Repair rusty cast iron

[LarryS.]

Hi all,

As part of my restarting my woodworking endeavours I've
just bought a second hand record planer thicknesser PT260. One of the feed tables has some heavy rust which I want to do whatever I can with.

Can you give me any advice of where to start??
Thanks

Paul

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[MattRoberts]

Give it a swizz with a wire brush to remove the majority, then sand with a high grit and some wd40 to remove the rest

 

[porker]

Probably the best way would be to get it surface ground by an engineering company possibly using a blanchard grinder. Not sure what it would cost or if the part could be easily mounted. If it was mine I would probably put it on my bridgeport and flycut a few thou off it. Does anyone skim engine heads these days? They could also probably do this.

Or do what Matt says above as it doesn't look like it would affect operation as most of the surface looks pretty flat.

 

[MikeJhn]

I would use wire wool to take off the marks and then a coat of http://www.axminster.co.uk/axminster-ma ... x-ax957553 , that is what I used on my second hand Kity 439 brought it up like new.

Mike

 

[morturn]

I know the thicknessing tables are cast iron on this machine, but thought the jointing, in feed, out feed tables were hardened aluminium with a none slip coating.

I think I would just be tempted to give them a good clean with a light abrasive then wax polish it. I would certainly check to see if the tables are still coplanar

 

[LarryS.]

Morturn turns out you know about the machine I bought than I do!
I've just checked the website and it turns out the tables are hardened aluminium so perhaps it's the coating that has deteriorated, I'll be out there this evening to clean it up and do some more investigating.

I'm hoping the coating whatever it is is repairable, even if it doesn't affect the function of the machine I'd like to sort it out even just for the aesthetics, can't make an ugly machine!


Paul

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[LarryS.]

So it turns out the title is indeed wrong, I've got a rusty aluminium table!

Saying that I'm not even sure if it's rust or just the coating having worn away, I've taken a couple more photos, so what do people think, is it rust or wearing, and can I just respray it to clean it up or is it more complicated? (I'm betting the latter!)

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[MattRoberts]

Ah, that's not rust (aluminium doesn't rust). It does indeed look like the protective coating has corroded (aluminum can corrode).

I'd still recommend the site brush / wool and then sanding technique, and then applying a protective coat of wax or lacquer - I'm no expert though!

 

[Eric The Viking]

What Matt says, but do go really gently.

Personally I'd use something like plastic scouring pads (so you _can't_ easily do damage. WD40 to start with (to lubricate the scourer really) wipe off with paper towel and repeat, until it feels smooth. You won't remove the marks and you want smoothness and flatness rather than a nice look. Once done, check across and along the tables with a straightedge and light behind, to check you haven't caused a hollow, and then apply wax - I use Liberon machine wax, but I expect the Axminster stuff is very similar.

The dark colour is the protective anodising coating, which seems to have been damaged, possibly by water standing on it. You will need to keep applying wax fairly regularly in future, as it no longer has corrosion resistance, but with that as a given, those tables look as though they should turn out OK.

I've got a very old Kity 439 that;'s had a hard life (someone dragged 6" nails across the thicknesser bed, it seems), and, although that's lost its coating in several places, it actually works just fine.

E.

 

[LarryS.]

Thanks Eric and Matt, that's put my mind at a bit more ease. When you say "plastic scourer" Do you mean the ones that come with a bit of sponge and a scourer side? (dishwashing type)

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[MattRoberts]

Thanks Eric and Matt, that's put my mind at a bit more ease. When you say "plastic scourer" Do you mean the ones that come with a bit of sponge and a scourer side? (dishwashing type)

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Any scourer would work, but those ones are pretty soft. You can afford to use something more robust if you want, with firmer 'bristles'

 

[Jacob]

It may look bad but is it bad enough to affect a workpiece as it goes over? Probably not. I'd dislodge loose rust, candle wax it, and see how it performs.

Anything sticking up could affect the workpiece but hollows (within reason) may just be floated over in a straight line.

 

[Eric The Viking]

It may look bad but is it bad enough to affect a workpiece as it goes over? Probably not. I'd dislodge loose rust, candle wax it, and see how it performs.

Anything sticking up could affect the workpiece but hollows (within reason) may just be floated over in a straight line.

It's not rust, it's aluminium corrosion - prob. aluminium oxide.

 

[morturn]

Morturn turns out you know about the machine I bought than I do!
I've just checked the website and it turns out the tables are hardened aluminium so perhaps it's the coating that has deteriorated, I'll be out there this evening to clean it up and do some more investigating.

I'm hoping the coating whatever it is is repairable, even if it doesn't affect the function of the machine I'd like to sort it out even just for the aesthetics, can't make an ugly machine!


Paul

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Hi Paul, indeed I have owned one of these machines in the past. Have to say that they are quite a good small machine for the price. You will find in use that the coating quickly wears off the tables anyway with use, so a coat of wax polish will do nicely. Make sure you do the cast iron thinknessing bed too, otherwise the wood will tend not to feed evenly.

When you set it up, decent straight edge will do; clean the under he gibb strips etc. You will probably find that the tables are not perfectly flat, but they will be ok. It a good reason to get used to finishing off with a hand place, great practice if you new to it.