Tamiya Paint Question.

[turbo]

PH levels for cerain commonly consumed beverages

http://www.gcaustralasia.com/Upload/product/pdf/96/Acidity-pH-chart.pdf

coke is right up there with stomach acid, and just behind battery acid. Lordy lordy what have I been doing?.

Yep, most people are a bit shocked when they learn that about soft drinks!

So since Coke contains a WEAK solution of Phosphoric acid it can remove SOME LIGHT surface rust but it is NOT going to attack heavily rusted nut and bolts

I've used Coke in combination with polishing with aluminium foil to remove rust before. Can't remember the chemistry offhand but something to do with Al having a higher reduction potential but can't remember the role of the acid.

 

[mikewint]

pH: the lower case "p" is for LOG (short for logarithm) and the H for hydronium (hydrogen ion) then to reverse the sign of the resulting number we negate it thus: pH is the negative log of the molar concentration of the Hydrogen ion).
A pH of 7 is a hydrogen ion content of 10^-7 Molar or 0.0000007 Moles per liter. Coke classic at 2.50 has a concentration of 0.0030 moles per liter hydrogen ion. Lest that twitterpate you, RC Cola is 2.38; Cranberry Juice is 2.96; lemons are 2.29 and Limes are 2.17.
pH in and of itself is NOT the sole criterion of acid strength that goes to DEGREE OF IONIZATION. Hydrochloric acid is strong because it ionizes 100% whereas Concentrated Sulfuric acid is a weak acid because it is mostly molecular and unionized (that's why it can be shipped in steel RR cars)

 

[mikewint]

I've used Coke in combination with polishing with aluminium foil to remove rust before

The Coke is unnecessary to the entire process and water works as well: Rust is basically oxidized metal or another words metal that has taken on extra oxygen atoms. As heat is generated by the friction of rubbing the aluminum foil on the chrome, a portion of the aluminum will oxidize to produce aluminum oxide. Aluminum has a higher reduction potential (i.e a tendency take on electrons and in the process reduce or break itself down) than the chrome, and will therefore leech oxygen atoms away from any rust on the chrome surface which changes the chemical properties of the rust and breaks it down. Lastly there is also a polishing effect trom the Aluminum Oxide produced. Aluminum oxide is harder than steel, and the microscopic grains of aluminum oxide produced during the cleaning process creates a fine metal polishing compound which, mixed with the water you added, creates a paste that smoothes and polishes the chrome surface.

 

[parsifal]

You know your stuff mike by the look of it.

 

[mikewint]

Nothing works like it did in the long ago but that M.S. in Chemistry was worth something anyway.
Hydrofluoric acid is a weak acid (ionizes very little) has a high pH but etches glass and will uncouple protein molecules

 

[vikingBerserker]

Whoa really? That's what I use to clean my airbrush after using the thinned paint. Not sure I like the idea of mixing a soapy ammonia fluid with my paint. It foams like crazy when I clean my brush.

You typically do not need that much, I normally only needed to add a few drops. The blue does not impact the color of the paint and it is pretty smooth. I've net noticed a difference between regular and ammonia free. I used it on my Buffalo and Swordfish in the group builds.

 

[Crimea_River]

I guess that works in small amounts but I tend to thin my paints with over 50% thinner.

 

[mikewint]

I tend to thin my paints with over 50% thinner.

So if I'm reading correctly one jar of paint becomes two? Isn't that awfully thin?

 

[dogsbody]

The water I use with Tamiya paint is from a gallon jug of distilled water that I bought at the local drugstore.


Chris

 

[Builder 2010]

I've been using Tamiya paint since they were introduced into the US. I've been using 91% IPA bought in large bottles at the drug store for significantly less than any proprietary thinners. I don't no what the other ingredient Tamiya includes does (possibly extends drying time and improves flow), but Tamiya paint airbrushes wonderfully. It's my main paint type. IPA will even bring paint that's almost crossed over the other side back to life.

But with other brands, it's not so hot (like Model Flex or Vallejo). Vallejo clumps up, gets gummy and clogs airbrushes when you use IPA. I'm using their recommended thinners.

I clean the gun in Water, then IPA. For deeper cleaning I will shoot acetone through it which dissolves dried acrylic.

 

[Crimea_River]

So if I'm reading correctly one jar of paint becomes two? Isn't that awfully thin?

Yes, it's very thin but makes for better finishes, especially for mottling.

 

[parsifal]

a couple of people have mentioned using water as a thinning agent. ive always shied away from that. Does anyone feel confident to explain whether using water as a thinning agent is an okay choice?

 

[Airframes]

It should be OK with many acrylics, unless the manufacturer specifically states otherwise, although of course test first.
All of the acrylic varnishes I use can be thinned with water, as suggested on the various bottles, and the few acrylic paints I've used also suggest water (Revell and Vallejo), and I do think I once thinned Tamiya with water too, but it's so long ago I can't remember.
However, even though all acrylics, in theory, can be thinned with water, this may be fine for brush-painting, as artists do, but some re-act better for spraying with a dedicated thinners, most of which are alcohol based.

 

[fubar57]

I just used distilled water with Gunze Sanyo paint on my GB Macchi. No adverse effects

 

[mikewint]

I just used distilled water

IF you are going to go that route then I would most definitely recommend the use of distilled water. Ordinary tap or bottled water contains minerals that will precipitate out as the paint dries. My own preference is to use the manufactures thinner as they know their own formulations and what will work. I also like the idea of the increased evaporation rate of alcohol based thinners especially in the more humid summer months. After all that assembly work and time why take a chance?

 

[vikingBerserker]

I guess that works in small amounts but I tend to thin my paints with over 50% thinner.

Well, I cannot argue with your results!

 

[JKim]

Late to the party but I thin my Tamiya and Gunze acrylics with 91% iso alcohol.