Collision Blast

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Stripping Paint Down To The Metal

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In this article I am going to post a few videos demonstrating the different ways to strip a car to metal.  I am often asked if it is necessary to strip the paint finish to metal when performing a complete paint job.  Or, they feel stripping the paint to the metal will produce a higher quality result.    However, if the paint on the vehicle is in good condition, it is not necessary to strip the paint off.  In fact, it’s better to leave the original finish and e-coat that was applied at the factory.  If that is the case,  all that is needed is proper cleaning and final sanding and you’re ready to paint.

What if the paint is not is good condition? Well, that is when stripping comes in.  Some of the paint defects that may require stripping are: peeling, rust, checking, cracking, paint too thick, etc.   If one of these paint defects are present, it may be necessary to partial strip or strip to metal.  I know of three ways to strip: media blasting, chemical strippers, and sanding.  Well, if the paint is not adhering well you can also blow, pressure wash or scrape the paint off.   Below I fond a few videos on YouTube demonstrating  a few of stripping techniques.

[youtube]http://www.youtube.com/watch?v=nB318hvRHZQ[/youtube]

Media Blasting

[youtube]http://www.youtube.com/watch?v=jwwZAZi2N1c[/youtube]

Chemical Stripping

The third way is to use a Dual Action sander and sand the paint off with course grit sandpaper followed by a finer grit sandpaper.  If you only have one or two panels to strip, I believe that this is the easiest method to use.  Most shops do not have a media blaster and chemicals are messy.  However, if you are doing a restoration job that there is evidence of rust, I would recommend the media blasting.  You may have to sublet that out to a company that is know for doing good work.


How To Apply 3M Finish Glaze – Collision Repair Training

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This video demonstrates how to apply the new 3M and how to sand the glaze. Once sanded and featheredged, you’re ready to mask and prime with epoxy primer.

HOW TO APPLY TRADITIONAL FINISH GLAZE

In this video a BCC student demonstrates how to use traditional glaze.

Benefits Of Using Finish Glaze

  • Can be applied over sanded body filler, sanded primer, or sanded paint.  I would recommend to sand with a no finer grit than 180 to assure proper adhesion.  Glaze will not stick to non-sanded substrates.
  • Spreads smooth and sands easy.
  • Can be applied over small dings and dents without removing factory e-coat corrosion coatings.
  • Minimal Shrinkage

Disadvantages Of Using Finish Glaze

  • Costs more than body filler.
  • Can not be applied as thick as body filler.

STEP BY STEP PROCEDURE

The body filler has been block sanded and finished in 80 grit sandpaper.  Now you are ready to feather edge and apply glaze.

  1. Feather the paint edges around the repair area with 220 grit sandpaper on a DA.  Sand each layer of coating to expose at least 1/4″ of each coating.
  2. Blow repair area with compressed area to remove all dust.
  3. Apply (either type 3M or traditional) glaze from paint edge to paint edge.  (slightly overlap onto the sanded painted surface.)
  4. Allow to fully dry and block sand with 80 grit sandpaper. (just knock the highs down…do not sand on the painted surface to eliminate 80 grit scratches on paint surface.)
  5. Apply guide coat to help identify highs and lows.
  6. Block sand glaze and finish shaping with 150 grit sandpaper.

That is it!  Now you’re ready for primer and paint.  We’ll hit that in another lesson!


BCC Student Demonstrates Block Sanding Primer

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In this video we are demonstrating how to block sand primer surfacer.

1. Apply guide coat to the surface.

2. Using a block and 320 grit sandpaper, cross sand the surface.

3. Sand the surface until all guide coat is sanded off. If you sand through the primer surfacer and the epoxy, you will need to re-prime and block.

4. I all guide coat is sanded off and no filler or metal is showing, then you are ready to unmask.

5. Using a smaller block, sand the harder to get areas and all edges.

6. Using a DA, inter surfacer pad, and 500 grit sandpaper, sand over the surface where sealer and paint will be applied.

Now you’re ready for final prep and masking for paint.

3M Dynamic Mixing System Review – Finishing Glaze

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Mixing and Waste
I recently used the finishing glaze that 3M has for their new Dynamic Mixing System and was well pleased. The product mixed instantly as it exited the tip. I purged the glaze, but all product fully hardened on the paper towel. I concluded that a technician could use this product with minimal waste. The product mixes instantly, which will require minimal purging and you can apply only the amount of glaze you need to the surface that you are working on. Therefore, I found the mixing capabilities to be excellent and wasted product to be minimal.

Spreading
The glaze was easy to spread and produced a pinhole free layer of glaze.

Drying
The 3M glaze tended to heat up faster and dry quicker than other glazes that I have used. Works great and will increase repair time. However, do not try to over work the glaze. Apply the glaze with a tight coat followed with looser pass while leveling the glaze. If you move too slow or try to over work the glaze, it will start to harden and cause problems

Sanding
After allowed the glaze to fully dry I knocked the highs lightly with 80 grit sandpaper. Then I guide coated the glaze and finished it out with 150 grit sandpaper. The glazed sanded easy and produce a defect free surface that was ready for primer.

Satisfaction
I am satisfied with the 3M finish Glaze and would recommend it to others. If you do not use the product daily or weekly, the cost of the application gun may not be worth your investment. Therefore, this is an excellent system for a body shop, but not for the DIY enthusiast that only uses fillers once or twice per year.