Phosphating and Chromating

[non-stick]

I don't know if you all keyed into the fact that there are different types of "wash" treatments as far as bond goes on this site, but I'll give you the inside skinny before Caswell cross-lists these puppies.

We all know that a phosphating solution to your steel available in the powder coating section. But what do you do for that home-run grip on aluminum or copper/brass?

For aluminum, ALCHROM880 is a great choice to use. Same pretreatment, but best suited for non-ferrous white metal such as aluminum. It's even mil-spec approved! ( approved by the U.S. Government as a viable treatment). For those of you coating valve-covers and intakes.... THIS is your home run in the prep-process.

For other metals you might be coating in the brass/copper family, A02 is the way to go. In my humble opinion, brass and copper (especially) are the hardest substrates to powder coat and this would best help your adhesion during the whole process. Order this product and you'll no doubt have a good chance at longevity for your coating.

Stainless has always been a bear to coat as well. SSB370 is the way to go if you need it. Who knows... you may have a reason to finally powder coat that DeLorean that's sitting in your garage after all!

Tip for those who coat Stainless Steel and copper/brass while on the subject. When these metals heat, they oxidize very quickly. If anybody's ever tried to buff that off, you'd know what a pain in the you-know-what that could be. Make a simple solution of Hydrochloric Acid (found at your local hardware store) and water and "dip" the part for approx 30 seconds. Right before your eyes, the oxidation will sluff off and leave you with your original finish yet once again. It's even a good idea to do this on your cookwear once in a while to keep those old pots and pans looking "fresh" for years to come . Please remember to wear the appropriate eye/hand protection while doing this. HcL is VERY acidic and will burn most anything it comes in contact with almost immediately. Hope that helps somebody out there if they had an adhesion problem......Russ

[mcaswell]

These products are available at http://www.caswellplating.com/aids/metal.htm

[drfjr1976]

I am going to purchase a gallon (which will make 32 gallons) of the Iron Phosphate Primer. The thing I was needing to know is, Will the ceramic boiling heaters http://www.caswellplating.com/suppli...c_heaters.html work for this solution since it will be a 30 gallon tank?
or will the ceramic plating heaters be better? http://www.caswellplating.com/supplies/heaters.html
I know the boiling heater is made to bring the solution temp to a boil which is defanetly to hot for the phosphate and that the plating heater is preset at 110 degrees. Phosphate range 70-160degrees. But I didn't know if I would need the larger one since it is 30 gallons. Thanks

[drfjr1976]

OK got a nother "?" for you. How does the Phosphate leave the finish? Does it change the apperance in any way, color or texture? The reason I am asking is because i do a lot for aluminum parts that I polish certain areas of and I do this before coating.
If the phosphate will affect the polished areas, will the High temp tape keep the phosphate off. Or will it remove the tape since it is a detergent so to speak.
And if the tape will protect the areas, will it need to be removed and fresh tape applied before coating.

Thanks again

[non-stick]

ok... first things first.....

The second heater ( PRODHEAT110 )is the more logical choice as they "regulate" the water to 110F. Of course... for 32 gallons, this may be taxing for just one element. I'd say that one will be good per 10 gallons otherwise you may not get that temperature up from a cold start. It may even be as low as 5 gallons per heater, I don't know the specs on this one to be quite honest with you. I would assume just for giggles on this one... that if you were going to be doing this on a constant basis, 3 heaters from a dead stop at room temperature would heat up a tank of the solution nicely.

With that said...... traditionally in an industrial situation, the iron phosphate is set up into a large washtank in stages. Temperature is "targeted" to be approximately 140F but there's always a loss of heat value when factoring in the ambient air temperatire, heat loss due to surrounding part and tank wall temperature, etc. The temp usually settles down to 120F.... so you won't be that far off base in your "tank" configuration. Usually the higher temperatures dissolve oils faster and create a quicker chemical reaction from phosphate to substrate which is why you have that "higher end curve" going. I personally see no difference between 160F for 30 seconds and 110F for 7 minutes. (much like the cure schedule on a powder if you pay attention!).

Next we have your question about how a phosphate leaves a finish. Well... chemically speaking, the "salts" or phosphates from your solution are attacking your substrate on a microscopic level. Oils are washed away and the pores of the metal are exposed. Therefore, leaving room for the structure of the phosphate to reside in. This is what is known as chemical oxidation. (use this example if it helps you.... put a piece of copper out on the ground. Nice and shiny, right? After years of rain, the water and natural "salts" or "minerals" in the air turn the copper green through oxidation. Phosphating is no different. Your metal is steel, your vehicle is the water, and your "salts and or minerals" are the phosphate. Same process, just that the time has been sped up due to heat and concentration of chemical reaction in a shorter time frame. Period). Anyways... when your part leaves it's phosphate wash, it is then rinsed to stop and neutralize the chemical reaction from happening. You do this simply by rinsing it with clean water. Then the part is dried. Either via an air-gun, or heating in a warm oven. NEVER wipe the water off or for that fact.... touch the phosphated steel with your bare hands. The reason is this : you have just applied a crystaline structure and washed the metal of any oils. When you touch it, the structure has been knocked down and the oils from your skin are left on the metal. Basically, you just reversed the process of which you just applied. Hang it from a hook and dry it properly. What you will be left with basically is a piece of steel that through the magic of phospating, looks for the most part blue. It's not unusual to see red,yellow,green,orange,etc.... but traditionally.... the colour left behind is a sort of bluish steel. All that happened here was the light bouncing off and refracting off of the surface of that crystaline structure. Different chemicals (or salts) will refract light differently. So don't be surprised when you see your part look sort of tye-dyed,lol. It's supposed to look that way. A pleasant (albeit brief) thing that just happend is this in a nutshell.... salts are minerals. Logic dictates that minerals turn to metals under the right conditions. So basically... you just degreased the part, filled the voids with chemically treated "metals" and not only primered the part, but "smoothed out" the conductive surface from applying a like minded "metal" evenly across the surface. Period. Of course... this leads us to your next question....

Does phosphate change the appearance of the metal in any way. Well... just to go over what I said. Basically, yes. You've "oxidized" your part chemically speaking. For steel, iron phosphate makes a "blue" because it is a ferrous (metallic) metal. Zinc Chromate (PRODALCHROME880) for aluminum will "yellow" in appearance. Can it be taken off after you've coated? sure it can! It's like any other oxidation. Just reverse the process. Wipe down with something acidic or base to release the bond from the structure and buff it to a shine. If you have areas where you have raised lettering on a valve cover, let's say? coat the entire thing and just take a flat sander and sand until you hit metal. Finish off with a high grit paper to get shine if you wish. You may be able to mask the part AFTER you phosphate or chromate, as the "detergent" will basically get underneath your masking and release the glue from the tape. Just be careful handling an already phosphated piece if you are going to do that,k?

I think I basically answer your questions,no? Just keep in mind... iron phosphate for steel,zinc chromate for aluminum. That's the general rule. Hope that helped and didn't make you more confused,lol.... Russ

[drfjr1976]

HAHA I was able to keep up with you on all that and I know that you have mentioned before about useing Zinc Chromate (PRODALCHROME880) for aluminum, but I was under the impresion, from the web page, that the phosphate could be used on steel,zinc and aluminum. I know that Zinc Chromate is better for aluminum but I was trying to keep my chemical colection to a minumum. One chemical for cleaning.

[non-stick]

hey! Either I'm becoming a better communicator or you my friend, are learning a few new things and becoming a more informed coater! ( I vote for the latter.... I know for a fact my communication skills havn't changed,lol). Yes, while the phosphate can indeed be used on aluminum... it's a situation of good/better/best. I won't usually recommend something if there's a better alternative out there or if you have no choice. Here on the site you do have a better alternative and a choice in your options and therefore, I suggested it. After all...... we both know that you only want to powder coat something the 1 time, am I right? In that 1 time deal... you do indeed want the best for your parts and possibly a clients' word of mouth advertising because "this stuff is awesome and I have no complaints", am I right? Small investment for good advertisement, let's say. I suggest phosphate for steel and chromate for aluminum, and that's all I'm gonna say on that one. Your decisions are your own and my knowledge is based upon the mistakes I've made in the past. One may take the risk themselves and learn like I did and gain wisdom from another's errors. That's all I'm saying ..... Russ

[drfjr1976]

I got ya.
Thanks

[drfjr1976]

Anyways... when your part leaves it's phosphate wash, it is then rinsed to stop and neutralize the chemical reaction from happening. You do this simply by rinsing it with clean water.

Clean tap water or should we be using distilled?

I know.

[non-stick]

clean tap, my friend. Unless you're doing something way out in left field like medical instruments or such that need to have exotic powders and plasma treatments.... it's just not necessary. Rinse with clean tap water, dry off and you'll be good to go ..... Russ

[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