Powder Coating Small Steel Parts

[@thomasdoyle4485]

I worked in the Box Anneal in a major steel manufacturer, and when the steel turned blue it meant oxygen was in the annealing chamber. we used temperatures much higher than 450 F, however all the steel was in a sealed chamber and oxygen was vaccumed out, so it was an indication of a leak in the chamber if it turned blue. we tested this by passing current through sacrificial little test strips inside a sealed box and a small hose connected to the vacuum port after it was sucked down. Every once in a while we would loose vacuum and the whole coil would come out blued....

[@dougp3841]

Looking good Craig...nice job! I imagine that the home depot steel is going to have a bit of residual oil on it, but your acetone "sheep-dip" should do the job. FYI- I use a scotch brite pad on things before I acetone them just to help loosen up the stuff that may be adhered to the surface. Pre-heating is probably going to be more necessary with old pieces of unknown history that you are stripping a finish off from, or any cast metals (they are typically porous and filled with gunk). I know anytime I go to TIG weld cast aluminum or cast iron it is a b!tch to get all the oils out to avoid weld porosity. I typically don't have any problems with other metals as long as I do the scotch brite before the acetone cleaning. I like the colors by the way. That bronze is slick.

[@TomZelickman]

Hi Craig,So I was getting the same issue with the little spots and it was actually lint from the towels. I started spraying my parts and letting it evaporate and the spots went away. I also agree that your pressure is too high. 3-5 psi is probably more than enough so you don't waste as much powder in the spraying process. Another thing that I do is use a flashlight to check for even coverage before I put it in the oven.Hope these tips help! Really enjoy your projects and am adapting your bending dies for a similar job I have to do here soon. Hope the X2 is up to the job...Best wishes,Tom Z

[@craigsmachineshop2040]

+Tom Zelickman (Inspiration Metalworks) - Cool, great to know! I was thinking I wasn't cleaning it good enough. So are you just spraying the parts with acetone with a spray bottle? Yeah, The pressure regulator on the air compresssor is pretty bad. I should get separate one. Thanks, I'm glad they are helpful! I'm sure the X2 can do it. You too. Craig

[@snowgoer540]

Hey Craig, nice video. If you don't mind, I noticed two things. First, the pressure seems too high. I usually apply at about 10psi, it just creates a dust cloud (lack of a better description) and the static does the rest. It allows you to get a more even coating. Second, a professional powder coater told me this secret for removing lint and similar debris: go over the part entirely with a propane torch. It's just a quick burn, not enough to heat the part really but you'll see the stuff burn off. I tried this and it ends up making the job MUCH nicer. It got rid of my pitting and spot marks you show at the end of your video.

[@craigsmachineshop2040]

Thanks! Yeah, I got a better pressure regulator and have it at around 10 psi. A torch sounds like a good idea. I don't use rags anymore though. I just blow the sand blasting dust off with an air gun and then use a triple acetone dip. Seams to be working.

[@snowgoer540]

+Craig's Machine Shop I don't use rags either (should have mentioned) but it still burns stuff off and drastically improved end product! I'm looking forward to seeing your drag knife work on the tormach. I'm confused about how the head moves, because on the routers it always looks like they turn the knife in the direction of the cut before moving down in z and cutting

[@craigsmachineshop2040]

Cool, I'll have to give that a try. The dragknife head is completely controlled by the x,y,z steppers. Dragknife compatible CAM programs manipulate the head to get the blade to cut sharp corners. Otherwise the offset in the blade and the design of the dragknife cause it to turn. I usually align the blade but I think it may not matter if the cut arcs in. The blade will just align as it approaches the geometry. Still new to it. I will have 2 more videos on it coming out.

[@peterdahlman]

Nice! I'am working on a larger oven for my garage, hope to get the last parts this week. Waiting for the electronics 😁

[@craigsmachineshop2040]

+Peter Dahlman Thanks Peter!. Cool! I am getting ready to build a powder coating booth. I guess I need to think about a larger oven in the future.

[@peterdahlman]

+Craig's Machine Shop I made a "ghetto-style" booth out of OSB Wood and Hinges. I'am starting to get Low on garage space...so it's nice to be able to fold it and get it out of the way when not used. Also added a fan to the back to get most of the powder away from my face :)

[@craigsmachineshop2040]

+Peter Dahlman - Mine will be osb and wood frame but It will be pretty big. I'm enclosing my metal car port soon. 12x18 feet of new work shop for dirty stuff like powder coating.

[@turningpoint6643]

No way to tell for sure until you run some trial tests Craig. But you might possibly be getting some minor re-contamination while dipping your parts in the acetone. There's a certain amount of oil residue left on the metal from processing it at the smelter. Dipping the parts might be leaving something like a very thin mini oil slick or some oil in suspension in the acetone that your then pulling your parts back through while dipping them. Might even be from the paper towels as someone else suggested as well. That has to be a frustrating problem. Only some really rough guess's that I can think of for your finish issues tho.

[@craigsmachineshop2040]

+Turning Point - Thanks! I'm starting to think its from the towel. I looked closely before powder coating and saw a lot of tiny cloth fibers so I blew them off with the air gun. I may try powder coating without preheating and see what happens.

[@stevefriedlander7053]

Turning Point I would only use ‘shop’ towels and not regular paper towels.

[@VikingBladeWorks]

The out-gassing bumps are probably the second acetone dip. if you use cleaner/degreaser preheat after each cleaning. The purpose of the preheat is to drive off anything in the pores of the steel. After cleaning and preheating do not wipe with anything or handle with bare hands. I am applying Cerakote, but the procedure works with powder coat too. I use a less aggressive 100/120 blast media to prep the surface. The Blast media that you use should never be used to blast anything else that is greasy or oily as that gets in the blast media and them could be deposited back on the parts you are blasting. Preheating does not need to be at high heat, at least that been my experience using Cerakote on knife grade steels, CPM D-2 A-2, etc. I also use brake-klean as my degreaser. I allow for a 30 minute soak, air dry the parts, then preheat at 300 for 60 minutes. Allow to air cool again and apply powder coat. if you have to touch the parts, use powder free nitrile gloves. if you're getting raised bumps, that's off gassing of trapped impurities. My guess is the second dip without preheating the parts.

[@craigsmachineshop2040]

+VikingBladeWorks LLC - Thanks! Yeah, I have been moving away from handling the part with gloves or rags. I think a lot of the spots may have been the fibers left from the rags. Since I started blowing the parts off before powder coating, it has been much better. Now I don't even use rages.

[@CNC4XR7]

Great Job Craig. I see no reason to wipe at all the Acetone should decrease and it evaporates quickly. Plus no risk of contamination. I think two dip tanks though so no cross contamination.

[@craigsmachineshop2040]

+CNC4XR7 - Yeah, I will try that. Thanks!

[@SOCOLVN]

Great video Craig .

[@craigsmachineshop2040]

+SOCOLVN - Thanks!

[@stevefriedlander7053]

Great video for a newbie like me and love all the comments back and forth. I have a picky question: depending on the part, how would you coat the area where the hanging wire touched the part?

[@craigsmachineshop2040]

Steve Friedlander - Thanks. Thin parts are tough. Some people will hang parts from a threaded hole on the bottom of the part. The actual contact area is very small so it’s mostly coated. Could use a thinner wire also.

[@JeffreyVastine]

Craig, what is the purpose of preheating the parts when you just let them cool down afterwards? Now your parts changed colors during the preheating process due to the steel's carbon content and thus the preheat actually tempered the parts. Peace!

[@awschmitz7]

Have you tried out the kg industries or cerakote products? Both offer top quality coatings and the max thickness on either product is around .0005.

[@EZ_shop]

Pretty interesting.

[@craigsmachineshop2040]

+Crivo152 - Thanks!

[@Hirudin]

Could those little marks be lint? I see you're using premium towels, but I wonder if a little bit of lint is being picked up anyway. Have you given Ajax/Comet a try? What was that black stuff on the towel? Was it dust from the sand blaster? I wonder if you could skip the preheating and both acetonings by cleaning the blasted covers with Ajax and a nylon brush (nylon to avoid lint). Rinse, blow off the water, and powder coat.

[@Hirudin]

I'd turn the pressure down even more too.

[@craigsmachineshop2040]

+Hirudin - Maybe it is lint. Maybe I will try skipping the preheat without using the towels. No, I haven't tried it yet. It seems to work good for you. Thanks!

[@craigsmachineshop2040]

+Hirudin - Yeah, I need to get a better regulator. The one on the compressor is pretty bad.

[@Hirudin]

Ah, that makes sense.

[@craigsmachineshop2040]

+Hirudin - What, are you night shift like me?

[@damionchrist]

Try an earth ground!

[@craigsmachineshop2040]

Thanks.

[@shaneclendennen522]

Your contaminated your acetone when you dipped the parts in your bucket.

[@craigsmachineshop2040]

Good point, thanks!

[@LOZBRY]

you got it too high turn air down a bit

[@craigsmachineshop2040]

Thanks, yeah that was a while ago.

[@NuttyforNissan]

So these are for light fitting terminal covers?

[@craigsmachineshop2040]

Light pole hand hole covers.