Necessary to sand 2k

'68 Coronet R/T

'68 Coronet R/T

Oldtimer
I always sand my 2k primer but have thought a couple of times that it looked good enough to paint over just the way it was.
Has anybody ever done this? Is it not correct to do so? Adhesion problems would seem likely but . . .
 
I came here to ask this question, got excited when I saw the title of the thread, disappointed there are no answers...

One of my biggest pet peeves of the whole auto restoration hobby is trying to make sure I got all the sanding dust off a a panel.

Seems like it would be easier to keep the top coat clean if I could just shoot right after the 2K.

I can't always get the epoxy to lay as flat.
 
For many years in the collision shops I used urethane primers as a sealer by just adding more reducer and there was never a problem. Your recoat time is a lot less than epoxy though. Best bet would be to check with Barry. I would guess there may be some high speed primers that might not work well like this.
 
2K urethane's need to be sanded with the exception of when thinned down to use as a sealer and then you have a limited re-coat time, usually 15-45 minutes.

Also another exception is, some painters for insurance work will scuff a new e-coat fender and for cut in purposes, spray a wet coat of primer and in 10 minutes spray base and clear.

To spray 2-3 coats and then paint could be risky for hold out down the road.
 
one other thing to note is that some primers that arent meant to be sprayed wet on wet as a sealer and are, can and sometimes spray a little gritty just from the pigments and fillers not being fine enough. the spi 2k sealer is a urethane primer but also a sealer. you can tell there is a big difference in how smooth that is compared to reducing down regular build 2k primer and spraying a coat of that.
 
Jim C;n80011 said:
one other thing to note is that some primers that arent meant to be sprayed wet on wet as a sealer and are, can and sometimes spray a little gritty just from the pigments and fillers not being fine enough. the spi 2k sealer is a urethane primer but also a sealer. you can tell there is a big difference in how smooth that is compared to reducing down regular build 2k primer and spraying a coat of that.
Click to expand...

Exactly!
 
Wow, I thought my question was taboo or something since it never got a reply.
So basically it depends on the use. If shooting a number of coats of SPI 2k primer for build then it needs to be sanded. If shooting a single coat or as a sealer your good. Does that sound right?
 
SPI 2K sealer can work as a primer or a sealer, if you are inclined to experiment with wet-on-wet processes, it is the thing to use.

Sealer is # 6401, 6402, & 6403, gray, white & black.
 
If it is not mentionned in the product that it cant be sprayed on without sanding or scuffing, I never do it, there's nothing I hate more to repair a job that is peeling. If that is what is required, I use the SPI 2K sealer in my shop. Nice thing about it, used as a primer, it works pretty well too, and sands very easy. But beware a 2k sealer will never do the job the primer will do in certain cases, such as covering filler.

I only use the sealer when I really have to, otherwise, I prefer to spray my paint on a nicely prepped surface.
 
Quick one what nozzle you guys use for the 2k sealer as a primer 4:1 this thing is thick i have a 1.8 and i can tell i need bigger nozzle just not sure how big
 
If using as a sealer use your base gun, it should be thinned enough for your style of painting that it should spray like a base coat.
 
'68 Coronet R/T said:
Wow, I thought my question was taboo or something since it never got a reply.
So basically it depends on the use. If shooting a number of coats of SPI 2k primer for build then it needs to be sanded. If shooting a single coat or as a sealer your good. Does that sound right?
Click to expand...

Correct and, sorry about missing this! This year we have been so busy, I scan this when I can and I do know I have missed posts but there is so many experienced painters on here, I don't worry about the question getting answered.
Also if I do miss a post don't feel shy about PMing me to look at post,
Barry
 
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