Best Wood Filler for MDF Projects: 2025 Expert Review
DR Joinery
Expert Joiner & Bespoke Fittings Specialist
Working with MDF (Medium Density Fibreboard) is a staple of modern joinery, especially for painted alcove shelving and fitted wardrobes in York's Victorian terraces. It's stable, smooth, and paints beautifully—provided you prepare it correctly.
The most common frustration homeowners face when painting MDF is the 'fuzzy' edges or screw holes that shrink back after a few weeks, revealing the fixings. Standard poly-fillers often don't bond well with the dense fibres of MDF, leading to cracks down the line.
In this review, I've selected three fillers I use on site. Whether you are filling screw countersinks, smoothing over joints, or repairing a ding in a shelf edge, these products help achieve that high-end, seamless look.
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Specs vs. The Real World
The Spec: "One-Time Fill Application"
"Marketing often claims 'fill once, paint immediately'."
MDF is absorbent. Deep screw holes almost always shrink back slightly as the filler dries. For a truly invisible finish, plan for two thin layers rather than one thick dollop.
The Spec: "Stainable Claims"
"Many fillers claim to be 'stainable' to match wood."
On MDF, you are almost certainly painting the unit. Ignore 'stainable' claims; focus on 'sandability' and how smooth the transition feels under your fingertips.
My Top 3 Recommendations
Three options to cover different needs and budgets
Bartoline Ready Mixed Wood Filler White 500g
Bartoline
This is a classic 'workhorse' filler. For less than the price of a coffee, you get a substantial 500g tub that is perfect for filling dozens of screw holes in MDF shelving. It dries relatively quickly and sands very easily, which is crucial when you are prepping a large unit for painting.
The Good
- Incredible value for money (£5.98/kg)
- Easy to sand flush with MDF surface
- Good adhesion to MDF faces
The Bad
- Can shrink in deeper holes (requires two fills)
- Not flexible enough for structural joints with movement
Installer Tip:
Use a damp cloth to wipe off excess filler around the hole before it dries. Because this filler is white and MDF is usually brown/green, it's easy to see where you've filled, but keeping it tidy reduces sanding time significantly.
Priced at £2.99 at the time of writing
Check Price on AmazonRonseal White Wood Filler Tube 325g – Includes Filler Tool & Sandpaper
Muelo
This Ronseal bundle is excellent for homeowners who want to achieve a professional finish but might not have a workshop full of tools. It includes a high-quality ready-mixed filler, a metal application tool, and three grades of sandpaper. The filler itself is denser than budget options.
The Good
- Comprehensive kit consisting of everything needed
- Tube allows for cleaner application than a tub
- High-quality Ronseal formulation
The Bad
- Significantly more expensive per gram
- Tube can be harder to squeeze when nearly empty
Installer Tip:
The included metal tool is great, but be gentle on MDF. MDF is softer than metal, and if you press too hard with the corner of the knife, you'll gouge the surface, creating more work for yourself.
Priced at £16.99 at the time of writing
Check Price on AmazonRonseal White Wood Filler Tube 100g – Includes Filler Tool
Muelo
Whilst expensive for the quantity, this compact 100g tube with the included tool is perfect for 'snagging'—the final stage of checking a job. When you spot a tiny hairline crack or a missed pin hole on a finished alcove unit, this precise tube allows you to fix it without dragging out heavy tubs or mixing boards.
The Good
- Perfect for small touch-ups and extensive snagging
- No mess application
- Easy to store in a kitchen drawer for maintenance
The Bad
- Poor value for bulk filling
- Only suitable for minor imperfections
Installer Tip:
Use this strictly for the final touch-ups. If you are building a unit from scratch, use the budget tub for the main holes. Save this tube for the final walkthrough before the last coat of paint.
Priced at £12.49 at the time of writing
Check Price on AmazonFrequently Asked Questions
Does standard wood filler work on MDF edges?
Can I screw into wood filler on MDF?
How do I get a smooth finish on filled MDF?
Should I use powder or ready-mixed filler for alcove shelves?
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