Sunday, January 6, 2019

Making My Own Cold Bleached Linseed Oil: Part II

About two years ago I wrote on this blog about an experiment refining my own raw linseed oil. This post generated more feedback than any other I've done. It's weird that I haven't written about this stuff since.
Today I bottled up what I made in my second batch that I started about a year ago.
Take your pick: a Maß or a caña.
I was able to get about two and a half liters of the finest BLO type finish I've ever used. I love this stuff because it doesn't smell like chemicals (but it does smell like the Mediterranean Sea), It covers wood nicely, and it dries quickly (and then is odorless).

I think a better name for this stuff should be: Refined Linseed Oil. It's great that it can be done at home.


This time I did things only a little differently. I started by buying a five liter jug of raw linseed oil (good stuff from a boutique shop). I couldn't find the lid to the big jar I used last time, so I went and bought three more.

I bought plastic ones because they were cheaper. This was a mistake. It worked out alright, but I was continually worried that they would come apart while shaking, and there was indeed some leaking. Next time I'll make sure to use glass jars.
Plastic jugs for refining the oil this time. Do yourself a favor and use glass jugs.
Just so you can see the difference, here is a picture of the stuff I made last time next to the jug of raw linseed oil.
Refined vs. raw.
Last time I went to collect sea water and sand from the beach when it was a bit stormy. This time I got some water and sand that was much cleaner to start with. These materials are easier to clean before starting the refining process, and the final product smells only a little like the Med, as opposed to smelling like sludge water from the harbor.
These raw materials were far superior to what I used last time.
A bit of sand in the bottom of each jug, a liter of seawater and a liter of linseed oil in each jar. Shake like crazy and wait. Plus, I still have about two liters of raw linseed oil to make some more.
Freshly shaken mixture.
After a while you can see the oil floating to the top, above a layer of fat that we are refining out of the oil. The clear stuff is seawater and there is sand on the bottom.
After an hour or two.
This time I left each iteration to rest a day or two. You can clearly see the layers in this photo.
A day or two later.
Here's an interesting photo: It shows how quickly things start to work. The one on the right I haven't shaken yet, the one on the left was shaken and rested about five minutes, and the one in the middle I have just finished shaking. I think this was after the first shaking, I racked off the oil on top and mixed it with plain seawater - no sand.
Different stages.
After doing this for a few weeks (and couldn't be bothered doing it any more), I put the resulting oil in glass jars and put them in a sunny room where they wouldn't be bothered. They stayed here for about ten months. I left the lids off completely for a few weeks, then just rested them on top to help keep debris out.
Let's wait for the sun to do it's part.
The idea is sunlight does the last part of the process, which is to make the oil lighter in color. I think if all the fat is rendered out of the oil, the sun will eventually turn the oil colorless. The color I am at is just fine for woodworking, artists making oil paints might want it a bit clearer.

It could also be that the area I put the jars didn't get quite enough direct sunlight. The sun shines in that window only a few hours every morning.

Once I collected the jars from their resting space, I filtered out any debris that was in the jars. I just ran the liquid through a clean shop towel, and in about ten minutes it was all done.
Straining debris from the jars of oil.
Much of the debris in the oil already collected on the bottom of the glass jars, and since I poured the oil out as gently as I could, it stayed there.
It looks like Weinstein - the debris that is sometimes at the end of a bottle of wine..
I decided to keep the oil in plastic jars that I bought especially for this purpose, because they do better on the bounce test with the tile floors in our apartment. I'll keep an eye on them and if the plastic starts to degrade I'll switch them over to metal or glass containers.

It was an accident that they now look like the urinalysis cups that we used when I was in the Army.
New batch on the left, old batch on the right.
I have enough raw linseed oil left over for one more batch.

I really like this stuff. It has no harmful chemical driers, and only smells like seawater for a day or two after it is applied to a wood project. So far, it works just like BLO, without the toxic smell. With the exception that I haven't come across the need to apply more than one coat.

One might find it a bit thick, but you can mix it with turpentine to thin it out a bit, something I've done with BLO before on first coats. Usually, however, I just slather it on my project, wait a few minutes, then buff it out with a dry cloth.

The first batch I have been using by itself, and I plan to experiment with this batch mixing it with some other things to try some other finish recipes that usually include BLO. I'll report how it works.

I would certainly recommend this to anyone who wishes to try something a bit different. I think the resulting oil is of higher quality, and a lot safer and pleasant to use. The process is simple and easy, but it does take some time and patience.

If you have no access to sea water, I'm pretty sure a heaping tablespoon or two of table salt in tapwater would work just fine. I've also been told an alternative to clean sand is kitty litter. Perhaps I'll try it this way someday when I get back to Munich.

Check out my original post for more info on the process.

Finally, some of the comments on the last post suggested a much simpler alternative to this process is just to buy plain old stand oil. I'm told it is a similar product. I promise I'll get some and do a comparison one of these days. I've also been told that it is a bit different than regular stand oil, and is instead comparable to this oil (the German translates literally to "sun-thickened linseed oil), which is 234 Euros per liter at the time of this writing. For obvious reasons, I'll not be comparing my oil to this stuff.

Give this a go if you'd like to try it. I'm sure you'll be happy with the results. If you do, please let me know your experiences with it.

Tuesday, January 1, 2019

American Trestle Table - Part IV - Notes for the Pause

I was able to get a surprising amount of shop time in over the holiday. Sadly it wasn't enough to finish this table before I go back to Spain. I'll have to finish it up next time I'm here - probably this spring.

Lucky thing my client won't need the table until at least after September. Maybe later.

I did some real thinking about what to do since I made mortises in the upper supports rather than cut joinery for bridle joints. I decided to go with what I have. The tenons will be plenty strong (probably stronger than bridle joints), but to make them look less weird, I sawed about 1/2" of depth from each of the supports. This will give a little bit of  distance between the top of the trestle's mortise and the horizontal edge of the support.

I think if I hadn't done that, the bottom of the support would touch the top of the trestle's mortise and look weird.

Let's get to it:
Layout lines for the lower tenon on the leg
Layout is critical for this. I'm not used to committing like this. Whatever I mark now is the final height of the table, period. I decided to make the table a standard 30" height. To get that, the end of the bottom tenon must be 30" from the end of the upper tenon - less the 40mm thickness of my table top.

Considering that I already had a mortise in this beam, The end of the upper tenon had to be exactly six inches above the bottom of the trestle's mortise. This is because the trestle is six inches thick, and the bottom of the trestle rests on the bottom of the mortise.
Exactly six inches above the bottom of the mortise.
So the pictures are in the wrong order. I marked the end of the upper tenon, then marked the length of the entire leg (the end of the lower tenon). After that, I marked the shoulder line for the lower tenon and cut the tenon.
I missed my honking BadAxe tenon saw. It's perfect for this kind of joinery.
After some tuning of the tenon with my router plane, the tenon fit perfectly.
Three more to go.
While doing all this, I had been suffering with an Ohio O7 jointer plane that wasn't quite working right. I never had the time to rehab it, so I was just using it with a Hock replacement blade.

The problem was I was getting some chatter. But not chatter like I had ever seen before. The wave of this chatter was really slow. You couldn't really see the bumps, but you could sure feel them.

It turns out there was a nasty hump on the face of the frog. Likely this plane never worked well for anyone, even when it was brand new.
A few swipes on my stone shows a nasty hump.
I got the frog 90% sorted, and it made a world of difference with the jointer. It's still not perfect, but it got me through sizing the beams.

Next I sawed the upper braces so they were a bit thinner, as I described above.
A well tuned ripsaw is a wonder.
After this workout, I did it again on the second one.
Two of these rips is a lot like work.
After cleaning the rough surfaces and planing to exact thickness, I cut tenons on the uppers the same as I did on the lowers.
Look! Some sticks!

Now that all of the mortise and tenons are cut, it's time to fettle them. It's been a long time since I used a shoulder plane for this job. I learned how to do it with a chisel for the sake of having that skill. It's a great skill to have, but I decided to pull this shoulder plane out one last time before I sold it.

Holy Moly! I forgot how easy this made tuning tenon shoulders. I was done with four perfectly tuned tenons in about twenty minutes. I'm sure I could have done it with a chisel, but it would have taken hours to get them to the level of perfection they are at with this tool.
I suppose my LN large shoulder plane has earned it's place back in my tool chest.
After that's all ready, I marked out the taper of one of the upper supports. First I marked the centerline on the middle of the the mortise, then I was able to mark out an equal length to each side from there. The end of these braces will only be one inch thick, so I am now able to mark the taper to give an even taper all the way to the leg beam. It's just a matter of cutting it out.
Another job for the rip saw.
I was only able to get the one support roughed out before my shop time ended.
When I get back to this project in a couple months, I'm sure I'll forget what I was doing, so this post is mostly a reminder for my future self.

Future self: the next thing that needs to be done is to plane the taper on this brace down to the line and smooth it out and cut the ends to length at the angle I marked. Then once the other is done, the taper on the feet can be done. But not so aggressive of a taper!

Once everything is shaped and smoothed, the beams can be planed to thickness so the surfaces all meet. Next is a chamfer.

I suggest to my future self to make the trestle and fit it before drawboring and wedging everything. You know how you are!

As far as the slab top goes, it needs just a little bit of work: a big chamfer on the underside to thin out the look of it, and some epoxy for the little cracks in the center.

Hopefully I won't forget I wrote this here until after I've done something irreversible.