I just tried my first finish. I used the instructions included in my palmetto order. It came out splotted. I bead blasted and didn’t clean prior to dipping. Temperature was 190. Palmetto’s instructions were different than what was in this thread. When the finish was bad I searched and found this forum. Is it splotchy because it wasn’t clean? Do I need to re-blast and start over? Have you seen this before?
Hi gimmea250swb. I use the Palmetto system as well with both zinc & manganese. I also use a bit of a different process, but it is close to the same and generally get a great result unless of course the parts are not properly prepared or get contaminated.
Regarding the splotchiness, it is contamination. Contamination can be from various things, but the key is to make sure that you're blasting is very thorough, and that your blasting is the same consistent color all over. If there is any variation on your part before phosphating it will be the same after.
As has been pointed out, some previous coating that you may not be aware of, like zinc plating, anodizing, cad etc are often difficult to remove. Also residual petroleum products etc.
For my process I I start by washing the part in soap and water if there is no grease or rust.
If there is grease or oil I use the parts washer first. Then I go right to the dry media blaster.
From the media blaster depending on the part I may vapour blast the part if I want a shinier finish like on some fasteners and other parts. Then I submerge the parts depending on size i various containers and build to between 190-200 degrees.
Then I usually put the parts in small metal baskets with hooks on them if the parts are small. For bigger parts like hood springs I just drop them right in the container. I leave the parts in for 10-15 minutes max.
Then I rinse with water, then blow dry with compressed air and then spray directly with Boeshield and let dry. I generally don't wipe down the parts and just let the boesheild dry fully overnight or for 24 hours approx.
I may try adding the oil step just before Boeshield to see if it yields a darker finish.
FYI I just did some hood spring tonight that were previously cad plated and they did not take well. So I blasted them a second time and they still did not take well. The good news is I can see the areas that didn't take well and know which areas still need to be blasted longer. Hopefully another thorough blast will yield a good result. I didnt see this article until after I left my shop but will post a photo tomorrow. Take a close look at the photos I posted of the hood springs and you can see the difference in color. Even this subtle difference makes a big difference in the final result.
Here are some parts I have done using my method. Like other have said it is quick and simple and yields a great result as a rule. Note that the Axel studs were previously zinc platted and turned out fine with proper blasting time.
FYI I also recently tried to phosphate some shackles that were stainless steel and they don't take at all as the meal is not phosphorous.
Good luck with that stubborn part.
