Filling a hairline crack

[PeteHB]

I have a hairline crack that has developed post machining and have thought about filling it with powdered wood from sanding and superglue. Never done it before but heard about it.
Does it work? Any tips or suggestions.

 

[Myfordman]

Depends on how you propose to finish the work. Any staining process is highly likely to have different absorption due to the glue in your filler so that a nicely sanded surface with a near invisible crack will leap out at you when stained. a coat of water based varnish should be less of a problem.

 

[TRITON]

Depends on how you propose to finish the work. Any staining process is highly likely to have different absorption due to the glue in your filler so that a nicely sanded surface with a near invisible crack will leap out at you when stained. a coat of water based varnish should be less of a problem.

Was taught to do the finish first in some circumstances(french polishing) so that any repair wouldnt show. Put on a coat or two of shellac, then do the repair. which if memory serves me was a coloured wax filler.

 

[Inspector]

Can the crack be closed easily with a clamp. If so take the clamp off and carefully flex the crack open. Then work the glue into the crack and clamp. Clean off the squeeze out, wait until cured and continue with construction. Now if the crack showed up days or weeks after machining because the wood dried you'll have to fill it.

Pete

 

[Mike.R]

Make a fine wood powder, (the dust produced by a power sander with a fine grit paper) from a piece of timber the same species and colour of the item you need to repair and mix to a paste with the intended finish and use that for a filler.

This way, the refractive index of both filler and finish are as close as can be.

 

[Mike.R]

Edit to say, I harvest the fine wood dust by taping a latex glove over the extractor port of my orbital sander, slit the end of one finger so the glove doesn't blow off and sand for a few minutes whilst the other 3 fingers and the thumb collect the valuable product.

I'm not proud of this technique but needs must when the Devil drives.

 

[recipio]

A homemade filler is likely to reject any finish and can stand out when varnished .Some two pack fillers claim to absorb varnish and stain - can't say I've tried them. Whether for furniture or turning I simply use a black shellac stick which runs into the cracks by a kind of surface tension and seems to blend into the wood no matter what type .

 

[GuitardoctorW7]

Probably get shot down in flames for this but it may help... I discovered a new technique last year that is really effective for making a close match filler that takes lacquer well. I needed to find a mahogany filler to match chip out where a new fingerboard was glued to an old neck and it drove me nuts to get it right as I'm a bit of a perfectionist . Thanks to t'internet someone suggested using brown pastel artist chalks and water thin superglue. You can buy them in various shades as a set. Make a fine dust out of them, pack it in the crack and drip (carefully) the CA on to the chalk dust, I use 'whip-tips' for this. The CA seals the crack and doesn't absorb finish and I've achieved (virtually) invisible repairs. Experiment a bit with scrap wood before committing to the repair.