Cathodic protection for cast iron

[David_Edge]

I've had a Record bandsaw with a CI table for a few years and it's never had a hint of corrosion, but I've now acquired an Axminster spiral planer and it rusts fast. I've used Camellia oil and machine wax, clearly not enough. At this time of year there will be condensation, but I'm wondering if anybody has tried using cathodic protection - ie bolting a lump of zinc to the table?

 

[MARK.B.]

Not sure it will make any difference at all (but i am probably wrong) Bolt a chunk on and try it,you have nothing to lose by trying other than a little time and the cost of the zinc ingot.

 

[Pedronicus]

Perhaps the cast iron used in the Record unit is of better quality than that used in the Axminster unit. I fancy you will need a lot of condensation present for the cathodic protection circuit to even think about working.

Maybe a word with Axminster would be in order.

 

[Spectric]

At this time of year there will be condensation, but I'm wondering if anybody has tried using cathodic protection - ie bolting a lump of zinc to the table?

Wrong type of corrosion, cathodic protection requires an electrolyte which means you either submerge it in liquid or bury in it the ground. Items like boats and oil rigs work due to the sea and pipelines due to the damp soil but a machine in a workshop suffering surface rust I don't see it working unless maybe you can achieve very high humidity.

 

[Jameshow]

Wrong type of corrosion, cathodic protection requires an electrolyte which means you either submerge it in liquid or bury in it the ground. Items like boats and oil rigs work due to the sea and pipelines due to the damp soil but a machine in a workshop suffering surface rust I don't see it working unless maybe you can achieve very high humidity.

Maybe he's thinking of using his aximinster / holziman as a anchor weight in Poole harbour! Best place apparently!

 

[baldkev]

Hello david, i think a dessicant dehumidifier is on your to get list

 

[furnace]

Having suffered condensation rusting I'm trying Metalguard. So far it's been perfect despite very damp conditions here

 

[johnnyb]

I would suggest regular application of wax until the pores are filled.

 

[Distinterior]

I would suggest regular application of wax until the pores are filled.

That's exactly what I've done with all my cast iron topped machines.....Then, keep the tops covered with an old towel when not in use.
Never had any problems. I use Axminster Machine Wax. The tin seems to last forever......

 

[Myfordman]

Fit low power heaters onto the undersides of the tables. No more rust.
https://www.ukworkshop.co.uk/threads/tis-the-season-of-rust-and-mellow-fruitfulness.55942/

 

[Bojam]

That's exactly what I've done with all my cast iron topped machines.....Then, keep the tops covered with an old towel when not in use.
Never had any problems. I use Axminster Machine Wax. The tin seems to last forever......

I also use the Axminster Machine Wax. I bought two tins a couple of years ago. I’ve used maybe half a tin so far. However, the open tin seems to have gone “off” (for want of a better expression). It’s kind of grainy now and rather than lubricating the machine beds it is actually making them sticky.

The thicknesser on the PT was refusing to feed stock under the outfeed roller the other day (getting jammed). I thought maybe the roller needed adjusting but I tried re-waxing the bed first. It just made it worse. So I thoroughly cleaned the bed and opened the second tin of wax. Notably different consistency. Applied and buffed that in and it worked perfectly.

There is no expiry date on the tin that I can see but I guess the first one is finished. Unless anyone can suggest a way to reverse its change of state? Any suggestions on how to avoid the second tin doing the same thing? I keep them with the lid firmly closed on a shelf in the workshop. Being in the tropics, the ambient temperature is in the high 20s and relative humidity is very high too.

 

[Distinterior]

I use a section of cotton sheet about 100mm square to apply the wax. I keep it Inside the tin when not in use and it keeps it moist.....I reckon I've had the tin for about 3 years and there is still more than 80% of it left....The wax still seems to do its job okay.

I recently (over the Xmas period) waxed the tables and bed on my Hammer A3 31 and it seemed to apply & wipe off fine.

 

[Ttrees]

This thread from Argus might be worth reading.
It is the most informative post on this subject that I've ever came across.
https://www.ukworkshop.co.uk/threads/wet-and-dry-a-little-bit-of-measuring.126919/
Being in the tropics, I wonder if you could rig something up to warm your machine(s)
hotter than the surrounding air, as to stop the condensation that way, be it solar or water?

 

[David_Edge]

Thanks all
Good point about cathodic protection needing moisture.
I did speak to Axminster who claimed that the CI is the same quality as Record, but then started talking about how perhaps the records were seasoned longer.
I do use the wax, apparently more is needed. I've got the Liberon wax and it is grainy too. Perhaps I should put it through the honey decrystallisation programme in the oven.
I was sceptical about silica gel, but realised that if I put a polythene dust sheet over the machine the damp may not get in too fast; if that doesn't work, the heaters it is.
Many thanks to all.
d.

 

[MARK.B.]

Try a different type of dust sheet, polythene will hold the moisture inside against your machine

 

[David_Edge]

Well the point of the polythene was in conjunction with silica gel, hence the need to stop wet air ingress

 

[TheTiddles]

Polythene will trap condensation near your metal and resist letting it out if your desiccant can’t grab all the water and do it fast, then you will have the same or worse problems.

The mistake people make with desiccants is not understanding that they’re there to grab the last residual water in a sealed container, they can’t keep up with an open system.

Machine wax and a breathable cover should see you through

 

[kinverkid]

You might try former Pope Benedict XVI.

Oh. Scrub that. Just re-read it. Cathodic protection.

 

[thikone]

Zinc dust might help!

But I did think of trying to plate cast iron tables with Nickel. It is possible to buy nickel electrolyte and then use a sponge with electrode and second electrode is the table itself. Some rubbing (wax on, wax off) and very thin layer is there. Heck, you can even plate it with that zinc ingot that was mentioned before, just need some appropriate electrolyte for that. But usually people put copper layer first for surface bind and smoothness, then a bit of nickel, then layer of chrome. But I never heard of this being applied to woodworking machines tables for some reason...

 

[David_Edge]

Wear might be one reason. Also, the Record machine is made with a high quality cast iron and doesn't corrode; it's only the Axminster/Guangzhou Novelty Co effort that isn't and rusts as soon as you look at it. Ironic that the most expensive machine I have is the only one I won't be able to leave to my son.