Green Gunk warning...

[ChrisButch]

It's been many years since I've used Gunk for degreasing: but when in Halfords recently I noticed there's now a 'Green' version - biodegradable, fewer noxious chemicals, can be poured down drains etc. etc. Thought I'd give it a try. I have a nice but rather elderly Dura-Ace rear mech which I've been meaning to service, so last night I dunked the whole thing in a bath of Green Gunk and left it overnight. Should have known better and tested it first. This morning I returned to find the surface covered in an evil grey-blue froth. I gingerly fished out the mech to find that all the surfaces so nicely polished by Mr Shimano had been eaten away. Green it may be, but that doesn't mean there isn't some nasty stuff in it. Can only speculate about what was reacting with what...

[Brucey]

did you use to do the same thing with the old stuff?

Is that something they recommended at any time?

BTW I quite often use the dish- er 'parts washer' for this sort of job.

Good to know about the new style gunk though.

cheers

[cycleruk]

From the sound of it the chances are that the "Green Gunk" contains a caustic solution.
Caustic is well know for attacking aluminium alloys.

[reohn2]

sorry to hear about the Gunk attack.
I've never felt the need to leave bicycle parts soaking for more than a few minutes even then it would only be a chain no matter how cruddy.
I know I'm always banging on about White Spirit but with either an old tooth brush or a 2inch paint brush and a old baking tray to work on,any cycle parts including chains can be thoroughly cleaned within a couple of minutes,then rinsed off with hot water with a squirt of washing up liquid in it, follwed by a blast of GT85,any left over WS can then be poured into a jamjar and reused over and over.
I've even reused WS for cleaning cycle parts that I've cleaned paint brushes in.After leaving in a jamjar to settle for a couple of weeks it becomes clear with the paint residue at the bottom.

TBH I use so little,about 4ltr in over 7+years the enviromental impact is less than buying Gunk on a total loss system and throwing or recycling the Gunk tins after use IMHO

[Mick F]

Yes, sorry to hear of the damage.

However, I would never let something soak overnight in a chemical. White Spirit is just an oil, but even then, soaking for hours can dissolve things. I used WS to clean some parts recently and it started to dissolve the plastic container! Gotta be careful with soaking things IMHO.

Normal Gunk has a variety of warnings on the tin - usual stuff: ventilation, ingesting, skin, gloves etc. The main warning is to keep it out of "aquatic environments" as it harmful to organisms. It does say though, that you brush it on a warm engine, allow it to soak, then wash off with fresh water. Where does this water go? Onto the drive! But it says it's harmful to tarmac - this must only be in its "neat" concentration, because after it mixes with water, it goes milky and just washes away. So long as you don't put it in your garden pond, it'll be harmless.

Green Gunk?
What's green about it?
What's NOT green about Normal Gunk?

[Brucey]

IIRC (and I may not, it is a while since I used some) the instructions for 'old Gunk' were adamant that you should leave it on for no more than a few minutes, presumably because it might cause some dreadful corrosion or something.

It is a bit rough finding out the hard way on a DA mech though.

cheers

[reohn2]

It is a bit rough finding out the hard way on a DA mech though.

cheers

I agree it's a hard lesson.

[ChrisButch]

I too usually use white spirit for these jobs, and have done for years. That's how I came to be careless about leaving something to soak, as I usually do this with chains etc in white spirit, without any problems. Incidentally, the instructions on the Green Gunk can do mention soaking, but only for 10 minutes...
As for traditional Gunk, there's been a lot of adverse publicity recently about toxic chemicals in degreasing agents and a claimed link with Parkinson's, though I don't know which if any of these Gunk use in their current formulation.

[ChrisButch]

Another thought about this....has anybody tried to home brew a citrus degreaser? I wonder how many kilos of lemons you'd need to produce a usable quanitity, and what the process would be.