoroughly clean your spray gun after each use. Here is a detailed step-by-step guide on how to disassemble and how to clean a paint gun. This article is focused on the Apollo AtomiZer A7700 HVLP turbine spray gun.

We recommend having the following supplies on hand before beginning the cleaning process:

• Apollo A7700 spray gun parts list
• FS1900 spray gun cleaning kit
• Acetone, Lacquer thinner or other VOC compliant gun cleaning solution
• Wrench included in spray gun kit (A7534)
• Safety glasses
• Respirator
• Disposable Nitrile Gloves
• Metal mixing bowl
• Shop towels or paper towels

Steps for cleaning the cup and assembly: 

1. Pour several ounces of acetone, lacquer thinner or gun cleaning solution into the bowl.

2. Remove the gravity cup or the siphon-feed pressure cup.

3. Dip a brush from the paint gun cleaner kit into the solution and clean the outside of the cup with a brush. Dry with a paper towel or a shop towel. Be sure to get under the rim of the cup.

4. Don’t leave acetone in the cup, especially if it’s Teflon lined. Acetone will eat Teflon over time.

5. Remove the cup assembly using the wrench.

6. Remove the Air Feed Connector (A5211), check valve and tubes. Pour a few drops of cleaning solution through it. Use a small brush to clean the insides of the parts.

7. Remove the filter from the bottom of the stem (siphon feed only). Clean it with a brush dipped in cleaning solution and dry it.

8. Pry off the gasket from the assembly and clean it with a brush.

9. Clean the inside of the lid under the gasket as well as the outside of the cup.

10. Use the long brush to clean the inside of the siphon feed stem.

11. Use the small brush to clean the Air Connector on the lid of the assembly.

12. Reinsert gasket & replace filter at the bottom of the stem

Steps for disassembling and cleaning the spray gun:

1.  Remove and soak the following parts in the gun cleaning solution:
2. Unscrew and remove the Air Cap Ring (A7501-NS), Gasket (A7501-GK) and Air Cap (A7502)
3. Remove the Needle (A7520) by unscrewing the Material Adjustment Screw (A7522) at the back of the gun. Pull the trigger and then pull the out the needle from the back.
4. Use wrench to loosen and remove Nozzle (A7503)
5. Lift off all of the following pieces and be sure to separate all of the parts from each other. (Note: Older models have a pin on the inside of the gun body. Do not remove the pin. Newer models have the pin attached to the Air Distributor (A7506-NS)).

• Air Cap Seal (A7504)
• Air Distributor Gasket (A7556)
• Air Distributor (A7506-NS)
• Air Distributor Plate (A7507)
• Fan Adjustment Ring (A7508)
• Seal (7509)

7. On the back of the spray gun, use the wrench to loosen and remove the Air Valve Retaining Nut (A7519), Gaskets (A7518 & A7517), Air Valve Return Spring (A7516), Air Valve Stem (A7515). It is not necessary to remove the Bushing (A7514).
8. With the wrench, loosen and remove the Material Blanking Cap (A7533) from the front of the spray gun.
9. Take out the Gland Seal (A7527) and Nut (A7528). Use the back end of the needle to pop it out.
10. Use the various brushes dipped in cleaning solution to thoroughly clean all of the inside and outside surfaces of the gun body.
11. Wipe down the entire spray gun body with a towel. Set it down to dry while cleaning the rest of the parts.
12. Thoroughly clean each of the parts that have been soaking in the cleaning solution using the tools and brushes included in the Spray Gun Cleaning Kit. Be sure that all threads are free of dried paint and other debris. Ensure that all holes and apertures are clear.
13. Dry each part and set out to dry.
14. Pay particular attention to the outside threads on the Air Distributor housing (A7506-NS) as dried fluid can lock the ring lock onto the threads making it extremely difficult to separate.
15. When cleaning the Needle (A7520), be sure that the entire surface is smooth and free of material, which tends to accumulate in the middle where the needle meets the Gland Seal (A7527).

Reassemble the spray gun:

1. Once all the parts are clean and dry, reassemble the spray gun. There is no particular order to reassembly except to put in the Nozzle (A7503) before inserting the Needle (A7520). 

2. The Air Cap Ring Gasket (A7501-GK), has a thin edge and a larger flat edge. The flat edge goes into the bottom of the groove. 

3. The Fan Adjustment Ring (A7508) goes on with the slits at the top and bottom (6 o’clock and 12 o’clock). The slits on the Air Distributor Plate (A7507) should line up with the slits on the Fan Adjustment Ring. 

4. For older models, the Air Distributor has four holes at the top and five at the bottom. The fifth hole will be filled by the pin, leaving four at the top and four at the bottom. 

5. Newer models of the A7700 have a pin attached to the Air Distributor. The pin should be inserted in the space inside the gun body, leaving four holes at the top and four at the bottom. 

6. The Nozzle should be replaced just tightly enough so that the Fan Adjustment Ring is able to move freely. Overtightening will cause binding, but leakage can occur if there is not a snug fit. 

7. If the spray gun will not be used for a longer period of time, leave the Air Cap Ring loosely seated over the Air Cap. This will help prevent the two parts from locking together if there is still coating residue on the threads. Be sure to tighten it again when getting ready to spray. 

8. The cone end of the Gland Seal goes in first, leaving the flat end to sit up against the Gland Seal Nut. 

9. After the Needle has been reinserted, tighten up the Gland Seal Nut using the Wrench. It should be just tight enough so that the Needle may be pulled out with a little tension, but not so tight that the Needle will stick inside the gun body. Proper tension will prevent material from escaping through the Nut. 

10. The small end of the Needle Spring should be inserted first, leaving the larger end toward the back of the spray gun. 

11. Prior to replacing the Material Adjustment Screw, apply a few drops of Spray Gun Lube to the threads. Spread evenly. 

12. It is also a good idea to lubricate the outer threads of the Air Cap Seal before replacing the Air Cap Ring.