3rd August 2008

How To Respray A Car - Part Six - Using A Guide Coat

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Although this step is not absolutely necessary, it is certainly a good idea if you want to achieve a really good result. Also I wouldn’t recommend doing this with ordinary primer/surfacer as it is usually not thick enough to rub back.

The first step is to grab yourself a pressure-pack can or tin of black acrylic if you don’t mind using the spray gun again. Usually a decent sized pressure pack can will be sufficient for most cars, just be sure it is acrylic not enamel as enamel will react with the top coat acrylic if there is even the smallest trace of it on the panel.

The next step is to spray a light coat across your panels. Read the instructions and allow enough drying time before sanding.

For the next step I use 800-1000 grit wet and dry paper used wet and with a sanding block. Once again you want to follow the lines of the panel and keep plenty of water on the surface. As you can see (hopefully!) from the pictures some of the repairs that we did are far from perfect and although the door looked good these imperfections would have showed up after the top coat was on. Hence the reason to use a guide coat!

 The beauty of high-fill primer is that 99 percent of the time you can sand out these imperfections without the need for more filler or reaching the bare surface below. Be extra careful at the edges of the panels as it is easy to sand through the primer there and as with the speed file, don’t be tempted just to sand one little area to get rid of all the guidecoat, keep the sanding block moving across a large area until all the guide coat is gone. If you do happen to sand through the primer it is simple a matter of applying some more primer and a guidecoat to the area and sanding again.

Once you think you have sanded the entire panel wash it down with clean water and check for any remaining guide coat, re-do any problem areas and finally either dry the panel with compressed air or leave it out in the sun for an hour or two. 

An important note regarding primer - 99 percent of primer/surfacers, spray putties etc are porous meaning that they will absorb moisture. The amount of time between applying the primer and the top coat should be as little as possible and once the wet sanding is finished be sure to dry the panel down as much as possible. Any moisture trapped in the primer has the ability to ruin our nice new paint job. Not good!

Part Seven is finally done - Click Here

This entry was posted on Sunday, August 3rd, 2008 at 6:07 pm and is filed under Car Repainting, DIY Tutorials. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

There are currently 7 responses to “How To Respray A Car - Part Six - Using A Guide Coat”

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  1. 1 On August 8th, 2008, Leigh said:

    Fantastic so far!

  2. 2 On September 10th, 2008, Steve said:

    No rush but i am just wondering how long until you think Part Seven will be posted? Are you going with a metallic paint and clear cloat? What is written on the handle on your spray gun? most of the guns on ebay seem to be HVLP. Been great reading as its hard to find information explaining the entire job. Thankyou for sharing. Also do you recommend a certain temperature range in which you do all the body filling and painting etc? So that it dries correctly.

  3. 3 On September 10th, 2008, craig said:

    Hi Steve,
    I’m slack I know! I’ve been having a lot of trouble with my back, got a couple of buggered discs from bending over bonnets for ten years and am having trouble getting to the spray painting tutorial. If you can hang out a bit longer I’ll get on to it as soon as I can.
    Yes, I will be using a metallic paint on the Commodore with a couple of coats of clear over the top.
    The letters HVLP on the spray guns refer to High Volume, Low Pressure which is exactly what you need for spraying acrylic and/or 2 pack enamel’s.
    As for the temperature range, acrylic paint and body filler is fairly forgiving in this area however I would try and avoid extremes - anything under 10 degrees or over about 25 or so should be avoided in my opinion. Also if there is any moisture in the air don’t paint, pick a day that is nice and sunny to avoid getting any moisture blisters under the paint surface.
    I hope this has helped you and I’ll send you an email when I get the rest of the tutorial done if you like.

  4. 4 On November 4th, 2008, Josh said:

    Awesome information so far. Any idea when we will see the finish (or should I say, when your back recovers)?

  5. 5 On November 4th, 2008, craig said:

    Hey Josh,
    My recovery is taking a lot longer than expected and to be honest I’m not sure when I’ll be able to finish the tutorial. My apologies, believe me I am going nuts sitting around and can’t wait to get back into it(pardon the pun).

    I’ll let you know the minute I get the next instalment done.

    Thanks for your patience.
    Craig

  6. 6 On November 23rd, 2008, bones said:

    Absolutely brilliant DIY, as I am slowly,(also due to a re-accuring back problem),restoring an EJ Holden that needs to be taken back to bare metal.
    It has been a great help in pointing me in the right direction. I know how the back feels, but am eagerly waiting for part seven and beyond.

  7. 7 On November 23rd, 2008, craig said:

    Thanks for your support! I’ve made a promise to stop feeling sorry for myself and get on with things so expect Part 7 to be posted Tuesday this week, Wednesday at the latest. I’ve just got to get some photos organised from this weekend and do the write up.
    I’ll send you an email when it’s up if you like.

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