Soda Crystals and washing machines

Soda Crystals Soda crystals are reputed to be good at dissolving grease. They can be used to help clean out a gunged up washing machine, or more importantly to help prevent a build up of grease).

Can soda crystals damage the washing machine drum?

The last time I used some I noticed that on the back of the packet they say that it should not be used on aluminium. I instantly thought about the alloy drum spiders inside washing machines and wondered whether soda crystals could cause any damage.

Door-seal-greasy So I sent an e-mail to a manufacturer of soda crystals. They told me that there shouldn’t be anything to worry about. The only reason they advise against using the soda crystals on aluminium is that it can cause pitting (small indentations). This would be undesirable on anything on show. But as no one can see the drum spider it shouldn’t be a problem. I don’t think the soda crystals would undermine the strength or stability of something made of aluminium, just maybe cause small pitting.


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25 thoughts on “Soda Crystals and washing machines”

  1. To Washerhelp,
    Thank you for your comments however please remember it is not just detergents that can cause corrosion of aluminium. As I mentioned in the post above anything aqueous with a pH above about 8.0 can cause aluminium to be corroded.
    Detergents have a pH above about 8.0 or they will not work. The powdered Oxi products contain sodium carbonate and sodium percarbonate both of which are corrosive to aluminium. It could be argued that including the sodium percarbonate in the damaging laundry aids is a little unfair as, when mixed with water, it disassociates into hydrogen peroxide (for the cleaning) and sodium carbonate. Borax and sodium hydroxide, in solution are also corrosive to aluminium at the required concentration.
    What I did not mention above, not wishing to cloud the issue is that aluminium is also generally corroded by acids with a pH below about 4.0. Nitric acid is a well-known and well-documented exception to this.

    When I first dismantled our 7.5-year-old Frigidaire built Kenmore front loader due to bearing failure I thought the deposits I found on the spider were clumped unused detergent. I soon realised I was wrong when they would not dissolve and flush away, they were even difficult to remove with the pressure washer and even then they were not completely removed.
    When I first saw the corrosion of the spider, after the deposits had been removed I initially thought it was galvanic corrosion, being familiar with the galvanic corrosion of aluminium in the presence of steel and seawater. However further thought and investigation soon convinced me I was wrong, particularly when I discovered the above about the corrosion of aluminium in aqueous solutions, this includes pastes by the way.

    On discovering the above information I put a drop of 5% bleach solution, straight from the bottle, and a drop of vinegar, in different, previously undamaged areas of the spider removed from our machine. The following morning there was no sign of the vinegar and no sign of damage to the spider where it had been. Where the bleach had been was a nice little pile of white corrosion products that closely resembled the deposits I had previously removed. Additionally these products were difficult to remove close to the aluminium when, with a 6x magnifying glass slight pitting of the previously undamaged aluminium could be seen.

    It has taken me all of the above to get round to asking you – are you really sure that it is detergent that you are seeing or could it possibly be detergent and/or products of corrosion? You have seen what you describe I have not, and I can only describe what I found and what I concluded from my experiences removing it and the tests I later carried.

    One other question if you do not mind. Have you ever seen a fractured spider without any sign of the white deposits?

  2. Hi David: You obviously have experience in the more technical side of these reactions. Yes I have seen many drum spiders where one or more of the arms have a fine crack all the way through yet they are perfectly clean and unaffected by any visible corrosion.

    Most of the ones I’ve seen that are really bad the alloy (I’m not sure they are 100% aluminium) has crumbled away and usually caked in jelly-like gunge and grease as described here Washing machine smells – causes of grease, slime and black mould inside washing machines

    The fact that it only affects a minority of washing machines implies it’s caused by something specific to them. I’ve always assumed it was not using enough detergent allowing a build up of the grease and slime.

  3. To Washerhelp

    Thank you for your response and comments.
    Yours is the first post that I have seen, or heard of, where fracture of the spider has not been accompanied by corrosion. Unfortunately it begs more questions:-
    1. Are there many of these in comparison to those where corrosion is evident?
    2. Are they across the board or are they limited to only specific manufacturer(s)?

    No metal is 100% pure, even precious metals of high purity usually have it quoted as 99.9something% pure, meaning, in essence that it is in fact, by definition, an alloy.

    I know that not all complaints of foul odours can be traced to build ups in the spiders, there are documented other sources in many posts on the web. However I do believe that when all other sources/remedies have been tried, it will be found that the majority of those remaining, should the investigation be completed, that the source will be found to be build up on the spider, there is virtually nothing else left. I have actually found a couple of posts where owners, other than myself, have dismantled their machines, removed deposits the same as mine, and the foul odours have disappeared.

    I agree it would seem as though there is something specific about the machines, or the way they are used, and that does not imply misuse-deliberate or otherwise, that causes these problems and I, for one, would like to try and find out what it is. As an example the two instruction books that came with our machines state that it is in order to use powdered detergent, just use less, and that it is in order to use bleach again with a quantity limitation. This could be construed as a desire to induce early failure in the hope of selling more machines. A point you have made elsewhere!

    When I dismantled our 7.5-year-old Frigidaire built Kenmore (purchased in the USA, we now live in Canada again) it was because of the racket the machine had started to make. We have a second, very similar machine in our guest apartment, now about 3 years old and purchased in Canada, so noise comparisons were very easy. I had no idea what I was getting into. I had wondered to myself, when we purchased the first machine, what they had done to enable the bearings to take the very high out of balance cantilever load that these machines impose on their bearing arrangement. I now know, nothing! Prior to dismantling our machine I did not perform any research or even investigate any tips for dismantling.

    I just took it apart. Prior to this dismantling the only repairs I had carried out were to tighten up the two halves of the outer drum relative to each other because of a slight leak and remove the drain pump and hose to clean them out because the Chief Laundress, who has a much more sensitive sense of smell than I, was complaining of a mouldy/mildew kind of smell coming from the machine. Soaking in bleach, hot wash cycle had done nothing to reduce it; according to CL. Again I/we had done no internet investigation. Our efforts at that time did not produce the desired result. It was not until after the bearing repair, when CL informed me there was no more smell that I put 2 and 2 together.

    Not long after I had completed the repair to our machine I was asked to have a look at a similar machine belonging to one of my sisters-in-law, because of the smell. Even I could smell it. When I got by the smell I discovered the bearings were on the way out.
    The machine was dismantled; the bearings, although on the way out, had not deteriorated sufficiently to render the seal ineffective, there was no evidence of water or corrosion in the bearing housing. There was a build up of foul smelling gunk around the hub of the spider. There was very little evidence of corrosion on the spider and I considered it suitable for further service. Said sister-in-law stated that she only very rarely used bleach, had only ever used liquid detergent (Tide) and did not use liquid fabric softener.

    These are the only two front loaders I have ever worked on, in fact the only other two machines I have ever worked on were a TL Kenmore (manufacturer unknown) on which I changed a timer and an old Hoover with the impeller on the side of the tub, this later was about 40 years ago. So my experience with the guts of the machines is extremely limited. We also seem to be getting away from the original subject of this thread. Sorry about that.

  4. Further to my posts above I have now found a very informative and, I think, easy to read, one page paper by a Gaute Svenningsen on the corrosion of aluminium. To read it just Google “Gaute Svenningsen Aluminium Corrosion” and click on the appropriate link.

    I know his description as micro galvanic corrosion, which I agree is a good description, is at variance with my assertion that it is chemical corrosion. I am still trying to work out how to describe it in the future! The bottom line is however that it corrodes and the end result is exactly the same.

  5. I wonder if you canhelp me please my indesit washing machine is not draining out from the machine ,however it drains out when i take the hose and put it into a bowl on the floor the machine is about 4 years old . i rang indesit who said it seems like it needs crystals to clean it out i have now purchased these rather expensive things but was curious to see your write up on soda crystals are these just the run of the mill crystals you can buy in the supermarket and more to the point could this solve the problem .
    many thanks

  6. Hello Everyone!

    This is all very complicated and technical. Can anyone please recommend a totally safe product to eliminate unpleasant odours from washing machines and to keep the pipes etc. clear (especially as I live in a hard water area)? Some products which are commercially available are designed to be used every time you use the washing machine and therefore can work out to be quite expensive. Thank you so much; your help is very much appreciated.

  7. Oliver: Soda crystal are supposed to be safe. There’s no issues with them that I’m aware of other than they can cause mild pitting on aluminium but that’s only cosmetic not structural.

  8. Hii there!

    Have you any suggestions on how the residue left by soda crystals in the drum can be removed.

    I used them to give the machine a good wash and flush through, but there is a white residue layer in the machine that seems to only move if you rub it away

    Any suggestion of what i can used. I run the machine with an empty drum but to no avail.

    Thanks in advance.

  9. Hello Stuart. I’ve not know soda crystals to leave a residue and we’ve used them many times. Maybe the residue is grease that the soda crystals loosened but got deposited? I would try using more, on a boil wash. Failing that I’d just try putting it on with ordinary detergent, no laundry and boil wash. Sometimes a few maintenance washes are needed.

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