Opinion on which primer system for 68 mustang with new panels.

ndaniel246

New Member
I have a 68 mustang Ive built with all new dynacorn sheet metal. so the panels are straight, no dents but have some waves that are typical of new panels.

I wanted some opinions from those more knowledgeable than myself about which system I should use for this situation

DTM polyester primer for laser straight panel and then seal with epoxy followed by basecoat/clearcoat?

or

epoxy and then highbuild urethane followed by basecoat/clearcoat?

I have heard of epoxy, then polyester, then 2k

I have also heard of filler then epoxy and basecoat/clearcoat if panels are straight...given that polyester primer is sprayable filler, i figured 3 coasts of polyester primer (roughly a gallon) followed by 2 maybe 3 coats of epoxy as a sealer would be perfect.

What are your thoughts on this? Like I said there arent any dents, just waves from being a new pannel but if the poly gives a better base with less shrinkage and pullback than a 2k and the epoxy is a better sealer and more waterproof than 2k why wouldnt I just polyester primer and then epoxy as a sealer? My thought process may be wrong but thats where my head is at right now.

Thoughts are appreciated.
 
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texasking

Active Member
80# da to metal, clean with 700, wait an hour or more, 2-3 coats epoxy unreduced. Wait 48 hrs. up to 7 days, spray poly primer, guide coat, block with 80-120 and see what you have. You may need filler to fix some of those "waves". Don't expect 2K to repair them, not what it is made for.
 

ndaniel246

New Member
80# da to metal, clean with 700, wait an hour or more, 2-3 coats epoxy unreduced. Wait 48 hrs. up to 7 days, spray poly primer, guide coat, block with 80-120 and see what you have. You may need filler to fix some of those "waves". Don't expect 2K to repair them, not what it is made for.
Ok, so you think i should epoxy first then polyester? Ive heard polyester isnt water proof so I would need to either seal with epoxy or 2k on top of the poly correct? I would prefer epoxy so I dont have to buy another product if basecoat/clearcoat are good to put over epoxy.

if the polyester primer is direct to metal. could I not spray the polyester direct to metal to get it straight first and then seal everything off with the water proof epoxy for a corrosion barrier?
I now many times you filler direct to metal and then epoxy over the filler and given that poly promer is sprayable filler would that be acceptable?

Im just trying to get it all straight. theres is alot of overlap in the uses of the primers even though they are all a little different.

Thanks for the help!
 

El Toro

Member
Evercoat has a newer product that is a 4:1 mix Polyester primer that is a direct to metal product ?? BUT I would still go what Texas said 80 grit to bare metal then SPI epoxy primer wait 48 hr then poly. And epoxy as a sealer coat. The Car sounds like it's worth doing it right. Keep us posted and some pic's
 

texasking

Active Member
@ndaniel246 Metal needs epoxy FIRST. Don't believe all the DTM hype. No polyester or urethane has the corrosion protection SPI epoxy has, period. Not even close. Once you get the epoxy down, you have a solid foundation for whatever product you want to use next, and the foundation is the key to longevity. The reason the epoxy is such a good sealer before base is it is impervious to solvent or moisture. Wouldn't you want that on your metal?
 

ndaniel246

New Member
Evercoat has a newer product that is a 4:1 mix Polyester primer that is a direct to metal product ?? BUT I would still go what Texas said 80 grit to bare metal then SPI epoxy primer wait 48 hr then poly. And epoxy as a sealer coat. The Car sounds like it's worth doing it right. Keep us posted and some pic's
Thanks for that! No Problem with epoxy first. I guess the main thing I wanted to confirm was that poly primer does need a sealer on top of it before base/clear coat and that epoxy is ok as that sealer as most things I have seen have 2k as the last step. Just wanted to confirm epoxy as a sealer after poly and before base/clear was cool.

Ill make sure to post some up in the next few weeks!
 

ndaniel246

New Member
@ndaniel246 Metal needs epoxy FIRST. Don't believe all the DTM hype. No polyester or urethane has the corrosion protection SPI epoxy has, period. Not even close. Once you get the epoxy down, you have a solid foundation for whatever product you want to use next, and the foundation is the key to longevity. The reason the epoxy is such a good sealer before base is it is impervious to solvent or moisture. Wouldn't you want that on your metal?
DTM just means it can be sprayed direct to metal. I know tha poly prmers are not water proof which is why I was always planning on using epoxy. I was really asking since Im using polyester primer that says it can be sprayed direct to metal without a primer base, and since its basically sprayable filler which is used before epoxy usually and then sealed with the epoxy after blocked, can i use polyester first and then seal everything with the epoxy after blocksanding the poly primer. It would still be sealed with epoxy regardless to protect from corrosion but I was trying to avoid blowing the car up to epoxy all panels then putting panels back for poly primer and blocksanding to line up all style lines and then blow the car up again to seal everything and then paint.

If i can spray the poly dtm, then block sand, then blow up the car and seal all panels front and back, then paint it would save me alot of time. I was always going to seal with epoxy. i was hoping to only have to blow up car and seal everything once. I hope that makes since. most poly primers are not dtm and require a primer base but there are several that have good adhesion to bare metal though.

Thanks for the input, the help is appreciated
 

Raymond_B

Hobbyist
The guys are trying to tell you (not sure you're making the connection) that Epoxy pretty much ALWAYS first, filler can be put over the Epoxy. So again Epoxy as the starting point over bare clean metal.
 

Chris_Hamilton

Trying to be the best me, I can be
Not all epoxies are created equal. SPI is the best automotive epoxy on the market. The old standard was PPG DP (not the DPLF crap they sell now) and many of us lamented that it was no longer available. SPI is a better epoxy than PPG DP and that's why so many of us swear by it and sing it's praises.
Think of it like a foundation for a home. Whatever you build over your foundation is only as good as the foundation itself.
It's all about adhesion and corrosion protection. SPI EPoxy has superior (the best there is) adhesion and corrosion protection. It is the best base for any paint job. Flexibility is outstanding as well. If you want a solid job like TK outlined above, start with 80 grit DA'ed bare metal, 2 coats of epoxy, do any filler work over the epoxy, re-epoxy and go from there with either more epoxy, 2k urethane or poly.

Do a search and read some of the many threads here about it.
Read the tech manual as well.
 

RosharonRooster

Active Member
Might i just add my 2 cents. Those repop panels arent as straight as they look. Trust me. The ecoat on there gives off a good sheen and they may look good but some 180 and guide coat is going to tell you the truth. I just finished prepping my 61 fenders and my process was this.

1. Bare metal with 60 grit then 80 grit
2. 2 coats epoxy
3.poly primer over rust repair patch
4. 80 grit and guide coat the poly. (It says start with 320, dont believe it just like it says DTM.
5. Little filler work 80 and 180
6. 2k primer 2 heavy coats
7. Guide coat and block 320
8. 2k primer again. Guide coat and 600 wet.

Waiting for rain to stop so i can paint
I like evercoat super build more than i like slicksand. But both seem to have a hardened shell that u have to crack open with 80 grit first then 180. I dont see how they claim to sand that with 400 then basecoat. Unless im doing something wrong
 

ndaniel246

New Member
Might i just add my 2 cents. Those repop panels arent as straight as they look. Trust me. The ecoat on there gives off a good sheen and they may look good but some 180 and guide coat is going to tell you the truth. I just finished prepping my 61 fenders and my process was this.

1. Bare metal with 60 grit then 80 grit
2. 2 coats epoxy
3.poly primer over rust repair patch
4. 80 grit and guide coat the poly. (It says start with 320, dont believe it just like it says DTM.
5. Little filler work 80 and 180
6. 2k primer 2 heavy coats
7. Guide coat and block 320
8. 2k primer again. Guide coat and 600 wet.

Waiting for rain to stop so i can paint
I like evercoat super build more than i like slicksand. But both seem to have a hardened shell that u have to crack open with 80 grit first then 180. I dont see how they claim to sand that with 400 then basecoat. Unless im doing something wrong
Thanks for you input.

I think my procedure is going to be nearly identical. Can I ask why you chose 2k urethane instead of epoxy as a final sealer before painting? Just curious as to why one would choose one over the other. I know the standard is to 2k over epoxy before basecoat because it fills and blocks to a degreee but if I use poly primer after epoxy Im wondering if there are benefits of using 2k instead of epoxy for a sealer before paint?

Please dont think im arguing or disagreeing with what youve done. Just trying to understand the theory behind using the different primers for my specific application and if basecoat adheres as well to epoxy sealer as 2k sealer it would save me from having to buy a 3rd product. Does 2k make a flatter surface to paint on or if I cut the epoxy with 400-600 before basecoat will I get the same result?

So I was going to:
epoxy
poly prime and block
epoxy seal and cut with 400-600
basecoat/clearcoat

I can use 2k instead of epoxy to clear but i would like to not buy a 3rd product if the 2 work the same. If 2k is superior before basecoat then thats an easy decision. just trying to understand all the differences.

Thanks again
 
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RosharonRooster

Active Member
Thanks for you input.

I think my procedure is going to be nearly identical. Can I ask why you chose 2k urethane instead of epoxy as a final sealer before painting? Just curious as to why one would choose one over the other. I know the standard is to 2k over epoxy before basecoat because it fills and blocks to a degreee but if I use poly primer after epoxy Im wondering if there are benefits of using 2k instead of epoxy for a sealer before paint?

Please dont think im arguing or disagreeing with what youve done. Just trying to understand the theory behind using the different primers for my specific application and if basecoat adheres as well to epoxy sealer as 2k sealer it would save me from having to buy a 3rd product.

Thanks again
Let me be clear. I dont do this for a living lol. I work in healthcare . but i like to restore rust buckets on the side. Me personally i dont have a booth. I have a spray foamed insulated paint room. I use epoxy as a sealer when i have break thru between 2k and filler etc. If i 600 grit the 2k without break thru i spray over that depend on the color of basecoat. Sometimes when i spray epoxy as a sealer i get trash because of the environment and that results in more work. The epoxy is basically a sprayable glue. So dust sticks to it. Unlike spraying basecoat over a wax and greased 600 grit panel. I always epoxy over bare metal. I think the poly primers are meant to be finished in 180 grit. I cant see them being finished in 400 or 600. I think epoxy is step 1. Poly step 2. 2k step 3. And sealer is optional. 2k primer sand finer than the poly to answer your question. Poly is sprayable body filler and epoxy if sprayable glue. U dont sand bondo with 400 grit so i wouldnt sand poly with it either.

Someone correct me if im wrong but a urethane sealer is only used to make a panel uniform for better basecoat coverage. Where as epoxy offers that plus adhesion
 

ndaniel246

New Member
Let me be clear. I dont do this for a living lol. I work in healthcare . but i like to restore rust buckets on the side. Me personally i dont have a booth. I have a spray foamed insulated paint room. I use epoxy as a sealer when i have break thru between 2k and filler etc. If i 600 grit the 2k without break thru i spray over that depend on the color of basecoat. Sometimes when i spray epoxy as a sealer i get trash because of the environment and that results in more work. The epoxy is basically a sprayable glue. So dust sticks to it. Unlike spraying basecoat over a wax and greased 600 grit panel. I always epoxy over bare metal. I think the poly primers are meant to be finished in 180 grit. I cant see them being finished in 400 or 600. I think epoxy is step 1. Poly step 2. 2k step 3. And sealer is optional. 2k primer sand finer than the poly to answer your question. Poly is sprayable body filler and epoxy if sprayable glue. U dont sand bondo with 400 grit so i wouldnt sand poly with it either.

Someone correct me if im wrong but a urethane sealer is only used to make a panel uniform for better basecoat coverage. Where as epoxy offers that plus adhesion
That makes sense. Just to be clear I wont paint over poly primer I will put either epoxy or 2k over the poly primer. Im just not sure which one. If 2k and epoxy give the same quality base when used as a sealer I will just epoxy over bare metal, poly prime and block, then epoxy seal and cut with 400-600 to prevent me from having to buy the 3rd product

If 2k gives a better base than epoxy for basecoat then I will epoxy over bare metal, poly prime and block, then seal with 2k and cut with 400-600. The 3rd product isnt that big of a deal I was just hoping to save 100$ if there was no real need for the 2k with my application.

Im probably way over thinking this and if im just way off please tell me. welding and bodywork is much easier for me!!!
 

RosharonRooster

Active Member
That makes sense. Just to be clear I wont paint over poly primer I will put either epoxy or 2k over the poly primer. Im just not sure which one. If 2k and epoxy give the same quality base when used as a sealer I will just epoxy over bare metal, poly prime and block, then epoxy seal and cut with 400-600 to prevent me from having to buy the 3rd product

If 2k gives a better base than epoxy for basecoat then I will epoxy over bare metal, poly prime and block, then seal with 2k and cut with 400-600. The 3rd product isnt that big of a deal I was just hoping to save 100$ if there was no real need for the 2k with my application.

Im probably way over thinking this and if im just way off please tell me. welding and bodywork is much easier for me!!!
Ill trade you. I suck at sheet metal work but i love blocking 180 grit lol
 

texasking

Active Member
There is nothing wrong with 2K when used correctly. The 2K is not superior to epoxy before basecoat, but it is acceptable and easier to sand. On a vehicle like yours, epoxy is the ultimate. On an everyday driver or collision job, I spray base over sanded 2K all the time. On restoration jobs, I use epoxy almost exclusively. Epoxy, filler, more epoxy, poly if needed, epoxy, blocked, more epoxy if needed, finish with 400-600. Epoxy mixed 1:1:1 as a sealer, then base. Really no need for another product. Everything that 2K does can be done with epoxy, it just takes a little longer, and you end up with a superior final product with close to zero shrinkage later.
 

ndaniel246

New Member
There is nothing wrong with 2K when used correctly. The 2K is not superior to epoxy before basecoat, but it is acceptable and easier to sand. On a vehicle like yours, epoxy is the ultimate. On an everyday driver or collision job, I spray base over sanded 2K all the time. On restoration jobs, I use epoxy almost exclusively. Epoxy, filler, more epoxy, poly if needed, epoxy, blocked, more epoxy if needed, finish with 400-600. Epoxy mixed 1:1:1 as a sealer, then base. Really no need for another product. Everything that 2K does can be done with epoxy, it just takes a little longer, and you end up with a superior final product with close to zero shrinkage later.

Thanks for that! and it looks like when you epoxy as a final sealer you reduce it a little? does that help it lay flat, less texture? Do i need to wory about it running more or anything like that or does it still spray the same?
 

texasking

Active Member
It flashes much faster reduced, but it doesn't cover near as well. No need to flood it on, just a nice, even, wet coat lays down as slick as a coat of base and gives the base unmatched adhesion.
 

Chris_Hamilton

Trying to be the best me, I can be
Put out of your mind the stuff you read on other forums. So much misinformation about paint and refinish products out there it's mind boggling. You can however trust the information you get on this site. Giving correct information and advice is something that most of us here take pride in and many of us here are Professionals who do this for a living or very serious Hobbyists who do very high quality work as well.
Spend some time reading topics here. Use the search function, and you will find everything has been covered from metal to final finish and buffing. Just with buffing alone you won't find a forum with more real world proven info. And the info is correct, unlike with nearly every other paint and body forum out there where there may be some correct info but so much stuff that is wrong or outdated.

Read the SPI Tech Manual. Read The Perfect Paint Job article in the Tech Manual.

This forum is truly the best forum out there for info on how to learn and do high quality paint and body work.
 
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