Is this a live scan or an AI diagnosis of my airbrush?

No. It is a rule-based guide. Nothing is inspected and nothing is measured: your answers are compared in the browser against a fixed set of written causes taken from this site's troubleshooting library, and the result is a ranked reading list. It cannot see your brush, hear your compressor or test your paint.

What is the first thing to check when my airbrush starts spitting?

Confirm what is happening before assuming the mix. Check the tip face and prove a short pass on scrap, then check that the trigger actually moves the needle and that the compressor holds its working pressure with air flowing. The paint and airbrush manuals come first; dried paint on the tip face is a common cause, not a diagnosis on its own.

Why does my airbrush bubble in the cup?

Bubbling can mean air is moving the wrong way back up the paint path, but not every bubble is a defect. Some brushes are intentionally backflushed during cleaning and can bubble then, so check your model's manual and whether you are performing that procedure. If it bubbles during a normal spray, check the front-end assembly the way the manual describes and confirm paint can leave the cup. Thinning will not seal a leaking seat.

Does the diagnostic tell me which part to buy?

No. It ranks written causes and gives you the checks in order. It does not identify a part number, and it cannot tell whether a needle or nozzle is worn. If the same fault returns after a full clean and a fresh pass, that is a question for your manual and the manufacturer.

Does anything I type or select leave my browser?

No. There is no upload, no account and no storage. Your symptom and answers are used in the page to pick the ranked causes, and they are gone when you close or reload the tab.

Troubleshooting diagnostic

Airbrush Troubleshooting Diagnostic

Say what the brush is actually doing — spitting or splatter, bubbling in the cup, tip dry, air only, or water in the line — then answer five follow-up questions. You get possible written causes in rule order, by how well your answers fit, the reason each one is on the list, and one fix checklist to work through in order. It is a rule-based guide decided in your browser: nothing is uploaded, stored or sent anywhere.

Describe the fault

Pick the symptom you are actually seeing on the scrap, then answer five follow-up questions. The ordering is an authored heuristic worked out in your browser against a fixed list of written causes; it is not a probability, a measurement or a parts diagnosis. Nothing is uploaded, stored or sent anywhere.

What is the brush doing?

Match what the brush is actually doing, not what you expected it to do.

Has the brush sprayed properly at any point in this session?

This splits a fault that was there from the first fill from one that arrived mid-job.

Which feed does the brush use?

A siphon feed has to pull paint up a tube; a gravity cup only has to let it fall.

When does the fault show up?

When it happens matters as much as what it looks like.

What changed most recently?

Faults that follow a change usually belong to that change.

How would you describe the mix in the cup?

Judge by how it moves when you stir it, not by a ratio you were told.

Your rule-based result

Choose the symptom and answer the five follow-up questions, then selectRun the diagnostic. You get possible written causes in rule order, by how well your answers fit, the reason each one is on the list, and one combined fix checklist you can work through and copy.

How this diagnostic works

Answer the symptom and five follow-up questions and you get the likely causes ranked, with the checks to run in order.The ranking is a rule table, not a measurement or a probability. Each written cause carries a set of conditions; when your symptom and answers match, it sorts higher. That order is an editorial heuristic for choosing what to check first, not evidence that a particular part is at fault. Nothing is inspected, nothing is fetched and no result is generated by an AI service.

The order of the checks comes from the troubleshooting library already on this site: work the symptom map on the homepage and the air-only diagnostic in theairbrush blowing air but not paintguide, and you will recognise the same sequence here. Diagnose before you order parts, change one thing at a time, and prove each change on scrap.

Match what the brush is doing. Spitting, bubbling, tip dry, air only and water in the line point at different systems.
Answer the follow-ups honestly. When the fault started and what changed last narrow the list faster than any single symptom does.
Work the checklist top to bottom. It is ordered so the quick, reversible checks come before anything that involves taking the brush apart.

What each symptom points at

Spitting or splatter: Dots, coughs or sudden spatters on an otherwise steady pass. Spit on a steady pass can come from the front end, the mix or moisture; no single symptom proves which. Check the tip face, the trigger and needle movement, and the actual model's manual before changing the mix.
Bubbling in the cup: Air comes back up through the paint in the cup and the pattern stutters. Bubbling often means air is moving back up the paint path, which can point to a seating or blockage fault. It is not always a fault: some brushes are intentionally backflushed during cleaning and can bubble then. Check your model's manual and whether you are backflushing before treating it as a defect.
Tip dry: A star, a crust or a dead start after a pause. Tip dry often looks like bad thinning. Clear the tip face and prove a short pass before you rewrite the mix.
No paint at all - air only: Air hisses at the tip and nothing lands on the scrap. Air at the tip only shows that some air is leaving the brush. It does not prove the compressor holds working pressure or airflow under load. Check the trigger and needle movement, the model's manual and the paint path: supply, tip face, then front end.
Water in the line: Sudden thin spit or a blush, often after a humid or cold session. Sudden thin spit after a humid session points to moisture first. Water thins the paint mid-pass, so the fault can look like an over-thinned mix.

Five symptoms, 10 written causes. The diagnostic can only rank the causes it knows about, so if your fault does not fit any of the five symptoms above, start with the tip face, the trigger/needle movement and the paint supply — those checks are quick, reversible and rule out common air-only faults. A hiss at the tip does not prove the compressor is holding working pressure or airflow under load.

A worked example

Say the brush sprayed the first panel of a kit, then started coughing dots across the next one. You choose Spitting or splatter, then answer: it sprayed and then died mid-session, gravity cup, the fault arrived after a pause, nothing changed on the bench, the mix moves freely.

The first cause comes back as dried paint on the tip face — the pause is what put it at the top — and the checklist starts with an air-only trigger pull, a wipe of the tip face, and a short pass on scrap. Leaving the mix alone is the fourth step, and that matters: thinning to clear a blockage makes the pass worse once the blockage clears.

Run the same fault as No paint at all and the list changes. A hiss at the tip only shows that some air is passing; it does not prove the compressor holds pressure under load. The ranking starts with whether paint can leave the cup, then the tip face, then whether the actual trigger is pulling the needle back as the model's manual describes.

What this diagnostic does not do

It is not a live scan and not AI analysis. It cannot see your brush, hear your compressor or test your paint. It compares your written answers against written causes.
It does not identify parts. It will not give you a needle size, a nozzle part number or a replacement to buy. Your manual's parts list and the manufacturer's guidance come first.
It does not override your manual. How your brush assembles, what may be soaked and what may touch the nozzle are all decided by your manual. Where this page and your manual disagree, your manual wins.
It ranks, it does not prove. The top item is the closest written match for the answers you gave, based on an authored heuristic. It is not a probability, a confirmed fault or a diagnosis of a specific part. Work the checklist and let the scrap pass decide.
It cannot judge paint chemistry. Two products in the same family can behave differently. For layering questions, use themodel paint layering order checkerinstead.

Troubleshooting diagnostic questions

Is this a live scan or an AI diagnosis of my airbrush?: No. It is a rule-based guide. Nothing is inspected and nothing is measured: your answers are compared in the browser against a fixed set of written causes taken from this site's troubleshooting library, and the result is a ranked reading list. It cannot see your brush, hear your compressor or test your paint.
What is the first thing to check when my airbrush starts spitting?: Confirm what is happening before assuming the mix. Check the tip face and prove a short pass on scrap, then check that the trigger actually moves the needle and that the compressor holds its working pressure with air flowing. The paint and airbrush manuals come first; dried paint on the tip face is a common cause, not a diagnosis on its own.
Why does my airbrush bubble in the cup?: Bubbling can mean air is moving the wrong way back up the paint path, but not every bubble is a defect. Some brushes are intentionally backflushed during cleaning and can bubble then, so check your model's manual and whether you are performing that procedure. If it bubbles during a normal spray, check the front-end assembly the way the manual describes and confirm paint can leave the cup. Thinning will not seal a leaking seat.
Does the diagnostic tell me which part to buy?: No. It ranks written causes and gives you the checks in order. It does not identify a part number, and it cannot tell whether a needle or nozzle is worn. If the same fault returns after a full clean and a fresh pass, that is a question for your manual and the manufacturer.
Does anything I type or select leave my browser?: No. There is no upload, no account and no storage. Your symptom and answers are used in the page to pick the ranked causes, and they are gone when you close or reload the tab.

Next steps

Use the diagnostic when you can describe the fault but not the cause. Spitting or splatter, bubbles in the cup, tip dry, air only or water in the line — pick the symptom, answer the five follow-ups and let it rank the written causes. It narrows the list; it does not confirm that a part has failed.

These are the guides to open next, either to check one symptom in depth or to work the fix behind a ranked cause.