Thread: Rust removal with molasses.

Originally Posted by 87County

While this thread is headed molasses, I'll add this for general info....

IMHO the first thing to do is to decide whether rust conversion (to phosphate) or rust removal is required.

If rust conversion is required there is a product called ranex rustbuster (from bunnings type shops) which is available in a spray bottle, obviously a phosphoric acid type preparation which converts a lightly rusted finish to a dark grey phosphate - it depends on the film of rust to have something to convert to the phosphate

If rust removal is desired, citric acid can be used instead of molasses. Mixed 2%-5% powder to water, it is great for removing the rust that is usually on garage or clearing sale items including screws, chisels, screwdrivers etc etc. Items need to be totally immersed in the mixture and it doesn't seem to "keep attacking" the base steel or iron. After 8hrs, the first layer of corrosion can be carded off with coarse cloth or hessian, and the item returned to the solution.

NB: Use only on ferrous alloys or iron (they're the only rusters anyway)

Citric acid is obtainable from grocery suppliers and is used in the food industry in things like lemonade (also has other industrial uses).

The stuff I use is produced by Windsor Farm Foods - Home. I imagine that they would be happy to tell you who sells it near you. A 1 kg container of the powder is under $15 - lasts a long time

With the use of molasses, pour a small amount of beer into the mix, this speeds up the start of the process. It works best when used in warmer temperatures. The ratio of molasses to water is not critical, its more likey to become contamenated with mould etc rather than become exhausted. Mixture as weak as 30:1 seem to work. Another alternative is vinegar, this makes alot less mess than molasses. I have tried it on a conrod from a model T and it didn't seem to harm the bearing babit. It also seems to work on alloy, just try an experiment first.

Molasses is also a fantastic addition to your lawns/garden as the microbes in the soil go ballistic on it giving you healthier plants/grass.
I just use 2 cups in a 9L watering can and keep topping up with water till all the molasses has dissolved.
Try it on a patch of grass and see the difference over a few weeks.

Originally Posted by Stormy

With the use of molasses, pour a small amount of beer into the mix, this speeds up the start of the process. It works best when used in warmer temperatures. The ratio of molasses to water is not critical, its more likey to become contamenated with mould etc rather than become exhausted. Mixture as weak as 30:1 seem to work. Another alternative is vinegar, this makes alot less mess than molasses. I have tried it on a conrod from a model T and it didn't seem to harm the bearing babit. It also seems to work on alloy, just try an experiment first.

A 1:4 (molases:water) will eat white metals like aluminium, lead and zinc. Put a siezed block into a bath and in a couple of weeks you'll have a clean block with the rings sitting in the hollow bores.

I currently have a bath in the shed with a couple of unpainted RRc sill tanks that have been outside unprotected for 18 months, after 4 days I had to end for end then to do the other end. This morning in went a D^D pick head. I should do a couple more and take them to Corowa!

When happy with the result how do you clean the molasses off ? Just water ?

And these ratios people talk about - is it diluting the molasses slgightly with water, or mostly ater with some molasses added ?

Originally Posted by VladTepes

When happy with the result how do you clean the molasses off ? Just water ?

And these ratios people talk about - is it diluting the molasses slgightly with water, or mostly ater with some molasses added ?

Clean with water, dry and you can watch the rust form......needs to be protected fairly quickly.

Mostly water. Have seen 12:1, 7:1 and various ratio's quoted, mine is about 7:1.

Colin

Originally Posted by VladTepes

When happy with the result how do you clean the molasses off ? Just water ?

And these ratios people talk about - is it diluting the molasses slgightly with water, or mostly ater with some molasses added ?

me gig lot ater lit lases!


I have seen documents with ratios (water:molases) of between 3 or 4:1 to as dilute as 12:1.

The more concentrated the quicker it works and potentially the more corrosive it is to white metals.

It doesn't remove paint.

With heavily rusted items it is worthwhile soaking for a few days and then removing and hitting it with a wire brush then return it to the bath. The surface is quite reactive when removed from the bath and after hosing off you will see surface oxidation occurring before your eyes.

Even something like WD40 can be used to protect the surface temporarily.

Originally Posted by Lotz-A-Landies

A 1:4 (molases:water) will eat white metals like aluminium, lead and zinc. Put a siezed block into a bath and in a couple of weeks you'll have a clean block with the rings sitting in the hollow bores.

I currently have a bath in the shed with a couple of unpainted RRc sill tanks that have been outside unprotected for 18 months, after 4 days I had to end for end then to do the other end. This morning in went a D^D pick head. I should do a couple more and take them to Corowa!

The reason for the eating away of white metals may be due to an electrolytic action like happens in a battery or cell. This happens when differeent metals are immersed in an electrolyte. One of the metals is "sacrificed" during the action. It is very important to test with an experiment first when ever any chemical is used for cleaning etc. The bath used must also be non metalic to prevent this happening. I use corregated plastic feed troughs maid by Minto, they are available in various lenths and long items like axle shafts etc can be immersed if rquired.The 200 litre barrels with the top cutoff are good for engine blocks. Try the vinegar alternative. I like it, it make a lot less mess and is very good for small parts. To protect against rust recurring, use ensis fluid. This comes out of the tin with the viscocity of dlesel, but dries like grease and will protect for years if need be. It can be removed with turps when the part is needed.

However if you have a seized block where you have tried all the regular methods to get the pistons out, the fact that it eats white metals, is a benefit!

New pistons are easier to find than a 1948 side plate Landy block.