Catalyzed Base Coat????

[BeoBob]

I have read where a lot of people suggest adding hardener to the base coat to improve adhesion and long term durability. But no one seems to discuss what kind of hardener or how much to use.

For my current project will I will be using House of Kolor Apple Red Kandy base coat (KBC-11), Jet Black (S2-25), and Planet Color Extra Silver Metallic (PC2710). Looking at the data sheets from HOK there is no mention of adding hardener. Data sheet for the Planet Color is unavailable.

Any idea if adding hardener to these paints is advisable? And if so, what kind of hardener and how much would I use?

Thanks!!!!

 

[TAZ]

You can add hardener, but I don't see that would help adhesion. I see it only helping speed the drying of the basecoat.
I'm sure you've seen some paint jobs that chip easy. Like a white pearl (white base, pearl coat, then clear). If you spray the white and pearl and don't give it sufficient time to dry and you clear too early, it will trap the soft base and midcoat thus making it prone to chips.
The basecoat hardener helps this.
It's good for the 'thicker' paint jobs. Also it helps cure the paint good so you can do tape layouts a little earlier.
You can also add this to the intercoat clear.

It's simply 'basecoat hardener'

 

[BeoBob]

I posted this question on a few other forums. Man has there been a lot of chatter and conflicting info. Here are a few important points I have gathered:


- Adding hardener to BC will improve adhesion and add pliability, reduced potential for chipping
- HOK recommends you do NOT add hardener to their BC
- HOK BC does not include a specific chemical that most BCs include which reacts with the hardener
- Different BCs contain more or less of that specific chemical, and therefore will take varying amounts of hardener safely
- "Basecoat hardener" is simply regular hardener for clear reduced down, making it more difficult to screw up the ratio
- Pros have been adding regular hardener to HOK BC at the rate of 1oz per sprayable qt for years with no problems
- Adding hardener at this ratio to HOK BC will slow the curing process slightly
- Too much hardener will slow the cure time significantly
- General consensus is that HOK is not what it used to be, more marketing than anything, and there are much better paints available


These are all based on combing through tons of information and what others have posted on the internet, so take it with a grain of salt.

 

[txwayno]

Well that makes it clear as mud, lol.

 

[TAZ]

lol.

In other words try to avoid the basecoat hardener.

Just be sure and let it cure properly before sandwiching it under the clearcoat

 

[txwayno]

one thing I have learned doing these cups is DO NOT TRY AND SKIP THE CLEAR BETWEEN COLORS! I will screw it up some how either by "scuffing", tape marks, scratching with exacto blade, etc...

 

[TAZ]

Yea, interclear is good to use between colors if you have a lot of masking. You could always not do this step if you got a simple 2 colors with a pinstripe for separation.
But the more involved jobs, yes, you should interclear. Or if it's going to sit a bit, just top coat clear and resand, THEN add your graphics.

 

[txwayno]

That's what I have been doing. One problem that's come up is after letting UC-35 set up overnight, scuffing and adding a SG-100/Candy. The SG-100 crinkled up the UC-35. Happened to me twice.

 

[TAZ]

That can happen, especially if you load it up or you use a 'hot' thinner or reducer.
Normally happens on edges where you sand the clear and you get it a little thin.
The reducer will bite into this easier.

 

[BeoBob]

I have the same problem occasionally... the next step will wrinkle the intercoat stuff. If I use regular clear I do not have any problems.

 

[TAZ]

I have the same problem occasionally... the next step will wrinkle the intercoat stuff. If I use regular clear I do not have any problems.

You really shouldn't be having a problem with the intercoat clear since that is just a basecoat clear. So you would be applying basecoat over basecoat.

 

[BeoBob]

I know. I know, and I haven't found a good explanation for it either.

I've tried using the intercoat stuff as carrier for candy, pearls, and flake as well as for a protective coating in between steps. 80% of the time it does fine. But it's that 20% that kills me. It will work on one part. But the next part (same paint laid at the same time) will wrinkle like crazy. Sometimes it wrinkles what it's going on top of. Sometimes it wrinkles underneath the next step... applied a week later. Sometimes it spiderwebs.

Too hot, too much material, material too thin, solvent too fast, solvent too slow, polyester versus acrylic base coats??? I don't know, can't figure it out, too many variables. All I know is that several pieces have been ruined using it. And I have read numerous reports where others have the same problem.

Rather than deal with it directly, I just avoid it by using the regular 2K clear. Good solid barrier between steps. No wrinkle problems since.

Maybe one day I will work it out.

 

[txwayno]

BoeBob,
that what I've been doing too. For me UC-35 NEVER lets me down. I hate having to dump out the left over as waste though so I just bought the SG-150 to try instead. I know that it's the base for all the airbrush colors I use as well as the premixed candy basecoats. I never have a problem with them though. It's only the SG-100 by itself. Sometimes I'll spray silver flake and before I go on I want it to be smooth so I cover it with multiple coats of UC-35 and let sit up a day or two. Come back and sand it smooth, spray candy that I mix with SG-100 and before I can get a good coverage I can already see it "crinkling" up! My only guess is that I did not let it flash long enough AFTER I it smooth and degreased it as that releases more solvents. That's just a guess but I can't come up with anything else.
I went with the SG-150 in hopes that it will help the pearls and flakes I have been spraying lay down better requiring less UC-35 to smooth it out.

Lots of clear to smooth out this flake.

 

[txwayno]

Did it again. Orion Silver metallic, silver flake, sg-100 blue candy mix then UC-35. Customer wanted a little darker blue so I mixed up some more sg-100 a couple of days later. Sprayed it over the UC-35 and spots crinkled up all over the cup! **** IT! Had to strip it and start over. Never trying this again. For now on if it has been cleared with UC-35 already and they decide they want darker of I'm trying to add some additional highlights I will mix the intensifier into UC-35 and spray that.

 

[BeoBob]

That sux. Maybe there is another MFG out there who makes an intercoat that doesn't cause problems?

 

[TAZ]

Only thing I can think of is that you put on a light coat of UC-35 and the reducer bit into the clear when you added more candy.
OR, you used a very hot reducer and laid it on wet and it bit into it.
I do jobs all the time where I'm recoating over the UC-35
Not for sure what is happening.