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How to Use Etch Primer

The Uses and Application of Spray-On Etch Primer

Difficulty: Easy

Etch Primer is a very versatile primer that is designed to be applied directly to bare metal and should be used when you want to build up and sand down then overcoat. Etch primers also protect against corrosion. Etch primers contain a very mild acid that etches into the metal, creating an even stronger bond between the surface and the primer, so has excellent adhesion. Unsure whether Etch Primer is right for your project? Click here for a look at different types of primer.



Anything in an aerosol can may do damage to your health, so you must be prepared before using spray-on etch primer. A ventilator mask is the best way to protect your respiratory system, and you should also only ever apply the primer in a ventilated area. You may also want to use goggles and gloves.


You should always keep the primer away from fire as it is highly flammable and the can may explode if it gets too hot.


Step 1: Preparing Your Surface

To prepare your surface, you need to clean it. If it is dirty or greasy, your product will not stick. Use a good car cleaner and a microfibre cloth to make sure the area you'll be priming is washed properly.


Next, wrap a sheet of 400-grit wetordry around a sanding block and scuff the surface, while using a generous amount of water. This step will help greatly with adhesion. Make sure to wear a mask while sanding. Wipe any particles from sanding away with a clean, dry cloth.


Your surface should now be clean, dry and ready to be primed.


Step 2: Applying Primer

Shake your can thoroughly. This is important as if you don't shake it enough the primer won't be mixed properly and you'll end up with an uneven coat. If in doubt, shake more than you expect; you can shake too little, but you can't shake too much.


Hold the can 20-30cm away from your surface and spray, moving the can from side to side, overlapping slightly. It's a good idea to keep the same distance as this will help the primer apply evenly.


Wait for the first coat to dry for about three minutes before repeating for a second coat. You may also want to do a third coat when the second coat dries if you think this is necessary.


Step 3: Sanding

Wait 15 minutes for the primer to dry. Now, you can take the 400-grit wetordry paper and sand once more with water. This will help the topcoat stick to the primer even better.


Now, your surface should be primed and ready for an overcoat.


Products Used In This Tutorial

Etch Primer

GTi Etch Primer Grey Aerosol 500ml


Indasa Aerosol Etch Primer, Grey, 400ml


Microfibre Cloth

Farecla Finishing Cloth (Pack of 3)


3M Microfibre Detailing Cloth



3M Maintenance Free Half Mask Respirator, FFAP3R D Filters



Sealey Safety Goggles with Direct Ventilation


Protective gloves

Colad Black Nitrile Gloves Large (Box of 60)

Car Cleaner

Concept Go Foam Aerosol 450ml


Wetordry Paper

3M P400, 230mm x 280mm, Wetordry Sheet 734, Qty of 25

Sanding Block

3M 70 x 125mm Soft Hookit Sanding Hand Block


Water Sprayer

Concept Mini Water Spray Bottle 600ml