SPI base not adhering to SPI epoxy

[Kenzie]

On the 26th I sprayed 2-3 coats of white epoxy on my side mirrors (abs body on a metal base) 30 mins between coats, sprayed around 8 pm near the open garage door when it was likely around 93-95 out with 30-40% humidity. I’m new to painting so I probably had some areas heavier than others but the epoxy seemed to go on without issue.
The next day at around the same time and under the same conditions I sprayed 3-4 coats of SPI white basecoat (2011-1) with very slow reducer and a capful of very slow activator, waiting 30 minutes between each. Due to their odd shape, and me being a complete newb, I know for sure my coats weren’t even on the base.
The next day I accidentally scratched my nail on the underside of one of the bodies and the base flaked right off the epoxy. I gave it till today before checking again but it’s the same. While sanding them back down it seems like it’s just patches that didn’t adhere and other are areas are just fine.

I’m really hoping this was just caused by me being too heavy handed on some of the hard to reach places. I haven’t checked any of the other parts I painted in the same batch yet

 

[Kenzie]

Update: I tested two of the other parts I primed/painted in the same batch and they peel as well. They’re painted much more evenly since they’re not oddly shaped but the places where they’re peeling seem like they actually might be a little thin (undersides and edges that are fully covered but seemingly not as thick) I was just making sure that everything was evenly white, not that the base was thick necessarily, because it will all get 2 coats of heavy flake in intercoat and 4-8 coats of clear before it’s done. The white base likely won’t even be visible in the end.
I’m not sure where to go from here. I still have the body of the car and hard top to prime/paint but I don’t want to proceed if I’m doing something wrong (although I’ve been following the perfect paint job procedure, I thought) I have *just* enough epoxy to finish.

 

[dhutton01]

I think maybe next day is too soon to spray base over 3 coats of epoxy. I would have waited 48 hours.

Mandatory backyard hack disclaimer inserted here….

 

[Kenzie]

I think maybe next day is too soon to spray base over 3 coats of epoxy. I would have waited 48 hours.

Mandatory backyard hack disclaimer inserted here….

Someone on the Facebook group just suggested this as well.
I was just referencing some of the info I have saved as well as the tech manual in an attempt to find where I had gotten the idea that the max I could wait before applying base was 24 hours. In the “Important Notes” at the end of the “Epoxy primer” pages it states, “If the vehicle does not leave the booth, you can apply any premium quality basecoat or single stage up to 24 hours after the epoxy without sanding first.”
I wanted to avoid sanding (since some of the parts have complex curves and tight spaces) and I didn’t have enough primer left to do a sealer coat if I waited too long.

 

[Jimthecarguy]

Was the epoxy reduced?

 

[dhutton01]

Someone on the Facebook group just suggested this as well.
I was just referencing some of the info I have saved as well as the tech manual in an attempt to find where I had gotten the idea that the max I could wait before applying base was 24 hours. In the “Important Notes” at the end of the “Epoxy primer” pages it states, “If the vehicle does not leave the booth, you can apply any premium quality basecoat or single stage up to 24 hours after the epoxy without sanding first.”
I wanted to avoid sanding (since some of the parts have complex curves and tight spaces) and I didn’t have enough primer left to do a sealer coat if I waited too long.

I think that is referring to reduced epoxy. Three coats of unreduced epoxy likely needs 48 hours. At least that is what I would do.

Don

 

[Jim C]

24 hours is generally fine for epoxy BUT wait time and how heavy or # of coats really plays a factor. 1 super thin reduced coat can be based on in say 15-20 minutes while 2 med coats is 24 hours, 3 heavy coats maybe 48 hours. its hard to say if what you did would cause an adhesion issue though. typically what i see in the pictures is what would be typical if you let say 2 coats cure for 4-5 days then base directly on it.

 

[strum456]

24 hours is generally fine for epoxy BUT wait time and how heavy or # of coats really plays a factor. 1 super thin reduced coat can be based on in say 15-20 minutes while 2 med coats is 24 hours, 3 heavy coats maybe 48 hours. its hard to say if what you did would cause an adhesion issue though. typically what i see in the pictures is what would be typical if you let say 2 coats cure for 4-5 days then base directly on it.

I wonder if the epoxy got some time in direct sun with the open garage door.

 

['68 Coronet R/T]

I guess I never read the "Important Notes" in the Tech Manual before. The wording does make it sound like you need to apply "within 24 hours".

When I look at the first picture, it seems there are 4 layers there. Could it be one of the lower layers reacting with/to the epoxy???

 

[Kenzie]

Before doing anything else I called the tech line this morning (one of the main reasons I chose SPI, even though I hate feeling like a pest)
I believe I spoke with Barry (I’m terrible with names ) he was awesome and told me not to worry, it’s likely that everything just hadn’t finished curing. It’s also been pretty humid here in AR and that’s probably contributing to a longer cure time. He says the “chipping” isn’t as much of a concern as “peeling” is and it’s definitely just tiny flakes, no smooth peels.
He’s suggested a few solid days in direct sun and then reassess the spots where I did the test scratches.
All the parts I’ve primed/painted over the last few weeks are now chilling out next to my shop so we’ll see how they look over the next few days.

 

[dhutton01]

“I believe I spoke with Barry (I’m terrible with names )”

Had to LOL at that….

Barry is the recently unretired? owner of SPI….

Don

 

[Kenzie]

“I believe I spoke with Barry (I’m terrible with names )”

Had to LOL at that….

Barry is the recently unretired? owner of SPI….

Don

Yea I know who Barry is, primarily from the forums here, I just wasn’t sure if he was the person I spoke with…I don’t even know if there is anyone else I could even have gotten ahold of on the tech line though

 

[Kenzie]

One of the big reasons I went with white for this car is to keep the inside a little cooler (it’s a 94 Miata…the AC can only do so much and track days get HOT with the AC off and gear on) but that’s working against me now
Panel temp on the black car next to the parts is 146-153 while the parts are only 96-113. Our UV index today is 10.4 and this spot gets sun until just before sunset, so let’s hope it does the trick

 

[Rbm]

You sure the mirror is ABS ?

 

[Kenzie]

You sure the mirror is ABS ?

No, but the adhesion in question is between the epoxy and basecoat and it’s happening on the plastic part of the mirror as well as the metal. It’s also happening to other parts I’ve primed and painted over the last few weeks and they’re a variety of materials. The only thing I sprayed that needed adhesion promotor (float test) was the back bumper and it’s chipping the same.

 

[Jim C]

i know barry said he would not be worried yet but that would make me nervous. i personally have never had that happen with base on fresh epoxy, only too cured epoxy. was both the epoxy and basecoat shaken really well? nothing in the bottom of the cans? was this new materials or stuff you had used on another job or jobs? i have seen that when paint is not mixed great and it gets used. it starts out ok as resin is on top and pigments on the bottom but as you use more of it then eventually your mix has too much pigments for the resin and its overloaded and wont adhere right.

 

[Kenzie]

i know barry said he would not be worried yet but that would make me nervous. i personally have never had that happen with base on fresh epoxy, only too cured epoxy. was both the epoxy and basecoat shaken really well? nothing in the bottom of the cans? was this new materials or stuff you had used on another job or jobs? i have seen that when paint is not mixed great and it gets used. it starts out ok as resin is on top and pigments on the bottom but as you use more of it then eventually your mix has too much pigments for the resin and its overloaded and wont adhere right.

The epoxy is from late Nov or early Dec and has always been stirred till there was no sludge on the bottom (I actually thought something was wrong with it when I first got it because it took so long to stir, lol) All my materials are stored in our climate controlled office that’s kept around 70-74°.
I mixed the epoxy well in a dedicated, clean paint cup and put the lid on. I keep it in the office as well till I’m ready to use it (usually a few hours) and stir or swirl it a few times when I go through the office during the day. Before pouring in the gun I stir it again and strain it with 60-70 mesh strainers from Harbor Freight.
The base was purchased in May, I believe. Mixed immediately before using, stirred well, and strained.

I didn’t wipe the panel down with anything between the epoxy and paint, just sprayed it off with air, visually inspected, and sprayed.

The air hose I use is only used for paint and ran through a Harbor Freight air dryer (along with a few in-line Husky filters between that and the compressor)

Everything is back in the sun today (since 9am) but every time I barely touch any of the flexible parts the paint just cracks and falls off. I’m trying to be patient but I’m honestly really bummed with myself and feel like I must have messed up somewhere.

This is all on my 94 Miata that I take to autocross and road courses occasionally, so I’m not too worried about it in the long run. But it’s practice for my Yukon XL Denali that has factory white paint that is starting to peel pretty badly. I was hoping to repaint it myself next year and I absolutely care about it looking as nice as possible.

 

[Kenzie]

This was the epoxy the first time I stirred it. It took forever to stir but just as I was about to throw in the towel and post this picture asking if it was normal it finally started to smooth out. Now it just takes a few minutes to break up the bottom of the can, seems fine to me.

 

['68 Coronet R/T]

I'm not sure what is happening here but having painted a 1990 Miata (and a bunch of other vehicles) using SPI Epoxy, 2k Build Primer and Euro Clear, it makes me wonder if something got mixed wrong? The other possibility is a contaminant entering via the air supply or maybe even the mixing cups?

 

[Jim C]

Yeah thats normal for epoxy to settle out in the can when it sits for awhile. I honestly dont see anything wrong with your procedure unless you sprayed the base really dry for some reason. At this point i would take reducer and a rag and wipe the base off the epoxy, give the epoxy a good sanding with 320-400, shoot a sealer coat of it mixed 1:1:1, give it a 20min flash then put your base right on it. Should be good to go after that