Ppg Prima K36 - Wow!

[JTisMe]

For those of you who shoot a lot of auto body refinish product this may be old news but I shot an Ash strat yesterday with this stuff. all I can say is wow. Builds fast, dries quick and sands easier than anything I have *ever* shot. It was cold here in Washington yesterday as well. While it's not cheap it is now permanently on the rotation for any solid color (or even car:-) that I do from now on.

Also, since I had retired my old primer gun I pressed a Harbor Frieght garvity feed HVLP with a 1.4 tip into service. Even running the lower pressures I like to in my garage I was able to get good build with no spits.

Did I mention that I like this stuff :-)

-jeff

[Mickguard]

Builds fast, dries quick and sands easier than anything I have *ever* shot.

Hi,

I'm just getting started finishing a guitar for the first time. I'm using auto spray (primer, color coat, clear) in rattle cans.

I'm wondering what you mean by 'builds fast' ?

Could you describe the process you're using?

I'm a bit confused about how to proceed, I've read through the Reranch site, and the StewMac trade secrets and others, but I'm still trying to figure things out...

So far I've done a couple of coats of sealer. I'll sand the second one tomorrow, then I want to do the primer.

Then I sand the primer, right? What grit do you use for that?

And what grit do you use for the color coat?

Thanks for any tips!

Mickey

[JTisMe]

Mickey, The info on the Stew-Mac and ReRanch sites is applicable to the instrument specific applications the materials they sell are designed for.

That being said some concepts are universal. One being the better you prep the surface you are finishing the easier each subsequent step will be.

Get the wood perfect before you whip out the product and you'll be smiling later.

On to specifics:

Warning: the products discussed are intended for professional use and are known to carry significant potential health risks. Proper care should be taken to insure that they are used in accordance with manufacturers recommended safety guidelines.

PPG K36 is a sand-able primer/sealer. It's is designed to spray over existing finishes, bare metal, etc to provide a consistent chemically stable surface for the topcoats to adhere to. Pro refinishers need this to go on fast, bond perfectly to *anything* clean and sand easily. Builds fast refers to the primers ability to quickly build up to a significantly thick level, a couple millimeters actually. in a minimum of coats. Every minute in the spray booth is money so pros need to cut the coats to a minimum and get the next rig in as soon as reasonable. If you can get adequate thickness in two coats you've got a product you can sell. It also needs to flash off or set up in less than 20 minutes as well. More of the time is money doctrine.

Once your primer has dried it's time to sand. In the case of K36 what I found was that id sanded very easy with little effort and did not clog even 400 grit paper, dry. It just came off in waves under the 9" block and contours were like butter. In my case I end up sanding off 75% of the accumulated primer leaving a smooth as glass surface that is perfectly matched for the basecoat coming next.

This is the last time abrasive less than 1500 grit should ever touch the surface of one of my guitars (not that that ever happens:-). In the case of the guitar I currently have in progress the next step is base coat. Since we're talking PPG in this thread I'm using a Deltron DBCxxxx base coat. I mix it with the appropriate reducer and shoot to cover. What this means is I'm not going for thickness or luster or shine, but simply to get the depth of color that I am personally looking for. This should not take more than 2-3 coats and will be fairly thin and dull. Runs, specs and such at this point need to be addressed with care. Super fine pointed instruments and purpose designed tools are best and you only have minutes to act before the finish sets up.

Once you have achieved a the desired depth and coverage of color it time to switch to the clear gun. High solids clears are the amazing. That finish on the new AMG Benz that you drool over in the parking lot at work? Two, maybe three coats and it will last for 25 years. It takes a while to get used to them, though. When they say "medium wet" coat they mean "lay this sucker on till you think it'll run off in sheets, then spray some more just for good measure" :-) I mean this goes on thick. It will flow out so smooth you may not even need to finish sand. Freakin' amazing stuff. Since I've already tossed out a couple PPG products here's another Concept 2021. Technique is pretty key with clears, you have to practice a bit to get a good feel. Wait till it flashes, maybe 10-20 minutes depending on ambient temperature then blast on another coat. If you think it needs another you're probably wrong but you may be able to get away with it.

Clean your guns, change the filters on your fresh air respirator and pop a cool one, you've earned it. The next day you'll need to decide if you need to hit it with 1500 or just a super fine cut cleaner (Maguire's #2, followed by #9 on a random orbit sander).

Assemble and play.

-jeff

[JTisMe]

What I did not do in the last post was address the cost of using these paints. You need multiple spray guns, a "better than Costco" compressor and most importantly a fresh air respirator system to keep the Isocyanates out of your lungs.

This is the technology that allow robots to paint thousands of cars a day in Michigan and Ohio and what's safe for a robot is not necessarily safe for an actual living being :-)

Since a climate controlled dust free spray environment is required for just about any finishing method (the old tree out back works just as well for this as it does nitro) that's a given.

-jeff

[VanKirk]

Great info. Thanks!

What part of Washington are you in?

[Mickguard]

PPG K36 is a sand-able primer/sealer. It's is designed to spray over existing finishes, bare metal, etc to provide a consistent

-jeff

Hey jeff,

Thanks for the heads up...clears up a lot of my questions!

Or almost-- will EVERY primer act as a sealer? All I have right now is automotive primer (same brand as the color and clear coats I'll be using). (I'm going to start a new thread with this question)

Obviously I'm not going to invest in a lot of expensive gear-- I'm only finishing two guitars!

I did however buy a good respirator mask with filters and I'm really glad I did. Cost me 30 euros.

I have a large old garage to work in. It's not dust free by any means, so what I've done is rig up a 'booth' of sorts ...Basically a couple of ladders boxed in and wrapped with a large sheet of plastic ...seems to work okay...so far with the tests I've done and the spraying I've done to my headstocks, they come out pretty clean.

I'm not going to rival a professional job, of course...I'm going for a two-meter 'foolability' level... (in other words, someone looking from a couple yards away will think it's a commercial guitar)...

[JTisMe]

I would not assume that any particular primer is also a sealer, although many are. While there is a overlap they do serve distinct purposes. Basically, a primer's job to provide an even, chemically compatible surface for the topcoats to adhere to. A sealer's job is to keep those topcoat chemicals isolated from what lies below (old paints, weird materials, etc.) to insure that no unpredicted reaction occurs which could cause blemishes in the finish. The best way to tell is ask your supplier. If you are buying off the shelf then try the manufacturers website, they usually have the tech and application sheets available, and some even have discussion boards hosted by reps.

-jeff

VanKirk - I'm up past Everett, although I do commute in Bellevue every day.

[www]

I just emailed you. My questions were answered after I read the whole post.

**Hijack**I wonder how many people are from Washington on the forum? 4 with Sacred anyone else.

[wolfcoast]

I was living in Washington (Bremerton) up until a few weeks ago.. I'm in the Navy and just finished moving to Guam now.

And the best part of it is.... I finally have a GARAGE!!!!. In Washington I had no real covered area to work and was HIGHLY dependent on the weather. I can finally have some place to work and start building.. Was practicing on pine for a while.. Have a nice Alder blank waiting for my first real attempt

[LGM Guitars]

I did however buy a good respirator mask with filters and I'm really glad I did. Cost me 30 euros.

That is not enough protection for spraying the K36 or any other isocyanate based paint.

I've used K36 for years, also Endura, I just always hesitate talking about them on here because the primers are typically worse than the paint itself, you tell somebody how great they are and some idiot will go buy it and spray it with minimal protection.

Isocynates are NOT Paints to use UNLESS you are fully prepared to use a fresh air (forced air positive pressure) respirator. Half mask pos pressure doesn't really cut it either as these paints will absorb through skin, eyes etc. They are also cumulative poisons meaning that they will never leave your system, they sit there forever.

Same with the clears, most of the urethane base paints are not that deadly (they still require a good respirator though) but the clears are deadly toxins as well.

In other words

BE CAREFUL!!!!!!!!!

[Mickguard]

I did however buy a good respirator mask with filters and I'm really glad I did. Cost me 30 euros.

That is not enough protection for spraying the K36 or any other isocyanate based paint.

In other words

BE CAREFUL!!!!!!!!!

Thanks for the heads up. You're right, you can't be too careful with this stuff.

Anyway, I'm not using K36, though, that's the other guy ;-D

...I'm using normal rattle cans...and even though I'm using a respirator (with filters rated for this usage), I'm not taking any chances...I spend very little time in there with the paints (in other words, I'm doing fast thin coats then running away...). I'm also heavily covered in clothing, gloves, even eye protection.

I'm not about to sacrifice my health for a guitar...