Cycling UK Forum

I had to struggle recently with a stuck cassette locking ring and, on a different bike, a stuck crank. I used various techniques but 20 mins after applying PlusGas in both scenarios, I was successful. However, I have no idea whether it was the PlusGas that made the difference or just perseverance in whatever I was doing.

So my question is, is there any consensus out there as to what PlusGas really does. My own feeling is that I am entirely sceptical: it's a sort of lazy man's snakeoil - a product that is full of promise but in practice makes little difference.

Do we actually know?

horizon wrote:I had to struggle recently with a stuck cassette locking ring and, on a different bike, a stuck crank. I used various techniques but 20 mins after applying PlusGas in both scenarios, I was successful. However, I have no idea whether it was the PlusGas that made the difference or just perseverance in whatever I was doing.

So my question is, is there any consensus out there as to what PlusGas really does. My own feeling is that I am entirely sceptical: it's a sort of lazy man's snakeoil - a product that is full of promise but in practice makes little difference.

Do we actually know?

Why did you get some then?

I think you've answered your own question in your first couple of sentences.

Certainly when I worked as a fridge engineer in a frozen food factory it was the favourite of the fitters who fixed the veg processing machinery. Knowing what those guys said about it I'd say it does what it's meant to.

.

pete75 wrote:
I think you've answered your own question in your first couple of sentences.

Well, I would like to think so but of course there's no hard evidence that one was the result of the other. If other people say they get similar results, then may be. I wondered if someone had done some scientific tests, that sort of thing. The other crank is soaking as we speak so we shall see. . .

I've found plusgas to be effective (all anecdotal of course). IMHO even better was the 'rust dissolver' spray I bought from Lidl a few years ago. Of course (as is often the way with the vendor) I haven't seen it for sale since, and it won't squirt any more. How dangerous is it to try and puncture the can to extract the remaining fluid? Maybe a nail in a long stick could be tried?

I found this:

Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts.
Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker.
*Don't forget the April 2007 "Machinist's Workshop" magazine comparison test.*
**
*They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment. *
**

*Penetrating oil ..... Average load*

None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster .............. 214 pounds
Liquid Wrench ........ 127 pounds
Kano Kroil .............. 106 pounds
ATF-Acetone mix.......53 pounds

horizon wrote:I found this:

Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts.
Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker.
*Don't forget the April 2007 "Machinist's Workshop" magazine comparison test.*
**
*They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment. *
**

*Penetrating oil ..... Average load*

None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster .............. 214 pounds
Liquid Wrench ........ 127 pounds
Kano Kroil .............. 106 pounds
ATF-Acetone mix.......53 pounds

Did they compare it with the old favourite - warming the fitting with a set of gas bottles.

An old friend and bloody good cycle teck sadly now departed recommmended this stuff to me yonks ago... he ordered a case as he had others who wanted it, I still have a half empty can. It worked for me on bike stuff from memory but when I removed the complete rear axle assembly from my Ford Focus st170, it didn't do what it claimed on the tin.... when I decided to rebuild and renew all the bushes brgs links , that said I doubt if anything would have moved those nuts and bolts and we cut each one off with the grinder and a thin metal cutting blade...He had said it was hard to source back in those days, dear knows who stocks it now and if its the same chemical constitution... will

Under discussion since 2013 viewtopic.php?t=75840&start=15

Where do you buy it? I haven’t seen a tin for years.

IIRC a UK-based motoring magazine did a similar test and they found that GT85 was the most effective penetrant of those that they tried.

Solvents in penetrants are always a compromise between being able to penetrate well (small molecules are best) and not evaporating too quickly (which requires larger molecules). So plus gas evaporates fairly quickly but not as quickly as a lot of other things. Concoctions using paraffin evaporate most slowly. Oil-only mixtures can penetrate well if they and the parts are heated well; for example ATF is almost as runny at 200C as many solvents are when at room temperature.

FWIW acetone is an interesting choice of solvent; it is bad because it attacks some paints and many plastics and it evaporates quickly, but it is good because it is very inviscid (so penetrates well) and has a very high affinity for water. I think it works partly by removing water from the structure of rust, thus loosening the grip that corrosion has on rusted parts.

Rust can, in many cases, be 'mostly water' by weight, and expands (by becoming further hydrated) to fill close-fitting spaces, hence seizure. If you remove the water, the parts simply ain't seized together in the same way any more. If you want to remove all the water by heat alone, in a short length of time, you need temperatures of several hundred degrees.

One of my mad ideas is that if a low power heater is used (on a seized seat pin, say) then water can be driven out slowly at low temperatures and seized parts might more easily be removed after a few weeks of that kind of treatment.

cheers

Brucey wrote:
One of my mad ideas is that if a low power heater is used (on a seized seat pin, say) then water can be driven out slowly at low temperatures and seized parts might more easily be removed after a few weeks of that kind of treatment.

cheers

What about leaving it somewhere warm like a boiler room for a few weeks - would likely have the same effect.

maybe; I'm thinking 60 to 100 degrees C though; boilerhouses are not usually that hot...?

cheers

Paulatic wrote:Where do you buy it? I haven’t seen a tin for years.

Amazon. eBay. Didn't take much finding.

It’s the first thing I go to for seized rusty parts, then let it soak in for awhile. Word of mouth recommendation from an older engineer when I was working.

We used a variety of anti seize compounds and plus gas did seem to be the best. Though it was always applied from a tin and not a spray.

jb wrote:We used a variety of anti seize compounds and plus gas did seem to be the best. Though it was always applied from a tin and not a spray.

Plusgas isn't anti seize compound. It's a penetrating spray used to free off seized components. Anti seize compounds are things like Coppaslip that are applied to components before joining with the aim of stopping them seizing.