Thought I would share some more of my experiences in powder coating. I have been scouring the house and shop for anything metal not too heavily bolted down and powder coating it. This time I grabbed a Penn Model 111 2/0 senator that was lying around that had some severe corrosion on the chrome parts. The 111 is a classic reel for west coast USA salmon trolling.
The plan was to experiment with a fancier multi-coat, muti-color scheme of Lollypop red over light chrome. This is a more difficult paint scheme as the translucent red will show defects more readily.
I made it at Techshop: http://www.techshshop.ws
Step 1: Prep
Step 2. Outgas bake at 400 degrees for 30 minutes. May not have been necessary. I assumed that some corrosion-x or other oils meant to minimize the chrome damage may have leached into the brass. After parts cooled, I washed with simple green and air blasted dry.
Step 2: First Coat
Apply the “light chrome” (chrome colored paint) coat. I got lazy and did not use sillicone plugs to mask the threaded holes, figuring I could tap them out later, plus I needed at least one screw in each of the reel posts to attach a hanging wire.
The chrome coat came out quite well. There were a few cosmetic imperfections, but not many, and I wasn’t particularly careful in my prep work. It looked like highly polished silver anodized aluminum.
Step 3: Second Coat
Note the high-heat tape applies to the spindle (shaft). Powder coating does not come off easily!
Step 4: Assemble
The second coat made the coating fairly thick, but the spool still cleared the rings until the reel was assembled, now a slight scraping. It needed a little of strategic sanding on the spool and rings, but not through the paint, and not in any visible location.
Step 5: Observations
1. Paint selection.
There are UV resistant and Salt spray ratings in the specs, and it can vary by color. The highest salt spray rating I have seen is 3000 hours, but there are powders out there that are advertised as Marine grade with a 1000 hour rating. Most “chrome” colors need a secondary protective coat, which can be a clear. Urethane and Polyurethane powders are probably the best bet.
2. Number of coats.
Powder goes on relatively thick, around .004-.006 inches per coat. If you take the original chrome off and add a single coat, you are plenty close enough for redoing typical chromed reel parts. As you add coats, there is more of a risk to have to go in and do a bit of strategic sanding to get a snug fit on the screwed together parts and clearance for moving parts.
Getting the first coat to stick and cover easily is not a problem, but as you add coats, the quality of the sprayer (need a pro gun with 50 KV or more) and the skill level of the operator needs to go up.
3. Dealing with threads
Once baked on, the paint is very tough. Any threads that have been painted will have to be retapped, or the entire part needs to be stripped so you can try again.
Hi temp silicone plugs are a good choice for protecting threaded holes.
4. Considerations regarding heat
Since the process requires heat, any risks associated with exposing the part to heat must be considered- here are a couple:
Typical powder coating baking temp is 350-400 degrees and the time is 10-15 minutes AFTER the part has come fully up to temp. This means that any grease or oil that has leached into the metal will leach back out. Cast metals would be the worst for this, as they are the most porous. This can be rectified by pre-baking to “outgas”, but this adds to the time and cost of the procedure.
If the part has any pressed in bushing that are oil impregnated, I would check to see if the temps applied would affect the longevity of the bushing.
As noted before, it would probably be wise to choose a powder that was rated for UV and at least 1000 hours salt spray.
The powder coat itself is extremely durable. It has tremendous adhesion. It cannot be easily sandblasted off (more than I can say for the original chrome plating). And while very hard for paint, it is still paint, and will not be as hard as anodized Aluminum or chrome plating, so scratching from sharp metal objects (e.g. hooks) could be an issue. I would not expect corrosion to be a big problem unless the scratch was deep enough to get all of the way through the paint. Urethane and polyurethane powder coats can be affected by a few strong solvents such as acetone, although it takes aircraft paint stripper or benzyl alcohol to fully remove the paint.
The colors, esp multi-layer combos are pretty breathtaking. The photos of the 2/0 senator do not do it justice. It really looks like a lollypop coating. There are also texture choices, and pseudo-anodized looks.
Powder coating is pretty much a one shot deal It generally cannot be touched up like liquid paints. This is one reason why cars are not powder coated. The old coating has to be removed with special solvents, and the paint reapplied from scratch, This means no fixing scratches and living with any imperfections baked in during original coating (accept it as part of the powder coat aesthetic). When working with fresh stock metal, this has been less of an issue than rehabilitating older parts. A dedicated powder shop with clean paint areas should be able to do a better job than me. Getting a smooth surface texture is not too much of a problem, esp on smaller parts like reel frames and spools.