Can I do this with epoxy sealer?

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Lizer said:
Ideally you want to sand about 90% of your poly off, at least until you get down to the primer underneath.

When you block it’s a good idea to sand until guide coat is gone, then apply more guide coat and block some more. You’ll find you’ll still have low spots even though you thought it was good on the first pass.

If you’re happy with where it’s at now, then you’re done. You could go to epoxy next but you need to refine your sand scratches first, which is why I give a coat or two of 2k, sand that with 400, then it’s ready for epoxy sealer.
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Okay that 90% is doable. Now I have an idea of what to do.

Thanks,
 
crashtech said:
You're only over sanding if you're hitting lots of metal spots and continuing to sand. I think it's way more common to not sand enough.
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I'll keep sanding, I know I have plenty of material there from the last coat of epoxy and the Clausen high build. Since Lizer says 90% of the Clausen will sand off, I'll just keep sanding. I'll stop if I hit metal.
 
Worn Out Welder said:
I say it’s gonna be slick….but I’m not one to advise.
I’m glad you are doing the Clausen because it gave me some insight.
I’m hoping Deans 24” block and some Clausen rust defender help me resolve my issues.
It’s very deceiving looking at pics of SPI epoxy that lays out very nice.
I thought I was done after many hours of blocking
but as you said the bock doesn’t lie.
Thank you for your contribution.
It helps Neanderthals like me.
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Trust me, I'm still learning. This is why I am a little freaked out seeing all the exposed epoxy after blocking the Clausen High Build. The panels I've blocked where flat before my last coat of epoxy, and the Clausen. I will tell you this, Black Diamond blocks are no joke, they will make a panel flat.
 
What grit are you sanding with in those pics? Are you breaking through to the epoxy almost right away?
 
OJ86 said:
What grit are you sanding with in those pics? Are you breaking through to the epoxy almost right away?
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That was with 180, was going to pick up 120 today.

I had taken millage readings before spraying polyester. After spraying I did millage readings again. I sprayed 4 to 7 mm of polyester on average.

I think I'm doing something wrong. I watched several video's of guys spraying polyester and sanding. They didn't remove all of the polyester. They left a flat surface of polyester. If I had to guess, they left anywhere from 3 to 4 mm.

What I'm doing just doest feel right, especially if I remove 90% of the polyester I sprayed.

At this point I don't know what I'm doing.
 
What you are seeing in those pics is normal. Once you start seeing the exposed epoxy under the poly then you are done in that area for the time being. It may also indicate that you didn't apply it as heavy as you may have thought you did. Its your first time using the product. Personally, if you block the car out and it looks like there is a lot of breakthroughs like you are seeing then I would do another round of poly. Just my $.02.
 
OJ86 said:
What you are seeing in those pics is normal. Once you start seeing the exposed epoxy under the poly then you are done in that area for the time being. It may also indicate that you didn't apply it as heavy as you may have thought you did. Its your first time using the product. Personally, if you block the car out and it looks like there is a lot of breakthroughs like you are seeing then I would do another round of poly. Just my $.02.
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Okay ....... so is the main goal to have a consistent thin millage layer of polyester over the car without any break thru's? Like I had with the epoxy before spraying polyester?
 
MJM said:
Okay ....... so is the main goal to have a consistent thin millage layer of polyester over the car without any break thru's? Like I had with the epoxy before spraying polyester?
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Block till you hit epoxy and stop if you have any lows scuff it with 180 blow off the surface and glaze them. You can spot prime the areas with poly. Or reprime the whole panels if you want. Poly does build up fast the idea is to keep the mill build down especially with poly. Have seen it pounded on before then had to go back and fix cars with it it’s kind of insane how much material you can build up with poly. Then after all poly blocking is done I would shoot two coats of epoxy and prep for paint.
 
You are leveling the surface out so the thickness is going to be all over the place. I wouldn't worry about the millage at this point as you can obviously see that the devils primer isnt as thick as you may think! Just block it out as you are as when you see it getting thin and epoxy showing up then stop in that area and move on. If you find really low areas where you are seeing epoxy and still aren't touching the poly in the low area you may need to add some filler and do some bodywork in that area.
 
MJM said:
That was with 180, was going to pick up 120 today.

I had taken millage readings before spraying polyester. After spraying I did millage readings again. I sprayed 4 to 7 mm of polyester on average.

I think I'm doing something wrong. I watched several video's of guys spraying polyester and sanding. They didn't remove all of the polyester. They left a flat surface of polyester. If I had to guess, they left anywhere from 3 to 4 mm.

What I'm doing just doest feel right, especially if I remove 90% of the polyester I sprayed.

At this point I don't know what I'm doing.
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You’re not spraying mm of material on the car. 7 mm of poly is over half a centimeter which is about a quarter inch. A mil is a micron which is a thousandth of an inch.

This was the bed of my truck blocked with poly. When I can just start seeing epoxy start to peek through in one area is when I stop.

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Up until your final coats, if you are not hitting metal or epoxy if using 2K or poly then you are leaving extra mils on the panel that don't need to be there. It's silly to want to have a solid coating of poly if your car/panel doesn't need it. Excess mils especially with poly are chips waiting to happen. I know you don't believe that but it's true.
 
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OJ86 said:
You are leveling the surface out so the thickness is going to be all over the place. I wouldn't worry about the millage at this point as you can obviously see that the devils primer isnt as thick as you may think! Just block it out as you are as when you see it getting thin and epoxy showing up then stop in that area and move on. If you find really low areas where you are seeing epoxy and still aren't touching the poly in the low area you may need to add some filler and do some bodywork in that area.
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Your statement in bold was great and humorous way to help me understand what I've been missing. I followed Clausen's instructions with one medium wet coat which should yield 5 mils of build. I know I'm in the ballpark of that 5 mils. After spraying Clausens's I took millage readings and had 4-7 mils added to the car.

I can't believe this step in the painting process has messed with my head like it has. I really thought after having the car in all epoxy primer with no break thru's, it would be easy sailing for the remaining primer steps of either Poly or 2K. How wrong I was.
 
zachm said:
Block till you hit epoxy and stop if you have any lows scuff it with 180 blow off the surface and glaze them. You can spot prime the areas with poly. Or reprime the whole panels if you want. Poly does build up fast the idea is to keep the mill build down especially with poly. Have seen it pounded on before then had to go back and fix cars with it it’s kind of insane how much material you can build up with poly. Then after all poly blocking is done I would shoot two coats of epoxy and prep for paint.
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Thank you for your reply and help.

What would be considered excessive polyester primer millage, 10,15, 20, 30 mils?
 
After these threads drag on and on it just becomes a giant difference of opinion about things and just turns into a debate. I guess when I look at those pics you posted the clausens is damn near transparent. There isnt much there.
 
OJ86 said:
After these threads drag on and on it just becomes a giant difference of opinion about things and just turns into a debate. I guess when I look at those pics you posted the clausens is damn near transparent. There isnt much there.
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I concur. I've been given the information to move forward. Time for me to perform or strip the car to bare metal and start over, lol

Thanks for your help, partner
 
Lizer said:
You’re not spraying mm of material on the car. 7 mm of poly is over half a centimeter which is about a quarter inch. A mil is a micron which is a thousandth of an inch.

This was the bed of my truck blocked with poly. When I can just start seeing epoxy start to peek through in one area is when I stop.

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Is that sanded polyester or freshly sprayed polyester?
 
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