PDA

View Full Version : Rust & Cast Iron - What To Do



Dunc
05-18-2009, 04:29 PM
Bought a table saw at a garage sale. Unlike most today this one has cast iron table, trunnion etc. Also uses a separate, 1 hp motor with pulley/belt drive. It is a "Beaver" brand (a Canadian subsidiary of Rockwell back in the 60's or maybe early 70's).

Innards are good: no play in the height or tilt mechanisms or the saw arbor.

The table top has a lot of rust. Not really deep as there is no evident pitting of the table.

Removed most of the loose stuff with a fine wire brush (by hand, not power). Wondering the best way to remove the rest. Available options (in no particular order) include: fine grit wet-dry sandpaper (240 grit upwards) more hand wire brushing, plastic abrasive pads (hand or power). Are the anti-rust solutions appropriate?

Realize this does not need the flatness of a milling machine table but I would like to finish it up nicely and certainly not ruin it by by using an inappropriate method.

Thanks

Alistair Hosie
05-18-2009, 05:14 PM
why not try a sanding machine hand sander oscilating.Alistair ps I have used this and it works fine.

shadoof
05-18-2009, 05:25 PM
Have a look at this on Frank Fords site,

http://www.frets.com/HomeShopTech/QuickTricks/RustRemoval/rustremoval.html

I've tried this method in a tank/vat and got good results.

Loads on the net about this process.

Lee

bborr01
05-18-2009, 05:51 PM
I use WD40 and sandpaper. If the rust is heavy, I start with a fairly coarse paper and work to a finer paper. The WD40 also impregnates into the cast iron and helps prevent future rust.

SGW
05-18-2009, 05:53 PM
I've had good luck with "Scotchbrite" green scouring pads and kerosene. (n.b. I've found the generic scouring pads don't stand up as well, so get the real Scotchbrite ones.)

nheng
05-18-2009, 07:39 PM
Just as with metal working machinery, it's a good idea to not remove any metal ... yet.

I start with a gray Scotchbrite pad as it is quite fine and would take a long time to remove a measurable amount of metal. Rust is another thing and it works quite well on that. A shot of WD-40 and the pad should work well, especially if not pitted.

On several older Delta machines, I've hand rubbed the tables by backing the gray pad with a flat block of wood. Rotating with the original grinding arcs leaves a really nice appearance and also seems to get into the original grind "grooves", cleaning better than an opposing direction would.

If you need more of a brushed shine, you can always get more agressive later. It's always harder to put metal back on :)

Den

lane
05-18-2009, 08:32 PM
Knotted wire brush on a angle grinder. You would have to grind till dooms day before you took 2 tenths off.

Scishopguy
05-18-2009, 10:33 PM
I have an old Craftsman 8" that my dad left to me. It was covered in fine surface rust (no pits) since we lived 3 blocks from the Atlantic ocean since the saw was new in 1956. :( I used the green scotchbrite with mineral spirits and graduated to 400 grit wet and dry on a pad sander with mineral spirits. In a couple hours I had it down to bright metal. Once finished I used Johnsons paste wax to keep it from rusting. I checked the top with a straight edge and found that I had not put any depressions in the top (the rust layer was pretty uniform).

With a cast iron top you want it to be as smooth as possible so that your wood slides over it without dragging. THe paste wax helps out with that too. I had access to a much newer 10" Craftsman at work that had a cast iron table. It was rough as a cob, having been face milled in a circular pattern around the blade cover plate area. The old ground table saws are much more pleasant to use in my opinion.

Good luck with your saw project. You will appreciate the smooth table if you ever use a new one. :)

clint
05-18-2009, 10:43 PM
Walmart sells a rust/paint remover either in the paint bondo section, or the hand tools, dremel section. Put that on a drill and go to town, I have used this before, no metal removal, I guess you could remove metal if you really went to work on one spot after eating a dozen bananas. It's red or black on color, and works great.

J Tiers
05-18-2009, 11:29 PM
Knotted wire brush on a angle grinder. You would have to grind till dooms day before you took 2 tenths off.

+1

Well you might get there a little faster with power equipment, but light oil and sandpaper won't ever take any amount of solid metal off that table......

It's a hell of a lot of work to take 1 square inch down a thou with sandpaper, let alone a table top.

To take it down an amount that a woodworker would notice would take a long time. I'd rather do time at hard labor breaking rocks than have to take the table down 1 thou all over with oil and 400 grit sandpaper, which is all you need for rust.

kendall
05-19-2009, 12:06 AM
When I moved into this house there was an old craftsman model 100 table saw in the shed, looked it over and noticed that the whole top and extensions were covered with rust, so I left it there for a few years more.
Later on the spindle bearing went out on my old Delta, so I went and checked the berings on the Craftsman which turned out to be good and tight, so I dragged it into the shop.
I used a razor scraper to get all the loose rust off, then moved to my diamond stones, working from coarse to fine.
Started out using mineral spirits as a fluid, but that dissolved the adhesive on the stones, so switched to plain water with the rest.
Worked fine, took about four hours and the table looked great, and was as flat as could be. There were a few pits, but nothing that affected the operation.
Those old craftsman's are great saws, traded that one off because my shop's too small to keep two table saws. (so later I picked up two more old saws....)

Ken.

lakeside53
05-19-2009, 01:42 AM
1) Degrease, dewax and clean.

2) Make a tray from 6 mil plastic and 4 pieces of wood.

3) Turn table saw upside down and put in the tray close to the bottom on a couple of spacers.

4) Pour in enough evapo-rust to submerge the surface.

5) Wait a few hours (above 70F) or overnight if cool, lift table, wash off.

6) Go over the surface with a nylon scrubber, and if required, back to step 3.


I have cleaned up several large wood and metal working machines this way, and even resurrected gear clusters frozen together with rust. I recently restored the table on a 6 foot long jointer... heavy...

NO metal or paint is removed -only iron oxides. You can buy evaporust at Harbor fright. Reclaim after use - it lasts a long time.

www.evaporust.com

garagemark
05-19-2009, 07:45 AM
I restored all my grandfathers old woodworking tools tools (early 50's vintage lathe, table saw, stationary belt sander, shaper, band saw. All cast iron construction). Thing to keep in mind is that losing one or two thou off a woodworking tool has zero impact on it's accuracy.

If you want to keep the original swirl marks, hand equipment is the only way. However, in my case it just wasn't possible. So, after a wire brushing BY HAND, I used a 6" DA sander with 220 grit paper. It made a beautiful bright finish. Then I used the same 220 paper and used a very slow buffer to very lightly put the swirl marks back into it. Yes, you can tell that they aren't the original machining swirls, but they are pretty darn good looking. Then, as someone else has mentioned. A good thick coat of Johnson's Paste Wax followed by a good hand buffing. My tools still look good after 15 years with only a little paste wax touch up.

I would not use a knotted wire wheel. It can really dig in and create an ugly appearance. If I were to use a wire wheel under power, it would most certainly be straight wire. Softer the better.

Mark

gnm109
05-19-2009, 08:31 AM
I keep a jug of 70% phosphoric acid handy. It will remove rust fairly quickly when applied with a brush. If the part is small enough, you can dip it in a bottle of the stuff. It does a great job.