My Hand Planes

[cae2100]

Ive been thinking about this for a while, mostly pertaining to the T rabbet plane that I cast in bronze. That pine that I made the pattern from has some issues and is horribly unstable. It was fine until I put shellac on it, which took quite a good bit of shellac because of how porous the wood is and how much it absorbed it in, and how much it took till it started actually building up a layer of shellac on the outside to smooth it off. Ive made plenty of patterns with it and almost every single one, it's been the same on how much shellac it takes to seal it up. The T rabbet plane pattern was a bit thinner than the normal patterns Ive made with it, and I think the thickness of the patterns kept it from moving that much in the past.

The problem with it was that when I put the shellac on it, the wood really really bowed hard in towards the parting line, causing it to warp pretty extensively, and I had to clamp the pattern down to get it back flat. Thankfully, the pattern ended up going back flat when the shellac had fully dried on it's own, and I figured that would have been the extent of it. Well, when I left the pattern out at the molding bench and it had rained that night, the pattern once again did that, and I had to wait for it to dry back out before it would flatten back out again to be able to ram it up, and it kinda warpped again once I rammed it up from the moisture out there I think. It has gone back flat again now that it's in a box of patterns here in the house.

That really got me thinking after seeing something, about wood finishes and paints and such, how they tend to create kinda a plastic layer on the wood that blocks moisture from getting in, and with the pattern having thinner coat on the parting line to seal it up and multiple coatings of shellac soaked into the outside to seal it up and smooth it off so it releases from the sand easily, I think the shellac on the outside is blocking the wood from evenly absorbing the moisture and moving evenly, and instead just warping like it is.

That got me looking into various old old finishes and saw linseed oil paints, which was mostly just raw linseed oil with pigments and cooked with some red lead added in to act as a chemical dryer, which even in some old patternmaking books, I saw that mentioned. I was watching a video a while back from the 1930s that was on the one foundry, and they were showing some patternmaking. When they were doing the coatings, they were talking aboutvarnishing the patterns with shellac, but to me, it really did not look like shellac at all and honestly looked more so like a thin runny paint, which was added right after using some putty on it to fill in dowel pin holes and nail holes.

I was looking at very oldschool linseed oil paints for houses and such, which can let the wood breathe and let it move easier, but adds some protection to the wood and makes it very smooth, and it looks exactly the same as in the old video and the same linseed oil putty was used in it too. Ive been kinda going down this rabbit hole for a few weeks now, and while I wont be using red lead as a dryer, zinc oxide works as a chemical dryer too, just not as quick to dry is all. So instead of a few hours for it to dry, it might take a day or two for it to fully dry and cure. With the linseed oil paint, it seems to not be waxy or grippy like modern paints either, wont flake off like some finishes, and seems to come out nice and smooth in the end, so seems to be an interesting experiment to try anyways.

I had some flax seed oil here that has been sitting in the cellar for years, so I grabbed it out and mixed it with some salt water and sand in a jar, and keep shaking it a few times a day to refine it. I figured that I would try to refine the flax seed oil into raw linseed oil, which seems easy enough to do really, since I already have everything needed, and I'd try making a small batch of the paint. The old patternmaking books also talked about using woods like oak and such, which is very unstable and warps really badly seasonally, yet alone with the large humidity swings in the sand molding area, so I think there might be something to the whole linseed oil paint and such on the patterns.

I realize that I should just stop using that pine for patterns and anything that needs to be precise in the future so I dont run into this again, which Im already planning on not using again in the future, but figured I'd try seeing if I can figure out other finishes that would work too, and compare them, just in case I make up a pattern again and I find that it starts to give me problems, or if I have to make up a pattern to get sent off to get cast at a commercial foundry for someone else, then I can paint it up with the standard foundry colors so there's no confusion on what goes where for the molders.

Just alot of thoughts on finishes for foundry patterns, where Im coming from, and experimenting just being dumpped here I guess, lol. I think if I can find something like how I am thinking the linseed oil paints will work, even with the less stable and rougher grain woods, that would open alot of possibilities up to me on materials I can use since up till now, Ive been limited to the pine and cherry, and be able to use hard maple and other woods that also have finer grain, and is much harder and would hold up much better long term to the abuse. Ive tried a few different paints and have not been happy with any of them because they've always been very grippy, and/or wouldnt go on very smooth, so kinda abandoned the idea of using paint up to this point, but if I can find something else for patterns than shellac, it might be good for some patterns where they might be likely to warp due to shape, or might be good for use on 3d printed patterns for matchplates and such too.

Sorry about the huge write up/book, just throwing out alot of thoughts really, lol.