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swvalcon 03-26-2012 05:41 PM

2-k fact or fiction
I had a guy trying to tell me the other day that if you sand 2-k primer then let it set for more than 4 hrs with out sealing or painting it you should resuff or re-sand before you do. I can kind of see where he's coming from but not all that sure he's on the right track. I can see his point if you really loaded up the 2-k or your shop was a little on the cool side when you put it down.Will admit sometimes if I have a job ready to paint and then quit for the day without painting it I will hit it with a scuff pad and re-tack before I paint the next morning.

Centerline 03-26-2012 06:37 PM

Hmmmmm..... never heard of that one.


"Speed has never killed anyone, suddenly becoming stationary, that's what gets you." - Jeremy Clarkson

deadbodyman 03-26-2012 07:05 PM

Me either ,and I've heard a few....
I hope not :sweat: :sweat: :sweat:
after I sand it usually doesnt get painted until at LEAST the next day.....but the first part of my prep work always starts with a hand scuffing while looking over every square inch of every panel to be painted wether its primed or not'after that I'll give it a good bath in W&Gremover ..Most times I'll stop and wait till the next day and start masking while I'm fresh in the morning,Then if its not to late I'll paint....A lot of times I'll want to paint a big job while I'm fresh too, so that s 48 hrs after my prep scuff....
As the myth busters would say ....BUSTED

MARTINSR 03-26-2012 08:33 PM

Whoa there boys, yes, in the tech sheets of some urethane primers there was recommendations for this. Sherwin Williams Tint Prime was down to something like 2 hours as I remember, no kidding!

Ahh, I found it.

Maximum recoat time after Wet sanding: 1.5 Hours. After 1.5 Hours, solvent clean and
scuff with nylon pad.


MARTINSR 03-26-2012 08:39 PM

I don't remember the particulars but there may be some curing help by the moisture like window urethane which is a moisture cure 1K. I am thinking you wet sand it and you are pushing the cure so it gets harder and smoother?

What you are doing when you sand if you think about is you are increasing the surface area, the dips and valleys of the scratches make it "longer". Think about getting a piece of paper and folding it like an accordion. Pull it out and it gets bigger right? I am thinking (and trying hard to remember) that this curing process makes it smooth out somehow on a microscopic level.


deadbodyman 03-26-2012 08:43 PM

There ya go ya learn sumtin every day...I never used any primer from SW though.....Theres others out there as well ? makes me want to read the directions on my SPI Urathane prime now..never got past the mix ratio... :sweat:
Now every knows why us old fossils hate using new or different brands...BTW was that stuff any I am asking a matin senior guy if sherwin willams stuff is any good..... :spank:
hows that for an unanswerable question :D gottcha
unless it IS good and you say it is ...hmmmmm
HEY... what if you dry sand it ????? wont it cure all the way?????

MARTINSR 03-26-2012 08:54 PM

I LOVE Tint Prime, I one of the best urethane primers I ever used.


deadbodyman 03-26-2012 09:02 PM

Fer Real ????? Why so? I never heard of it

TucsonJay 03-26-2012 09:06 PM

Pretty soon we will have to perform 60 hours of work within one day "for maximum adhesion". LOL!

Sometimes I have let my sanded 2K primer wait weeks before paint.... and never had any adhesion problems. If I had to do that on every job, I'd find a different product.

deadbodyman 03-26-2012 09:41 PM

LOL,its a conspirecy,Thats what happens to when the body shop owner and then insurance companies get together and make a pro shop...

MARTINSR 03-27-2012 12:13 AM


Originally Posted by deadbodyman
Fer Real ????? Why so? I never heard of it

It fills great, you sand it and paint it with no sealer done deal. I have had great success with it.


deadbodyman 03-27-2012 04:46 AM

My problem is Isometimes all day to sand a car so when I got done I'd have to go back and resand and I'd be stuck in a perpetual sanding loop until there was no primer left on the car then I'd have to reprime and start again. :sweat:
Sounds like bodyman hellto me :mwink:

Old Fool 03-27-2012 06:07 AM


Originally Posted by deadbodyman
My problem is Isometimes all day to sand a car so when I got done I'd have to go back and resand and I'd be stuck in a perpetual sanding loop until there was no primer left on the car then I'd have to reprime and start again. :sweat:
Sounds like bodyman hellto me :mwink:

Sounds to me like it is more suited to panel or spot repair than an overall.

shine 03-27-2012 07:17 AM

the tail solvents in a urethane primer will self heal the scratches if left to set. costing you mechanical bond. with epoxy sealer it's no problem but base over it can be the weak link.

trees 03-27-2012 07:36 AM

I am a total novice when it comes to paint, but there is no way I am going to put anything on any primer within an hour and a half after wet sanding!!! The high moisture content will create more problems than letting it set over night or longer, in my humble opinion. Will look forward to what BK has to say about this.


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