1964 Powermatic Jointer with rust on feed tables

Bob Beasley

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25
I'm restoring this old jointer that's got rust on the feed tables. I've tried WD40 and a scotchbrite pad as well as 0000 steel wool. This rust is deeper than this approach will address. I'm wondering what the next step should be?

Not suggesting either of these is the next step, however I to have access to a blasting cabinet as well as a mill.

Thanks!
 
Hi Bob. Welcome aboard. I can't help beyond what you have already tried, but I bet there are a few people here with derusting expertise that will chime in. Glad you found us.
 
Deep stains are a badge of honor . . . just kidding. I thought I would make you feel better. I have lifted some severe shadows out of cast iron with Rust Free. These were "spot" fixes and not entire surfaces. It is caustic and can do more harm than good if you don't follow directions. On the other hand it has removed things I thought would never come out.
 
Are the tables smooth after the WD40 treatment, just stained discolored? Or are they pitted, with deep craters and a rough surface?

If they're smooth, I'd just leave them alone, and live with the staining. It won't affect operation.

If they're heavily pitted, then refinishing - preferably by Blanchard grinding - is in order.
 
Thanks for the ideas! Here's what I've done so far on the none machined side of the fence.
jointer.png
 
Single edge razor blade as a scraper. takes all the layers of rust of down to clean metal. Then use the scotchbrite and steel wool methods. I use one of those retractable blade holders for the razor. I cleaned a Delta 6" long bed tables in about 30 minutes with one or two blades.
 
A lot of folks swear by "Evaporust". I've always had good luck using electrolysis. For a jointer, even if it's pitted in areas, as long as it registers flat along the length of the tables, the rust won't effect the machine's accuracy or useability. Before I got set up for electrolysis, I used Boeshield "Rust Free" with great results. Some people use lemon juice (citric acid will eat the rust).
Good luck with it.
paulh
 
Electrolysis, my machines sat for 20 plus years uncovered In a metal building, take everything part (real pain) and cook it for about 24 hours. Gets down deep. Google it.

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Are the tables smooth after the WD40 treatment, just stained discolored? Or are they pitted, with deep craters and a rough surface?

If they're smooth, I'd just leave them alone, and live with the staining. It won't affect operation.

If they're heavily pitted, then refinishing - preferably by Blanchard grinding - is in order.


My thought zactly. No gold stars for pretty.
 
Nice paint job on the fence! That looks really fantastic, and great color choice as well.

Electrolysis will remove rust other techniques fail at... If you don't need to or can't take it all the way apart (there may be other reasons to do so like re-shimming or adjusting various bits) other techniques may be worth exploring.

You can get a pretty good result by soaking rags in evaporust and laying them on the surface then wrapping in plastic and letting it set over night followed by abrasion on the surface. The main problem with evaporust is that it leaves a black iron oxide layer that is difficult to remove entirely (especially if there is minor pitting it tends to stay black/gray in those areas). The upside is that the black oxide actually helps protect against future rust. If you go this route you'll probably need to degrease the surface some in order for the evaporust to get in there. You'll still want to sand the surface back, a linear sanding block (like from automotive shops) is nice for large flat surfaces like this, don't be afraid to go a grit or two coarser, say 220, 320/400, 600, 1000 would be a somewhat reasonable progression.

There are also some other straight abrasive tools like the rust erasers: http://www.garrettwade.com/wonderbar-rust-eraser-gp.html or http://www.leevalley.com/US/garden/page.aspx?p=10509&cat=2,42194,40727 (free shipping is on ;)) that would work a bit better than straight sandpaper. I would be slightly hesitant to use those on your jointer tables though in fear of increasing the wear substantially because flat matters there. They do remove rust a lot better than just a scotchbrite pad though (the local orange borg store had something like these although I haven't tried them from there yet.

I've also had pretty good luck with citric acid (you can buy 10lb bags on ebay quite cheaply say $15+sh which is enough for a LOT of rust removal). It doesn't seem to get into the pits quite as well as evaporust, won't "unstick" frozen parts like electrolysis, and tends to eat a bit more surface metal than either of those techniques (minimal but measurable). It also has no rust inhibiting properties like evaporust so things pulled out of it need to be treated asap or you get flash rust on the surface really quickly. With that all kept in mind its still a pretty effective way to remove some stubborn rust without having to setup the electrolysis tank or spend the extra $$$'s on evaporust. My technique is to add a small amount (say 1-2oz per 20g) and see if bubbles are forming after 5-10 minutes, if not then dissolve another oz in a bit of water and stir it in. The chemistry depends a little bit on what you're derusting and your local water chemistry, and an excess of acidity increases the base metal removal rate so sneaking up on it isn't a bad idea (and uses less of the acid so that's also nice).

Personally in this case I'd either go with electrolysis or the evaporust followed by a linear sanding block to polish the surface. I wouldn't be super worried about a bit of pitting unless it was functionally a problem which would have to be pretty bad (yours doesn't look that bad imho). If there is a fair bit of minor pitting, treating with something like evaporust or some other rust inhibitor to stop future rust in the pits would be a good idea.
 
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