Paint Reactions / Primer

  1. Marmite

    Marmite New Member

    Messages:
    5
    Location:
    South Wales
    Could anyone help with my paint choices?

    I always prime with red oxide if hand painting (free from work), but I’ve hit a problem spraying over it.

    For some reason I decided to spray a high build rattle can primer over the red oxide, but it reacted.

    Should I avoid RO in the future (rather not!) or what spray paints go over it without reaction? Never had an issue painting over it in the past.

    It’s a job for the missus, so way more important than normal!

    61BEBF2A-C6A2-4E7E-8A75-5EF9DE62EF66.jpeg
     
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  2. Dcal

    Dcal Forum Supporter

    Messages:
    1,820
    Location:
    Antrim Northern Ireland
    Welcome to the forum

    Get the TDS for the primer and go with what it tells you to over coat it with.
    If they don't have (or don't recommend) a paint that suits you, go with a different primer and paint system.

    There's red oxide and red oxide (it's just a colour) so good and bad.

    I just used some Jotun Penguard in red oxide and you could overcoat that with pretty much anything but it is two pack.

    Nice pig
     
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  3. carbon

    carbon Member

    Messages:
    1,412
    Location:
    S. Glos. U.K
    Ive had problems with red oxide before when spraying over it. I found that leaving the red oxide a couple of weeks before spraying was best
     
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  4. steveo3002 Member

    Messages:
    5,223
    cambridge uk
    was the red oxide brushed on ? if so can take forever to dry fully

    aerosol is high in solvent and that solvent will attack the underlaying primer

    best stick to a system rather than mixing and matching ...aerosol etch , then high build would give you no bother
     
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  5. Marmite

    Marmite New Member

    Messages:
    5
    Location:
    South Wales
    Good points, it was brushed so may not have been fully cured.

    It’s paint from BSS, our pipe supply company. Obviously the new friendly version of red oxide. Never seen any other colour over it than ochre yellow (gas pipe), or black Jotun / Blackfriars on my own jobs.

    It’s free so it would be nice to continue using it. Even my TIG trolley is gas pipe yellow!
     
  6. anjum Member

    Messages:
    1,150
    Location:
    London UK
    The spray tin high build primer is the problem. When I tried to use it in the past it always caused problems.
     
  7. Edward Yemm Member

    Messages:
    90
    Location:
    Forest of Dean, Gloucestershire, England
    Try spraying some barcoat or isolator over it after you’ve sanded the reaction area out. You’ll have to spray something like cellulose primer over the top of the barcoat. Barcoat will basically cling to the reaction and stop it getting past. Basecoat doesn’t like barcoat though and reacts with something that’s already holding in a reaction? Damn paints! Hence the cellulose primer over the top.
     
    Last edited: May 18, 2020
  8. Al Strachan

    Al Strachan Member

    Messages:
    177
    Location:
    insch aberdeenshire
    +1. i hate the stuff.
     
  9. Edward Yemm Member

    Messages:
    90
    Location:
    Forest of Dean, Gloucestershire, England
    It’s hit or miss with spray cans. Sol epoxy primer spray can doesn’t react with most things. If it does then barcoat over the top. Upol high build and pro spray super high build spray cans like barcoat. Tetrosyl spray gun primer likes it also. About to test some upol p88 high build primer over a tiny patch of barcoat.
     
  10. the snooper

    the snooper getting older by the day

    Messages:
    20,350
    Location:
    Hull UK
    Basecoat is fine with barcoat I've never had a problem with it, if you follow the instructions it's fine, make sure you give it a full coat leave an hour minimum to cure and do not flat it then on with whatever you need
     
  11. the snooper

    the snooper getting older by the day

    Messages:
    20,350
    Location:
    Hull UK
    If you have brushed on any type of paint I don't see the point in then spraying as the brush lines will just show through, spraying is used to get a smooth finish you won't achieve that so may aswell continue with a brush
     
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  12. Edward Yemm Member

    Messages:
    90
    Location:
    Forest of Dean, Gloucestershire, England
    There’s very little information about this stuff. I stumbled across it after years of searching paint reactions and finding no answer. I’ve seen one solitary video where it is used. A Russian guy uses it over basecoat that’s reacted. He then wet flats it and sprays basecoat over it. Unless he’s just flatting the overspray around the patch he’s sprayed then? On my tin it says primer must be used over the top of it. I have the old style liveried UPOL. It says on the instructions that it should be sprayed with a 1.4-1.8 suction feed gun. It sprayed ok with a 1.4 gravity fed gun but I bought a suction feed 1.8 as that’s what’s recommended. The new liveried UPOL barcoat cans have a different story on their data sheet. Gravity fed gun? If I get a reaction as I’m spraying basecoat I’ll try basecoat over un flatted barcoat then? God, this whole painting lark is one big minefield!
     
  13. steveo3002 Member

    Messages:
    5,223
    cambridge uk
    my advice , dont get sucked into using barcoat , its for bodging up a mess and will most likley come back and bite you later

    in 99% of cases its not the correct answer to putting a job right , i painted cars for over 20 years and saw one tin of it , its simply not needed if you know what youre doing
     
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  14. Edward Yemm Member

    Messages:
    90
    Location:
    Forest of Dean, Gloucestershire, England
    I only used it because
    I only used it because the BMW Black Sapphire Metallic 1k basecoat cracked and it doesn’t like anything bring sprayed over the top of it once sanded back. I expect it’s small patches of it that I didn’t sand off that caused my problems. The original basecoat and lacquer on the car doesn’t react with anything you spray over the top of it. I presume it would be 2K. Maybe less reactive like epoxy primer for example? I’m still learning. This is my second attempt at re spraying my current car. I’ve sprayed cars in the past with no paint reactions at all. Only blooming because I painted under a sheet outside in the damp and disappearing paint once because I painted in a workshop with an extractor fan over me and it must have sucked the wet paint droplets off. Ha ha.
     
  15. the snooper

    the snooper getting older by the day

    Messages:
    20,350
    Location:
    Hull UK
    If you need to use it apply it, wait 1 hour then on wilth some primer without flattering, once the primer has dried you can then flat the primer, don't rub through and you're good to go
     
    Edward Yemm likes this.
  16. the snooper

    the snooper getting older by the day

    Messages:
    20,350
    Location:
    Hull UK
    I've used it when I didn't have time to strip back to bare metal, it's not usually needed if you're dealing with original paint
     
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