Several questions have come up in the past weeks that are of interest. I thought that while the bleaching process continues on the Singer sewing machine cabinet that I might take the time to address some of them. But first, here’s an update on how the sewing machine is going.
All of the parts are now stripped and I have begun to sand them lightly with 180 grit sandpaper. This is done for two reasons. First of all, I have to make certain that I open the grain enough for the bleach to penetrate. Regardless of what stripping method I had used, there would be a certain amount of residual finish on and in the wood. This would serve as a barrier to the bleach getting in and doing what it needs to do within the structure of the wood.
The same is true for the wiping stain when we get to that point. So, opening the grain is the next step.
The oxalic acid product that I purchased is sold by weight. The instructions say to mix the contents of the container with two gallons of hot water. Well, being a frugal as I am, my intent was to figure out how much acid was necessary for a quart of liquid. I certainly won’t need more than that. Not having a gram scale at my disposal, I resorted to the old fashioned way of figuring out how much oxalic I had in a volume measurement and then dividing that up toget what I needed for a quart.
Oxalic acid crystals have the consistency of wet sand. Everything sticks together. It didn’t pour out of the container very well. But once I got it all measured, I found that I had 18 fluid ounces of volume. If 18 ounces was needed for two gallons of water, then 2.75 ounces was needed for a quart.
How do you measure a fluid ounce accurately? Well, a level tablespoon is half an ounce. I put six level tablespoons into a quart of water and called it a day. It is ever so slightly stronger than the correct proportion but I doubt if that will be a problem.
As I write this I am waiting for nature to take its course and that means that the lid of the cabinet is drying. I have sanded it and applied oxalic to the stained areas first followed by the whole surface ten minutes later. Then, I waited 15 minutes before wiping the whole piece down with a clean, dry cloth.
Assuming that I am satisfied with the results, the next step will be to use the neutralizer on the wood surface. There is a warning in the instructions that oxalic acid left on the wood may cause problems with water-based stains and other coatings. From what I have seen thus far, the oxalic may cause the surface tension to be raised and fluids may not flow out on the surface.I noticed this as I applied the oxalic to the bare wood. If this were to remain the case, that could make for a rather messy looking stain job!
I will also want to sand again after the bleaching process is completed. There are a number of places where there are chips in the veneer that will need to be filled. Also, there are still some small gaps in the veneer where water damage caused those joints to spread and curl up. I’ll want to fill and sand all of those so that the finish will bridge those spots.
One person suggested that using a cottage cheese container to mix my stripper in might not be a good idea. He was concerned that it might melt or that it might tip over. I suppose that different parts of the country have different kinds of plastic containers in use for food. Perhaps in his area there is a less stable plastic used. Out here in the Northwest, I have been using cottage cheese containers in my shop for years. They are made from plastic #5 according to their recycle label. That means that they are a polypropylene. I have never had any problem with any melting due to chemical reactions. I use lots of quart cottage cheese containers as well as some pints.
Are they “tippy” in any way? Not for me. I use them all the time. Thanks to my dear wife, a steady supply of containers appears in our plastic food storage drawer and about twice a year we clean those out and they go to the shop for use in my projects. Waste not…want no, I think is the saying.
More answers to your questions next week.
Until next time...spray on!
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