Applying Poly-Tone on Metal Parts
There's as many methods out there for good paint jobs as there are builders. I don't suggest my method is better but thought I'd offer up some detail in our forum for others to consider. Mitch has helped me through this process and I'm very happy with results. Time will tell of course, how good a job it is but early signs point to this being a coat that will last. Here's the process I followed:
Applying Poly Tone to Metal/Aluminum parts
1) Clean the part very well using MEK or denatured alcohol (only use the MEK if the metal is really dirty or greasy). If you don’t clean before scuffing, you’re actually forcing some of the impurities into the surface of the metal.
2) Right after cleaning, scuff entire surface including edges using an Ultrafine Scotch-Brite pad. Don’t overdo it. In fact use a worn pad, it will get the job done just fine. You do not want to be able to feel the scuffing but it should be visible.
3) Wipe with a clean dry cotton rag. Now I clean it once more with an aerosol product that I found at a local automotive paint shop. HighTeck has a product called Wipeout Surface Prep 7800. You spray this on and immediately wipe off with a clean rag. It evaporates quickly but if you hit it right away it leaves the surface very clean. (MEK tends to leave a residue that can impact adhesion).
4) For priiming I went with one of the primers that the boys in the plant are using. Sherwin Williams GBP 988 Self Etching Primer. (grey). It's possibly that this self etching primer is good enough to skip the scuffing but I wanted to give it a good chance to adheare.
5) Once the primer is fully dry I scuffed again. This removed any dust specs and helped again with some tooth adhesion. Clean the surface again with a new clean rag. Wipe it until there’s no grey residue on your rag. If some spots come bare while scuffing I touched up with more 988.
6) Now it’s time for BullDog Adhesion Promoter. Follow the instructions and you’ll be fine, but basically I was spraying on a wet coat and waiting 3 or 4 minutes. Then a second coat and waiting 5 to 7 minutes before I applied my primer.
7) Now I move on to my finish coats. I went with 2 coats of Poly-Tone #105 Insignia White. You could probably get away with one heavy but I prefer a light first coat then hit it again 20 minutes later. Poly Fiber recommends this white base coat under yellow and I agree that the white necessary and will produce a brighter finish. It covers the Poly-Spray silver very well. You’ll use a lot more Yellow if you try to cover the silver directly and could get some discoloration if the coverage is not consistent.
8) After consulting with Poly Fiber I decided to go straight to Cub yellow on the same day. It doesn’t hurt to wait at least 2 hours but Hualdo at Poly Fiber said it was fine to go right ahead with yellow after the white reaches tack. The book recommends 2 hours but any time after tacky stage is fine. Clean your gun between white and yellow coats.
9) Before you start your final coats (white base and yellow final) you should have all your paint and reducer out and ready and final paint shaken ready for reducing.
10) Remember to chill your paint (yes, in your fridge next to the milk) overnight before using. If you take it out of your hot trunk or garage the paint will set up too quick and you’ll minimize the small amount of gloss you can get out of Poly Tone.
11) Control the temps in your paint booth or only paint on days when the temp is between 60 and 75.
12) Check every finish coat (including white base coat) for dust or impurities in the finish and give it a light scuff if necessary. Scuff with used 320 Grit
13) For your last, final coat, turn your nozzle so the fan is horizontal. Then apply the paint by “pushing” this coat (moving forward) and moving your gun vertically on the piece, at a slight angle, shooting the paint forward. This minimizes the amount of overspray on the area you’re leaving behind and you’ll see the gloss appear immediately behind your work. I used this technique only on the final pass of the final color. It gave me just the amount of gloss that I was looking for.
14) If you’re looking for the classic Cub look, Poly Tone #143 Cub Yellow is the way to go! Just be sure that’s the tone you’re looking for as it’s a very orange yellow.
Applying Poly Tone to Carbon Fiber and other Composite parts
I followed the same procedure as described above for applying Poly Tone on Aluminum with one exception.
Point #2) use 320 or 400 grit sandpaper to scuff the surface rather than Scotchbrite pads. Don’t overdo it as you’re taking some of the surface off so you just want to have a light dusting coming off as you’re sanding the surface. Then proceed and clean it thoroughly and follow all other steps described above. Note – in some cases I just used clean water or Windex and rags to clean these parts right after scuffing rather than the Wipeout Surface Prep.
Hope this can be a help.
Paul
Reply With Quote
Originally Posted by terry
