epoxy primer question

[mad dog]

Good morning, My 340 is coming home from the machine shop....
I usually prime my engines with epoxy (transtar) before i shoot 2k automotive urethane usually PPG Omni.
Im out of transtar gray epoxy and was thinking about useing a new epoxy for the engine, everyone here raves about SPI epoxy, what do you guys use?
Im painting this 340 orange ....and what color epoxy do you guys use, black or gray? I usually use gray but i see the painter on GYC use black epoxy under the orange.
any input is welcome...Rich

 

[Dartsun]

I've heard great things about the SPI epoxy, I've personally used the Nason brand and liked it. Tried the summit brand and it was decent for the price.

 

[JDMopar]

I use SPI epoxy exclusively on my projects and it has never disappointed me. I have never used it on an engine, but would not hesitate to. I know @Jim Kueneman uses SPI too, and he may be able to advise on using it on an engine.

 

[George Jets]

Here is what I use for all my auto body work and painting.

Paint engines and transmissions with it too as a primer base coat over bare cast iron and bare cast aluminum.

Thins with a good quality lacquer thinner ( not the gun cleaner as it dries too fast).

Can leave it a bit thick and brush it on (dab) on cast iron, let dry for 1 hour and it's ready for topcoat. Can also thin it 1:1 with lacquer thinner and spray it.

All Gray Primer Based


☆☆☆☆☆

 

[Jim Kueneman]

I use SPI epoxy exclusively on my projects and it has never disappointed me. I have never used it on an engine, but would not hesitate to. I know @Jim Kueneman uses SPI too, and he may be able to advise on using it on an engine.

I spray SPI epoxy on all my engines (cast and aluminum) before the final color. Never had one fail. Thousands of miles later they look like when they were first done.

 

[junkyardhero]

Here is what I use for all my auto body work and painting.

View attachment 1716445891

Paint engines and transmissions with it too as a primer base coat over bare cast iron and bare cast aluminum.

Thins with a good quality lacquer thinner ( not the gun cleaner as it dries too fast).

Can leave it a bit thick and brush it on (dab) on cast iron, let dry for 1 hour and it's ready for topcoat. Can also thin it 1:1 with lacquer thinner and spray it.

View attachment 1716445892

View attachment 1716445893

View attachment 1716445894

All Gray Primer Based


☆☆☆☆☆

when were those pics taken and how does that stuff look now, after some time & mileage?

 

[barbee6043]

You can not beat SPI epoxy on quality and price. Plus they have excellent tech sheets\support.

 

[mbaird]

I spray SPI epoxy on all my engines (cast and aluminum) before the final color. Never had one fail. Thousands of miles later they look like when they were first done.

Question . .. I am putting together a 408 right now and the block was not stripped of the old paint . It was run through a solvent bath and cleaned up . I have some SPI epoxy left over from my paint job . Can I spray the epoxy over the old MP engine paint with any success? Of course I would clean it further with solvent then wax and grease remover before applying.

Thanks .

 

[mad dog]

Thanks to everyone here for your help, i will order up a quart or SPI epoxy and activator....

 

[barbee6043]

Question . .. I am putting together a 408 right now and the block was not stripped of the old paint . It was run through a solvent bath and cleaned up . I have some SPI epoxy left over from my paint job . Can I spray the epoxy over the old MP engine paint with any success? Of course I would clean it further with solvent then wax and grease remover before applying.

Thanks .

Just my opinion. I would scuff the old paint and IF it on there solid, clean with waterborne wax and grease remover, let dry an hour and shoot. Let cure a day before topcoat.
Good thing about epoxy primers, is it will stick to even fresh chit!

 

[Jim Kueneman]

Question . .. I am putting together a 408 right now and the block was not stripped of the old paint . It was run through a solvent bath and cleaned up . I have some SPI epoxy left over from my paint job . Can I spray the epoxy over the old MP engine paint with any success? Of course I would clean it further with solvent then wax and grease remover before applying.

Thanks .

Was the block hot washed or anything? If you think the paint has adequate adhesion to the block (that is the beauty of epoxy it will stick to bare metal better than anything else and paint under it could have a worse bond) then Barry told me to spray it down with Windex and blow it off. If you can spray W&G remover that is even better.

Jim

 

[mad dog]

jim, doe SPI have an expiration ...
I found some from 2023, is it still good...Rich

 

[Jim Kueneman]

jim, doe SPI have an expiration ...
I found some from 2023, is it still good...Rich

Activator has a 1 year life but it it was unopened and not in a place the temps were super hot it should be fine. Mix up a bit and brush it on something and see if it sets up. If so then it’s fine.

 

[mad dog]

Jim, i got my 340 back from the machine shop and for some reason he primed my intake manifold with rustoleum self etching primer, i read the data sheet for SPI epoxy and it said that acid etch primer will not work with SPI epoxy. Is self etch the same as acid etch?
I remover as much self etch primer as i could, theres still some in the nooks and crannies on the intake, its tough trying to sand in those tight areas.
am i over thinking this, i dont want any adhesion problems, theres very little self etch left on the manifold, I know you guys love this spi epoxy.

 

[Jim Kueneman]

Jim, i got my 340 back from the machine shop and for some reason he primed my intake manifold with rustoleum self etching primer, i read the data sheet for SPI epoxy and it said that acid etch primer will not work with SPI epoxy. Is self etch the same as acid etch?
I remover as much self etch primer as i could, theres still some in the nooks and crannies on the intake, its tough trying to sand in those tight areas.
am i over thinking this, i dont want any adhesion problems, theres very little self etch left on the manifold, I know you guys love this spi epoxy.

Sorry I have not experience with this. If it were me and it was just in the nooks and crannies I would just clean it good with SPI 700 W&G remover (or Windex like Barry suggested) and shoot it.

 

[mad dog]

thanks jim, can you answer this for me , i cant find it in the spi tech sheet...
after 2 coats of epoxy whats the soonest i can spray 2k urethane single stage over the epoxy?
this is for my 340 engine

 

[mad dog]

i think i can topcoat spi epoxy with single stage within 24 hrs with no sanding, does that sound right to you?

 

[JDMopar]

The recoat/topcoat window is longer than that, but you can do it in 24 hours without a problem. When/if you wait beyond the allotted time, you have to scuff it up to paint over it with anything. I've got a 65 Barracuda fender sitting on a stand that I'm ashamed to say how long I've let it sit after SPI epoxy and then adding filler to some dings. Needless to say, I'll be sanding the whole shebang instead of just the filler....lol.

 

[Jim Kueneman]

If you did not lay it on thick the next day is fine. If you hammered it on I’d wait a couple days unless you put it in the sun. If sunny figure 1 hour in the sun equals 4 hours in the shop in curing.

 

[mad dog]

guys , thank you for all the help, i only have today to get this 340 painted.
can i lay 2 coats of spi epoxy this morning and then paint in the late afternoon?
my old epoxy says i can topcoat 30 min after application for wet on wet...

 

[Cuda416]

guys , thank you for all the help, i only have today to get this 340 painted.
can i lay 2 coats of spi epoxy this morning and then paint in the late afternoon?
my old epoxy says i can topcoat 30 min after application for wet on wet...

Ultimately I think if you call the folks at SPI, they'll be happy to tell you exactly how to ensure their product is successful for what you want to do with it. Lots of great advise here, but they are the absolute experts with their stuff.

They are passionate about what they do and would rather guide you through it, then here how it failed because someone didn't read the tech sheet or ask questions.

Good luck!

 

[Jim Kueneman]

guys , thank you for all the help, i only have today to get this 340 painted.
can i lay 2 coats of spi epoxy this morning and then paint in the late afternoon?
my old epoxy says i can topcoat 30 min after application for wet on wet...

If it is out in the sun all day probably be ok. I definitely would not do it that soon with 2 heavy coats. When using it as a sealer and you have it reduced 20%-50% with one coat then you can lay on the final coat in 30 minutes.

 

[mad dog]

im thinking bout painting it 6 hrs later after 2 coats of epoxy...not 30 min

 

[JDMopar]

Thin the epoxy out for use as sealer, put a coat on, wait 30 minutes and put the last coat on. Then wait the 6 hours and do your color. It should turn out fine. Put it out in the sun all day after the 2nd coat of epoxy and turn it around every now and then so sun shines on it equally all day.

 

[mad dog]

JDMopar thats exactly what i did, thanks so much guys, lots of dumb questions on my part and i really appreciate your time...
I put so much time and effort into prepping this 340 I didnt want to screw it up... thanks again FABO