Barcoat overspray and high build question

  1. ross_m Member

    Posts: 54
    Scotland
    I sprayed my car with barcoat and I have overspray in places which has become quite rough. Your not supposed to flat the barcoat or touch it at all before priming over it so what should i do? Can i lightly sand the overspray off being careful not to sand through the barcoat, then use tack rags, or am i ok to just spray barcoat over the top straight away?

    How long after the first coat of high build primer can i spray a second coat roughly? I mean is it when its touch dry? Id rather flat in between coats but Im just wanting to make sure I get enough on so I dont sand through as its tight for space in my garage and can miss bits. I wont need any more than 2 coats as i did a lot of prep before barcoat anyway

    Thanks
  2. tux Member

    If it were me I would just go straight to high build and hit it with a couple of decent coats then block sand that, assuming the Barcoat doesn't look like the north face of the Eiger!.
    You should be fine to go on with another coat of Barcoat if you wish, after a light sand.
    You can re-coat high build as soon as it is touch dry or even go wet on wet while the first coat is still slightly "tacky".
  3. ross_m Member

    Posts: 54
    Scotland
    Well I have already went stright onto high build as I couldnt wait any longer for a reply:laughing:so that gives me piece of mind. I gave it 2 or 3 coats on the roof so i can flat it and if I flat through to the barcoat by mistake I can always give it a fresh coat of high build.

    Also tried the two methods for spraying high build you mentioned and it went well.

    cheers for the help.
  4. ross_m Member

    Posts: 54
    Scotland
    Ok so I sanded the high build down lightly and it has gone through ever so slightly to the barcoat. Does it really matter? Can i just spray top coat over it or will it have to be completely covered by high build primer before top coat? cheers
  5. the snooper

    the snooper old school demolished

    Posts: 8,144
    EARTH UK
    if your bar coat was really rough i would have flatted that area and give that area another coat.
    if you have rubbed through the primer to the bar coat but not throught the barcoat you should be ok just re-prime
  6. ross_m Member

    Posts: 54
    Scotland
    Thanks for the reply. It flatted ok but in one place it has gone through slightly. So I HAVE to re-prime or can I go straight to colour? The only reason not to go straight to colour that I can see is because it might change the colour of the top coat slightly as its covering yellow and not grey. Or can doing this cause a reaction? Wouldnt have thought so as top coat is just celly like the primer....
  7. the snooper

    the snooper old school demolished

    Posts: 8,144
    EARTH UK
    just give a coat of primer then your top coat
  8. MG David Member

    Posts: 300
    Warwick UK
    Having used barcoat about 10 years ago and still having the car there are a few comments I would make.

    Only use it for the purpose it is intended for. That is as a barrier coat over old paint that might otherwise cause problems for the new paint. A paint factor I no longer use suggested I use it on bare metal as well. What I have found is that its adhesion to bare metal is poor. (When I pull my competition numbers off the door paint comes off as well).

    For a few years now I have used U-Pol Acid 8 on bare metal and can't fault it.

    As for sanding barcoat I see no problem with sanding overspray off. The important thing is not to get water on it as barcoat absorbs water. You should check the data sheet, but I think it should only go on as a thin coat.
  9. ross_m Member

    Posts: 54
    Scotland
    Cheers for the reply. Yeah Im using it as an intermediate layer between acrylic and celly. High build has been on for 2 weeks and no sign of reactions which was what I was worried about.

    Going back to the original question, I have ran out of high build so cant give some panels another coat of high build to cover the barcoat thats showing through. And I mean its hardly showing through. You can just see it in a few places.... Is there any reason why I shouldnt go straight to top coat or can I get away with it?

    Thanks again
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