Black Spots on Saws

[Eric Gracka]

Hello All:

I have several saws with black spots (a form of iron oxide?) which, don't seem to be able to be removed.

I've tried:
1. Evapo-Rust
2. Natura - Safe Strip
3. Straight Vinegar
4. Citric Acid
5. Hydrogen Peroxide
6. Kerosene
7. Mineral Spirits
8 Baking Soda
9. Detergent Soap
10. Borax
11. Isopropol Alcohol
12. GooBeGone (probably a Canadian product)
13. Sanding (400 & 600 grit wet)
14. Other home-remedy suggestions)



On one website, a seasoned metal worker said that I shouldn't waste my time with these concerns, because, unless the metal is pitted, there will be no decrease in performance. Furthermore, he says, any acid remedy will etch the metal and potentially cause more problems, and those marks will show up again when the metal is used to work on wood, unless you pay a little bit of attention to your metal.

I agree, but I would like to have nice looking tools.

[Richard Krushner]

I have found that if a fine grit paper will not remove it then it is best to leave it. As you said above, no pits, no loss of function.

I have not tried it on something as flexible as saw, but you can fill pits with a mix of fine metal filings and epoxy and smooth off. I have done this on cast iron planes. Whilst it does not make the repair invisible, it is not that obvious.

In fact, if you use steel wire wool instead of iron filings, you even repair minor cracks in planes. On a plane I repaired you can hardly notice. It is certainly less risky than a weld repair on cast iron.

Sorry I have deviated off topic slightly.

[Jim Matthews]

I scrape with a paint remover single razor blade, then use the Klingspor Sandflex blocks.

That's it. It's enough.
Wax the plate or oil it, if you like.

http://www.theruststore.com/Sandflex-Rust-Erase-3-Pack-P11C7.aspx

286854

[steven c newman]

been trying out a wadding polish on some of my stuff. Called "Never Dull" from Eagle One Industries.

www.eagleone.com

Stuff stinks to high heaven, but does work. Clean rag to buff it out is needed, though...

[Mel Miller]

In fact, if you use steel wire wool instead of iron filings, you even repair minor cracks in planes. On a plane I repaired you can hardly notice. It is certainly less risky than a weld repair on cast iron.
.

This seems like an exercise in futility. A crack in cast iron will travel until it comes out the other side somewhere as the plane is used and flexed. Epoxy and steel wool will do nothing to stabilize a crack like that. There is nothing risky about brazing or welding cast iron if you know what you're doing.

[Eric Gracka]

I have found that if a fine grit paper will not remove it then it is best to leave it. As you said above, no pits, no loss of function.

I have not tried it on something as flexible as saw, but you can fill pits with a mix of fine metal filings and epoxy and smooth off. I have done this on cast iron planes. Whilst it does not make the repair invisible, it is not that obvious.

In fact, if you use steel wire wool instead of iron filings, you even repair minor cracks in planes. On a plane I repaired you can hardly notice. It is certainly less risky than a weld repair on cast iron.

Sorry I have deviated off topic slightly.

Agreed with your 1st statement.

I think we are becoming too anal with our tools. If they appear (in looks) reasonably well, and function as intended, why take the chance of ruining them.

[Richard Krushner]

This seems like an exercise in futility.

Almost certainly, but that has never stopped me. :)


A crack in cast iron will travel until it comes out the other side somewhere as the plane is used and flexed. Epoxy and steel wool will do nothing to stabilize a crack like that. There is nothing risky about brazing or welding cast iron if you know what you're doing.

Yes the crack can propagate, and if it is on a structural area then it is not a simple repair. However, sometimes in other areas you can file out a crack to the root and stop it travelling. The repair, as I have described, is not to then to support it structurally (as you rightly said, it cannot), but foremost to remove rough or missing faces that can do damage to work. It also makes it less noticeable cosmetically.

As an example I have done this on a plane with a crack at the mouth. Small at one corner. Maybe where someone had advanced the blade with the frog in the wrong position. Certainly not an area that should have load into the casting under normal use. I have no facility to weld or braze. The plane does not warrant the cost of someone repairing it professionally. I now have a good user plane. I have had no issues, but then I am sample of one. This may not be a great sample size for a positive statistic for success.

May be more people than I imagine have access to welding facilities for cast iron. If you do, go for it, it is defiantly a better solution than mine.

[george wilson]

You can drill a little hole at the end of the crack to stop it spreading. But,be aware that the crack will extend farther than you can see it. So,leave a little distance beyond where you can see the crack stops. Then drill your hole. You can fill the hole with J.B. Weld. It will not be invisible,but the crack will stop spreading at least. If you don't drill at the complete end of the crack,it WILL keep spreading,though.

We were on a trip,and a 2" crack appeared on the windshield. It soon spread to 6" just due to the slight vibration of traveling on a smooth highway. When we stopped for the night,I bought a battery powered Dremel tool and a diamond ball bit. I drilled a hole at the end of the crack and it stopped spreading. We were able to drive hundreds of miles home without the crack going all the way across the windshield.

[Mel Miller]

:)

As an example I have done this on a plane with a crack at the mouth. Small at one corner. Maybe where someone had advanced the blade with the frog in the wrong position. Certainly not an area that should have load into the casting under normal use. I have no facility to weld or braze. The plane does not warrant the cost of someone repairing it professionally. I now have a good user plane. I have had no issues, but then I am sample of one.

Cracks at the back corners of the mouth come from overtightening the blade and/or from overworking the plane. The thin casting can't take the stress, especially on low angle planes. This is a high stress area on a plane.