MTK kind of thin . . . .

The mixture called out for OMNI MTK is 4:1:1, which is what I've always followed. But the mixed paint has always seemed thin, and requires much care to avoid (most of the time) runs. Particularly on the International whites and yellows I've been using lately, it takes quite a few coats to cover adequately. Do you OMNI users always use the 1 part solvent reducer? If it's just there for flowability, it seems too thin already. Any reason I couldn't leave it out altogether?

Thanks for your help

Paul

I purchase automotive finishes locally from Finishmaster, which I understand is a national supplier chain. They still carry OMNI but I"ll ask them about it next time I"m over there.

Thanks again!

Paul

Another thought. Most tractor parts, if done individually, are relatively small. Even tractor hoods. You can cover one coat in a matter of a minute or less, unless you are doing many parts at the same time. It is therefore more important than ever that you observe the minimum recommended flash (dwell) time between coats - five to ten minutes at 70F per the MTK tech sheet. Even extending that to 10-15 min for individual tractor parts will do no harm. If you get started with the second coat before the solvents from the previous one have evaporated to some extent, that will only aggravate your run problem. For individual parts, go liberal with the flash time.

I have never used the MTK in either white or yellow but I would guess those might be a little harder to cover well over the darker MP170 epoxy than some other colors. I have never had a problem with nearly full coverage in one coat with orange MTK. I have no experience with turbine guns so can't help out there with any gun adjustments. Having to use 5 or 6 coats to cover sounds like too many to me and suggests you are not applying heavily enough. On the other hand, your experience with runs suggests you are applying too heavily. You might try a different reducer or hardener, depending on temperature at the time of spraying. There are 4 different reducers and 3 different hardeners for the MTK. The PPG tech sheet is not clear which to use at what temperatures. However, I have developed my own interpretation - presented in this prior post. I generally tend to move up to a hotter (slower) reducer than generally recommended - but I am used to doing that. Your application technique could require a move to a colder (faster) one than generally recommended to eliminate runs.

I would not leave the reducer out altogether. I have never found the need to tinker with recommended mix ratios. The MTK in the proper mix ratio is, indeed, a little thin - at least when compared with premium paints that cost two or three times as much. But you should be able to apply it without runs on vertical surfaces and fully cover in no more than about 3 coats, possibly 4 for those colors that cover hard to begin with. I notice that the tech sheet permits an optional, higher solids mix ratio of 4:1/2:1 - half as much reducer as the normal 4:1:1 mix. I have never tried that, but you could and still be within the manufacturer's recommendations. Furthermore, since the MP epoxy is now available in white (MP171), you could also try that to help the apparent coverage with the light colors white and yellow although I don't think that should be necessary. CNKS would know better than I since he's used OMNI white topcoat and I haven't.

The only other thing I can think of is improper atomization by the gun but I can't help with that on turbine-supplied units.

Just some food for thought.

Rod

It should be but it is probably dependent on your local supplier. It's my understanding that high volume ("Platinum") PPG dealers have insisted and now have "their own" brand label for an economy line PPG automotive paint. I believe it is called "Shop-Line" or some such. If your local dealer is a high volume one and carries the Shop-Line brand, he probably will not also carry the OMNI line. I am told that Shop-Line is essentially a rebranded OMNI product with different product identifiers. I have no problem still getting OMNI from my local supplier, so I think it is a local supplier issue. I also tend to believe it is somewhat of a scam to rebrand the same stuff with different labels. It only tends to confuse the customers - unnecessarily so.

Rod

So in other words the omni is still omni, just under a different name? Let me guess, shop-line is probably more expensive than omni. Thanks for the info, Doug N

I strongly dislike such marketing gimmicks and if I had a choice of local PPG dealers, I would, without hesitation, avoid the Shop-Line in favor of OMNI - just because. I doubt that Shop-Line is inferior to OMNI but I also doubt that it is better in any way. I have not seen a cost comparison between Shop-Line and OMNI but I wouldn't be a bit surprised if what you suspect about price is true. My local dealer carries OMNI but not Shop-Line. He's the only PPG dealer within any reasonable distance, so Shop-Line is not available to me as a practical matter, even if I wanted it - which I don't.

Just for fun, here's the tech sheet for epoxy primer in Shop-Line and here's the tech sheet for epoxy primer in OMNI. Different label, different ID - but it sure looks like the same product to me.

Rod

As far as mixing, dry times, applications, and properties, they are d*mn near identical. There is only ONE difference that I can see, omni gray is 4.3 lb/gal and shop-line gray is 4.2 lb/gal.

You're right, I think they are the same. I printed out the specs. I'm gonna take them to my buddy and see what he thinks. He's been in his own business for about 15-20 years, and I trust him, he's got PPG diplomas all over the place. I can also see that you know what you're talkin about too. It's just I see so many people talkin about different stuff and I get all confused. Guess I should leave the paint to the pros, and I'll just stick to my trade, welding. I really appreciate your time and info. Doug N

Thanks for your suggestions. I'm using a turbine powered HVLP gun, with a 1.3mm projector tip. Typically, the air control is wide open, and paint control I turn in about 1 1/2 turns from maximum. I get a nice wet coating and it looks fine, except on vertical surfaces I have to be very careful to avoid runs. Perhaps I should purchase a smaller tip and see how it performs (next size down is 0.8mm). I know these tip sizes relate to the gun pressure so they may not be in agreement with another type system.

I'm typically painting over 170 epoxy primer, and that lays down perfectly. However with MTK, because the paint appears to be so thin, I have to go over the surface 5 or 6 times to cover the primer gray, and thus increase the potential for runs. I never noticed the problem as much with Farmall Red, but with the lighter colors the problem is much more pronounced. I could cut back on the paint control, but I'd think that would make the coverage even less.

I'd appreciate any further suggestions . . . I've done a couple tractors, but I would like to improve my technique and it sounds like there are some improvements I can make.

Paul