Filler from sanding dust - advice…

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Torx

Established Member
Joined
11 Apr 2020
Messages
377
Reaction score
157
Location
Cheshire
I’m restoring a pine staircase - nothing fancy, there’s another thread somewhere - and have dozens of holes and cracks to fill. I’m not expecting it to look perfect by any stretch, but just a bit tidier and **slightly** less obvious.

The advice here was to use sanding dust for the best colour match, so having reached that stage I did a quick experiment on a tread that was too far gone to save. I didn’t know if PVA or epoxy would work better so I had a go with both. I’m also tempted by Fiddes filler gel.

Both experiments have come out a lot darker than the surrounding wood. Did I get the ratio of dust to glue wrong? I’ll admit that the dust I used was from the first sand at 40 grit which contained a lot of muck as well as wood dust, and I was planning to use the dust from the next sand to make the final filler, but to my eye the dust looks much lighter than the dried filler.

I’ve seen this done with great success but I’m obviously doing something wrong - tips?

F4DA567D-18FB-4606-A400-24317E171691.jpeg


62E0FA7D-CE49-4BCE-B7E7-27BF131CB287.jpeg


EA7FE323-DC3C-49ED-96D3-A865EF3FADB7.jpeg


25599A36-2580-42FF-B0FD-23BC9A8C3A1D.jpeg
 
The problem with making your own filler using sawdust and glue is that any finish you subsequently use will not be absorbed on the fill. Use a filler such as this which will take a stain and your finish product. It won't be perfect but it might be acceptable.
Brian
 
In my experience, (limited), and the comments of others, filler of the background wood dust with some form of adhesive will always come out darker than original wood.
One tip is to use a darker wood to make it seem like a natural feature. Other than that, you're into blending dusts to achieve match - WAY beyond my skill or patience!
 
I never found a formula to work perfectly. The Woodful range of fillers claim to absorb stains and Liberon sell Earth Pigments in various shades to mix your own filler. If I have to use a filler I use the Liberon Shellac sticks which run into cracks by a kind of surface tension.
 
One thing I know from doing commercial work is that decorators detest joiners mixing PVA with sawdust. It won't take stain and the glue always shows through the finish, especially if the finish is clear or the timber is an open pore species such as oak of ash.

Instead, what is often done with architectural joinery is that providing the joints and holes are small enough, the staining and polishing are done then defects are filled using either coloured shellac sticks or soft waxes. Several colours can be mixed to get a near match shellac requires a heated applicator (a bit like an electric soldering iron - at one time they used spirit burners to heat the impliment).

The quick and dirty way with waxes is to warm the waxes on a beaker of hot water, scrape material off the sticks and roll into a ball in your hand before pressing into the gaps with a heated spatula or well worn stopping knife. A few minutes later once the wax has set (a few minutes) any excess can be can be scraped off with the stopping knife

Waxes an shellac sticks can be had from firms like Liberon, Hafele and Konig

These are not cabinet making techniques but are designed for volume work
 
Works well on parquet flooring! Not sure it's the best when you are filling at eye level, though

Edit: To explain - floors are first coarse sanded with a heavy duty sander and a low grit number belt. The resulting sanding dust is mixed with a filler adhesive such as Lecol 7500. Once this "putty" has set the floor is resanded all over with a higher grit number belt. Not quite the same process you'd use to sand skirtings or a newel post I feel
 
Last edited:
Fiddes wins so far, not dry yet (although only takes 30-60mins)

These are all mixed with the same dust

0602ED95-48D0-4CA2-8D64-69E3F0DE25A1.jpeg
4FE7DECC-82FA-409E-8825-701B7D6E6F0A.jpeg


Will be interesting to see what it’s like sanded back
 
Don’t go too mad, the various cracks from age give it, it’s own unique character
 
Back
Top