When you are repairing a cracked window frame, filling knot holes in a pine panel or restoring an old oak piece of furniture — that is when you need a filler that moves with the wood rather than against it. Rubinol linseed oil putty is Ernst P's own answer to that question. This guide covers what the product is, how to choose the right colour, how to apply it like a pro, and why linseed oil putty is still the standard in traditional Swedish joinery in 2026.
First — an important disambiguation
Before we begin: there is a medicine with a similar name — Robinul (glycopyrrolate) — used in healthcare against salivation and certain muscarinic effects. It has nothing at all to do with Rubinol linseed oil putty. The names are similar and the spelling is easy to confuse, but the article you are reading now is solely about Ernst P's wood filler for joinery, parquet floor repair and furniture restoration. If you were searching for the medicine — continue to FASS.
What is Rubinol linseed oil putty?
Rubinol is a linseed-oil-based wood filler that Ernst P manufactures in-house. It is a traditional blend of:
- Cold-pressed linseed oil as binder
- Mineral filler (chalk/barite) for volume and strength
- Colour pigments matched to different wood species
- Small amounts of drying agent to control the curing speed
Unlike modern acrylic fillers which cure by evaporation, linseed oil putty cures by oxidation — the linseed oil reacts with oxygen in the air and builds up a flexible, durable and water-repellent polymer network. The same chemistry that keeps a hundred-year-old linseed-oil-painted window sash weathertight in an old parsonage.
Why linseed oil is still the standard
Linseed oil putty has been used in Sweden for over 150 years. Despite newer products coming along, linseed oil putty holds its ground for several reasons:
- Flexible after curing — follows the wood's movements with moisture and temperature without cracking
- Bonds to linseed oil paint — the same chemistry in both products gives full adhesion
- Solvent-free — no VOC emissions, the odour is mild and natural
- Ages beautifully — darkens gently alongside the surrounding wood instead of fading
- Repairable — old linseed oil putty takes new linseed oil putty without primer
This is why heritage conservators, boat carpenters and furniture restorers almost exclusively use linseed oil putty for traditional wood.
Ernst P's Rubinol — manufacturing tradition
Rubinol is not a bought-in product we merely repackage — it is our own recipe, mixed and filled in Sweden. That gives us control over:
- The pigmentation — we can match wood colours that do not exist in generic fillers
- The linseed oil quality — cold-pressed, not solvent-extracted
- The consistency — stiff enough for vertical surfaces, supple enough for fine filling
- The drying time — balanced so it neither hardens in the tin nor takes unreasonably long to cure
We have been making Rubinol for decades and the recipe has been fine-tuned as we have heard from carpenters, window restorers and parquet layers across the country.
Complete colour guide — all 20+ Rubinol shades
Rubinol comes in a wide spectrum of wood colours. Here is an overview of which shade to choose depending on wood species:
Light woods
| Colour | Wood species it matches | Typical applications |
|---|---|---|
| Furu / Björk / Gran | Pine, birch, spruce, larch (light) | Window frames, architraves, furniture in light softwood |
| Ask ljus | Light ash, untreated beech | Skirting boards, stair treads, light-coloured furniture |
| Ask vit | White-oiled ash, white-lacquered birch | Modern furniture with a white-pigmented finish |
| Ljusgrå | Grey-glazed pine, grey-pigmented wood | Modern Scandinavian interiors |
Oak and similar
| Colour | Wood species it matches | Typical applications |
|---|---|---|
| Ek ljus | Light oak, untreated oak | Parquet floors, oak skirting, dining furniture |
| Ek | Medium oak, standard stain | Average oak parquet |
| Ek mörk | Dark oak, stained oak | Older oak furniture, fumed oak layers |
| Rökek | Smoked oak, dark-toned oak | Premium parquet, modern fumed oak floors |
Dark hardwoods
| Colour | Wood species it matches | Typical applications |
|---|---|---|
| Mahogny | Mahogany, teak in warm shades | Antique furniture, boat interiors |
| Körsbär | Cherry wood, fruit wood | Fine furniture, kitchen doors |
| Wenge | Wenge, dark tropical wood | Modern dark furniture, parquet |
| Rödbok | Steam-treated beech, red beech | Beech parquet, older beech furniture |
| Bok/Hevea | Natural beech, hevea | Kitchen worktops, lamella-glued beech wood |
Tropical and exotic
| Colour | Wood species it matches | Typical applications |
|---|---|---|
| Merbau ljus | Light merbau | Merbau parquet |
| Merbau mahogny | Dark merbau | Darker merbau interiors |
Special colours
| Colour | Use |
|---|---|
| Svart | Ebony, black-toned oak, contrast joints |
| Ljusgrå | Weathered outdoor trim, grey-stained oak |
Sizes — 100 g tin vs 1.5 kg tin
Ernst P supplies Rubinol in two basic formats that cover everything from individual nail holes to entire parquet floors.
100 g — small projects and colour testing
The 100 g tin is enough for about 10–40 normal nail holes or 3–8 larger knot holes. It is ideal when:
- You have a single project — a door frame, a piece of furniture, a window pane
- You are trying several colours to find the right match
- You are unsure whether linseed oil putty is the right choice and want to try
- You have several wood species in the same project and need several shades
We recommend buying 2–3 different 100 g tins the first time so you can blend shades for exact colour matching.
1.5 kg — professional projects and larger surfaces
The 1.5 kg tin is for those repairing entire parquet floors, restoring larger furniture suites or working continuously as a window restorer or carpenter. It is enough for:
- A typical full parquet floor (80–120 m²) with average damage
- Several furniture restorations over a season
- Full-house window restoration (15–25 windows)
Linseed oil putty keeps for 3–5 years in an unopened tin and 1–2 years after opening if you seal the lid properly. Trick: place a piece of plastic film directly on the surface before putting the lid on — it reduces oxygen contact and extends the shelf life considerably.
Application — step by step
Linseed oil putty is easy to use but there are a few technical details that separate a good repair from an excellent one.
1. Surface preparation
A clean substrate is half the job:
- Vacuum or brush out loose wood dust from cracks and holes
- Wipe away grease, oil or wax with white spirit or paint cleaner
- Sand lightly with P120 around the damage — roughens the surface for better adhesion
- Wipe the surface completely dry — linseed oil putty wants a dry substrate (below 15% wood moisture)
Never skip the drying — linseed oil putty and water are poor friends in the first few hours.
2. Application with a spatula
Use a steel or plastic spatula depending on the type of damage:
- Steel spatula (Japanese spatula 40–60 mm) for flat surfaces and larger repairs
- Plastic spatula for curved surfaces and furniture where you do not want to risk scratches
- Your finger for small nail holes and knot holes — linseed oil putty is skin-friendly
Press the putty firmly into the damage so it fills right down to the bottom. Air pockets are the most common reason linseed oil putty later cracks or falls out.
Fill generously — about 1–2 mm above the surface. Putty shrinks slightly as the linseed oil oxidises and you want material to sand off, not a dip to fill again.
3. Smooth flat
With the spatula at a 30–45° angle — draw across the surface so the putty sits flush or slightly proud. Work in the direction of the wood grain to make the putty surface blend visually into the pattern.
4. Drying time
- Touch-dry: about 30 minutes at 20°C
- Sandable: 24 hours
- Fully cured: 48–72 hours depending on layer thickness
Thick layers (over 3 mm) should be laid in two stages — base fill, let dry for 24 h, finish layer.
5. Sanding
Once the putty is sandable:
- P150–P180 to remove excess
- P240 as an intermediate step
- P320–P400 for finish sanding before surface treatment
Always sand in the direction of the grain with light pressure. Hard pressure tears up the half-cured putty.
6. Surface treatment
Linseed oil putty accepts the following surface treatments:
- Linseed oil paint — perfect combination, no primer needed
- Alkyd paint — works excellently after 48 h of curing
- Hard wax oil / wood oil — let cure 72 h, sand P320
- Water-based lacquer/paint — requires 72 h of curing and possibly a blocking primer
- Shellac / spirit stain — works, but always test on a sample piece first
Rubinol for parquet floor repair
Parquet floors have two types of damage that require different tools:
- Small scratches and shallow marks: use hard wax (melted and dripped in — see our parquet floor repair guide)
- Larger cracks, edge damage and joints: use Rubinol linseed oil putty
The Rubinol + hard wax combination
A pro trick for parquet restoration is to combine:
- Base-fill deep damage with Rubinol — press into the edges and depth
- Let cure 24–48 h
- Top-coat with hard wax for the finish surface — hard, wear-resistant and ready immediately
This gives you a repair that is cheap at the base (Rubinol is cheaper per volume than hard wax) and wear-resistant on the surface (hard wax handles floor wear better than pure linseed oil putty).
For full parquet floor repairs we recommend the larger 1.5 kg tin — you use more than you think when you have several damages spread out.
Rubinol for furniture restoration
Old furniture is the classic home territory for linseed oil putty. It is used for:
Knot holes in pine furniture
Untreated pine often has cracks around knots that worsen over the years as the wood moves. Fill these with Furu/Björk/Gran Rubinol and linseed-oil-paint over — the repair is not visible at all after a few months when everything has oxidised equally.
Nail holes from earlier hardware changes
When you remove old hardware from a chest of drawers or wardrobe, they leave small holes from screws and pins. Match the colour to the furniture's finish — Ek, Mahogny or Wenge — and fill with your finger. Sand lightly after 24 h and buff in with furniture oil.
Cracks in boards and worktops
Old thickness-planed boards crack along the fibres as the wood dries. Linseed oil putty flexes with the wood as it moves with the seasons, unlike hard plastic fillers which are pushed out over time.
Gaps in lamella-glued constructions
Glue joints in old furniture sometimes open up. Rubinol fills the gap, the linseed oil penetrates the wood fibres on both sides and locks the joint together again — not as strong as new glue, but visually and physically durable in a normal indoor environment.
Rubinol vs Hard wax vs Baowachs — when to choose which?
Ernst P has three main products for wood repair and it is not always obvious which is right. Here is the comparison:
| Property | Rubinol linseed oil putty | Hard wax | Baowachs |
|---|---|---|---|
| Form | Paste in a tin | Wax stick that is melted | Soft wax in stick/box |
| Curing | Oxidation, 24–48 h | Cooling, 10–20 sec | None — ready immediately |
| Damage size | Medium–large (2–30 mm) | Medium (2–10 mm) | Small (under 5 mm) |
| Wear resistance | High after curing | Very high | Medium |
| Floor compatible | Yes (with top coat) | Yes, including traffic areas | Limited |
| Paint & oil compatible | Excellent | More difficult | Worse |
| Colours | 20+ wood colours | 50+ wood colours | 50+ wood colours |
| Flexibility | Follows wood movement | Semi-hard | Soft and flexible |
| Typical use | Windows, furniture, parquet | Parquet, traffic surfaces | Nail holes in trim |
Simple rule of thumb:
- Are you going to paint or oil over afterwards? → Rubinol
- Are you repairing a floor with wear? → Hard wax (or Rubinol + hard wax top coat)
- Are you filling nail holes in trim where the colour already matches? → Baowachs
Read more in our dedicated guides for hard wax and parquet floor repair and Baowachs and nail holes.
Traditional manufacture — linseed oil as a historic method
Linseed oil putty's origins reach back to 18th-century painter tradition in Sweden. Linseed oil was already the binder in the linseed oil paint that coated almost every old wooden building, and when cracks needed filling, the same linseed oil was taken, chalk and pigment mixed in, and stirred into a stiff paste.
Why the method has survived
Modern binders — acrylates, polyurethanes, silicones — have better properties on paper. But for traditional wood in indoor environments, linseed oil keeps up:
- Same material class as the wood's treatment — no dual chemical environment
- No VOC emissions — an important advantage now that heritage conservation is becoming a standard requirement
- Repairable with more of itself — future generations can easily maintain
- Ages in parallel with the wood — linseed oil and wood darken similarly over the years
Modern heritage conservation in Sweden — both state projects and private restoration — almost always specifies linseed oil paint and linseed oil putty for culturally significant wood. Ernst P's Rubinol follows that tradition.
Ernst P's recipe
Without revealing exact proportions: we use cold-pressed Swedish linseed oil (not solvent-extracted), natural chalk and barite as filler, earth pigments and mineral pigments for colour, and minimal amounts of lead-free modern drying agent (Pb-free, per EU directive). The recipe has been fine-tuned decade after decade from feedback from window restorers, floor layers and furniture joiners.
Reuse — can old Rubinol be used?
A common question from customers: "I have a half-opened tin from last year — does it still work?"
Short answer: Often yes.
Check:
- Look at the surface — a thin skin on top is normal. Scrape it off.
- Stir with a spatula — if the putty underneath is smooth and pliable, it is fully usable
- Test the consistency — if it feels stiff but can be kneaded, add a few drops of pure linseed oil and stir in
- Visual taste test — even colour and consistency? Use it. Lumpy or hard all the way down? Discard.
Tips for extending shelf life:
- Place plastic film directly on the putty surface before closing the lid
- Store cool and dark (below 20°C)
- Make sure the lid sits tight — use rubber sealing around the edge if needed
With these routines, we have customers who have used the same 1.5 kg tin for over 5 years without issue.
More products in the Rubinol range
The full range is available in the linseed oil putty category with all 20+ colours.
Common mistakes
Mistake 1: Layers that are too thick
Linseed oil putty cures from the top down — oxygen reaches the surface first and hardens there. If you apply 5 mm thick, you get skin on top while the underside is still soft.
Fix: Apply no more than 3 mm per layer. Let dry for 24 h. Top coat if needed.
Mistake 2: Sanding too early
12 hours after application the putty may feel dry, but it is not. If you sand too early it smears over the surrounding wood instead of giving a clean surface.
Fix: Wait 24 h before sanding. Thicker layers: 48 h.
Mistake 3: Painting too early
A similar problem — if you paint over putty that has not fully cured, the paint bonds to the putty but not to the wood. Result: the paint may flake later.
Fix: At least 48 h before linseed oil paint, 72 h before water-based paint.
Mistake 4: Damp substrate
Linseed oil putty in a hole where there is moisture → the linseed oil oxidises the surface but the moisture behind makes the putty release and fall out.
Fix: Dry completely before application. If needed — hot-air dry for 30 minutes beforehand.
Mistake 5: Wrong colour without a sample piece
You grab the nearest tin without testing → once the putty has cured and darkened it shows clearly in the room.
Fix: Always test-fill on an underside or hidden surface first. Wait 48 h and check in daylight before starting on a visible surface.
Safety and environment
Rubinol is solvent-free and contains no classified hazardous chemicals. But linseed oil has one peculiarity every carpenter should be aware of:
Spontaneous combustion risk in rags. Linseed-oil-soaked rags and sandpaper can self-ignite if left in a pile — the heat of oxidation can build up enough to start a fire. Rule:
- Place used rags in a steel bucket with water after use
- Or hang them individually until fully dry before disposal
- Never mix linseed oil rags in a pile with other waste
Nothing mysterious — everyone who has worked with linseed oil knows. But it has to be mentioned.
Related
- Repairing parquet floors and laminate with hard wax — complement for wear surfaces
- Filling nail holes in trim with Baowachs — for smaller damage
- Oiling a worktop — how often — linseed oil tradition for worktop care too
- See the full linseed oil putty range
Sources
Last updated 2026-04-18.
- Ernst P AB — Manufacturer of Rubinol. Own product specifications, formulation and product tests carried out in the workshop.
- Svenska Byggnadsvårdsföreningen — Recommendations for traditional wood filler and linseed oil paint. byggnadsvard.se
- Traditionella Byggvaror — General properties of linseed oil putty and application conditions. traditionella.se
- FASS (Robinul) — Disambiguation, the medicine glycopyrrolate. fass.se
- Riksantikvarieämbetet — Care recommendations for culturally significant wood where linseed oil putty is specified as the primary choice. raa.se
Vanliga frågor
What is Rubinol linseed oil putty?
Rubinol is Ernst P's own brand of traditional linseed-oil-based wood filler. It is a blend of cold-pressed linseed oil, mineral filler and colour pigment used to fill cracks, knot holes, nail holes and gaps in wood. The putty is solvent-free, flexible after curing and comes in 20+ colours matched to different wood species. Ernst P has manufactured Rubinol in-house for decades — the recipe builds on the classic Swedish linseed oil putty tradition.
How is Rubinol different from the medicine with a similar name?
There is a medicine called Robinul (glycopyrrolate) used in healthcare to reduce salivation and muscarinic side effects. It has nothing to do with Rubinol linseed oil putty — the name is similar but spelled differently. The Rubinol in this guide is Ernst P's wood filler for joinery and furniture restoration.
How do I choose the right Rubinol colour?
Match the colour to the wood species you are repairing. For pine, birch and spruce — use Furu/Björk/Gran. For oak — choose Ek ljus, Ek or Ek mörk depending on shade. For mahogany, wenge, cherry, beech or merbau there are dedicated shades. If you are unsure: buy several small tins (100 g) and test on an underside first. Linseed oil putty darkens slightly as the linseed oil oxidises over the first few days — choose a slightly lighter tone if in doubt.
How long does Rubinol linseed oil putty take to dry?
The surface is touch-dry after about 30 minutes, but full curing takes 24–48 hours depending on layer thickness, temperature and humidity. Thick layers in deep cracks may need several days. Linseed oil putty cures by oxidation — meaning the linseed oil reacts with oxygen in the air — so good ventilation speeds up the process.
Can you paint or oil over Rubinol?
Yes. Rubinol is particularly well suited as a substrate for linseed oil paint because the linseed oil components bond to each other. It also works excellently under traditional alkyd paint, hard wax oil and natural wood oils. Let the putty cure for at least 24 hours before painting, and sand lightly with P180–P240 for best adhesion. Water-based paints can be used but require longer curing (48–72 h) since water can otherwise slow down oxidation.
What grit should I sand with after Rubinol?
P150–P180 for coarse sanding of excess, P240 for the intermediate step and P320–P400 for finish sanding before surface treatment. Always sand in the direction of the wood grain. Wait at least 24 hours after application before sanding — if the putty is too soft it will smear instead of sanding cleanly.
Which size should I choose — 100 g or 1.5 kg?
The 100 g tin is enough for individual nail holes, window frames, small furniture repairs — about 10–40 normal nail holes. 1.5 kg is for parquet floors, larger furniture restorations, professional workshops and renovations where you know you will be mixing and repairing continuously. Linseed oil putty keeps for a long time in a closed tin (several years) so it is rarely wrong to choose the larger one.
Does old Rubinol that has dried out still work?
If the top layer has formed a skin but the putty underneath is soft — scrape off the skin, stir and use. If the whole tin is hard and cracked, it is spent. Ernst P's recipe is robust: a properly sealed tin can sit for 3–5 years and still be usable. Tip: place a small piece of plastic film directly on the putty surface before putting on the lid — it reduces oxygen ingress and extends the shelf life considerably.
