What Filler Can Be Drilled?
Which Selleys filler can be drilled and screwed into?
Not No More Gaps. If you want to fill holes in timber and then drill and screw into the filled area — to hang verandah brackets, for example — Selleys No More Gaps is not suitable, because it is highly flexible and does not cure hard. A screw driven into it will simply deform the filler and pull straight back out under load.
The product for this job is Selleys Plasti-Bond Heavy Duty bog. It has excellent adhesion to a variety of surfaces inside and outside the home, and it is a two-part bog filler that can be sanded, drilled and screwed into once cured.
For best adhesion to the timber you are filling, make sure the surface is clean, dry, unpainted, and free from grease or oil. Bog does not bond through a paint film, and on old verandah timber there is usually more than one.
Why a flexible filler cannot hold a screw
It is worth understanding the mechanism, because it applies to every filler decision you will make. A screw holds because the material around it resists being deformed — the thread bites into something that pushes back. No More Gaps is engineered to do the opposite: it stretches and compresses so that a moving joint does not crack it. No More Gaps Interior Multipurpose has an elongation at break over 300% and a movement capability of up to 15% (ISO 9046). That is excellent behaviour in a skirting joint and useless behaviour under a screw thread.
The same logic rules out the surface fillers. Spakfilla Rapid and Spakfilla Heavy Duty both carry the instructions do not nail into the dried filler and not for load bearing applications, since the filler can be crushed. They set hard, but they are lightweight fillers, not structural ones.
Using Plasti-Bond Heavy Duty
Plasti-Bond Heavy Duty is a two-pack multipurpose putty for filling holes and cracks in building materials, supplied as a resin that is used with a separate hardener. Because it is a two-pack system, the working time starts the moment you mix — mix only as much as you can place in one go.
- Prepare the timber. Clean, dry, unpainted, and free from grease or oil. Sand back any coating over the area to be filled.
- Mix the resin and hardener according to the instructions on the pack.
- Press the mixed filler firmly into the hole, slightly proud of the surface, and work it in so there are no voids behind it.
- Allow it to cure fully before doing anything else to it.
- Sand level.
- Mark and drill a pilot hole for each screw. A pilot hole matters more in filler than in solid timber — it reduces the chance of the filler cracking as the screw is driven in.
- Drive the screws.
Two things worth being clear about
This is not a structural repair. The question that this answer originally addressed was about decorative verandah brackets that carry no structural load, and the advice fits that case. A filled hole is not the same as sound timber, and it should not be relied on to carry weight or resist wind load.
Plasti-Bond Heavy Duty is classified as a hazardous product. It is a two-pack polyester system with a separate hardener. Read the label and the safety data sheet on the Selleys website before you mix it, work in a ventilated space, and wear gloves.
The alternative: Knead It Multipurpose
If the hole is small, Selleys Knead It Multipurpose is a hand-kneadable epoxy that does the same job with less mess. Its listed uses explicitly include anchoring bolts, screws and housings and moulding to reform or reshape damaged timber and metal.
| Working time | 3 to 5 minutes at 25°C |
| Initial cure | 60 minutes |
| Full cure | 24 hours at 25°C |
| Shore D hardness | 80 ± 5 (ASTM D2240, at full cure) |
| Compressive strength | 55 MPa |
| Lap shear tensile strength | 5.5 to 6 MPa on steel |
| Packaging | 110g plastic tube, 50g blister pack |
Indicative data only, not intended for the preparation of specifications.
After the 60 minute initial cure you can drill, sand, machine, file, saw and paint it. Set time increases below 20°C, so allow longer on a cold day. Wear a dust mask when sanding it, and roughen the bond area by scuffing or sanding before cleaning, for the best adhesion.
Common questions
Can I drill into No More Gaps?
No. It is highly flexible and does not cure hard, so it will not hold a screw.
Can I drill into Spakfilla?
Spakfilla is not designed for it — its data sheets say not to nail into the dried filler and not to use it in load bearing applications.
How long before I can drill Plasti-Bond?
Once it has fully cured. Follow the cure time on the pack; do not sand or drill a bog that is still soft.
How long before I can drill Knead It?
60 minutes after application, which is its initial cure. Full cure is 24 hours at 25°C.
Do I need a pilot hole?
Yes. Drilling a small pilot hole before driving the screw reduces the chance of the filler cracking as the screw goes in.
Does the timber need to be bare?
Yes — clean, dry, unpainted and free from grease or oil is the stated requirement for best adhesion.
Can I use it outside?
Plasti-Bond Heavy Duty is described as having excellent adhesion to a variety of surfaces inside and outside the home.
Can I paint over it?
Knead It can be painted after 60 minutes of hardening. For a bog, sand level first and then paint as you would the surrounding timber.
What if the bracket is structural?
Then a filled hole is the wrong approach altogether. This advice covers decorative fittings that carry no structural load.
Is there a related guide?
Yes — repairing holes in the home covers the wider range of hole-filling jobs.
Can I drill into No More Gaps?
No. It is highly flexible and does not cure hard, so it will not hold a screw.
Can I drill into Spakfilla?
Spakfilla is not designed for it — its data sheets say not to nail into the dried filler and not to use it in load bearing applications.
How long before I can drill Plasti-Bond?
Once it has fully cured. Follow the cure time on the pack; do not sand or drill a bog that is still soft.
How long before I can drill Knead It?
60 minutes after application, which is its initial cure. Full cure is 24 hours at 25°C.
Do I need a pilot hole?
Yes. Drilling a small pilot hole before driving the screw reduces the chance of the filler cracking as the screw goes in.
Does the timber need to be bare?
Yes — clean, dry, unpainted and free from grease or oil is the stated requirement for best adhesion.
Can I use it outside?
Plasti-Bond Heavy Duty is described as having excellent adhesion to a variety of surfaces inside and outside the home.
Can I paint over it?
Knead It can be painted after 60 minutes of hardening. For a bog, sand level first and then paint as you would the surrounding timber.
What if the bracket is structural?
Then a filled hole is the wrong approach altogether. This advice covers decorative fittings that carry no structural load.
Is there a related guide?
Yes — repairing holes in the home covers the wider range of hole-filling jobs.