Phosphoric acid w/ Blue Gold for reg cleaning

[spoolin01]

I had seen the MSDS for the Hydrosonic Solvent, just not the other name you were using. They say in the MSDS that neither the % nor the components are necessarily correctly ID'd, in order to obfuscate their trade secret. It's possible the product is truly concentrated phosphoric acid with the added butoxyethanol - the specific gravity seems consistent with that, and contrasts notably with what is reported for the Lawrence Factor Wash - it just seems surprising. They also term the product "organic acid" based on their website, so they are getting information wrong somewhere, maybe by design. Who knows.

I don't know to what extent MSDS are policed, it's never been my impression that they are. You can see from reading them that there is considerable variation in how the forms are filled in, or not in many cases. GMC are not in a regulated industry.

 

[davetowz]

I usually use a bit of store shelf vinegar for corrosion, Simple green for cleaning. I have found that if the corrosion on a reg requires alot of work to remove it, the reg probably will have issues due to the removal of plating. Orings etc don't like to do the job in those environments.

 

[Couv]

I have not been able to confirm the exact concentration of phosphoric acid in LFW or Tumble Juice, but I've heard that it it "can" be diluted as much as 8:1 If you know a retired chemist who could titrate a sample, that would be very handy.

I thin my solution down to 8.5%

An earlier post piqued my curiosity regarding a stronger solution, so just today I have 4 pieces of chrome plated brass I cut off of an old regulator yoke soaking in the following:
5% vinegar
2.5% vinegar (the infamous 50/50 most DIYers use)
85% phosphoric acid
8.5% (by weight) phosphoric acid

I'll give it a couple of weeks to work on the chrome and report back with the results.

Couv

Update: I'm back from vacation and here are the results and a picture. The samples were in solution from Nov 2-16, 2017. The chrome samples in 2.5% & 5.0% vinegar and 8.5% phosphoric acid had no noticeable chrome loss. The 85% phosphoric acid solution is a different matter. The plating was eroded down to at least the copper layer if not all the way to the brass. (The plating process for most regulator parts is Brass substrate, copper coated, nickel plated, chrome plated.)

 

[dberry]

I wonder to what extent the 8.5% phosphoric giving "no noticeable chrome loss" compared to 85% is just a matter of time. I suppose if cleaning is a very rare event then a little thinning (not noticeable) of the chrome with 8.5% is okay.

The results speak for themselves, but 'm a little surprised the 85% went after the chrome and the nickel - it's not a particularly strong acid, and even concentrated has minimal oxidizing power compared to other concentrated acids. Dissolving oxides (rust) is another matter (witness Naval Jelly.)

 

[Couv]

Thanks Dberry. The most surprising result was from the vinegar. After 2 weeks, I expected both the 2.5% and the 5.0% to have more effect on the chrome than they did.

 

[spoolin01]

Nice work, and useful. I just noticed your earlier comment about titrating acid content. Shouldn't be hard to do with simple materials, but I don't have anything, including the P-acid products, on hand to work with. I don't know whether the vinegar results are surprising or not, but again I'd be more worried about the effect on the brass underneath worn or low quality plating than on better stuff. How about putting the piece from the 85% phosphoric acid into vinegar for another week? Was it only half immersed in the 85%? It looks like an interesting part to test. If you have a good balance, you could weigh it first.

 

[rsingler]

I saw that, but he says glycol (antifreeze). I see that, I am thinking is he talking about ethylene glycol, aka car antifreeze, which is highly toxic. If it’s ethylene glycol, I don’t want to breathing on something cleaned in that.

Propylene glycol. Different

As for GMC ultrasonic soln, I use that too. I can get it for anyone that wants it, but it's expensive, tho not as much as LFW. It's diluted 4:1 to 8:1, so keep that in mind for whomever said that it's 80% phosphoric acid. I'm not sure it is - see below:

GMC specifically markets a phosphoric acid cleaner which works very well, but is specifically noted not to be used in the U/S cleaner. I don't understand that, since other phosphoric acid solutions are noted to be for the U/S. It may have to do with the earlier discussion of using an alkaline degreaser in the U/S, which would not be compatible with an acid solution. But the GMC phosphoric acid wash is very potent and bubbles stuff away quickly even without U/S. I often use it as a pre-treat before the U/S. I suspect that THAT solution is the one noted above to be 80% phosphoric acid, and is therefore not appropriate for the U/S. They note it is bad for the tank or connections or something. I can't remember.

So I've changed my homebrew U/S solution from Home Depot tile cleaner to that food grade phosphoric acid from eBay diluted to 5%, plus 1 tsp Dawn per 2 quarts solution, plus a splash of propylene glycol to aid solution penetration. Can't complain about its performance, even on soft parts, though I don't leave them in long.