RESOURCES

Spot Painting … Melting-in the paint edges.
By Carl Brunson
 
 
 
      Back in the late 60’s when I was learning to paint cars, we used acrylic lacquer and regular, not acrylic enamel … oh yeah, I can almost hear you guys thinking: Oh great, Old Carl is on another nostalgia kick and he is going to rant on about “way back when” again.  Well, yes and no.  Thinking about blending paint takes me back to the good ‘ol lacquer days when I did it every day… several times a day.
     Acrylic lacquer can be melted into old acrylic lacquer making a perfect repair.  The rule was that you could paint enamel over lacquer, but you couldn’t put lacquer over enamel because it wouldn’t melt in, or in the case of a repainted car, lift and wrinkle the enamel.  Because only GM cars came from the factory with acrylic lacquer … the lacquer over enamel rule was basically ignored.  We painters learned how to wet the edge of the lacquer to the point it needed little or no polishing and would bite enough into the panel without peeling because we rubbed the blend area with rubbing compound.  That gave the lacquer compound scratches to bite into.
     Not only can lacquer be painted out in the shop, it is a many times faster paint repair than enamel.  For painters being paid on commission, the faster the work got done, the larger your paycheck was.  For several years I worked in a shop that did the warranty work for a Ford Dealership.  At least 80% of that warranty work was done with lacquer.  There were countless non-GM cars running around with my “break the rules” lacquer spot jobs on them.
     So, in the early 80’s when the urethane base/coat clear/coat paint systems were being introduced and they told me I couldn’t wet the edges of the clear down.  That I had to paint complete panels … did I listen?  Nope!  I did make quite a few messes before I figured out what slow reducers would make a slick looking clear blend on a sail panel so I didn’t have to get into clearing the roof along with the quarter panel.  Sikkens paint came out with a solvent called SRA that you sprayed on the blend area before painting, that softened the old paint and then you sprayed the clear edge with SRA again and the clear edge just disappeared.  These days every paint company has a blending solvent.  Some blenders even come in rattle cans now!
     So, I bet you are wondering why the “wet the edge down” repairs are not as popular as complete panel painting if it works well.  Several things come into play here.  The major one being that the wet down edge of the clear or single stage color is very thin and doesn’t seem to hold up as well to the sun and everyday use.  The other thing I can think of is that it is a spooky thing to do for the painter.  The blending solvents are a very slow reducer and just a little bit too much or if the day is just a little cool … that clear edge you are trying to melt into the old paint can curdle up or turn into a big run that will cause you to have to redo the job.  Sometimes it is a lot smarter to take the time to paint a larger area than to take the chance of having to redo a job.

Except for the doors, hood and deck lid, Cobras are a one-piece body with no place to make a tape line to stop painting.  They are pretty much a pain to do paint repairs on.  Unless you want to clear the whole body, the paint must be finished with a melted blend edge somewhere.  Just painting one fender or quarter panel is a major pain on a Cobra because there is just no good place to wet the paint edge down.

When making this repair I chose to do the whole front end and make the blend behind the side pipes.  It is a lot of work to take a Cobra apart, but it made a quality repair for my customer.  The way I prep my blend area has changed from the days when I used to just rub the area with compound.  There are many brands of sanding pastes to prep for painting.  The one I use is from Presta and called Scuff Stuff.  I just use a wet rag and use the paste to dull the blend area.  A light polish with a foam pad will gloss the dull area that isn’t cleared pretty fast.  I don’t polish on the blend if I can help it.

When Ray Scarlata decided to switch from a 4-bar front suspension to a hairpin style, it left a spot where the 4-bar bracket hole was welded up and more messed up paint where the hairpin bracket was welded on.  Ray’s ‘32 coupe is painted with non-clear/coat urethane enamel.  The frame has been powder-coated black and just the top and outside of the frame rails were painted body color.  The underside of the frame was a snap to get black again, but I don’t want to take the car apart to paint the entire frame rail Washington Blue, so I am going to do a spot repair on the frame sides by melting the paint edges down

 Ok … the damaged areas have been smoothed, primed and block-sanded with 320-grit.  A light, black guide-coat is dusted on the primer so I don’t miss any 320 scratches when I sand again with P600-grit.  I am going to use DuPont’s version of blender.  DuPont’s instructions are simple enough.  Do your paint work and mix the blender 1 to 1 with the mixed paint for the last coat of urethane color or clear coat … stepping the paint/blender cocktail beyond the color or clear you have sprayed on.  Then with a clean spray gun, spray only the blender on the edges to melt them in.  I go one step more than the directions.  Because of my success with the early Sikkens SRA blender I wet the area where I am going to make my blend before I spray any color to soften it.  I think this step makes my blends just a bit better.  Sikkens has re-introduced SRA as SRA Agent.  Just a guess, but I bet the old SRA wasn’t EPA friendly.

Now, after I have sanded with 600, dulled the blend area with Scuff Stuff and cleaned the frame with grease and wax remover, it is time to finish masking.  What I am doing is called reverse taping.  I have laid wide tape on top of the frame rail at the roll down break and pressed it down with the flat of my finger so I can see the edge of the frame rail through the tape.  See the darker line in the tape?

Next I roll the tape back till only the edge of the frame is exposed and tack it back with tabs of tape.  Taping like this gives a soft paint edge of paint instead of the tape line you would get if you just taped the normal way on the frame’s edge

Now the color is on and I am going to make the blender/paint cocktail to wet the paint down.  Before I spray the cocktail and the pure blender coats … I roll that reverse tape edge back a little more so that soft edge of paint is melted down at the same time as my paint edges on the sides.  Reverse taping will let you use almost any body line for a place to stop painting.
 

The paint is now wet down and the edges are melted in.
 

Just a light polish to take the new paint shine off of the repair.  The last thing any guy wants is to have one area of his car looking like it just got painted.
 

Now that I have the hood and grille shell back on the car it looks like a deuce coupe that always had hairpins on the front suspension.  I firmly believe that if you can see where a paint repair has been done on any car … it is a bad repair.
Now, I am going to remind you that a blend that has been melted in is a weaker repair than making the paint repair by painting entire panels.  That is the bad news.  The good news is, this kind of paint repair might only last two or three years in the sun and with the regular abuse a paint job takes.  However, it may last decades the way most car guys take care of their babies