Epoxy as a sealer-time to base question

B

BoostedOne

This is my first time using epoxy as a sealer so I am already a bit nervous.
We are finish sanding the 2K(grey) and was hoping to get the white epoxy sealer on tonight to allow it it dry overnight per spi manual. I was going to do 2 coats because I am using ppg shopline white basecoat that will not cover very well.
Anyhow since we are running out of time, and I need to get tthe base shot tomorrow, how critical is the "overnight" dry time on 2 coats of epoxy as sealer vs the 2hrs for one coat? temps are in the mid 80s to 90 degrees. With those temps I am hoping 4 hrs is adequate? Maybe 5 tops?

And while I am on the subject, let me ask about the dilutionm. I see 5 to 50% mentioned. Is basically my goal to reduce it to the point that it drips like ready to spray basecoat(shooting for viscosity) or is there something else magic about the reducer ratio.

Thanks!!
 
well 2 coats doesn't mean much without the mix ratio. 2 coats sprayed at 1:1:1 for instance isnt very much but 2 coats at only 10% reduction is a bit thick for a sealer. if you are going for coverage then do 2 coats at 1:1:1. it will probably get you 60-70% covered without a ton of build. what i would do is get the epoxy on, let it set for an hour or two, spray the base then let it sit overnight and clear the next day.
 
I've been doing the epoxy sealer, spraying my base and clearing the next day, as jim recommended for me to try.. Works awesome this way.

Thanks for the tip jim.

However I have not tried this with two coats.
 
From a schedule standpoint I think that will work fine, epoxy and base today and clear tomorrow. Thanks! Will see how this goes.
 
Yeah usually i do tack off. Somehow even with the booth doors closed something settles on it
 
Again, thanks for the info. One thing I am curious about is why do you wait a day to clear?
And another question.. On unreduced epoxy typically you have a week to do something with it or you have to sand it all. Is there a difference if it was reduced? I don't see why, but I am not a chemist.

It worked out sorta great, sorta lousy, LOL... I'm still putting together funds to build another 40x40 building for parking vehicles and will also house a booth. Until then, I am still spraying in my pole barn which was converted to a shop. What worked out well is I was relieved to find that the reduced epoxy did truly spray and lay out like basecoat. I mixed 250ml epoxy, 250ml activator, stirred that for a minute or two, then added 250ml reducer. I think that would be 50% reduction?

Problem was....being a converted pole barn with the typical high center roof and lower side roof there is about a 1' vertical gap between the eave of my top roof and my side roofs. 9 times out of ten it makes for a nice, pleasant shop environment due to the ventilation, which is nice in Florida. As I we were finishing up the prep I could smell that there was rain coming, which is not usually a huge issue. Did 1 coat of epoxy.. Allowed it to flash, and because I wanted more hiding, I went for a second coat.

Keep in mind this is a small car, Dodge Neon.. It takes what, 15 minutes to spray a stage on the entire car?
Well, I got the roof, and passenger side shot with the second coat. Halfway through the side of the car my buddy went outside into the sunshine because he didn't have a respirator. I glance outside as I am doing the passenger fender, he's still sitting there messing on his phone. Halfway through the hood he comes running in, wet. By the time I get to the drivers side of the hood, its a full on downpour with the rain coming out of the North, wind blowing so hard the rain is at about a 30 degree angle from the ground... Well, the car was facing to the east, and the gaps between my roof I was mentioning are on the north and south sides of the building. SO.... The epoxy that was sprayed between 5 seconds and 5 minutes before this downpour began was either on the top of the vehicle, or on the north side... All of my fresh epoxy sealer was being pummeled by rain.:mad-new::mad-new: Thats the sorta lousy part.. No fault of the product, just a really crappy environment. On the other hand, I learned a new technique if I want to texture a surface to look like vynil/dashboard plastics!

Passenger side faired fine. I finally managed to get the roof, hood, and passenger side smoothed back out. Drivers side did not get affected. We are going to shoot for tomorrow morning(Friday) as the spray day.
I lost alot of time this week due to a minor injury to my shoulder Sunday night that prevented me from sanding on Monday, Tuesday was lost to the World Cup and still didn't want to stress my shoulder. So last night was when I got most of the car re-prepped. Wondering if I need to resand/scuff the drivers side if the reduced epoxy as sealer has been on there since Sunday. If not, my body would really appreciate it.
 
you dont have to resand that that side but you dont want to base right on it. you should mix an over reduced batch of epoxy and spray it before applying your base. epoxy does have a 7 day recoat window to put other primers or whatever you want on top but basecoat in my experience does not bond to cured epoxy well at all. for basecoat i limit it at 24hrs. after that i need to lay down more epoxy. the point of waiting overnight before you clear is to give a chance for all the solvent to come out of the paint film before you clear it. this will keep the paint shrinking and dulling to a minimum.
 
Hmmm, interesting. I assumed because epoxy was the only non-hygroscopic layer, that the solvents would escape just the same through the clear?

Great info on the basecoat vs other products over epoxy and the time frames. Do you think a 2K sealer would bond more like a primer or a basecoat? I grabbed some 2K sealer to use this go-round, because at the moment the car is in sanded white epoxy primer with several break throughs to grey 2K meaning I need to re-seal 60% of the car as it is... Considering the weather and other factors I need to have the basecoat on by noon, so I didn't want to lose 2-3 hours in dealing with the epoxy between the mixing/induction/flash time/dry time. Also squeezing me on that time frame is the car has deckstripes that need to get laid out. Sooo, figuring the time savings of the 2K is worth it in this scenario.. Just not sure if I need to scuff the cured epoxy prior to shooting it.
 
2k sealer over is fine. epoxy though you can mix it as a sealer and just got town like any other sealer. 10 min and your ready for base if you do it right. you already have epoxy down so you only need a super piss thin coat for adhesion. for the base always let it sit as long as you can. you dont want to bury or seal in solvents. sure they will come out after the clear is on over time but thats what you dont want. solvents coming out of the paint film down the road means the paint is shrinking into the surface. solvents out then clear.
 
The short story about waiting as long as possible to clear is that the more solvents you have trapped under the final layer of clear, the more gloss you will lose as time goes by as the solvents escape and the layers contract.
 
Yeah, makes sense after the explanation. Thanks alot.

As an update:
Job was an absolute fiasco, that I am happy that its almost over. Last post was last Thursday. The goal was to respray the car on Friday. Well, I managed to get home from work early enough to get the prep work done, and then a light rain came in which usually keeps the bugs at bay. So I went a step further and sealed the car with a 2K sealer, and even shot the base coat thursday night. That left only doing the deck stripes and clear Friday morning.

Friday morning buddy came over and we laid out the stripes. Planned to be done by noon. we were well on track until during the second coat on the stripes the fine line tape lifted at the end of the trunk :disgust: It was pulled too tight at the radius of one of the ends and seperated from the rest of the masking. My buddy had a plan to fix it, which didn't work. So after giving the base an hour to dry I ripped all the masking off the trunk and hit it with 320 and 600 to get rid of all the mess, and this time shot the entire area in blue(stripe color), then back masked the stripes, then painted the rest of the trunk white to match the rest of the car.. Finally got to shooting the clear at about 4 or 5pm.

The car did come out pretty nice for an open air barn job. Its obviously got some dust in it, and a gnat here and there. But I would say the car is a really nice 5 footer.. Where as 3 weeks ago it needed a new roof and looked horrible from 100 feet.

Glass should be going in tomorrow morning and will be wrapping it up!
 
Hey. I realize that this thread is from 2014 but it is all I could find on flash time for reduced epoxy.

The perfect paint job document says to let it sit for 6 hours. This old thread seems to say you can Get away with a lot shorter time.

Six hours is tough because I like to spray in the morning before it gets hot and windy. I’d like to mix 1:1:.5 but I’d only like to wait like 1or 2 hours.

Am I asking for trouble doing that?
 
1:1:1 (1:1:50%) can be recoated with base in as little as 30 minutes depending on conditions. Is it ideal? Depends on what you are doing. 1:1:1/2 (1:1:25%) can be recoated in 2 hours depending on conditions. You are better off waiting longer. Ideally you want to give the epoxy enough time to completely flash off/evaporate the solvents so there is no chance of dieback or trapping solvents in your base and them clear. The time in the perfect paint job reflects that. I can't really speak to how far you can push it because when I use epoxy as a sealer it is for a job where time is not the main factor. If time is a factor I will use urethane sealer.
When you push the recoat window the greater the chance you can have issues relating to it. If time is of the essence and you need to seal and then base within an hour or two, you may want to consider using a 2k urethane sealer. Rushing your sealer when using epoxy can lead to a lot of problems none of them good and many that will require a complete re-do of the paint job.
 
Ok thanks Chris. I appreciate your help. I’ll figure out how to wait 6hrs. I’d like to avoid taking any chances. Better to do it right than do it twice.
 
You must log in or register to reply here.
Back
Top