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Spray Gun Air Cap Size: How To Get It Right?


Struggling with sags, uneven coverage, or texture issues when spraying paint? The problem may lie with your choice of spray gun air cap size. Paint spraying perfection comes down to mastering many techniques. But before you focus on honing your skills, ensure you have the right spray gun air cap size equipped.


How Air Caps Work


The air cap on a spray gun is fitted to the front of the fluid nozzle. It has precisely machined holes that shape the airflow as it mixes with the paint. Air caps come in a range of sizes measured in millimeters. The size of the air cap openings determines the width of the fan pattern. Larger air caps produce wider patterns for covering big surfaces rapidly. Smaller air caps make narrower spray patterns for control and detail work.



The air cap size also controls the tip size of the fluid nozzle it's paired with. Smaller fluid tips work with less paint flow. Larger tips provide more paint for wider patterns. Matching the cap and tip size is crucial for proper atomization and pattern shape. Mismatched combinations can lead to fingerprints in the finish.



Common Air Cap Sizes


Here are the most common air cap sizes and what they're best used for:


1.0-1.2mm - Best for fine finishing work like auto detailing, model painting, furniture finishing.


1.3-1.5mm - Versatile cap sizes good for all-around use on moderate-sized projects. Good for painting cabinets, welding, automotive, crafts.  


1.6-1.8mm - Larger cap sizes designed for broad surface coverage like painting doors, siding, fences, barns, machinery.


2.0mm and up - Extra-large cap sizes mostly used for thick coatings like multi-component coatings, lacquers, truck bedliner.



How to Choose the Right Size


Choosing the right size air cap depends primarily on three factors.


1. Paint Viscosity


The thickness and flow of the paint matters. Thinner, lower viscosity paints like stains, inks, and water-based acrylics require smaller air cap sizes. These thin paints can't handle too much air pressure or wide spray patterns.


Higher viscosity paints like oil-based enamels, primers, and lacquers need larger air cap sizes to handle the thicker material and provide enough air atomization. Always check the product tech sheet. Matching these prevents flow problems.


2. Object Size


For large, broad surfaces like doors or siding choose a larger air cap size. The wider spray pattern and higher paint volume helps cover larger areas more efficiently.


Smaller objects like furniture, latticework, shutters, and trim need a smaller air cap size. Narrower spray patterns provide more control and less overspray.


Consider the size of the surface you need to coat and choose the spray width accordingly for the best coverage.


3. Desired Finish


Fine finishes like automotive paint jobs, cabinets, and detailed artwork require smaller air caps and a narrower spray pattern. This provides a more uniform mist and smooth finish.


Quick coverage on fences, decks, interior walls, etc can benefit from a larger air cap and heavier paint flow. Less fine tuning of the pattern is needed.


Decide the end look you want and choose an air cap size suited for that level of detail and desired final appearance.


It's best to start with a smaller air cap size, test it on an inconspicuous area, and then increase the cap size as needed for greater paint volume and spray width.



Buy Sets with Multiple Cap Sizes


To handle a range of spraying tasks, invest in full sets that include several cap sizes matched to a nozzle assortment. RONGPENG RP8311 Needle & Air Cap Set For Air Spray Gun sets come with 0.8mm, 1.0mm 1.3mm, 1.4mm, 1.5mm, 1.7mm and 2.0-2.5mm cap sizes as standard. Each cap with its size for quick identification.


All accessories feature durable construction with stainless steel needles, stainless steel nozzles, and plated brass air caps. The precisely machined stainless steel nozzles allow you to optimize atomization and control material flow rate. Having this range of caps on hand saves time switching out parts constantly.


This accessory kit equips your spray gun with a range of cap sizes from 0.8mm to 2.5mm for handling different projects, gives you the versatility to spray coating with professional quality results.


Needle: Stainless steel

Nozzle: Stainless steel

Air cap: Plated brass

Suit for RONGPENG air spray gun.

RONGPENG has quickly risen to become an unrivaled global producer of air-powered devices including air tools, air spray gun, air nailer, airless paint sprayer, and etc.

RONGPENG seeks independent sales agent to represent and market our industry-leading pneumatic tools. We support OEM, ODM, OBM customization, small order quantity is acceptable and samples are available.

Make any cooperation possible. Any services related to the product, inquire with us now! Rongpeng@Rongpeng.Com