Blocking Epoxy Primer?

[Machspeed]

Hey friends, I know there is a million ways to skin a cat but I'm left a little confused in a video I just watched regarding blocking and epoxy primer. The gentleman that did this video does some incredible work and as he is working on the same basic project I am working on, I've been following his work on YouTube. I just left him a question on YouTube requesting clarity on his methods but wanted to also bring it here.

So, he sprayed the trunk lid of his 69 Mustang in SPI epoxy primer. Two days after spraying epoxy, he used a block to find his lows, did a skim coat, blocked that, then sprayed another coat of epoxy. From what I can tell from his video, he did the whole car that way and never mentioned using a 2k high build sandable primer. Maybe I'm misunderstanding things but "The Perfect Paint Job" basically says epoxy, filler, block filler, 2K application, block and then seal. Thoughts?

 

[texasking]

Epoxy is a better product than 2K, so 2K not absolutely needed. Epoxy takes a little longer to build than 2K.

 

[JC Daniel]

I am using epoxy only at the time, I spray in the evening and block next day and spray more epoxy as needed. SPI epoxy is by far a superior product than any 2k build primer.

 

[jtfx6552]

All epoxy is better, but be advised unless things are really flat to start with, you'll be doing the spray 2 coats-sand, spray two coats sand for many iterations.

 

[Pacfanweb]

Epoxy is a better product than 2K, so 2K not absolutely needed. Epoxy takes a little longer to build than 2K.

So what I'm getting from this thread is, if you have the time to spray it, let it set, block it, spray it again, rinse/repeat until it's right....the epoxy is the way to go? And just use the 2k if you want to get the show on the road and get it over with?

 

[Chris_Hamilton]

Spray 4-5 coats. Also let your mixed epoxy induce for 8-12 hours. It will build more.

 

[dhutton01]

I use poly primer to build. Builds in one spray session. Doesn’t shrink like 2K urethane primer.

Don

 

[Chevynutz]

Spray 4-5 coats. Also let your mixed epoxy induce for 8-12 hours. It will build more.

When you induce this long do you stir at all or just let it set ?

 

[Chris_Hamilton]

When you induce this long do you stir at all or just let it set ?

Stir it well when mixing it. Cover it. Let is sit (induce). When ready to spray, stir well again.

 

[crashtech]

I think that attempting an epoxy-only job is a great way to improve one's skills. In fact I would say to leave the poly primer to more seasoned techs, because the tendency for newbies is to leave too much material where it doesn't belong, and this is far less of a problem with epoxy as it is with poly. Leaving too much poly on edges, around bolt holes, keyholes, etc. can make for some heartbreak on reassembly because it's more brittle than epoxy.

 

[Chris_Hamilton]

All (SPI) epoxy and Universal clear on a job, will be a very chip resistant finish. And what chipping that does occur will be smaller.

 

[Chad.S]

Epoxy only is a great method, one thing I would suggest though is to change colors at different sessions, it works great as a reverse guide coat.

Example, apply black epoxy over bare metal, do all body work, re-apply black epoxy primer, I always sand this stage as it helps remove imperfections. Then I would change to grey, when you are sanding it and see black you know you need to stop at this point as the black is already sanded and thin.

If you follow this method you have no excuses for sanding down to bare metal as you have the reverse guide coat to tell you when to stop.

 

[chevman]

Some really good advice above.
When doing metal work, I think its important to look for highs as well as lows. Today's brand new cars right from the factory can have minor highs and lows, let alone cars decades old, and there can also be highs around the low areas, displaced metal has to have a place to go. So leaving the high areas can result in too much material to make the panel straight.

 

[RosharonRooster]

Right now my car is epoxy only so far....but im going to hit it with 180 again then re epoxy and poly primer over it. I may skip 2k after and opt for epoxy instead. Cross that bridge when I get there.

 

[crashtech]

Right now my car is epoxy only so far....but im going to hit it with 180 again then re epoxy and poly primer over it. I may skip 2k after and opt for epoxy instead. Cross that bridge when I get there.

I'm curious, it sounds like you want to put poly primer on the epoxy before doing any filler work, is that right?

 

[RosharonRooster]

I'm curious, it sounds like you want to put poly primer on the epoxy before doing any filler work, is that right?

No. I did epoxy filler, and epoxy...filler work done I think

 

[MAKZ06]

Epoxy only is a great method, one thing I would suggest though is to change colors at different sessions, it works great as a reverse guide coat.

Example, apply black epoxy over bare metal, do all body work, re-apply black epoxy primer, I always sand this stage as it helps remove imperfections. Then I would change to grey, when you are sanding it and see black you know you need to stop at this point as the black is already sanded and thin.

If you follow this method you have no excuses for sanding down to bare metal as you have the reverse guide coat to tell you when to stop.

I wish I had done this on my current project. Would have saved me so much time on breakthroughs when block sanding, and for keeping up with how thick I was getting in other areas.

 

[Slofut]

Like Chris said, 4 or 5 coats epoxy to start with, block with a light touch, may not have to put more on. I like powder guide coat.