Breakdown of Paint over 100 Years
There are thousands of formulations, and manufacturers guard them like family recipes—except instead of spices, it’s polymers and things you shouldn’t inhale. Additionally these paint manufacturer recipes change sometimes annually due to cost factors, sometimes due to regulars
Let’s divide all paint Ingredients into simple groups:
Every exterior paint—whether from 1920 or today—boils down to four things:
- Pigment (colour)
- Binder (what makes it stick)
- Solvent (what makes it spread)
- Additives (what makes it sell)
1. Pigments (mostly irrelevant despite appearances)
Old-school pigments
- Iron oxides
- Chalk
- Carbon black
These don’t cause removal problems.
They just sit there while the binder laughs at you.
Dangerous pigments best left to professionals:
- Lead-based paints
- Chromium / cadmium pigments
What you really really don’t want:
- You don’t want to sand them dry
- You don’t want dust everywhere
- You definitely don’t want to breathe them in
In other words: less cowboy, more professional paint removal.
Modern pigments
Synthetic colours
Easy enough. No drama.
The real problem is still the binder holding them in place like a stubborn tenant.
2. Binders (this is the real battle)
Oil-based paints (linseed / alkyd)
These:
- Oxidise over time
- Go brittle
- Crack and flake
Sounds good, right?
Yes… until:
- They build up in layers
- Get baked on by weather
Removal reality:
- Scrapes nicely when degraded
- Absolute misery when intact
Too much heat and you’re into fumes and regret.
Lime / mineral paints
- Soft
- Breathable
- Usually thin
Removal reality:
- Often doesn’t need “removal”—just washes off or brushes down
- Can be removed mechanically without much drama
This is the rare case where the wall and the paint cooperate.
Enjoy it while it lasts.
Modern acrylic paints
This is where things get interesting.
- Flexible
- Water-resistant
- Designed to stick like their life depends on it
Removal reality:
- Doesn’t scrape cleanly
- Doesn’t dissolve easily
- Laughs at light sanding
Best methods:
- Strong chemical systems
- Abrasion (controlled)
- Sometimes DOFF / steam systems depending on substrate
This is the paint equivalent of chewing gum on a shoe.
Elastomeric / high-build coatings
- Thick
- Stretchy
- Crack-bridging
Removal reality:
- Worst of the lot – major cause of semi-professional paint removal failures
This is where people realise “just sand it off” was never a serious plan.
3. Solvents (why old paint behaves differently)
Solvent-based paints (old)
- Penetrate deeper
- Bond harder to substrate
Removal:
- Often requires stronger intervention
- Can be deeply embedded in porous surfaces
Water-based paints (modern)
- Sit more on the surface (generally)
Removal:
Easier in theory but not always easier in practice (due to acrylic binders)
4. Additives (the hidden troublemakers)
These are what turn a “simple job” into a long week.
Biocides / fungicides
- Can affect chemical stripper performance
- May require multiple applications
UV stabilisers
- Keep paint intact longer
Translation:
- Harder to break down
Water repellents (silicones, etc.)
- Resist moisture
Translation:
- Also resist water-based removal systems
Fillers
- Bulk out the paint film
Translation:
- More material to remove
- More passes required
The bit most people underestimate
Paint layers
You’re rarely removing One paint
You’re removing:
- 5, 10, sometimes 20 layers
- Different systems on top of each other
Example:
- Old oil paint
- Covered with acrylic
- Then elastomeric
That’s not a coating anymore. That’s archaeology.
The honest removal hierarchy (what you’re up against)
From easiest to worst:
- Limewash → basically cooperative
- Aged oil paint
- Modern acrylic → stubborn
- Elastomeric coatings → character-building experience
Practical reality
Paint is designed to:
- Stick
- Survive weather
- Resist breakdown
So removal is always:
- Slower than expected
- Messier than planned
- More technical than “just scrape it”
