Phosphating and Chromating

[Bennie]

Mr. Guru, Your recommendation for iron or zinc on steel hits things on the head. Zinc is a very sensitive system as we both, I am sure understand. The combination cleaner/phosphate system is very good also, but does not provide the level of performance the zinc does.

But my problem comes with you not injecting a couple crtical aspects of the process that could create sufficient post adhesion issues.

Here we go! You never gave any instruction for checking if the part is clean. Water tests for pull back. We know it is temp.,concentration, and time in the solution. I afraid that if a recommended time of this will be taken as gospel and parts will not be cleaned. The rinsing with local water probadly will not cause a problem most have TDS levels that will not contribute to any serious.

But what you failed to mention is proper rinse procedures, if this guy has a part that comes out of the tank/vessel and he does not immediately rinse he has problems. The part is warm it flashes quickly and the residue sets making good rinsing a problem, plus he is losing product from drag-out. Once the residue sets it just does not rinse well.

I suggest that as the part is removed a "halo spray" be used, this will reduce chemical drag out, and sets the stage for a complete rinse. Then check for water breaks. If the part is not rinsed well residue may dry, and not be rinsed,then when checking for water break it gives a false reading cause the water soaks in and it looks as it is giving a clean surface, but is not. In any cleaning/conversion coating process water quality is essential more than one failure has been contribute to it and improper rinsing. Been there. What you think there "guru". I know it is difficult to cover all aspects at times but you might address this rinsing process and render some advice to your readers. thank you, B. Stremming, E. Alton, Illinois

[11111111]

Bennie how do I build a halo spray set up
Jeff

[non-stick]

Ahhhhh.... somebody with experience under thier belt and wishes to add to the fun. For one.... I welcome you to the Caswell boards. Secondly, I never called myself a "Guru". That title is given to those whom have posted numerous times here and the board owner has set that into place. I'd much rather prefer "Been in the business for a great while but still strives to learn more about his craft as time goes on. Always helpful, but seldom the epitomy of all answers" Unfortunately, what was given to me as a generic stock title. Perhaps this may clear things up for you in that aspect. With that said..... let's focus on the reasoning behind what I've said as opposed to every nuance that should be expected from me....

""You never gave any instruction for checking if the part is clean. Water tests for pull back. We know it is temp.,concentration, and time in the solution. ""..... It's basically and assumption that we all know very well by now that if a part is excessively oily or greasy, said substrate will be degreased (pick your chosen method) and then media blasted and phosphated. It's throught this phosphating that the chemical reaction will occur (I'm sorry Bennie if these are things that you already know but for sake of the hobbyist, we'll clarify once again to avoid any further confusion). It is also understood (as per manufaturers' instructions included with each product you buy.... at least to some extent) that the rinse be enacted immediately post phosphating. Please keep in mind that this forum is not product support but merely an open channel for discussion for the powder coating hobbyist. Forgive if I gave the impression that one may indeed let a part set overnight and then it was safe to comply with washdown procedures. That was not my intention rather, my assumption that every specific procedure need not be discussed here unless a member has a question with it or problem. If it's terribly advanced/time consuming EVERYBODY here knows my e-mail and phone number are open to you. As a matter of fact, I've spoken in person with a great deal of members here only to have made new friends and have fun "talking shop" with them. That same offer is open to you as well.... you may e-mail me directly or call me during business hours if you wish should you have a problem that I may help you with. I certainly hope this is a two way street with you as well. We're a family here without any hang-ups in the realm of powder coatings and I'd like to see it stay that way. Anyways... I'm rambling. Let's move on, shall we?

""The rinsing with local water probadly will not cause a problem most have TDS levels that will not contribute to any serious.

But what you failed to mention is proper rinse procedures, if this guy has a part that comes out of the tank/vessel and he does not immediately rinse he has problems. The part is warm it flashes quickly and the residue sets making good rinsing a problem, plus he is losing product from drag-out. Once the residue sets it just does not rinse well.
""....In the past to ensure proper rinse I've used a filtration process which includes de-ionization and de-salinization so that the final rinse may be devoid of any free-radicals if you will. Quite often in industrial line applications, this is not the case. Hence my reccomendation to use "good 'ol fashioned tap" water. As hobbyists, members here cannot incur such expenses for rinse water and that needs to be kept in mind. While you and I may indeed have resources and funds to acquire the things we need in this industry, they do not. Please keep that in mind. Everybody here is on some sort of budget and that's most certainly a factor. Myself included. I'm guessing you have no "bottomless bank account" either and at times, have "cut corners" for sake of profitability. For thier applications and purposes, tap water will do and I stand by my word as I've not only suggested, but have used it in the past myself with a moderate amount of success. All other words in that statement are answered above.

"" I suggest that as the part is removed a "halo spray" be used, this will reduce chemical drag out, and sets the stage for a complete rinse. Then check for water breaks. If the part is not rinsed well residue may dry, and not be rinsed,then when checking for water break it gives a false reading cause the water soaks in and it looks as it is giving a clean surface, but is not. In any cleaning/conversion coating process water quality is essential more than one failure has been contribute to it and improper rinsing. Been there. What you think there "guru"."" This Guru thinks it's good advice. Rinse well.

"" I know it is difficult to cover all aspects at times but you might address this rinsing process and render some advice to your readers. "" ..... indeed it is. Keep in mind that this forum is not technical support rather more of the "moral" nature. We're here for each other to lean on and derive knowledge from one another much as you have been given the opportunity to when you first started out in this business. No hang-ups. No "secrets" to be held onto here, my friend. It simply won't be tolerated, truth be known. If this board spoils and we stop becoming family, I simply have the option of leaving as do the rest of you. I'm here much in the same aspect that the rest of you are. I learn from your mistakes and share my success stories without reservation. I whole heartedly invite you to do the same, Bennie. You look like a person that we can learn a lot from, and that can also learn in the eyes of a person just getting interested in the coating world all over again. I for one, value your judgement and give you respect for who you are just like you've already given us by becoming a member. At times you'll be looked upon as somebody who can fill the void where one of us has no answer as we've "never been down that road" before in history. At other times hopefully, you'll be able to look towards us in kind. It just so happens with people like myself, Dale (a VERY knowledgeable parson in the industry) and quite a few others here whom I can't even begin to thank, we've been down a lot of roads and offer insight. That's all, nothing more. I've said it before and I'll say it again.... "what I don't know can fill volumes" and I strive to educate myself everyday. In the mean time... sit back, relax and enjoy the threads.... after all, if you can't have fun here and learn a few new things, then what's the point? Am I right crew? I thought so. Regards to you all, and to our newest member Bennie...... Russ the "un-Guru"

[non-stick]

Jeff..... don't hit the parts with full force water. I liken it to the experience of a a garden hose spray nozzle. You know that point midway when you get a diffused wide-round pattern spray? That's what I'd use instead of a concentrated blast or stream of water focused in any one particular area. Much as you would when rinsing the soap off your car after washing it. I'm sure Bennie can explain the whole process further though and possibly a tip as to what type of egress for the water you can attach to your hose-end or what have you..... Russ

[11111111]

Thanks Russ

[11111111]

Can I wash these in my shop sink? I have septic tank. I'm not sure what these chemicals actually do so I thought I should ask.

[non-stick]

I don't see a *major* problem with it but I'll probably get called out on that one. I don't think there's enough there to upset the balance of bacteria in your tank to make a huge difference. I have a 3 stage septic here that I pour all sorts of things down (cleaning fluids from the house and soaps/detergents,etc) and have never had a problem. As a matter of fact, the septic guy came buy last week and he said everything looks really good.... so I'm happy. I'd think as long as you don't make an everyday habit of chemicals down your drain it would be allright. Just remember to flush with a lot of water as to dilute the concentration going down into the tanks and I think it just may be allright. Worse comes to worse, you can buy a box of that "good enzyme" stuff and put it down there as added insurance for bacteria.

[11111111]

Can ytou explain to me what is happening to the metal from the wash chemical ( steel and aluminum if thier is a difference). I read what you wrote a few threads back and I'm not sure what the heck your talking about and i think it is becuase I dont know what the chemicals are actually doing to the metal and how this is effecting the pc.
As always thank you for the knowledge I truly apreciate the help.
Jeff

[mcaswell]

You have to really be careful of anything that is a "chromate". These chemicals contain chromic acid and can cause extreme problems in the water table. If you've ever seen the movie Erin Brokovich, the contaminants that caused those people's problems were similar.

You should always rinse in a closed system and take the evaporated rinse water to your local municipal hazmat transfer station. That way, you'll protect yourself from lawsuits and protect your grandkids from much, much worse.

[non-stick]

okely dokely.... here's the long and short of it. As stated above (fifth entry down, third paragraph) you're basically oxidizing the part chemically. Just like when salty sea water hits copper for years on end and then dries... it turns green. It's being oxidized. If you took a chunk of it and put it under a microscope, you'd see a "crystallized" structure on top. The way this helps you as a powder coater is this..... and trust me, these are very "generalized" terms, so take it with a grain of salt (no pun intended)......

When "salts" are broken down in water, they become metals. A good explanation of this can be found here : http://www.chem4kids.com/files/elem_metal.html
take for instance table salt. Sodium chloride ( NaCl) is divided in the water and the positive ion is attracted to the part (Na being the salt portion) The Chloride (Cl) breaks off and stays withing the water. When you pull the moisture away, or it dries... the "positive ion" (salt) is on the part. Through chemical AND electricl reaction, the part is therefore oxidized. It just so happens that sodium (Na) is an excellent conductor of electricity and is spread evenly all over the part. We have two benefits that come from this. First being.... it is a "primer" now due to the fact that it's gripped into the pores of the metal. What is left has an agressive surface profile (like when you sandblast) so therefore, the powder that sticks to the "salt" is bonded through that oxidation. Secondly.... through the sodium chloride now changed to just sodium, which is an excellent conductor of electricity because it's now a metal, the powder is very much attracted to it and sticks better. There's an even coating of it so therefore.... a smoother electrically attractive surface has been formed. It's a win/win scenario. Good grip, and more accurately conductive for your part.

Now... with that said..... we use phosphate for steel and chromate for aluminum for two different reasons. Different metals are closer in the periodic table to other metals. Steel and aluminum generally don't like to mix... so different chemicals will want to be attracted to different metals. Someting that becomes (chemically and electrically) very close to steel, will be good for steel, and vice versa for aluminum. Will either chemical solution work for the opposite one? Sure.... I suppose it's better than not at all. But like chemicals and metals GENERALLY want to stay close to one another. Phosphate gets attracted to ferrous (magnetic... sorry, I see I entered metallic down there. that's a goof. I apologise. It should read "magnetic) metals as chromate gets attracted to non-ferrous (non-magnetic) metals. It gets broken down to what chemical fits best with what metal. A lot of people look at chemicals and metals with confusion and it's really not needed. Very simple if you stop and notice that some things on a periodic table are closer to others. Why do you think for centuries people have been trying to turn lead into gold,hummmm? So close to one another yet so far away by so little.

If I missed anything let me know. I tend to ramble on and lose my train of thought (as if you hadn't noticed,lol). If it's still foggy to any of you, we'll break it down further. Or maybe one of our other members with insight can shed some light on the subject for us. I'm more than willing to yield the floor to better ideas and explanations, you all know that. Until then as always.... I hope that helped somebody out there ...... Russ

p.s. ~ I in turn, always thank each and every one of you for your fresh insight as I learn from it as well. More than you know, truthfully.