Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 4 of 4
-
8th August 2019, 10:25 AM #1GOLD MEMBER
- Join Date
- Nov 2018
- Location
- Newcastle
- Posts
- 1,016
Safe rust removal +/- recoating jointer rebuild
The jointer I'm rebuilding has a fair bit of rust on some of the pieces, including the work surfaces.
Most is surface rust, with some slightly deeper pitting - nothing major or structural, but a bit more than a 10min Rust-Off can deal with.
I need some advice on safely removing this/ polishing the jointer surfaces. I don't want to damage the tables in my ham-fisted efforts.
This is a pic of one of the metal bits after a scrub with rust-off (it's removed the black coating of the original piece as well):
IMG_9612.jpg
And here's one of the pieces, untreated:
IMG_9607.jpg
Rust-off is going to Drive Away all The Dark (so it must be the Messiah-inna-Bottle).
And finally, one of the tables/wing things:
IMG_9598.jpg
So, questions are:
1. What's the best/safest way to deal with the table surfaces?
2. How should I deal with the deeper rust in the 1st pic?
For non-meshing parts like the clamps, I've done some gentle wire-brushing, followed by etch primer and a light spray paint. Painting won't be suitable for bits that interact with other bits though - like the metal slide in the fist pic, or the 2nd pic. Maybe gun blue? I'd rather not go into getting vats of chemical baths if I can avoid it, but if that's the way to go I'll have to do it.
I have some wire brushing bits and wheels, and a porta-cable random orbital polisher with some cutting pads and compounds that I've used to fix damaged paintwork on the cars. Not sure if that will be any use...?
-
8th August 2019 10:25 AM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
8th August 2019, 12:09 PM #2.
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 27,792
There are a zillion ways to remove the rust but the most reliable certain long term methods starts by disassembling the pieces and using either electrolysis or soaking in what is know as a chelating agent (eg a mild organic acid like citric acid or vinegar, or molasses[very slow and smelly], or tannic acid). These acids will remove the rust but won't dissolve the metal even if you accidentally leave the parts soaking for months. This is the best way of getting rid of rust inside crevices and threads.
"Rust off" is basically phosphoric acid (PA) which works better if you soak the parts in it but you cannot leave the parts it in PA for for too long. PA converts rust to Iron Phosphate which means it leaves a blue black coating on the rusted part as thick as the rust unless you rub it off but then you run the rust of it re-rusting. In your first picture the black bits you see in those small pits are iron phosphate.
I've tested PA and the unwashed/unpainted PA coating typically lasts 2-4 weeks outside but under cover (typical shed environment) before it starts re-rusting. Some testing details here Backyard Phosphating. It should last longer inside under a more stable temp/humidity environment but testing that is much more difficult and would take a long longer.
When you remove the parts from any rust removal agent do not wash them in water or they will start to rust again very quickly but air dry them with a compressor making sure you blow out all the crevices etc. The remaining layer acts as a short or long term anti-rust coating. However I do try to prime and paint directly. I usually use a spray can that does both. Etch primer should not be required.
If you decide you don't want to paint, apply a light application of oil or wax immediately, and then every month on so will minimise rust.
The most impressive chelating agent I have used to remove rust and leave a long lasting rust resistant coating is oxalic acid however, it does leaves a thin yellow coating on the metal - but that can easily be painted over. I did a bunch of experiments on this and other acids last year. This stuff is commonly used in industry. It is "mildly"poisonous and she needs handling with care.
Details here Solubility of mild steel in various rust removal acids. - Page 2
For parts that have to rub on each other, regular oiling or waxing is one method to reduce rust uptake. Ordinary gun blue is a tad fragile for tools that have to rub on each other and will wear away too easily. There is a bluing method called fume bluing that is more robust but it is a long winded task and requires exposing the parts to strong acids and boiling the parts in distilled water. I have posted a couple of threads about this in the MW forums, here is one More metal bluing.
On the TS table I would just use some steel wool to get the bulk off, and then maybe make up a little dam around the patch with some plasticine and fillet with vinegar and let it soak overnight to get rid of any rust in any pits. Then use oil or wax on a regular basis.
Hope that helps
-
8th August 2019, 05:51 PM #3GOLD MEMBER
- Join Date
- Nov 2018
- Location
- Newcastle
- Posts
- 1,016
I may have a go at the peroxide bluing method you describe, Bob. I only have 3%, so it may be a little long-winded, but worth a try. It can brew while I potter around with other things.
-
8th August 2019, 09:42 PM #4Member
- Join Date
- Aug 2016
- Location
- Ferny Hills
- Age
- 78
- Posts
- 94
I acquired a bandsaw with a rusty table and a Emco Rex 2000 jointer thicknesser in very poor condition which i successfully rejuvenated using a 1/7 vinegar/water mix. it was slow but removed all the rust.
Similar Threads
-
more rust removal
By morrisman in forum METALWORK FORUMReplies: 61Last Post: 2nd January 2015, 01:14 PM -
RUST REMOVAL - CLR?
By jim47 in forum METALWORK FORUMReplies: 10Last Post: 26th September 2014, 01:29 PM -
Rust removal Evapo-Rust
By neksmerj in forum METALWORK FORUMReplies: 7Last Post: 22nd July 2012, 01:26 AM -
Rust removal
By Wolfs in forum WOODWORK - GENERALReplies: 17Last Post: 24th February 2006, 11:45 PM -
Rust removal
By davo453 in forum HAND TOOLS - UNPOWEREDReplies: 2Last Post: 5th February 2004, 06:43 PM