What primer to use with DuPont Centari as the topcoat??

I use DP alot......under Dupont, HOK, Valspar, AutoAir, etc....never a problem.
Even used other primers over it like Evercoat and Dupont Velvaseal....
Let it cure a few days and scuff with a Scotch-Brite pad....
I just used DPLF40 on an Impala, with Valspar base over it, because I had a little bit of it left over from a previous project....admittedly though, I don't like how the LF sprays out.

 

You've just been chip screwed. I never let a customer pick a color off of a chip. Find a car with the color or buy 4 oz and do a spray out. Last time this happened to me a guy wanted a pretty blue and ended up with purple. Color chips are ****.

I guess it depends on the supplier and the volume of business you do but if they mix it you own it. Let them tint the paint at the store to match the chip and make sure and record what they added and how much so you can match it in the future.

 

DP is a ***** to sand dry and if you let DP cure out you have to sand it according to the tech sheets. The trick to sanding DP (or any other epoxy primer) is to wet sand it (220 is a decent start).....cuts like ****er, feathers out mint and doesn't ball up nearly as bad as if you dry sanded it.

-Bigchief.

 

Shoot a test panel (over the sealer your actually going to use on the car) before you shoot the counter guy. We just painted my '48 Ford in its original Maize yellow and the paint in the can had me a bit worried......once the clear was shot it looked fine, especially out in the sun.

In this day and age where they can shoot the surface directly with a spectrophotometer that'll spit back a paint formula then there's no excuse for the color being way off....and if it is they should at least tint it with you standing there so you can tell them when its good. If its really far off the mark and they don't want to help you out then its time to return the materials and find another supplier that'll work with you.

-Bigchief.

 

For any bare metal use an epoxy primer, probably go with Duponts 491-16 epoxy. Then for a sandable primer use 421-08 its made to go under enamels. Then seal it with 422-23. Then shoot your topcoat. You can find all these at your local dupont store.[FONT=Arial,BoldItalic]
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do you want a primer for build and sand then paint ?or a sealer then paint ?if you want to just seal it. then use dupount 1986s then paint it dont mix products..

 

Well,... months later (just a few mind you), and there are several areas, where the paint has chipped off by barely bumping the body at certain points, (ie. top irons mounting tabs, rounded edge of cowl, seat area,...etc.) I haven't the vaguest idea what the hell is going on here.
I was so rediculously **** about prepping everything just right to! Degreaser (presol), followed by a dry cloth, then wipinng everything down with acetone. All this after scuffing the entire body with red scotchbrite.

Here's the general process I followed in a nutshell:

prepped bare metal,... & scuffed
shot with DPLF40,...(three coats)
3-4 coats PPG high build primer,..(sanded betwen coats with red scotchbrite, then 600grit, and finally 1000 grit)
1 coat primer sealer (ppg product)....
3-4 coats of centari,...

Its weird to, because at some points the primer is still adhearing where as at many others, "everything" comes off in chips!?

I'll take a photo tomorrow,...

I can't figure this out. Temp was correct. Time between coats, mixing, etc. was spot on. I referred to the tech sheets every other time to make 110% sure I wasn't out of line when doing everything from priming to the top coat. No moisture in line,.... I'm stumped, and a bit PO'd....

 

DP40 is meant for bare metal .. not to be sanded.. how ever it can be scotchbrited to apply fillers over top of. it stays soft for a long time and is gummy when sanded ... it was never meant as a primer or a sealer for top coats.. Dp40 is a product that can be used after sand blasting has been done to protect the metal from corroding..and it works very well for that..

as for the Centari .. it was a good product at the time.. it covered well. as for what primer to use.. you can use a Hi build primer.3 plus 1 or 4 plus 1 . but I do believe a dupont sealer should be used before your top coat of color.... for proper binding.. dont sand your primer too smooth.. I wouldnt go any finer than 320.. you need the scratch for making it bind.. to smooth the paint will just sit on top.. and may peel..

some one might say different,, but this is from what I have experienced from the past..

 

I believe you did to good of a job! Bare metal 180-220 grit, and
primer 360-400 grit max. You need the 'tooth' as mentioned
mentioned by plodge55aqua.
Rich

 

Your sanding/prep was a little off which gave you bad adhesion on all the layers. For the are metal, a scuff will not do. Most reccomend nothing over 150, I personally won't go over 80. I try to stick to 40 in borad areas of bare metal. I'd rather spend some time sanding out a few scratches later on than have anything peel or chip.

The high build primer should have been applied wet-wet-wet. No sanding scuffing or anything needed in between, but thats not the major problem. Once the body is straight with the high build, block it up to and never above 400. I personally stick to 320. Then sealer, wet on wet with your Centari.

IMO, the entire job is compromised and needs to be redone. But at least you have an answer now.

 

I said "scuffed" at first regarding the prep work on the bare metal,... that was wrong.

I "should" have wrote, I used 180 grit, and "sanded" it with 180, not "scuffed" with scotchbrite!!
That's what you get for writing to late! Sorry guys.

So, yes, that's what I did right off the bat to the bare metal.
(it was top coated back in the beginning of Oct. hence my lousy recollection at about 1:30AM!)

The rest is pretty much correct though. Never sanded the DP,... only the high build, and yeah, final high built coat WAS actually "wet sanded!" with 1000 grit. That was actually recommended to me via a good friend who works at a body shop, actually near by "hot rod" shop!? I really can't imagine I was intentionally being F'd over with bad info here?

 

Which layers are actually coming off? I am guessing your base/clear is flaking off and leaving the surfacer primer showing?

 

My dad always told me, "If you want to get rich, don't talk to a bum, talk to someone who has done it already." Having said that, at Sema this past year, I talked to a few of the greats of the paint world. House of Kolors, Hot Hues just to name a couple that I remember, when I asked if they heard of a guy named Squeeg, they all said with a resounding yes and a story followed about a car they saw or heard of him doing.

Squeeg makes his own epoxy primer/filler/sealer and has used it exclusively for like over 15 years with no problems. That was enough for me to start using it and so far I like it. I don't so much mind the pastel yellow but others don't seem to like it. The only thing about this primer though is it's definitely not for production work. It takes a while to fully cure. But over all so far it's been great so X3 on the Squeeg's.

 

Old school lacquer primer, any brand, works fine under Centari. I've used this method for years. Not complicated, easy can do, works good, lasts a long time. (Wear a good mask especially when shooting catalyzed paint.) pigpen

 

The materials you're using are completely fine
-BUT I'm a little confused about some of this..


180 for bare metal? Honestly, if you're using 180 on a DA- it's really only "180 grit" for the first minute or less, after that, it's more like 320 and you're polishing the metal. The metal will be nice and clean, but not have much of a mechanical etch.
...180 grit (open coat) by hand isn't horrible, but definitely far from ideal under epoxy primer.


High build primer? ...is meant to fill aggressive sanding scratches. I would NEVER spray high solids primer over anything finer than 400 wetsand scratches.

Sealers (Del-Seal?, K36?) can take a finer scratch, but I swear- nothing finer than 600 wetsand.

If you sand into the chipped areas, and the material doesn't "feather" evenly, you'll be able to locate where your adhesion problem is coming from. If there is a shiny edge in front of any of the layers as they are sanded away, or if a layer wants to tear away in patterns instead of making a soft edge- it will be easy to locate the source.

If you have alot of material on the car--and sprayed in an environment where the metal of the car stayed relatively cool, and never really reached a good "cure" temperature for a day or two, you may also experience these problems as the job starts to really cure. Particularly if you don't have good mechanical etching.

Good luck.

 

This is a Centari out of the gun green/black no buff job. Acid etched metal, DP primer first, (DTM is ok also) Appropriate number of applications of Dupont Euro Fill next wet blocked with 320 then 400 and final sanded with 600 wet ( 1000 is too fine ) One coat of Velva seal , specks removed with 600, followed with 3 full coats Centari/hardener. Nothing was sprayed excessively thick and all excess material was sanded off to avoid too much film build. Sprayed in my shop built cross draft booth with a Devilbiss JGA conventional gun. Easily mistaken for a clear coat finish. JW

 

Like Fridge said, even 180 is too soft. Theres problem #1.

Problem #2 is 1000 before a sealer. Not a chance. Either your friend works for Maaco or he sweeps the floors in a real shop. The absolute highest I will ever go before a sealer is 600 wet. And thats only when its recommended in the sheets. Most of the time its 320. By the time all the sealer and topcoat are on, those scratches have all but evened themselves out. And cutting and buffing the final wipes anything left.

 

I agree...not enough bite. I'll 80/DA 120/hand bare metal, hit it with plenty of DP and let that set up for at least a day. Knock that down with 120 on a stick/block. From that point on its filler first then high-build urethane primer (K36 or 2K) until the panels are right. The filler gets the normal 80 through 180 treatment, the high build gets 180 on a stick or block.....pile it on heavy, knock it down ...repeat untill the panel is dead on. The second to last coat of high build sits on the car as long as I can stand it. Block that coat with special attention to detal, edging, etc. The last coat of urethane is reduced, sometimes sprayed through a conventional gun, and layed on smooth. More to fill any minor imps and sand scratches than anything else. Blocking of the final coat of urethane is usually done with 360 (wet) followed by a 'good going over' of every square inch with gray (fine) Scotchbright (dry). Clean/prep for paint. Then two coats of DP mixed as a sealer goes down as smooth as you can get it, let that flash off and sit for an hour then hit it with topcoat of your choice. I've never had anything go totally wrong with this method.

-Bigchief.