2k over thick coat of epoxy

G

GLHX

Last night I sprayed a coat of epoxy. Thinking I had the gun adjusted from the last time I sprayed to perfection. I forgot the I adjusted it somewhat heavy. It was very late at night and I had a bunch of metal showing in places so I had to spray it. I didn't notice it until one side of the car was done,

So I have the usual craters from spraying too thick.... And a run or two. While this isn't much of a big deal and I can sand it flat. My questions are.

Can I just spray 2k over it like this and sand the 2k flat. I'm out of epoxy primer. I have just enough to do filler work sanded to bare spots and it's already mixed.

How long can I leave this primer mixed before it's no good. I can't get back for 2 days. It was mixed 1 am last night.

I'm also going to put more filler on top of it. How many days can the epoxy sit before it needs to be scuffed for top coating and filler work. It says 7 days. But I've seen where people scuff it at 2
 
Also....I had epoxy on there with a full coat. I waited two weeks and hit it with a red scotch bright. I was told it had cured too much and I had to put another full coat of wet epoxy over it before I could put high build on top of it. Is this right
 
once you have your epoxy down, if it sets too long say 2 weeks then you dont need to put on a heavy coat. you can mix it really thin. 1:1:1 works well. then you just shoot a micro thin coat over everything. its just like an adhesion promoter to make sure what your putting on bonds really well. the primer you already have mixed will last atleast 2 days or even more if its cold. you can spray 2k over the epoxy in the spots where it got weird on you. i have done it and never had any issues with it ghosting back or anything like that BUT as good painting practices go its best to sand that area atleast semi smooth before the 2k.
 
I looked at the extreme creations web site. How many coats of clear are on those bikes....especially the red one.

Thank you for the info. That helps a lot
 
that varies depending on the job. for the most part though it can go from 4 coats up to 25. 4-5 are done in each session. whenever i need to bury a layer, get things smooth, or seal in some candy to prevent bleeding then its time for a round of clear.
 
Jim C;33554 said:
that varies depending on the job. for the most part though it can go from 4 coats up to 25. 4-5 are done in each session. whenever i need to bury a layer, get things smooth, or seal in some candy to prevent bleeding then its time for a round of clear.
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with spi clear do you have to let it cure completely and sand it flat every 3 coats. I was going to go with 5 or 6 on mine.....ready to completely sand the first 3 with 1000. I've. never done that before. Is this right or is there another way
 
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for general use on a restoration that you want really nice you would normally do 3 coats then block it then another 3 coats. 1000 is too fine. you wont be blocking those first 3 flat with that fine a paper. you end up with a more wavy finish. i will usually block with 400 then buzz a da real quick over with 600 an soft interface pad just to refine the scratches a little. wipe down then reclear. wait 24-48 hours between clear sessions.
 
Is there a trick to not burn through the edges. Maybe not sand them at all and be very careful around them. Or go with really fine paper on edges. What is the finest grit clear will stick to

What is the inter pad for
 
A soft interface pad provides cushion between the DA and the paper. This allows the paper to float over the curves so it sands evenly.
 
yes X2 what strum said. basically one you have it all blocked flat the interface pad with 600 will allow you to just refine the scratches without changing what you got. it sands with even pressure so you wont take your blocked surface and sand any lines, flat spots or anything else into the surface.

as for edges, no trick. its called just being careful and having a good feel for a block and a da. i dont like to go over an 800 grit finish. beyond that i feel its too fine for good adhesion. this is more critical for base than it is for clearcoat. clear can be put over finer but i try to avoid it and its not necessary for what you are doing.

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yes X2 what strum said. basically one you have it all blocked flat the interface pad with 600 will allow you to just refine the scratches without changing what you got. it sands with even pressure so you wont take your blocked surface and sand any lines, flat spots or anything else into the surface.

as for edges, no trick. its called just being careful and having a good feel for a block and a da. i dont like to go over an 800 grit finish. beyond that i feel its too fine for good adhesion. this is more critical for base than it is for clearcoat. clear can be put over finer but i try to avoid it and its not necessary for what you are doing.
 
When using the spi epoxy. I did what you said and sanded it mostly flat. Just for good measure scuffed the rest with red scotch bright and spot primed the places that were bare metal from some filler work. I waited 5 hours for the epoxy to flash as told to me by James at spi....then sprayed the 2k

I had some marhyde urethane 2k high build primer which was mixed 4:1. It was considerably thicker and my gun opened up wide as possible shot this stuff out very thin and grainy and dry. I couldn't even adjust it to fan out. The only pattern that worked was pretty narrow.....maybe spraying 4" on the car. I was able to get about 2 coats on there.....unevenly on the secon coat. My thoughts were that maybe the tip was too small. Because I'm doing primer work I'm just using a cheap gun. It showed the tip size at 1.4.........which would be fine for epoxy as it's so thin.

Is this this tip size too small?
I would like to get reasonably priced gun just for thick primer that is a quality brand....and a good Hvlp for spraying base and clear. The gun I have for spraying is a high pressure sata jet 90 that has been used twice in 7 years. What do you recommend. The sata works well, however I think an Hvlp will be better?

Also.....how do you block the bike fairings. Do you have curved blocks? That conform
 
With spi you have that 7 day window. If it's after 7 days your supposed to scuff it with red scotch Brite and run that another epoxy coat as adhesion promoter.

Just for good measure I hit it with a red pad after 2 days. This put 400 grit scratches in it and I read that 2k likes 180 scratches to stick to.

If the epoxy is still in its 7 day window. Does it matter what scratches are in it? I was guessing it didn't even need to be scuffed but I did anyway to sort of open it up

Just want to make sure this is ok as well as the 5 hour flash time frame I put 2k over it. I've heard ....overnight.....24 hours....and 5 hours
 
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