What is Guide Coat?

Guide Coat is necessary when doing bodywork.

When you’re looking at that jet black classic car at your local cruise in you may take for granted all of the steps it took to get the car looking laser straight and the finish so “deep” looking. A necessary step in doing bodywork and getting the body of your project straight is to use guide coat. Read on as we give you some insight on why you need guide coat when repainting or restoring a your car or truck.

The process for straight bodywork starts from the metal up but imperfections can be corrected during the body filler and primer stages. By using guide coat you can check your progress along the way and save yourself some surprises when the vehicle is painted and done. The process of guide coat is fairly simple. Typically you do your body filler and seal the repairs with gray primer. From there you can apply a contrasting color guide coat (usually black over gray primer or tan guide coat over black primer). The guide coat is misted onto the surface leaving a spotty looking finish.

After the guide coat dries you can take a long block sander and sand the panel in an “X” pattern; paying attention to how the guide coat comes off the panel. You will notice that 99% of the guide coat will come off with the first round of sanding. If there are any major lows the guide coat will settle in those areas and remain after block sanding. Occasionally you can block sand the entire panel to knock the surface down level with the low spot, but most times you need to fill that area with a small swipe of body filler, glazing putty or high build primer. After you’ve filled that area you can again apply a mist of guide coat and block sand. Once the entire panel is free of guide coat you’re sure the panel is nice and straight and will look perfect once painted.

Guide coat comes in a few forms with the most common being in an aerosol form which you spray on lightly. The second most common is a dry guide coat in which you brush onto the panel with an applicator. This style can be sanded almost instantly but does take longer to apply to larger areas.

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