Is it always just under/over activated?

BoondocksBoondocks Member Posts: 11
My background is composites (boat building, ballistic plate) and firearms manufacturing. Over the last year we have experienced chem shortages that have required substitutions.

Part prep is sandblasting 7075 T6 Aluminum w/120mesh garnit, complex shapes and various complex polymer parts (flame treat yes). Blow off in clean dry air 100psi.

History: New to the various processes of 'dipping'. Tank size for this R&d experiment is 3'depth by 4' width with ability to step up and step down water temp in +/- 0.5deg F, varied temps as high as 92F down to 80F. Base coats are a very well known brand/advertised as hydro-dipping paint requiring no primer. Films by TWN, activator by TWN and OHW. Iterations or attempts performed 60+ on eight different shapes with little care for stretch etc, just looking for no bubbles, pin holes, sticky, pot lids, slide offs etc to start.

Results: 60 plus failures, majority of attempts showed what is typically classified/described as under activation (various nozzles and adjustments made). Attempts to switch activator and or add activator volume applied resulted in sticky surfaces etc.

Further Action: Out of frustration I grabbed a part painted with Rustoleum (7 day old set at approx 80F), I did not bring water to temp (left it at 73F room temp, NO the paint booth is not 73F). Put the TNW films aside and pulled out some donated carbon pattern that was laying around unprotected for 30+ days. Film laid on 73F water, for 2 mins, over sprayed it with OHW aerosol activator, it glassed out, hand rolled the part.....it came out perfect. Not one pin hole, no stickiness, no blotches, would not rub off or rinse off, no seam (monolithic dip using no tape).

Why did I do it this way? On the last failed dip I noticed that the pattern that would not stick to the prepped part, was actually adhering to my vinyl gloves with no issue and looked rather good, looked really good compared to the parts and did not wash off the gloves.

Corrective action, went back to hydro base coat, 73F water etc etc , same terrible results as before. Went back to Rustoleum.....another flawless part.

So after a long azz page vomit, considering the price of hydro paints (HP), HOW DOES ONE DISCERN IF A BATCH OF HP IS NOT DOING WHAT IT SHOULD STRAIGHT AWAY WITH CERTAINTY? To avoid the repetitive part prep failures? As I have learned, not all issues or failures are activator.


Thank you for any and all help/suggestions

Comments

  • FontyscustomsFontyscustoms Member Posts: 71
    What paint are you using exactly?  It might be on too thick- I find most hydro paints go on lightly compared to many other coatings. 
  • studebakerstudebaker Member, Business Ninja Posts: 4,008 ✭✭✭✭✭
    edited July 22
    To answer what I perceive as the question that you were working up to, (Thank you for the in-depth scenario description) the answer is.... Wet your finger with activator and rub the basecoat prepped part. Does it feel kinda liquidy and slippery? Then it's in its "dipping window". Activator not only "melts" the clear fixative and pigmented ink on the film, it also minutely "melts" the basecoat paint.

    Corrective action: Don't buy TWN activator or paint. Their film is good.

    Also, some folks on the forum will "poo-poo" the idea of using aerosol activator. It has its place in this business of hydrographics, but the fact that it worked and TWN activator didn't is a BIG clue. Aerosol activators are "softened" by the propane propellant. The equivalent Activator to what you used in that spray can is SuperBrew Activator. Buy it, use it, be a continuing contributor to the forum. :-)
  • BoondocksBoondocks Member Posts: 11
    @Fontyscustoms. Snake brand aerosol, white and biscuit. Seems to spray and lay watery, the biscuit was better but exhibited the same frustrations getting things to stick. In terms of thickness varied from opaque to over-done.
  • BoondocksBoondocks Member Posts: 11
    edited July 22
    @studebaker. Thank you for that tech tip on testing the base coat with the activator. Thank you on the paint recommendation, but to go further, as its my current issue, how did you (others?) determine that brand is not a good choice?

    Yes to aerosol cans. I have enough guns that spray this, and guns for that, and isolated guns for hazards, small guns for cerakote, cabinets for this, refrigerator for that, labels , paperwork, ugh....would be nice if I could avoid increased shop chaos with less equipment. However, quality has no patience for convenience.
  • studebakerstudebaker Member, Business Ninja Posts: 4,008 ✭✭✭✭✭
    I will let these 183 pages of conversation about the quality of TWN's Activator speak for me.... https://k2forums.com/search?Search=Twn+njm
  • FontyscustomsFontyscustoms Member Posts: 71
    I am not as familiar with the paint you are using...somebody else might have a better clue.  The question becomes if you used the same activator on the failed dips and the successful dips it wouldn't be the activator but rather the base coat.  @studebaker what am I missing that you're seeing?  Lol
  • BoondocksBoondocks Member Posts: 11
    The base coat is OHW aerosol white and bisquit (snake brand I was trying to say it without saying it)). Yes, its the base coat. But how do I analyze base coats in the future if they are good, bad, expired? Im thinking if i paid for hydro paint no reason the Rustoleum should out perform it. With that said, what are the objective criteria for analyzing if your hydro paint is any good...just the 'activator to base coat slime' test?

    Much appreciated
  • FontyscustomsFontyscustoms Member Posts: 71
    edited July 22
    If it is OHW you have to barely color it...you are giving enough for adhesion of the ink to the part...not much more than that.  I like OHW but I use aqualac because in my experience it is more forgiving.  
    @onehitwonder can definitely help you get squared away- his customer service is top notch!
  • WileECoyoteWileECoyote Member, Moderator, Business Ninja Posts: 7,856 El Moderator
    Never seen OHW go bad, but I have seen LOTS of application problems. Don't shy away from mentioning a brand here, usually it's not the paint, and we are here to fix problems, not drag a brand down.
  • PagesHydroDippingPagesHydroDipping Member Posts: 833 ✭✭✭✭
    Can you post some pictures of these fails? We will need to see some pictures to help you diagnose your problems.
  • BoondocksBoondocks Member Posts: 11
    edited July 24
    @WileCoyote. So OHW is watery when sprayed like the $2.50 paint at Walmart? IS all Hydro paint that consistency ( I ask because we have only to date used OHW, looking around now for next brand) Also, what brand undercoat will stick to hydro film like I witnessed TWN film stick to non-base coated vinyl gloves. Thats what I want to use. And yes, thats why I placed this question....looks like its always LOTS of application problems but few issues related to product quality, variance, expirations etc. Its why im so confused, the film seems to be extremely attracted to vinyl and Rustoleum....not so much the Hydro Paint I received
  • FontyscustomsFontyscustoms Member Posts: 71
    As @PagesHydroDipping we need to really see pics...I am still thinking that you are putting the paint on too thick but without pics, I am shooting from the hip here.  But I would be willing to bet the paint is the least of your issues- especially since you changed quite a few variables with the rustoleum dip...
  • BoondocksBoondocks Member Posts: 11
    edited July 24
    @Fontycustoms: I hate thick anything, my industry you lose money, contracts with thick parts that delam. Plus Im a cheap azz, original response to paint thickness was a test variance from opaque to thick (watery paint easy to spray thin : ) Thin coats make me feel better plus it uses less chem (less cost per piece). But here is a pic.
  • BoondocksBoondocks Member Posts: 11
    Slide 4

    First Dip and Rinse Off with this pattern

  • BoondocksBoondocks Member Posts: 11
    edited July 24
    Slide 5
    Second Dip, adding a second dip over the bad one in hopes the spots that did not accept film will on second try. I actually like the double layer look, but not all of the pin holes would accept the ink. I decided because of the 'grungy' look of the double layer that it was actually sellable, but when I tried to recreate the double dip on another part with stretching, pin holes , rub off, pot lids none of the ink stuck to the exposed areas, so that method was out the window.

  • FontyscustomsFontyscustoms Member Posts: 71
    @studebaker might be able to shed some more insight but I am thinking soak time is too short?  
  • PagesHydroDippingPagesHydroDipping Member Posts: 833 ✭✭✭✭
    Looking over some of your pictures I am seeing a lot of cracking in the pattern. In the past I have found this happens when the film is dried out. What's happening is the film is expanding faster than the ink can liquefy. I have had this happen with some mossy oak film in the past. My fix was to very "VERY" lightly spray it with activator on the table. Let it sit for about 15 minutes then put the film in the water. This will soften the film up and allow it to expand properly. But you need to find more consistency in your testing. For starters get the water temp back up to 90° at a 60 sec soak time. And go from there only changing one variable at a time so that you can properly identify the problem. I also see you are using multi cam, it is a thicker film and requires a longer soak time( for us anyway) we dip a lot of that film and we have found 90° for 90 seconds it the key with no dwell time. Keep us posted and we will try to help you through this. Also just a question but have you had any training on this process? This is something that takes a long time to really learn and develop skills for. The most important part of this process in my opinion is learning how to read your film. Without thus skill you are shooting in the dark every time you dip.
  • BoondocksBoondocks Member Posts: 11
    @Fonty and Pages: Ok that makes sense THANK YOU, as stated the carbon pattern was laying around the shop exposed and open absorbing water from swamp cooler. Humidity here, well if it gets above 20% we start claiming God is trying to kill us. The TWN films kept in sealed bags, and resealed immediately when not being cut from (similar to all pre preg material). So 90 at 60sec soak is deficient when the film is dried out. And then Im just chasing my own tail with the activator, compensating/retarding for a really bad start.

    Question: If I need to cut open all the film sleeves so they can 'PRE' hydrate, what would be a good humidity level for them to live in?

    Further: Pre-hydrate condition aside, please see Slide 1 examples 6, 7, and 8. This is the hydrophil carbon pattern that was laying exposed. Item #6 using this pattern went right to Rustoleum 2x Clear coat matte as base directly on aluminum. #8 same film went to the base of Rustoleum, in each case the dip worked no flaws. It did not rinse off, would not rub off no pin holes, pot lids, not sticky etc etc. Now #7 is OHW, using same film and all other variables held constant, the paint did not like the film, failure to stick (as usual).

    SO when the film shows a clear desire to mate up with a base coat, yet fails with a different base coat...how do we read the base paint? A good test for 'openness was shared for the base. But if the film can be dry, what are the pitfalls with the various bases aside from thickness. Seems really illogical and unlike other chem processes that the bases have no issues. Does this industry have something like ASTM's?

    Thanks again guys, already opening the TWN sleeves to let the film breathe a little. Will try the pre spray hydration as well.
  • studebakerstudebaker Member, Business Ninja Posts: 4,008 ✭✭✭✭✭
    edited July 25
    Boondocks said:



    Thanks again guys, already opening the TWN sleeves to let the film breathe a little. Will try the pre spray hydration as well.

    Whoa.... Don't do that! We have a hard enough time keeping humidity OUT of the film, so it doesn't hydrate too fast and act erratic. Only introduce humidity into the film when it feels "crunchy". It's really had to get the humidity back out of the film. Humidity level should be around 45-50%

    Also, to keep things straight in your mind, call it pre-spray activation instead of hydration. And let it dry back out fully before placing it on the water. That trick is only to put the stretch back in the ink and clear fixative. There is such a thing as pre activating before the film is placed on the water, but that process requires a totally different activator and timing system with 40 micron film.

    Also, on Slide four, I did see a couple of air pockets and a couple of "activator spit" places and a little stretch in front of the trigger guard, (all normal and just needing touch up) but I'm not seeing the bad spots you are fretting about. Could you circle them or point them out so we can help diagnose the boo-boo's?

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