ANDREW PERKINS Posted June 18, 2021 Report Share Posted June 18, 2021 Theres so many to choose from -- Anybody suggest to me best one on the market ( spray and brush on ) Thanks Andrew Quote Link to post Share on other sites
glasgow4a Posted June 18, 2021 Report Share Posted June 18, 2021 Buy a gallon of Milkstone Remover from a farm supplier much the same as Jenolite [phosphoric acid based] but a lot cheaper! Quote Link to post Share on other sites
RogerH Posted June 18, 2021 Report Share Posted June 18, 2021 1 hour ago, ANDREW PERKINS said: Theres so many to choose from -- Anybody suggest to me best one on the market ( spray and brush on ) Thanks Andrew Hi Andrew, how much rust are you removing and how severe.? Anything from a dab on a paint brush to a needle gun may or may not work Most of the decent removers (there are many) require the part to be dunked from 1 to 24 hours and usually end up with a pickled clean component The converters can be brushed and these very quickly turn the surface purple/black. It does not remove anything. In theory what is underneath the dark skin is sealed in !!! Then you have mechanical methods - Grit, soda. dry Ice blasting to name but a few. They all have their advantages and disadvantages. The Milkstone remover is often mentioned and mus work but I haven't tried it.. BiltHambers DeOxC works very very well but you need to put the item in a bucket - possibly a very big bucket for 12 - 24hrs. The Gel's are not that effective as they need regular stirring. If you go for a brush on Gel or liquid cover the coated surface with news paper so that it all stays wet. The grit type medias work very well but you may have access issues in some areas. Roger Quote Link to post Share on other sites
john.r.davies Posted June 18, 2021 Report Share Posted June 18, 2021 I'm very fond of "Milkstone Remover"! It's cheap (c.£12 for 5L) for 80% phosphoric acid, when proprietary 'rust removers' can be twice or three times that. It works, by converting iron oxide to iron phosphate, which is the black stuff you see with the proprietaries. That phosphate, unlike all other phosphates, is insoluble in water, so stays on the surface of any existing rust, where it's a good foundation for paint systems. The acid is a 'weak' acid, so won't attack the unrusted steel - it will attack aluminium! - but it's still an acid, with a ph of about 1 in Milkstone remover. Use gloves, wear old clothes and eye protection! It's non-toxic - CocaCola contains 0.2%, which is what gives Coke its 'bite'! BUT! It's not a rust 'remover' - as said, instead, it changes the surface of existing rust. So mechanical removal of as much rust as possible is advised. AND, it's a liquid, that will run off vertical surfaces. Haven't tried 'gelling' it, should be possible, say with a food gelling agent. My method is to use hand and drill-powered wire brushes to remove as much rust as possible. No need to get down to bright metal, and the acid will get into pits and seams. Paint on the undiluted 'Milkstone remover', and leave to dry. Do once more, but drying it off with paper towels. Allow to dry. You should see all the rust gone black. If there are white deposits, then wire brush them off and repeat the process. Dry thoroughly and paint with your preferred primer. If you want a 'rust remover' then any other 'weak' acid will react with the rust to a soluble product, and dissolve the rust away, right down to the steel. Vinegar is acetic acid, non-toxic and cheap, but the vinegar at your grocer will be no more than 5%, and you can buy it 99% pure for less than the cost of 5L of Milkstone remover! But NB! Vinegar stings a bit in your eye; the pure stuff needs the same PPE if you use it. John Quote Link to post Share on other sites
ed_h Posted June 18, 2021 Report Share Posted June 18, 2021 This is the work of phosphoric acid. My bucket wasn't big enough to do it all in one go. Ed Quote Link to post Share on other sites
RogerH Posted June 18, 2021 Report Share Posted June 18, 2021 2 minutes ago, ed_h said: Although not phosphoric acid the DeOxC gives a similar finish. Roger Quote Link to post Share on other sites
ed_h Posted June 18, 2021 Report Share Posted June 18, 2021 I don't think the DeOx-C is readily available in the US, but it appears to be chemically similar to Evaporust, a product popular here. They both use a non-acid chemistry that is very effective, and safer than acids. I'd love to try some of the DeOx-C since it's a powder, so you can mix it to whatever concentration you want. Evaporust is a liquid. I use Evaporust for sensitive jobs where there may be plating or paint I want to preserve. Otherwise, it is normally acids, which are at least as effective, but much cheaper and long lasting. Ed Quote Link to post Share on other sites
Tim T Posted June 18, 2021 Report Share Posted June 18, 2021 2 hours ago, ed_h said: This is the work of phosphoric acid. My bucket wasn't big enough to do it all in one go. Ed What dilution is the acid? Cheers Tim Quote Link to post Share on other sites
Tim D. Posted June 18, 2021 Report Share Posted June 18, 2021 A lot of proprietary solutions use tannic acid. Similar idea to phosphoric. Makes iron tannate which I guess is insoluble. Tim Quote Link to post Share on other sites
RogerH Posted June 18, 2021 Report Share Posted June 18, 2021 I was under the impression that the DeOxC was based on Citric acid - I may be wrong. Roger Quote Link to post Share on other sites
PodOne Posted June 18, 2021 Report Share Posted June 18, 2021 Used both DeOxC and phosphoric acid and the latter works better and is much cheaper. I've had the same bucket on the go for around 2 years and its still removing rust from anything I've put in there so far from surface rust to thick crust. Once cleaned with warm water and dry your left with bright steel in the bottom of any pits. DeOxC was used for the rear of the bumpers which were filled like a bath but it was a slow process but seemed inert to the chrome. Andy Quote Link to post Share on other sites
Drewmotty Posted June 18, 2021 Report Share Posted June 18, 2021 This stuff from Homebase works well. I think that it’s more or less neat phosphoric acid: https://www.homebase.co.uk/hg-rust-remover-500ml/12807543.html?switchcurrency=GBP&shippingcountry=GB&utm_source=AWin-176013&utm_medium=affiliate&utm_campaign=AffiliateWin|Feed&affil=awin&utm_content=RedBrain&utm_term=Direct+Linking&utm_source=AWin-176013&utm_medium=affiliate&utm_campaign=AffiliateWin&awc=22367_1624046379_9955e754f1a10deb28048aafd97db88c Quote Link to post Share on other sites
ed_h Posted June 19, 2021 Report Share Posted June 19, 2021 (edited) 8 hours ago, RogerH said: I was under the impression that the DeOxC was based on Citric acid - I may be wrong. Roger That could be right, Roger. Their Safety Data Sheet shows nothing dangerous or toxic, same as for chelate type products like Evaporust. Citric acid has a low toxicity, so it may not have to be reported in the SDS. One sure way to tell would be to taste it. I would if I had some. If it is citric acid, it's way over priced. Ed Edited June 19, 2021 by ed_h Quote Link to post Share on other sites
ed_h Posted June 19, 2021 Report Share Posted June 19, 2021 (edited) 10 hours ago, Tim T said: What dilution is the acid? Cheers Tim Not really sure, Tim. The stuff I buy is around 40%, and I usually dilute it 50/50 with water. But this bucket is a few years old, and when the level gets low, I just throw in some acid or water or both, sort of at random. Ed Edited June 19, 2021 by ed_h Quote Link to post Share on other sites
PodOne Posted June 19, 2021 Report Share Posted June 19, 2021 As Ed says 40% got mine off e Bay. DeOxC is citric acid based. Quote Link to post Share on other sites
john.r.davies Posted June 19, 2021 Report Share Posted June 19, 2021 16 hours ago, Tim D. said: A lot of proprietary solutions use tannic acid. Similar idea to phosphoric. Makes iron tannate which I guess is insoluble. Tim It depends on the ionic state of the iron atom! Ferrous tannate is very soluble, but ferric is insoluble. We need a chemist to tell how to ensure the second! Quote Link to post Share on other sites
ed_h Posted June 19, 2021 Report Share Posted June 19, 2021 Rust is typically a pretty complicated mixture of various iron oxides or hydroxides. The mix depends on how much moisture and oxygen are present. I'm not sure the chemistry is even fully understood. Interesting side note on tannates: It's pretty well known that oak wood gets dark stains if it is in contact with iron or steel fittings or hardware with any moisture present. This is because oak has tannins in the wood that react with the iron. The process is even sometimes used to stain oak dark intentionally. Ed Quote Link to post Share on other sites
john.r.davies Posted June 19, 2021 Report Share Posted June 19, 2021 The Wiki article on "Oak gall ink" is illuminating. Iron sulphate, and tannic acid from oak galls produces an ink of soluble ferrous tannate, that is oxidised by atmospheric oxygen to the ferric form once written with, making the writing permanent. See: https://en.m.wikipedia.org/wiki/Iron_gall_ink An analogous method with rust might be to wet the rust with tannic acid, and then keep it wet for long enough for atmospheric oxygenation. So, wet newspaper? But no need to speculate! This paper describes its use tom protect rusted iron objects in museums! https://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/tannic-acid-rusted-iron-artifacts.html. But note "objects originally intended to be brightly finished or painted. As tannic acid produces a blue-black surface, it is suitable for wrought and cast iron, on which such a finish is appropriate." John Quote Link to post Share on other sites
ANDREW PERKINS Posted June 27, 2021 Author Report Share Posted June 27, 2021 On 6/18/2021 at 11:27 AM, glasgow4a said: Buy a gallon of Milkstone Remover from a farm supplier much the same as Jenolite [phosphoric acid based] but a lot cheaper! Thankyou so much for helping me understand this issue - Andrew Quote Link to post Share on other sites
ANDREW PERKINS Posted June 27, 2021 Author Report Share Posted June 27, 2021 On 6/18/2021 at 12:17 PM, RogerH said: Hi Andrew, how much rust are you removing and how severe.? Anything from a dab on a paint brush to a needle gun may or may not work Most of the decent removers (there are many) require the part to be dunked from 1 to 24 hours and usually end up with a pickled clean component The converters can be brushed and these very quickly turn the surface purple/black. It does not remove anything. In theory what is underneath the dark skin is sealed in !!! Then you have mechanical methods - Grit, soda. dry Ice blasting to name but a few. They all have their advantages and disadvantages. The Milkstone remover is often mentioned and mus work but I haven't tried it.. BiltHambers DeOxC works very very well but you need to put the item in a bucket - possibly a very big bucket for 12 - 24hrs. The Gel's are not that effective as they need regular stirring. If you go for a brush on Gel or liquid cover the coated surface with news paper so that it all stays wet. The grit type medias work very well but you may have access issues in some areas. Roger Thank you for this information == I'm forming an idea of whats involved now -- Andrew Quote Link to post Share on other sites
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