When restoring wooden doors, furniture, and architectural items, one of the most important factors is understanding what type of paint is on the surface. Not all paints behave the same, and not all removal methods work on every coating. At strippaint.co.uk, we specialise in matching the right stripping method to the right material — ensuring a safe, effective, and professional finish every time.
In this guide, we break down the difference between water-based and oil-based paints, why oil-based coatings can be removed in a caustic dip tank, and why water-based coatings often require a specialist chemical called DCM (dichloromethane) — a substance that’s now tightly regulated, extremely hazardous, and legally restricted to trained, licensed professionals.
Oil-Based Paints: Why They Can Be Removed With Caustic Dipping
Oil-based paints include traditional gloss, varnishes, shellacs, alkyds, and many older coatings found on period doors. These coatings react extremely well to caustic stripping.
Why Caustic Works on Oil-Based Paints
A heated caustic solution breaks down oils, resins, and binders, allowing the paint to dissolve and lift from the timber.
The benefits include:
- Deep penetration, even into mouldings and carvings
- Even removal, ideal for thick or multi-layered coatings
- Safe on most woods, when controlled correctly
- Fast, efficient, cost-effective
This is why caustic dipping is the standard choice for traditional doors, furniture, and antique items coated in older oil-based finishes.
→ Learn more on our Caustic Stripping page.
Water-Based Paints: Why They Don’t Respond to Caustic Stripping
Modern water-based paints, acrylics, hybrid coatings, and some “eco-friendly” paints behave very differently. They are designed to resist alkaline solutions and often remain completely unaffected by caustic.
Why Caustic Doesn’t Work
- Water-based coatings do not dissolve in alkaline solutions
- The binder structure is chemically resistant to caustic attack
- Even prolonged immersion may only soften the top surface
- The result is patchy, uneven removal
Trying to caustic-strip water-based paint is a waste of time, and can cause unnecessary exposure of a door to moisture without the benefit of proper stripping.
This is where DCM-based stripping comes in.
What Is DCM and Why Do We Use It for Water-Based Paint Removal?
DCM (Dichloromethane / Methylene Chloride) is one of the most powerful paint removers ever created. Unlike caustic, it works by penetrating and breaking down the polymer structure of water-based coatings, acrylics, and modern durable films.
Why DCM Works on Water-Based Paints
- Breaks apart tough acrylic binders
- Works on coatings caustic cannot touch
- Fast and highly effective
- Produces an even, clean finish
For many modern paints, DCM is the only method that will fully remove the coating without damaging the wood beneath.
DCM Used to Be in DIY Paint Strippers – Until It Was Banned
For decades, DCM was the main ingredient in off-the-shelf paint strippers sold in every hardware store. It was cheap, powerful, and extremely effective.
Why It Was Banned
DCM is highly volatile and highly toxic.
Untrained users working in confined spaces suffered:
- Fatal inhalation accidents
- Severe respiratory damage
- Neurological harm
- Chemical burns
Because of the number of public injuries and deaths, DCM was banned from general consumer products under EU and UK law. Retail paint strippers no longer contain it.
So How Can We Still Use DCM?
Although banned for public use, DCM is still legal for trained professionals who hold the correct HSE-recognised licence and meet strict safety requirements.
At strippaint.co.uk, we are licensed and authorised to use DCM for professional paint stripping. This includes:
- Mandatory ventilation and extraction systems
- Positive airflow and vapour containment
- Protective air-fed masks and PPE
- Controlled handling procedures
- Sealed chemical tanks
- Full compliance with COSHH and UK Regulations
- Documented risk assessments and method statements
DCM is never used casually and is only applied when absolutely necessary — typically for modern water-based coatings that cannot be caustic-dipped.
How Dangerous Is DCM? Very — Unless Handled by Licensed Professionals
DCM vapour is immediately hazardous. It can:
- Cause unconsciousness within minutes
- Displace oxygen
- Burn skin and eyes
- Create toxic fumes when heated
- Require specialist training to manage safely
This is precisely why the general public cannot legally purchase or use it.
Customer Reassurance: No DCM Remains When We Return Your Item
Although DCM is extremely dangerous during application, the good news is:
✨ No DCM remains on the item once the stripping process is complete.
After stripping, each item undergoes:
- Neutralisation / rinsing procedures
- Forced ventilation drying
- Evaporation of all residual solvent
- Final inspection before return
DCM evaporates completely — it cannot remain in the wood. By the time your door or furniture is ready for collection or delivery, all chemical traces are fully gone, leaving a bare, clean timber surface ready for finishing.
Your item leaves our workshop 100% safe, clean, and chemically neutral.
Which Method Do You Need? Caustic vs DCM
| Paint Type | Caustic Dip | DCM Strip |
|---|---|---|
| Oil-based paints | ✔ Excellent | Optional |
| Varnish / Shellac | ✔ Excellent | Optional |
| Multi-layer gloss | ✔ Fast & effective | Optional |
| Water-based paints | ✘ Ineffective | ✔ Required |
| Acrylic / enamel hybrid | ✘ Poor removal | ✔ Required |
| Durable “eco” coatings | ✘ No reaction | ✔ Required |
If you’re not sure what type of paint you have, we can identify it for you — often instantly.
Need Paint Removing From a Door or Piece of Furniture?
We offer both caustic stripping and professional DCM stripping, giving us the ability to remove any coating safely and effectively.
Explore our services:
Whatever type of paint you’re dealing with, we’ll choose the safest and most effective method — and you’ll receive the item back clean, neutral, and ready for restoration.
