Saturday, October 19, 2013

Paint part III: Spraying clear coat

The last part of a paint job, if doing a basecoat/clearcoat system, is spraying the clear coat.  This is what separates the boys from the men, where the car comes out looking like a show car or a dud.  For the task, I used SPI's Universal Clear, a high solids show-caliber clear, and probably one of the best for the purpose one can get.

The clear should go on the base very soon, usually within 24 hr or whatever the tech sheet states.  Alternatively one could use an intercoat clear, which goes on over the basecoat, and then is scuffed when the clear coat is ready to be applied.  However, there is one secret even the paint reps won't tell you (they're actually instructed not to tell), and that is--as long as the car is not removed from the booth so the base is exposed to UV and contaminants--SOME bases can sit indefinitely before the clear goes on, but it all comes down to the polyall used in the base.  I really exploited this as my car sat in base for several weeks.  I'm writing this here for my own archival purposes...for anyone else, just pretend you didn't read that last part.   Thinking of using that cheap, economy line base coat?  Situations like this is where you'd run into problems.

I sprayed about a gallon and a quart kit of clear on the entire car, over 3 coats.  This came to 2.5 sprayed gallons.  I was using slow to medium activator for the clear, which is mixed 1:1.  I had ordered the slow as I was thinking I would be doing the clear in much warmer weather, however the slow is still ideal for most temp ranges.  If faced with two different speeds of an activator or reducer to use in the same job, always spray the fastest one first.  The temp when spraying was in the 60's, letting 30 minutes of flash between coats.

I used an LPH400 with silver cap to spray, gun settings were 28 psi, fluid backed out 2.25 turns, and fan about 90%.  I mixed up 1.5 quarts at time to spray (not all of it is poured into the gun at once) so I could spray almost continually without having to stop to fill up more.  The decklid was removed and set aside so I could clear the trunk jam; the decklid will be cleared later.  The headlight buckets had also been removed so I could get better coverage on them with base, and they will be cleared separately also.

The adage goes spray it how you want it to look.  Well I wanted the car to look really wet.  I was also afraid of dry spray so was more willing to push it to a run in order to assure it wasn't dry enough.  These are called 'flow meters.'  Well my flow was working very well, and I got some pretty horrific runs on the passenger's door right under the top C body line, which will be a devil to run out.  It was technique that created this run as I went over it too many times trying to get coverage.  I'll have to deal with these when the time comes.  I had runs in other places too, but every painter gets runs, in fact the pro's expect at least several.  They are a lot easier to fix than dry spray.  With that being said, I do have some areas that also went on dry, or that I almost missed altogether, such as front and center of the hood.  I may have to reclear the hood. 

One other thing...the car should be tacked off very well several times before spraying clear, but never after the first coat goes on.  Now onto the pics.

Friday, October 18, 2013

Paint part II: Painting LeMans stripes, aka 'racing' stripes

The second part of this painting process involved painting white LeMans stripes (commonly referred to as 'racing stripes.'  The stripes were painted with SPI white basecoat.

Measuring, taping, and masking off the stripes can be an epic task just in itself.  The stripes are not a uniform width all the way back, but tapered.  The Shelby LeMans stripes specs and dimensions can be found here.

My stripes ran from the lowest front point of the car completely over the top to the lowest rear point of the car, so valance to valance.

Essential tools are 3M fineline tape (creates super sharp edge), regular automotive grade masking tape, 1.5 inches, masking paper, and masking plastic.

The distance between the two stripes is 2 inches.  I cut strips of masking paper at the distances I need, and had a mark in the center.  I used the center mark to align with a center pointed marked on the car panel, and then put a mark at each end of the masking 'tape'.  I made my markings with a pencil.  I only made my marks at the very front and rear, or top and bottom, of the panel.  If the fineline tape is started so it starts at one mark, you can pull it in a tight straight line to line up with the second mark.  On most of the panels there is a 'landmark' on the panel that is located exactly in the center, such as the gas cap, or license plate bracket for instance, or maybe a little screw for the window moulding trim, to help find the center.  Care has to be taken in getting the fine line tape to adhere and stick tightly in tight corners.  If it lifts the paint will creep under.  Here's the thing: once the tape goes on the car, you should plan to finish the job and have it back off that same day.  Never leave tape sitting on fresh base for extended periods of time.

Once the stripes are taped off with fine line, I taped off the center with masking tape.  I also ran masking tape along the outer lines, and tape down 18 inch masking paper along the entire length of the lines on every panel.  Then, painters plastic was taped to near the outside edges of the masking paper.  Be sure to seal the grates of the cowl that are to remain body color well with tape.  Otherwise the paint overspray will go down through the cowl grates and come up under your masking.

The striped areas are tacked off well.  I first spray a light to medium coat of paint along the tape edges and let it sit for 20 min.  This builds a bridge at the tape edges and prevents solvent creep.  I then came back and sprayed 2-3 medium coats in the striped areas.  After letting the white flash for 1 hr after the final coat, the tape is carefully pulled off.  Slowly pull the tape off at a 45 degree angle away from the fresh tape.  It was at this point where I marveled at how amazing the car looks.

It is inevitable that the tape will lift in some tight corners and the stripe color will creep through...mine did in several places.  The fix for this is easy and fast.  It can easily be sanded away with wet 1500 grit sandpaper.  Just sand gently enough to scuff only the undesired paint away. This job took me a nonstop 12.5 hrs, from measuring and masking to pulling off the masking.

The stripes are first taped off with fine line tape.

The rest of the car is then masked off.

The valances are the hardest to mask off with all their contours, while the roof and hood are easy and fast.

The stripe color is sprayed.

30 minutes after the last coat of white, the masking and tape can be carefully removed.

The fine line tape leaves laser crisp edges.

There were several masking breaches where the white managed to go beyond its boundaries.  All these problems with breached white here were remedied by very carefully removing with 1500 wet.  This provided little to no disturbance of the base or metallic.

Thursday, October 17, 2013

Paint, part 1: painting base coat

I'm WAY behind in getting this updated, as the car sits in the shop FULLY painted now, and for such a major milestone I have not said a thing about it.  So while I sit in a Delta Sky Lounge--alone and bored on a Wednesday night--waiting for my flight to France, I still have my laptop and free wifi; what not a better thing to do than update my blog.

The base I'm using is ProSpray, I order it from Chad at AutoRod technologies and he's good to deal with.  He ships, so if he's not near you, no problem.  I have mine shipped in.  The color is Viper GTS Blue, of 97 Dodge Viper notoriety, paint code PBE.  It is a beautiful, transluscent blue with metallic that glistens, and when cleared you can look into it about a mile.  It is probably one of the most beautiful car colors you'll see, and for sure one of the most beautiful blues you'll come across.  Because it is transluscent, coverage and hide is very poor, I have 4-5 coats on this, maybe even six on some parts, by the time it was all said and done.  All in all, I sprayed nearly 7 quarts (14 sprayable quarts when reduced 1:1) at a cost of $89/quart.  I used SPI slow urethane reducer, and added SPI universal clear activator (slow) at 1 ounce per mixed quart.

Starting out spraying the base I had issues almost immediately.  My Finishline wasn't giving me a good pattern try as I might to adjust it in.  I was getting a lot of moisture through  my line even though I had a two-part filter: water/oil filter and dessicant.  I was getting fish eyes and actual water spots all over the car in the base...water spots that looked like hard water had actually dried on the primer and then was sprayed over with the blue.  And I was putting the base on way too heavy and ran it in several spots, which meant I had to sand those spots down, which they then turn white and become very difficult to cover.  Finally, I had bad tiger striping on all the horizontal surfaces.  I will address how I fixed each of these.

My Finishline problem was solved when a friend sent me his Iwata LPH400 with purple cap for metallics and silver cap for clear.  Only the purple cap was plugged up so I had to use the silver cap for both base and clear, which it still worked just fine for the metallic base.

To fix the moisture, I bought a DeVilbiss Desiccant snake, which I ended up not  being able to use as it cut down my pressure too much.  I also put a 20' length of coiled 1/2" copper tubing between my compressor and air filters to help cool the air  before entering the booth.  And my desiccant was far too small of an amount to be efficient for the entire car, so I had to constantly be changing it out and drying it in a toaster oven at 250 degrees F until it turned blue again.  I had recharged desiccant going while I was drying the 'used' desiccant.

To remedy the water spots, I wet sanded the entire car with 1500, then sprayed another 2-3 coats over the entire car.

I had some crunchy base right in the middle of the roof where I didn't reach in good enough and fixed this with 1500 wet as well.  The base should go on medium wet--not so wet that it runs or dries shiny, but also not so dry that it looks dry or is crunchy.  However, even crunchy base will still look as good as everything else under clear.  If I was ever unsure about the base consistency, I sprayed it until it was real wet with SOLVENT based wax and grease remover; this simulates clear coat almost perfectly.  If it looks good with this, it will look great with clear.  Then immediately wipe the wax and grease remover off.

TO FIX TIGER STRIPES--and this is an amazing fix--I sprayed a medium wet coat in a direction perpendicular or at an angle to the existing striping.  Immediately after spraying the panel, WHILE THE BASE IS STILL WET, I increased the pressure 5 psi, held the gun 12 inches from the panel and sprayed a fast drop coat over the entire panel in one direction, then sprayed a second drop coat over the panel in a different direction.  It is important to do this while the base is still wet so the drop coat can melt into it.  Otherwise, the drop coat will go on dry and will not adhere, which means your clear will not adhere and might peel off in sheets.  Do this and the stripes will be GONE.  Don't worry if it looks dull and not shiny, that's what the clear is for!  Ideally the car should look satin.

I sprayed the car at ~ 25 psi, 90% fan, with the fluid 2.5 to 2.75 turns open, holding gun at 5-6 inches, with the Iwata LPH400 and silver cap.

Here's an example of what bad tiger stripes would look like.

Some paint dripped from the lid of my gun and fell onto the surface of the hood.  I learned you should not try to wipe it away or this happens.  This made a little crater.  Instead, let it dry, wet sand down with 600, then spray over the area again.

quarter panel in base

This is the car sitting in its final base.  You can see how effectively the hood was remedied just by another medium coat and some drop coats.