Question Regarding Duplicpolor on Planes

[HomerLee]

Dupli-color DE1635 seems to be highly favored for replacing japanning. When you use it do you use a primer first? I noticed the instructions on the can say to use a Dupli-color primer while on the DE 1634 low gloss enamel the instructions do not mention using any primer. Called Dupli-color tech help and was told no primer should be fine as long as the metal was cleaned up well and sanded. I would not sand an old plane to paint.
So what works for you?

Thanks

[JR1]

I used NAPA high temp engine enamel. I had derusted with acetic acid and did not scuff sand which they recommended.

[enjuneer]

On any plane that I repaint, all of the old japanning is removed by sandblasting with a medium aluminum oxide grit. This also roughened the surface to improve adhesion.

I wash down the plane with Brakleen and let it dry before masking off the areas that are not to be painted. Threaded holes are cleaned with a cotton swab and plugged with a bit of paper towel.

For the actual painting process:

1) Spray on one very light coat of gloss black (DE1613) and let dry for 15 minutes.
2) Spray on a heavier coat of gloss black, letting it "puddle" somewhat on horizontal surfaces. Let dry for 20-30 minutes.
3) Spray on a light coat of semi-gloss black (DE1635) and let dry for two hours. Carefully remove the masking tape.
4) Let dry for two days in a warm room before reassembling.

I have found that the gloss black builds thickness more quickly than the semi-gloss black. It levels the surface and helps it to look like real japanning. The initial light coat acts sort of as a primer, allowing the next coat to be applied heavy.

Here is a picture of the final product. One plane has been painted with the technique I just described, while the other is an untouched original. Can you tell which is which?

[HomerLee]

Hi Bob,

So you haven't found primer necessary. I have not tried it but would think Ospho would do well instead of primer.

Anyway, got a can of primer and I'll give it a try.

I'm guessing the one you painted is on the left.

[Snipe Hunter]

Duplicolor is typically used for "spot repairs". You can't really extend the primer to the edge of the spot repair or the repair would look bad. Most "repair" paints like this have adhesion promoters (glue) and etching acid in them. Some of the things that primers have. The acid etches the surface and the adhesion promoter glues it down. So theoretically, you don't really need primer to make it stick. Make sure everything is real clean. If you use any solvents, make sure you wash off the residue with mild soap and water. I like a little yellow ammonia in the water but it also needs to be rinsed off. Then rinse with clean water and dry it quickly. An air hose makes short order of drying out the threaded bosses.

[eg54string]

Nice work.

[Tony Z]

I've use Duplicolor with excellent results and I do use the primer. I completely strip off all old color/Japanning, thoroughly clean/dry and then prime. After sufficient drying time, I coat and top coat exactly per instructions on the can, observing drying between coats and curing.

The results have always been top notch, when instructions are followed. I do not do the edges of the sole and completely disassemble the plane, masking off areas, such a frog bottoms, holes, frog mating areas, etc. When completely cured, I clean off with a fine grit paper any overspray that may have gotten on the edges of the sole. Also, do all flattening of the sole, squaring of the sides before applying the Duplicolor. Results look like a brand new plane 9 times out of 10, of the $5.00 flea market pick-up!