29 replies to this topic

[UCANG]

I have read in older posts around the place about applying either urethane high build or colour (in hidden areas and what not) over the top of Epotec 408 wet on wet. I've been checking the tech sheet and I can't see any mention of this. All I can see is recoat time frames from as low as 10 hours minimum.

 

I was advised against going wet on wet by a Protec informant over the phone, he said once cured, just sand and apply your next product over. So this is what I have been doing which is okay because my urethane high build does say "Fully cured 2 pack refinish coatings that have been degreased and sanded".

 

Although places like radiator support where I don't want any build, I wouldn't mind scuffing, applying more epoxy and putting colour over wet on wet.

Or say I have had to remove high build to do some more filler work on areas that weren't quite right, once I finished filling and sanding, I wouldn't mind to spray a coat of the epoxy and straight into the 3 coats of high build w/w. My 2k high build doesn't recommend being put over the top of alot of filler / bare metal without an epoxy put down first. 

 

Can colour (like a satin black) be put over the top of well cured epoxy once scuffed, or is it recommended to cut back, coat with more then colour wet on wet?

 

And if wet on wet IS possible, how long must I wait to get the second product on the first?

 

I will appreciate any insight

[slar]

Hi Ang, wet on wet can be done in many of the situations you have described but I have to ask why the hurry with your paint system.

Wet on wet painting can give a superior bond in some instances between coats of epoxy and high fill primers but when it comes to top coats you would really have to know what your doing cause there is so much that can go wrong like poor finish, shrinkage and peel.

Wet on wet is usually used in high production environments to save time and money.

 

As for painting satin black over cured epoxy....I havent tried it....but I have painted solid 2K over scuffed cured epoxy and will be using this method on my resto on the underside of the boot lid, bonnet and doors where I dont want high build.

 

Epotec 408 is an epoxy primer surfacer and a very good one......surfacer being the key word being that it can be used to refine the final surface finish before top coat as it easily sands flat and has excellent protection qualities

Up to you but if it was me I would slow down and let each coating cure completely, sand or scuff as required then top coat... it will be a way better job.

Just my opinion others may contradict this.

[UCANG]

Hey slar, thanks for the info and your opinion. I do agree with you and that's exactly what I do now (prime, let cure, scuff, next product). I have no trouble with slowing down as my build is already pretty damn slow

 

It's just my confusion has been aroused from reading threads stating to quickly recoat epoxy and then go over that with your next 2k system wet on wet for chemical bond with no need for sanding in between. However it doesn't bother me to scuff and clean epoxied areas not entirely visible and shoot a solid colour over it .

 

So you're saying WOW can be done with epotec 408? How long must you wait before spraying over?

 

But let's forget colour for now, and talk about 2k high build. I'm currently using the sand and shoot method and so far so good. Just being pedantic because if any issues should arise from using this method, i'd prefer to nip it in the bud now before I go wasting any more in product - as we all know, the reality is, product wastage equals money wastage.

 

Cheers mate!

[slar]

If i was going wow on epoxy i would wait at least the required flash off time as per technical data sheet making allowances for temperature ie cold day....wait longer before recoating.
Again i prefer letting it cure first....hi fill bonds really well to cured 408 as well as top coat.
Cheers

[UCANG]

Thanks for the input guys, pretty happy with that

[claysummers]

Old thread, but for some continuity I'm posting results of applying some protec DG jet black over flash dry epotec 408. It's only about 26 degrees in my shed but the humidity is below 60% and in using a heat gun to move things along on a pair of custom offset 6 inch HT rims I've made up for the front of my FB ute. Three good coats of epotec down with the 1.4mm gravity touch up gun.

early Holden nut

[UCANG]

Those rims look silky smooth!

I’ve had no problems shooting direct gloss over cured epotec or flashed off epotec. Although the WOW method, it’s best to be pretty damn patient and let it flash off real good!
Also one thing I did notice once, is sometimes the DG colour over the top of epotec after it had flashed isn’t as smooth and glossy as if you were to let cure, cut back smooth and then shoot. But that could also be due to 1 of many different scenarios.

[claysummers]

I lazy and inpatient which doesn't help.

I probably should have waited a couple of hours at least. Have to stick a heater under them now.

early Holden nut

[claysummers]

Managed to salvage the job I think.

early Holden nut

[71xu1]

Why 3 coats of epotec if you are going wet on wet?

[claysummers]

Just using what I’ve got. Rims cop a hiding. I had a half litre of Epotec plus 25% hardener plus some reducer to rinse out the tin. Only had about 250ml of colour mixed. Good thick coat of primer at least the rims will be well protected.


Sent from my iPad using Tapatalk

Epotec has good build properties so that smooths out imperfections in the rim centres also.


Sent from my iPad using Tapatalk

[71xu1]

Cool, they look great.

Edited by 71xu1, 06 September 2021 - 12:51 AM.

[grumpy xu1]

I can't remember the mixing ratio of the epotec, but i didn't think it was a high solid content, so 3 coats would be my advice, however using just epoxy & then putting a metalic over it could come back & bite you in the bum. I'm not a fan of wet on wet. & a high build or some sort of primer in my opinion should be used in between the epoxy & top coat, even if you thin it down. But i like to do something that lasts as long as possible. Re doing things drives me insane.

[claysummers]

4:1 plus 10-20% and it is specified as a primer surfacer Gary. I wouldn't have tried wet on wet on panels. But on componrnts like these, why not. The epotec had been sitting for 9 months and there was in the order of 20% solids settled out in the bottom of the tin. I was using a 1.4mm gun whereas 1.8 - 2mm is generally specified.

I expect the adhesion to be very good considering the short application interval. I'm more concerned about effect on the final finish.

early Holden nut

[grumpy xu1]

I was addressing Dave's question about why you applied 3 coats of epoxy, hence why i chipped in. I don't believe that the epotec is considered a high solids content epoxy, as is some of the ppg, which i had asumed Dave was referring to regarding the amount of coats. You can do whatever you wish, all i stated as a general comment on a open forum, was the way that every paint company would recommend the products to be applied. There is numerous reasons why a number of dramas could occur from not following their prefered procedures.

[claysummers]

All good Gary don’t take my reply as criticism of your comments please. I did read somewhere that it has good build qualities, but it may have been earlier in this thread.


Sent from my iPad using Tapatalk

[claysummers]

Actually what I read was that it stands flat and offers good protection. Certainly agree that three costs is the way to go, specially with a smaller nozzle, maybe four. Just my experience which is limited to painting one car in my shed.


Sent from my iPad using Tapatalk

[grumpy xu1]

To be honest with you, the 2 systems are fairly different. Epoxy etch is certainly the way to go. It should be used on either bare metal or back over to seal any repairs done over the top of it. High build is next as it forms an appropriate base for the top coat types. Hi builds should not be applied over bare metal though. You could have a variation in the colour & sheen consistency by only using epoxy & or wet on wet only over epoxy. A lot of companies will also state that using metalics over epoxy can result in finnish problems. So i would definitely suggest that people not do that. Hopefully yours goes all good. Sand blasting ect in the first place gives excellent adhesion as does following the correct flash times, this is very important, please follow the recommend flash times & add in for temperature.

[claysummers]

I have been using it successfully without filler, including with Para Glaze G113 Metallic one shot urethane. Generally with full cure and 400 or 240 grit key, depending on how long the Epotec has been down. This is only on components, not panels, and on the advice of Steve Turner at Lonsdale Paints. Locals will know of him. I wouldn’t have got past square one without his advice.

Panel wise I’ve been using it under acrylic with Dulon premium primer surfacer. I haven’t used any 2k high build as I’m generally applying acrylic colour.

Just thought I would try the wow so I could get this small job done with minimum effort and a durable result. Time will tell.


Sent from my iPad using Tapatalk

[grumpy xu1]

You can definitely use 2 pack high build under acrylic top coat. P 600 would be the very minimum I'd use prior to a top coat.

[71xu1]

Many ways to skin a cat . If going acrylic I generally go 2pac hi fill, wet rub 320 grit, good key for the 1k primer, then wet rub 1k primer with 600 grit. Although most are dry rubbing these days okay for hi volume just can't get my head around it for what I try to achieve.

[grumpy xu1]

I can't understand why you would put a 1k primer over the top of a 2k primer, so you can spray it in acrylic top coats. Just use the epoxy etch, then hi build. Acrylic paint will adhere & perform well over that. & the substrates should have less movement on each other. I prefer wet sanding aswell.

[claysummers]

Once again, just following advice of Steve my paint guy Gary. I don't doubt what you say about stability. Job is about 9 months and 8000km old and no overall issues so far. First time I've used a spray gun seriously.

Wet sanding is only way to go I'm my opinion. It is healthier as well as more efficient and better result. Haven't done much paint work but I've been making polyester surfboards 45 years.

early Holden nut

[claysummers]

I'll talk to Steve about using 2k hi fill next time.

early Holden nut