Guide 01 / Prep
Surface preparation
A coating can only hold on as well as the surface underneath lets it. Most peeling, blistering and flaking starts here, long before the gun comes out.
Clean first
Oil, wax, salt and dust all sit between the coating and the surface. Degrease, wash and let it dry. On metal, remove loose rust and old coating that lifts with a scraper. A tape test on old paint tells you quickly whether it will hold a new layer.
Create a profile
Most coatings grip better on a slightly rough surface. Concrete is usually ground or shot blasted, metal is blasted or sanded, and glossy paint is scuffed. The product data sheet normally names the profile it wants.
Repair and fill
A spray coat follows the shape underneath, so it will show every crack, hole and pit. Fill and patch with a compatible repair material and let it cure as the maker directs.
Moisture and temperature
Damp concrete and cold steel are common reasons a coating lets go. Check moisture on concrete, keep the surface above the dew point and follow the temperature range on the data sheet. Mask anything that should stay clean.
Do
- Read the product and safety data sheets first
- Do a small test patch
- Mask edges and nearby surfaces
- Log the weather on the day
Avoid
- Spraying over dust or damp
- Skipping the profile on smooth surfaces
- Rushing past cure times
- Coating over failing old paint
Common questions
How clean is clean enough?
Clean enough that a strip of tape pulls away nothing and a wipe with a dark cloth comes back clear. The data sheet may name a specific standard for blasting.
Can I spray over old paint?
Sometimes, if it is sound and compatible. Scuff it, clean it and test a small area first. If the old coat lifts, it has to come off.
General information only. Follow the product data sheet and safety data sheet for the coating you use.
