Cog rust
 

How do you get light light surface rust from gear cogs without damaging the hardening? Is bead-blasting OK?

Re: Cog rust
 

With cogs/gears in place on machine:

I use an assortment of brass brushes, both hand and drill driven. No damage that way. After cleaning that way, I apply a rust converter and after that I apply a lube. Not a speedy method, but effective.


If you are in a hurry, you can remove gears and develop a safe process.

Re: Cog rust
 

After a good brushing, soak in evaporust

Re: Cog rust
 

In High School, I put in a trans with some gear teeth rust, turned OK.
Just filled with oil, drove it & NEVER looked BACK! "Maybe" we sometimes "over-wurry" about stuff???
Alfred E. Newman

Re: Cog rust
 

Check the pictures and description in reply #49.


https://www.fordbarn.com/forum/showt...+sanded&page=3

Re: Cog rust
 

If gears are out of trans, or any other rusty parts nuts & bolts etc , Down too Harbor freight buy there vibrator & green beads, squirt of detergent in the water & turn on , They will come out like new, Detergent takes any grease off, then spray with WD 40 , these are amazing units, Autum in NZ , Portland swap in 3 weeks , Turn your heaters on up there. & get your Model A parts out,

Re: Cog rust
 

I was lucky enough to buy a complete set of NOS cogs for a 1942 Chev truck. They have never been used, but have a light coating of rust. They are out of the gearbox.
Thanks Guys, I will try Evaporust and see how it goes.

Re: Cog rust
 

Evaporust is GOOD stuff ! Don't be in a hurry though, and it will do the job.
Especially, if only light surface rust. I found that if evaporust is heated somewhat...it works better for me. So, in sunny SoCal, I just sit it in the sun.

Re: Cog rust
 

For light rust, ... Vinegar works fantastic and is dirt cheap. There are lot's of video's on youtube explaining how to do it.

The only down side for myself, ... I really hate vintager in every way imaginable with the exception of cleaning up rust, ... that damn smell, ... ugh!

It's also good for putting in your radiator every now and then. Keeps the rust at bay inside the engine and radiator.

Regards
Bill

Re: Cog rust
 

Vinegar takes off rust. It also attacks steel. I put a rusted potato peeler in vinegar for a week and the rust disappeared, along with most of the steel blade.
Use Evaporust or even agricultural molasses. Both work well.

Re: Cog rust
 

I use molasses a lot and have found it very effective. However I have heard that it can harm hardened steel as in gears and crankshafts etc. I don't know how true that is (there is a post about it somewhere on this forum).

As both molasses and Evaporust are based on the chelation process, is it not reasonable to assume that Evaporust may also harm hardened steel? On the Evaporust website there is much talk about how safe it is, but no mention of using it on automotive gear cogs or other hardened steel.

Re: Cog rust
 

Yep, I've wondered the same thing?


By far my sandblaster removes most rust, mainly because it's quick and handy.

Re: Cog rust
 

That's why I said to look on youtube for instructions, they tell you to keep an eye on it. It's 5% acid so the "soak and forget" mindset is something you shouldn't have. Adding it to a radiator for 3 days or so, ... works miracles on the cooling system.

Sorry, but it does a better job than anything else other than media blasting.

Regards
Bill

Re: Cog rust
 

That's why I said to look on youtube for instructions, they tell you to keep an eye on it. It's 5% acid so the "soak and forget" mindset is something you shouldn't have.

Sorry, but it does a better job than anything else other than media blasting.

One could also look on youtube on removing rust through electrolysis if you want to "soak and forget" it.

Regards
Bill

Re: Cog rust
 

That's why I said to look on youtube for instructions, they tell you to keep an eye on it. It's 5% acid so the "soak and forget" mindset is something you shouldn't have.

Sorry, but it does a better job than anything else other than media blasting.

One could also look on youtube on removing rust through electrolysis if you want to "soak and forget" it.

ALSO, on youtube, there are a slew of videos doing rust removal comparison test. I'd advise having a look there first so you can see your options. Should be enough information to help you in not wasting time and money on stuff that doesn't work or barely works.

Regards
Bill

Re: Cog rust
 

https://www.fordbarn.com/forum/showt...S+RUST+REMOVAL

CAUTION READ THIS THREAD...

mISSING PHOTOS show a block with deep pits caused by molassas.

One guy put a good engine in molassas and all machined surfaces were pitted.

Some say no problem others had BAD experience with Molasses

Notice that it appears that there are two kinds of molasses ....


Here is photo of damage that I saved on my machine. This is the photo that PhotoBucket refuses to display unless they are paid $400 by original poster.

Photo on computer is much larger and shows more detail. Do not know why this one is so small !!

Re: Cog rust
 

Just so nobody misunderstands, I am not a “dip & forget” mechanic. I have tried all of the rust removal methods including muriatic acid, phosphoric acid, electrolysis, Evaporust and molasses. They are all good but I found that the molasses is as good as the other methods with no side effects except length of time in the bath and it is cheaper. It is easily available at any store that sells livestock products or in your local grocery store. The store has smaller quantities than the agricultural sources but you can get larger jugs and lower cost per unit from the ag suppliers. Molasses is the same whever you get it.

I think Evaporust is basically oxalic acid, citric acid also works and it comes from lemons, rhubarb and other fruits.

Here are some good links to more good info:
https://hubpages.com/technology/Rust...l-by-chelation

https://www.youtube.com/watch?v=6Ir1p4Eejl4

https://www.youtube.com/watch?v=6B9sRHOxhoc

Then there is also LASER rust removal. IF you have $50,000 to spend!
This method is AMAZING !!!!!!
https://www.roadandtrack.com/car-cul...remover-laser/