Which sander and abrasives to clean up old steel items?

[GaryLaroff]

In order to build some wooden plow planes, wooden hand tools from centuries past, I am recycling the metal parts from antiques that cannot otherwise be salvaged.  In particular, I want to reuse parts called skates which are an inch or two wide and up to five inches long.  These are old steel and have screw holes, so I can easily screw them down to hold them for sanding.

The advice I’ve received is to use a stationary belt sander, but I have Festool sanders and prefer to go the handheld Festool route.  I’m using chemistry to remove the bulk of the rust and tarnish but the steel is often slightly pitted and I want to get it as smooth and shiny as possible.

I have most of the Festool sanders and abrasives Systainers with good woodworking abrasives selections.  It is easier to list the sanders I don’t have than the ones I do have.  I have all the North American variants except the RAS, ETS 150/5 and RO 150.  

How would you go about cleaning and polishing the steel?  I haven’t played with the Vlies yet, is that what I should try with my new RO 90?  Which sanding pad would you use (hard, soft, etc.)?

Any advice would be appreciated.

Gary

 

[AlexThePalex]

The advice I’ve received is to use a stationary belt sander, but I have Festool sanders and prefer to go the handheld Festool route.  I’m using chemistry to remove the bulk of the rust and tarnish but the steel is often slightly pitted and I want to get it as smooth and shiny as possible.

I have extensive experience with sanding and spray painting steel, from work with cars, boats and industrial objects, so when I read this above I have some questions.

You talk about getting the steel shiny, does that mean you don't want to paint it? Because that doesn't work, you always have to protect steel, or it will dull and then rust very quickly. Unless you use stainless steel.

When you want to get the steel as smooth as possible, do you mean you want to sand it smooth? That won't work either. Steel is way too hard to sand. You can sand anything that's on the surface of steel, but not the steel itself. If you want to smooth the steel itself you'll have to grind instead of sand. Grinding + polishing steel is a daunting task by itself and not something I believe Festool tools are prepared for.  

It doesn't matter which sander you use for sanding steel, they all work. Since you mention they are small objects I'd suggest the RO 90, DTS400 or DX93. As for abrasives, Granat, Brilliant 2 and Titan work great. Forget about Vlies, you don't need it and it won't work as good as the others. Use the standard pad, not the hard pad. On steel you want a pad with some flexibility in it. Start with 100 or 120 grit, not lower. Steel scratches easily from sandpaper that's too coarse. Then use 240. After that, do some wet sanding by hand, with papers from 400, 800 and 1200.

I would never use a chemical to strip rust. We use an angle grinder with a steel wire brush, works a lot better and faster.

To remove all the pits from steel, well, we never did that. We just filled them up with a 2 part body filler. It was going to be sprayed anyway.

Finally, to clean steel we always use paint thinner. It is very effective and leaves no residue. There are many cleaning agents that will leave a small greasy film of residue on the surface of metal, even if it looks clean, and you want to avoid that at all cost. With paint thinner I mean the strong stuff that's used for oil based paints. Not terpentine, you should never use terpentine to clean, that leaves a residue.

 

[GaryLaroff]

Alex,

Thank you.  The steel will not be painted.  This skate will back up the blade in a woodworking plane and will be waxed to keep it from rusting.  The goal is to make it as smooth as possible to look nice and for wood to slide along it.

Gary

 

[greg mann]

I would never use a chemical to strip rust. We use an angle grinder with a steel wire brush, works a lot better and faster.

There is a product that might make you change your mind, Alex. Metal Rescue is a wonderful remover, non-toxic, biodegradable and not even harsh to your skin. It removes all of the rust without any impact to the base metal. We often receive raw castings with rust from condensation and this product works better than anything we have ever used before. It will work on deeper rust as well.

 

[GaryLaroff]

The "chemical" that I am using for rust removal is Evapo-rust, which is  non-corrosive to steel and does not harm brass, copper, aluminum, gold, lead, titanium, steel, cast iron, chrome, solder points, vinyl, plastic, rubber, silicone, glass, cork, or wood.  After researching it and searching for a vendor, I found it at my local hardware store.

It is non-hazardous, not a skin irritant and not acidic like Oxalic acid.  Evapo-rust has a pH = 6-7.

My assumption is that it is a chelating agent, but the data sheet and MSDS sheet do not give any details as the product is non-toxic and non-flammable.  I've used it in the past and it works well.

And yes, I am a chemist.

Gary

 

[RONWEN]

The advice I’ve received is to use a stationary belt sander, but I have Festool sanders and prefer to go the handheld Festool route.  I’m using chemistry to remove the bulk of the rust and tarnish but the steel is often slightly pitted and I want to get it as smooth and shiny as possible.
Gary

The belt grinder really is the best choice for what you have in mind.  Belts are available in a wide range for metal from grinding down to remove the pitting to progressively finer up through polishing the metal.  A buffing wheel or even leather belt on the grinder loaded with polishing compound can be used for final polishing.