Supplier of Johnson-Matthey Stop-Flo or similar

[Brian HParticipant @brianh50089]

Does anyone know of a UK supplier of Johnson-Matthey Stop-Flo or similar. I've spent the best part of this morning trying to find some without success.

I know that Tippex has been recommended in the past but I believe that should be the old type with Tric.

Brian

[Brian HParticipant @brianh50089]

[Engine BuilderParticipant @enginebuilder]

Th new "safer" Tipex works fine.

[AdrianRParticipant @adrianr18614]

This place lists it **LINK**

Adrian

[JasonBModerator @jasonb]

So long as it is solvent based tipex it works OK

[Keith HaleParticipant @keithhale68713]

As far as I am aware, the the "new tippex" is water based and is safe.

What did Johnson Matthey say about the composition and availability of their product?

Keith

[Brian HParticipant @brianh50089]

Many thanks for the replies. There seems to be a difference of opinion about the solvent is Tippex!

Keith (CuP) ; JM list 2 stop-offs. The interesting one is No1 which is for general use but the composition of both is given as "finely ground chemically inert and thermally stable compounds."

Brian

[Tim StevensParticipant @timstevens64731]

I have had success with jewellers rouge – the powder, not the grease-base stick. Mix with water and alcohol, and paint everywhere you don't want solder to run. And of course, rouge is indeed a 'finely ground, chemically inert, and thermally stable powder' – just not white. Which is better? I don't know – but silversmiths tend to have rouge and not tippex.

Cheers, Tim

[JasonBModerator @jasonb]

They do both solvent (Rapid) and water based (Eco), the solvent has changed from the original to stop school kids getting high, etc.

"The organic solvent 1,1,1-trichloroethane was originally used as a thinner in the product. This solvent is readily absorbed by the lungs via inhalation. It passes readily through the blood–brain barrier and may be lethal following acute exposure.^[3] 1,1,1-trichloroethane is also an 'ozone depleter', being one of the substances responsible for causing damage to the Earth's ozone layer.^[4] For both reasons, it has not been added to Tipp-Ex since 2000, and it has been replaced by aliphatic hydrocarbons.^[5]"

Edited By JasonB on 12/05/2020 07:00:51

[Dave Smith 14Participant @davesmith14]

Use 6 month old tippex yesterday absolutely no problems.

Dave

[SillyOldDufferModerator @sillyoldduffer]

Posted by JasonB on 12/05/2020 06:55:58:

They do both solvent (Rapid) and water based (Eco), the solvent has changed from the original to stop school kids getting high, etc.

"The organic solvent 1,1,1-trichloroethane was originally used as a thinner in the product. This solvent is readily absorbed by the lungs via inhalation. It passes readily through the blood–brain barrier and may be lethal following acute exposure.^[3] 1,1,1-trichloroethane is also an 'ozone depleter', being one of the substances responsible for causing damage to the Earth's ozone layer.^[4] For both reasons, it has not been added to Tipp-Ex since 2000, and it has been replaced by aliphatic hydrocarbons.^[5]"

Edited By JasonB on 12/05/2020 07:00:51

Trike is nasty stuff.

The 2008 Safety Data Sheet lists the contents of Tippex as a water based mix of:

Ethanediol (aka Ethylene Glycol, or Anti-freeze)
Titanium Dioxide (bright white non-fade paint pigment)
Limestone (Calcium Carbonate)
Ammonia

Two advantages of trichloroethane as a solvent: it evaporates quickly and is a degreaser.

In the new mix Ethanediol and water evaporate rather more slowly and Ammonia is the degreaser.

The important ingredients as a blocker are Titanium Dioxide and Limestone. Titanium Dioxide is heatproof, but made hot enough Limestone releases Carbon Dioxide gas and converts to Quicklime (Calcium Oxide). Probably a good thing because it stops the 'paint' sticking during the clean up, but might lead to poor blocking at the edges.

Titanium Dioxide is fairly expensive, so I'd guess JM replaces it with something cheaper that doesn't react to heat at all, giving slightly better results. (Couldn't find what's in JM Stop-Flo except it's water based.)

Amateur Knife-makers make Damascus steel by forge welding plates of hardenable steel inside a mild-steel container that's discarded later. They plaster the inside of the mild-steel box with Tippex to stop the Damascus billet welding to the mild-steel. In that application I guess Limestone breaking down with heat is an advantage because the gas would tend to physically break the weld, which is already inhibited by the inert Titanium Dioxide.

Can't think of a good reason why modern Tippex wouldn't work as well for Brian as the old stuff.

Dave

[JasonBModerator @jasonb]

Solvent based contents here Dave and a bit more recent

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