LaymarCrafts Woodturning Techniques


Metal Powder Fillers & Superglue

A popular method of filling cracks, knot holes and other blemishes etc. is by using Metal Filler Powders mixed with Epoxy Resin which is fine and the only real solution for large areas that require to be filled and where time is not of the essence.


For the smaller crack, shake, or hole etc. I have used as an alternative Superglue, with care and preparation this can be a useful and quick method with the resulting repair ready to turn almost immediately.

Primarily I use Metal Powder Fillers of the type used for Cold Casting (Chess Sets etc.), these come in all types of Metal such as Brass, Copper, Bronze, Aluminum and Pewter. These Powders are very fine and are the real thing as far as the Metal is concerned and must be handled in accordance with safety precautions in particular those applicable to the Inhalation of Powders and Dust.

The method described is however usable with many other Powders, and I have used Powder Paint, Powder type Fabric Dyes, the Ink Powder from the Photo-Copier (Jet Black), Fine and Coarse Saw Dust as well as Metal Fillings and Stone Dust. Again when using any of these you must wear a Mask to suit and take adequate precautions.

You also need to protect the containers from any accidental knock as these Powders flow like Water and if knocked over you can in seconds pour a few (or $) of Powder into the Wood Shavings around the Lathe. To overcome this I use small (100ml) clear plastic bottles with a pouring spout and cap, half filled with the powder it will easily flow in a semi-controlled manor from the spout right into the area to be filled, and any accidental spill is not so disastrous.

I use two methods, depending on the area to be filled, for small Cracks, Holes and Splits I fill the offending Gap first with the Powder from the spouted bottle and then using the THIN type of Superglue I let it dribble over the filled area. 

If the offending opening is right through the Wood you will need to back the opening up otherwise the Powder will Flow straight through. I use either Masking Tape, Blue Tack or Plasticine depending on Surface, Size and Access to the rear of the Hole, Crack or Opening.

Providing the area is not too large the Superglue will, via a capillary action, penetrate all the Powder Fill and almost instantly solidify, you can in some instances use a suitable spreader, Cocktail Stick or Dentists type Tool, to add additional filler if required to the Wetted Surface.

You can also choose the type of effect you achieve with this method by either slightly over filling the area and then cutting back to give a smooth finish or you can slightly under fill and therefore achieve a more textured result which works well on Burrs, Textured and Spalted Pieces.

For larger openings I may use the method above but do not completely fill the area to the top, then using the Intermediate or Thick Superglue mixed together with the Powder, on a pallet (off cuts of Plastic or old credit cards are good for this) and apply to the area using a suitable spreader as above. With this method you can have a reasonable time to perform the filling before the mix solidifies.

Alternatively I fill the Gap, Hole with this Thick Mix, however it is wise not to mix too much just in case you falter, get disturbed or drop something all of which are possible and in the 30 to 60 seconds you have the mix would probably become unusable. It is far better to carry out the fill in manageable layers.

It is often sometimes more convenient to use a Finger to spread and distribute the mix, but if using this method you MUST wear a Glove, for this I use the Thin Plastic Gloves that you can buy, these are the same as the Gloves provided at Petrol (Gas) Stations for Diesel users.

Once the Mix has set you can either cut it back to the Surface of the surrounding Wood, with the Lathe running, by using your preferred Turning Tool or by using Abrasives as normal.

A word of warning Superglue will stick anything including Body Tissue, wear a Respirator or Protective Glasses and a suitable Mask, do not initially stand directly in front of the Lathe try and cut from a position to the Left or the Right of the Glued Area. It is not unknown for the Glue to take longer to harden below the initial Hard Skin that appears, if in doubt then allow at least 5 minutes before you start to Turn the piece.

Superglue is a useful addition in any Workshop and, providing it is treated with respect, will stick most materials used by any Woodturner with incredible strength.

Some Tips on its use that I have come across and applied successfully over the years:

1)    If you use the Glue on a regular basis then leave the sealing cap off. Super Glue works on the principle of Curing when Oxygen is excluded, each and every time you use the Glue and replace the Cap there is the chance of trapping some Glue which because the Oxygen has been removed will set. This will either stick the Cap to the Spout or as most of us discover at some time will block off the Spout. You should replace the Cap if long periods between use are expected (i.e. more than a couple of days).

2)    If you use an accelerator to speed up the Hardening of Superglue and you do not want it to turn the Glue White, then allow 10 to 15 seconds before applying a light spray of accelerator this normally stops this Colour change.

Additional information on the use of Metal Fillers can be found at Coldinlay this Site also has  Links to Suppliers.

I received an e-mail re the Dangers of Superglue & Dust Inhalation, we have to be aware of any Dust, and not just that from Superglue, and therefore we should always take sensible precautions.

I always Wear a Forced Air Respirator, use a Dust Extractor at the Lathe and for good measure have a Workshop Ventilator to remove Airborne Dust whenever I am working in my Workshop.

The Superglue Safety Debate has been ongoing for a number of years, I have read some of the various reports and I believe I take the right precautions for the risk involved. if in fact there is any over and above those generally associated with Dust.

Superglue is freely available and apart from the cautionary note re Gluing of Body Tissue I have yet to come across any Warning as to any other effects on Health.. 

Satellite City the suppliers of Hot Stuff, perhaps the best known brand, in their information leaflet clearly state the "Eye Irritant" and "Bonds Skin in Seconds" Warnings we are all familiar with and adds "Use Adequate Ventilation" no mention is made re any other Health Hazards or Special Precautions when using Superglue.


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Last update 17 July 2007
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