Away for a bit…

Busy vacationing in Norway for the next short while. Doing some photography, checking out some museums, and generally having fun. Going to visit The Viking Ship Museum in Oslo, and a couple of open museums. Maybe I’ll even find some woodworking tool somewhere? Who knows??

Lots of posts coming in the fall, including finally getting the workbench done!

Removing rust – the experiments (i)

In order to determine which of the chemical means of reducing corrosion works best, I set up a series of experiments.  The first one applied four different rust removers against the task of removing rust from a series of large and small vintage rectangular forged nails. The rust on these nails is fairly uniform, as opposed to plane blades, which can often form varying levels of rust, depending on the environment they are stored in, and their composition. Each nail is be submerged about one-third in a rust suppressing liquid – Evaporust, vinegar, molasses, and Coca Cola. The nails were left in the solutions in glass jars for 5 days.

Experiment 1: SMALL NAILS

The first experiment was done with small nails, approximately 2″ in length. Here are the nails before treatment:

And here are the nails after treatment with each of the four solutions. The result?

  • Molasses – The rust on the nail has been reduced substantially.
  • Coca Cola – There is no effect on the rust, in fact submersion in the Coca Cola has added a surface layer of flash rust.
  • Vinegar – Somewhat less effective than the molasses, the rust has been reduced, with a noticeable differential layer where the vinegar ends.
  • Evapo-rust – Cleanly and efficiently removed all traces of rust from the nail.

Experiment 2: LArge nails

The second experiment was performed with 4″ nails, in rougher condition. There were noticeably similar results. The side effect of these treatments is that as in the closed jar environment, vapours often have an effect on the portion of the nails not in solution.

  • Molasses – The rust on the nail has been reduced substantially.
  • Coca Cola – Again there is no effect on the rust.
  • Vinegar – Somewhat less effective than the molasses, the rust has been reduced, with a noticeable differential layer where the vinegar ends.
  • Evapo-rust – Cleanly and efficiently removed most traces of rust from the nail.

So from these experiments it is clear that using Coca Cola is not at all useful in the process of suppressing rust. It doesn’t work. Most colas have a pH of around 3.4, and is more acidic than vinegar, and citric acid. But it is essentially a  carbonated syrup.  Over a long period it may be effective in removing tarnish from some metals, but not in-grained rust. Apparently some people have had success using cola and aluminum foil to remove rust spots from chrome. Vinegar and molasses are somewhat effective given time, and more importantly they are cost effective, which is especially good for de-rusting large pieces.



Building a new mantelpiece (i)

I have always liked the mantelpiece in our house, especially as it was made of somewhat rare chestnut. The problem is that  the fireplace is a somewhat big feature, and the mantelpiece is both too large and the grain on the chestnut is quite conspicuous.

The mantelpiece is of quite simple construction: the bottom plate is joined at the ends using a 45° miter. The top plate uses a mitred-butt joint at the ends. The entire mantelpiece is held together with 2″ nails, no glue anywhere, with a series of 2″×4″ blocks in behind for support. It is not exactly well constructed, but then again these were not high-end houses during the period they were built in Toronto (mid-1920s).

With the pale, orange bricks, we chose to rebuild the mantlepiece using cherry. The new mantle will be 1″ shorter on either side and the front, to reduce its footprint. The inset has also been reduced from 1″ to ½”, and the four pyramids have been removed. The joints at either end of the top and bottom plates will both be mitred-butt joints, to maintain some of the aesthetic appeal of the original.

Sandpaper for the Festool RO125 sander

For sandpaper there are two choices, the Festool paper, of which there are numerous types, and Abranet abrasive. Now the Festool abrasives are not exactly cheap, and it’s impossible to buy less than 10 in a packet… and there don’t seem to be any “test packets”, full of a range of abrasives (well except for the “125mm Sanding Disc Set” with 150 assorted discs) . For the cost of the sander, they could almost include this, instead of the lonesome 80-grit sanding pad. The Abranet is aluminum oxide bonded to a tough polyamide mesh. From the cost perspective, the Abranet averages about C$1.45 a disc, whereas the Festool Rubin2, Granat and Brilliant 2 range between C$1.80 and C$2.00 (Lee Valley pricing for a pack of 10). Pricing reduces significantly when buying in bulk packs. For example the Granat abrasive is C$2.00 each when bought in a pack of 10, C$1.00 in a pack of 50, and C$0.80 in a pack of 100.

Rubin, 60-grit

Festool offers a multitude of abrasives.

  • Rubin 2 -(close-coated aluminum oxide)  this is the primary one for raw wood. P40-P220
  • Granat – (hardened aluminum oxide abrasive with ceramic grit and stearate coating ) used for solid surfaces, plastics, composites. P40-P1500.
  • Brilliant 2 – For use with paints and varnishes. P40-P400. P40 to P60 for rapid removal, stripping stubborn paints and finishes.
  • Saphir – (aluminum oxide) For sanding thick coats on hard surfaces, P24-P80. Suitable for sanding wood, paint, plastics, fiberglass, composites, concrete and steel.
  • Titan 2 – (aluminum oxide) Suitable for solid surface and automotive finishes.P80-P3000
  • Platin 2 – (silicone carbide) Suitable or finishing fillers, finish coats, solid surface, fiberglass and plastics. S400-S4000
  • Vlies – (aluminum oxide fibre-mat) Suitable for cleaning, scouring and scuff sanding a wide range of materials. A100-A280

I would suggest Rubin 2 for rough sanding, followed by Brilliant 2 for higher end 320/400 grit sanding. I have used Rubin 2, 120 grit, followed by 180 grit, followed by Granat 220 grit for finishing hard maple to obtain an uber smooth surface. I have also used a Granat 320 to finish sand drywall, and it does an exceptional job.

Everything decays… mostly

The photo below is from a boat sitting on blocks in the harbour in Reykjavik. What it represents is a metaphor for most things on the planet – there is very little humans make that does not eventually deteriorate (well most things – glass doesn’t decay, but wears away once broken, and plastic, well some say a plastic bottle may take 500 years to break down). Marine environments may be the worse, but the biggest culprit is water. Wood will eventually rot away, and metal rusts. For wood to rot of course you need the presence of warmth, oxygen, and moisture. Take one of these away, and the process slows immeasurably. Same for metals really. That’s why logs underwater, and even wrecks in cold climes for 100+ years survive – no oxygen.

Check out this post which describes centuries worth of shipwrecks in the Black Sea. Below 150m, there is next to no oxygen, so the wood on some of the wrecks was so well preserved there were visible chisel and tool marks. On some wrecks, even coils of ropes were preserved. It’s also why underwater logging has become such an industry, reclaiming logs that sunk during logging 100+ years ago. Above water though, its another matter altogether. That’s the problem with oxygen… it plays together with moisture and warmth to rot things. Wood decays, because the moisture and temperature conditions allow fungi to grow in the wood tissue.

Ironically the woods that are most resistant to decay are also those which are hardest to work with. Black locust is a good example, or tropical woods such as ipe, or lignum vitae. Ipe can be cut (but not by hand), but challenging to glue, and impossible to shape. Old growth redwood was exceptional for decay resistance because it came from large trees with a good portion of heartwood. Newer growth trees have larger bands of sap wood, which offers less resistance. That’s why newer wood shingles won’t last as long, despite coming from the same species.

What we need is a fast-growing, CO2 absorbing, workable, highly rot-resistent wood. Think, the workability of beech/birch, the growth speed of the hybrid poplar, the rot resistance/strength of ipe, and the CO2 absorption ability of the silver maple (like who knew).