Kurust and Painting

Discussion in 'Mech Tech' started by Roxy46, Apr 30, 2013.

  1. Long time ago since I used Kurust but have just bought some. On the blister pack it says to apply it and then 'Apply topcoat after 3 hours'. Am I being silly or does 'topcoat' really mean 'primer'? Should the primer be an etch primer on top of the Kurust or is that just overkill?
    Naive questions perhaps but you have to start somewhere!!:)
     
  2. I always etch over the top...

    If you use upol acid 8, that is a primer and etch all in one. So if you're just rattle can painting, it's a lot simpler :)
     
    paradox likes this.
  3. Also make sure you key up the kurust once dried as we've found paint/primers dont always adhere to well to it.
     
  4. You'll need to wash the deposits off before painting with anything. As I recall, you get a white powder left.

    Kurust works fine, but it's basically only phosphoric acid that stabilises any modest rust by turning it into iron phosphate (the black stuff).
     
  5. Hi, kurust is ok and i have used it a bit, i find sanding/grinding as much loose bits off, applying some then when thats nearly dry give it another thin coat, Dont let it pool any where. When its dry i usually coat with zinc rich primer then a regular primer then top coat, i havent noticed the powder thing myself and kurust does etch by itself so we dont use that and be careful if you do key it (i don't) as its only a rust encapsulator so you could scrape through it to rust again
     
    Kruger likes this.
  6. Did it this afternoon and didn't have any white deposits so brush-painted some ordinary grey celly primer. Had a look a bit later and it looks like it needs another coat of primer so will do that in the morning and then looking to do a top coat in the afternoon if the weather allows!!

    Thanks for all the replies though - it's good to hear of everyone's experiences and I guess you learn accordingly!:)
     
  7. The only good use I found for Ku-rust was when I had a spot that kept reacting to the celly paint I was spraying. Ku-rust stopped it!
    You can buy Phosporic acid on Ebay in 5Ltr or 1 Ltr. 40% is the good stuff. Ku-rust is the biggest rip-off of all these potions IMO.
     
  8. Good news then, at least i found out about cheap eBay acid, woo
     
  9. Oh yes! Forgot to mention that but haven't looked yet. I thought Kurust turned rust into phosphoric acid so why would you want to paint some onto your bus?o_O
     
  10. Kurust is phosphoric acid :lol:


    ;)
     
  11. I have managed to create the black phosphate reaction on many other surfaces not just the rust, concreate floor, fingers, tshirt and face and it does etch in you have to pick through a few layers of skin to get it off, nasty stuff really
     

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