How to keep cast iron work tops rust free without much maintenance, and without imparting a greasy feel to it? I do a lot of /diy/ stuff on top of my table saw, it being the flattest and sturdiest surface I have. But even leaving a palm print on it tarnishes it.
Johnson paste wax - felt amazing to the touch, but barely any protection, tarnishing occurs within a few days and any moisture on the top would surely result in surface rust
WD-40/light penetrating oils - significantly improved protection, oily residue
I will not try a heavier oil or grease, because obviously despite being the best rust protectant, the surface has to be at least sort of clean to the touch. So basically, rust protection and 'feel' seem like inverse properties. Are there any substance that bucks this trend? Or perhaps, is there a good hard-coat that could be applied to bare cast iron to keep it dry to the touch, yet durable enough to work on and totally rust proofed?
There's also this, which is supposed to be great, but it's pricey.
Dont use WD-40, it attracts and holds onto grime which invariably collects moisture.
You can use it to help remove rust spots, but be sure to wipe the surface clean with mineral spirits afterwards to remove it.
Apply a generous coat of Boeshield T9. Let it sit for a few hours (ideally overnight), then rub down with a clean rag and apply your wax. Reapply a thin layer of wax every couple uses of the surface to keep it protected. And strip with spirits and reapply the boeshield every 4 weeks or so depending on how well the surface is holding up.
>Isn't Boeshield T9 just another wax?
Not even a little.
If you want to get technical, Its propane and butane propellants, mineral spirits and white mineral oil.
It applies nicely and resolves to a slightly tacky feel, not slippery like wd-40. I buff it down with a rag with some wax paste on it. Makes a nice rust resistant surface finish. That doesnt hold only grime easily like wd-40 will.
My old man who has lots of cast tools and surfaces uses mineral oil and beeswax. Right out of the same pot he uses to finish his wood projects.
Personally Id be leary of heating the surface too much.
I do recall a friend using cold gun blue on his cast iron top. He was treating it with boeshirld and wax afterwards. The only reason I never went that far is that my shop is environmentally controlled, he lived in florida at the time
Nope, it's to harden the steel, and it's only done to steel, not cast iron. I've watched a black smith do the process 18th century style to make a cold chisel. The bluing hardened the cutting edge of the chisel so he could cut other steel. In the old days, bluing gun barrels was done because it showed the steel wouldn't explode during firing because gun and steel making was still progressing. Today it's for looks, back then it was serious business.
>bluing isn't rust protection
Actually it's exactly that. Gun blue is controlled intentional oxidation.
>Nope, it's to harden the steel, and it's only done to steel, not cast iron
gun blue reacts with the Iron in the metal creating an oxide rust that is black in color. It imparts different chemical and mechanical properties to the surface. One o those properties is that blued steel resists rusting significantly better than plain steel.
Surface it with steelwool/light sand paper. Wipe it with denatured alcohol. And get a cover for it. Having nothing ontop has worked for me. And I keep my tablesaw out side on a covered concrete slab but exposed to blowing rain and humidity in the south eastern part of the US.
Besides that some say bees wax.some say car wax. And some say lithium grease.
There used to be stuff victorian era metalsmiths used, i know of it specifically from coal cooking stoves, but it was pretty durable, it was meant to protect the cast iron from rust without the fumes that even victorians knew could make you sick.
In fact they still make it for wood burning stoves. Graphite stove polish.
>>Nope, it's to harden the steel, and it's only done to steel, not cast iron
>gun blue reacts with the Iron in the metal creating an oxide rust that is black in color. It imparts different chemical and mechanical properties to the surface. One o those properties is that blued steel resists rusting significantly better than plain steel.
Then you're talking about a chemical bluing when the original bluing was a heating process. No chemicals, just a rhythm of heat and cooling that created blue steel not just surface deep. That's why it can't be done to cast iron, because it will turn iron to steel. I'd prefer true blue steel instead of a colored blue steel.
Original bluing was not a heat process. All forms of bluing are a surface treatment. Heating iron will likewise not turn it to steel.
Originally bluing/browning was a rusting process but that was labour intensive and required skill. The switch to a salt bath bluing increased production and lead to the famous royal blue finishes from Colt and S&W.
Case hardening and flame/nitre bluing were both heat processes but were not used for critical parts like the barrel or action.
Polish it. All these guys from /k/ are at least half right: bluing will protect it from rust, no matter what form of bluing it is. Some forms work better than others. But they're forgetting that before you blue you polish, at least in modern times, and if you take apart a lock from an 18th century flintlock you'll probably find that even the internal non-working parts were polished. We assume this is because craftsmen back then took more pride in their work, or weren't lazy like we are today, but at least part of the reason was to fight rust. If you take a steel or iron surface to a true 600 grit polish it will delay oxidation by a factor of at least two. Add a light coat of oil or wax, another factor of two.
Of course, have fun doing this effectively with cast iron. Good luck anon.
There are laboratory grade granite surfaces meant for critical measurements. I wonder what it takes to lap these things, or even just make granite countertops for that matter.
I use a piece of granite countertop to lap and sharpen my tools. They can be perfectly flat. Mine is polished to a shine and you can't detect any optical distortion whatsoever in the reflection.
This is going to sound a little over-the-top, but you can get that cast iron piece galvanized. There are a few places out there who will hot dip your item for a reasonable fee. I've seen whole car frames hot dipped, usually vintage stuff or Jeep frames that see a lot of rough overland use. Dipping a table saw top shouldn't be too awfully pricey, and it will remain rust-free for many decades to come.
There is no way in hell Id risk galvanizing.
The surface finish on the table is extremely important for smooth feeding of work pieces. Plus hot dip galvanizing leaves plenty of surface deformation around corners, exceptionally problematic on your track for pushers and sleds.
Once every couple of weeks and wipe it off.
Your workshop atmosphere is also a big player, especially if you use propane heaters.
To correct, bluing draws a temper (we're talking steel), you are right it is due to oxide transformation, and the colour corresponds to a specific temperature light straw colour is a light temper violet is a heavy temper.
Tempering allows the BCT atom structure in martensitic steel to transform back to a BCC structure, this allows for a slightly more malleable and flexible material (this is where the degree of temper is important violet is deep and straw is shallow). You temper steel because in the purely martensitic state (immediately after a high temp, high speed quench) it is very hard and extremely brittle (edges will chip easily), depending on purpose and use this might be an undesirable property.
Remove all the rust and clean it all nice as you'd like it to be. Cut a piece of plywood to fit on top of the saw. Put a layer of newspaper on the table, then put the plywood on top of the paper. The paper will absorb any shit you cleaned the table with. When you need the saw just move the wood and paper, wipe it with a dry rag. That's what i do. Works fine. When the wood gets fucked up from greasy car parts or paint or whatever, you can just replace it with a new piece.
Well, going by the jist of this thread.. just buy a new table saw every week or so. The new one won't have any rust. Definitely don't do that idiotic plywood idea or wd-40 every once in a while. Plywood only costs a little bit and a $3 can of wd-40 will probably last a whole year. I swear every time someone on here asks for advice they get dozens of asinine solutions from morons that'll shit on someone for buying something from a store but insist you should spend hundreds on the fix they thought of. Or thousands. Granite top. Retard. Do that, op. I'm sure it will be fun to move every time you need to rip a board.
>I wonder what it takes to lap these things....
You start with three almost-flat surfaces, and cover with a thin layer of marking fluid or ink. Then you add an abrasive compound and iteratively rub each of them together. 1-2, 2-3,1-3. Clean and remark. Rub again. INk removed evenly? No? Repeat. very slowly you end up with 3 flat surface plates.
Not expensive as shit... Surface plates without a big brand name are sub-$500 from the right supplier. A large piece of granite table top slab might be cheaper, and if you really wanted to go cheap, just make a polished concrete slab.