About to spray some 2K for the first time

J

jtfx6552

Member
I am real comfortable with SPI epoxy, was going to try to do the car with just that, BUT... Old hood just won't give up without a fight.

I bought the "regular" SPI 2K in gray.

Been using a 1.8 tip at the pressure suggested by Devilbiss for a finishline 3 gun for the epoxy.

Tech manual says 1.7 to 2.5 tip. Am I ok on the lower side of the recommended tip size? Obviously I am using the 2K to get some build , should I get a a bigger tip?

What are the typical things I'm gonna screw up the first time I use this stuff? I see thorough mixing being stressed, with a paint stick. Then pour through a strainer into the paint cup? Will "regular" strainers work or do I need something special?

Gonna be weird to mix stir spray with no inducing, lol.

Oh, I shot the epoxy on Sunday, will be spraying the 2K Friday, I'm thinking I should scuff, but with what?
 
Here are my preferences, I usually spray all of my primers through a 2.3 tip. I use the vapor guns from northern tool for primers, they are reasonably priced and work great for primers. (at least they have for me so far). The 1.8 you have will work fine with the reg build primer, but if you are going for build I would probably put three coats instead of two. A regular automotive type strainer work on the primer. As for epoxy on Sunday then 2k on Friday, you are technically inside the 7 day window, so you may be able to get by without doing anything, but if it were me, I would at least rub it lightly with 180 grit to rough it up a little. Hope this helps. I am sure others will offer more advice soon.

Kelly
 
Crap, I can't find a 2.2 tip local, won't be here until Tuesday and I wanna put some on today,will the 1.8 work ok?
 
I've used the same gun with the 1.8 tip with SPI regular build 2k and it worked fine.
 
Another, most likely obvious question, but the 2K can stay in the gun for all three coats, that are 5 minutes apart each, 10 minutes total? I'm not sure I can clean and reload the gun in 5 minutes, lol.

Oh, and how do I decide if I should reduce it at all?
 
Running into something similar.

The first time I used 2k I ran it Unreduced out of a 1.4 tip. It shot like mud and ran very dry.
The second time I shot it with a finishline 4 out of a 1.8 tip

Here's what I got
When going too fast it sprayed dry....when going too slow it had orange peel or I ran it.
When I was too close to the body I ran it
Wen I paused slightly to take a step I ran it
When I was too far away it sprayed dry

The settings were 30psi at the gun with trigger pulled
Fan wide open
Fluid turned all the way out and then 2 turns in

I had to da a bunch of the orange peel out and left enough to block sand. This saved a lot of time
Now I have this very straight car sanded in 180

And I'm scared to shoot any more high build on there to fill the 180 scratches and sand with 400-600
Here's why.

The runs and dry spray were not a problem as 180 cuts all of that up. 180 cuts and 400 flattens

If I spray more on there and get the same mess I'm afraid the 400 won't cut any un evenness out of it and it will end up wavy.....the 180 has it perfect. I'm just basically 1 step ahead of you with my blocking done.

In another post I saw where the guy was told that after he blocked the 180 and it was good.......to spray 2 coats of epoxy instead of high build. Just to cover the scratches.

Pin am curious about this. As I don't want to spray any more 2k right now. I've spend 40+ hours on lock sanding 2times and messing up.

My advice and what I did so I would dry spray it again is to check it first on a test panel. I still sprayed dry the second time but I adjusted the technique and moved slower and got closer. Some panels orange peeled and some were perfect. Just my experience.....shot with a 1.8

I will also say this. When I shot the first time with the 1.4 Unreduced it sprayed dry......and created very deep pin holes. They wouldn't leave with block sanding. The dust and powder from sanding filled them and you couldn't see the,......blow it off and clean it and there they were. I da all of it off till they were gone. I'd rather get orange peel and runs than to spray that dry again.
 
I have a finishline 3, that gun is supposed to have 28 I think, at the gun inlet to get the recommended 10 at the cap.

Is the recommended inlet for the 4 really 40?
 
No it's 23 with the trigger puller wide open. Some people run it at 30psi with the trigger wide open.

This is at the regulator at the base of the gun. With the gun closed I'm not sure what it is. I want to say its 90ps.

That's 30psi while primer is coming out of the gun and you have the trigger pulled all the way back. The 3 and the 4 are very similar guns.

My recommended psi is stamped into the cap on the front.

I'm going to have to spray more high build and suffer through it. My epoxy is black and can't be guide coated. It was only bought for a sealer. I usually use the gray epoxy.

I tried some 400 on a panel. It's not as rough on cutting as the 180 but I do think it will cut and flatten. I'm not sure though

- - - Updated - - -

Just don't spray it dry......it created a lot of pin holes that I filled with dry guide coat and they had to be removed.

I do think if I put more primer on there it would have sunk into the pin holes and shown up in the final product.

I will also say in removing all that primer I got to see a mistake I made. One I didn't know about before I sprayed the primer.
In doing the filler work and sanding with 80. I got some 80 scratches in the epoxy because I did the filler work on top of the epoxy 24 hours after it cured. I finished the filler at 180 but left some 80 in the epoxy around the filler. Then I primered over some of these 80 grit scratches. 6 months down the road or sooner......or later the primer would have finally sink into these scratches. Showing up in the clear as an 80 grit scratch.

Maybe it could be removed in buffing later but I wasn't sure. Not I never prime over 80 grit scratches and my filler work is finished with 180.

I will start finishing it with 220 to minimize the sinking. It's called shrinking primer
You want the primer to mechanically adhere so you need a scratch.....too high a scratch and it sinks into the scratch......too small or fine a scratch the primer won't adhere to the panel and lift later.

Now I'm trying to figure out if red scotch Brite will be enough scratch to adhere.....because I would like to use it in very tight and unseen areas.....I think it will....it's equivalent to a 400 scratch.....but who knows

[
 
I'm not sure I'm following you on your gun pressures. I have the regulator/dryer on the wall. A gauge on the inlet of the gun. The wall regulator is about 45 ish, when the gun trigger isn't pulled (I don;t think that matters), the pressure right at the gun is as close as I can see to 23 psi while spraying.

I'll make sure i don't spray it dry. I am going to do a test panel, well 2 test panels. I have a 2.2 tip coming Tuesday.

I couldn't resist blocking the epoxy "just a little" before I sprayed the 2K and sure enough broke through the primer. So I sprayed to wet coats of Epoxy on Friday, no 2K yet.

- - - Updated - - -

I'm not sure I'm following you on your gun pressures. I have the regulator/dryer on the wall. A gauge on the inlet of the gun. The wall regulator is about 45 ish, when the gun trigger isn't pulled (I don;t think that matters), the pressure right at the gun is as close as I can see to 23 psi while spraying.

I'll make sure i don't spray it dry. I am going to do a test panel, well 2 test panels. I have a 2.2 tip coming Tuesday.

I couldn't resist blocking the epoxy "just a little" before I sprayed the 2K and sure enough broke through the primer. So I sprayed to wet coats of Epoxy on Friday, no 2K yet.
 
As far as 2k primer goes I play as I go, I'm going to sand it anyways.... After my first coat I block at 120, second coat I go at 220 and then after the third go I use the DA with interface at 400. I feel like I am turning good primer to the floor but everything comes out smooth fwiw....

Also I block a bare steel panel to see what I have and what I need, fill, block, fill, block, then when I "think" its flat hit with 2k.

Also I spray 3 coats at a time.

- - - Updated - - -

As far as 2k primer goes I play as I go, I'm going to sand it anyways.... After my first coat I block at 120, second coat I go at 220 and then after the third go I use the DA with interface at 400. I feel like I am turning good primer to the floor but everything comes out smooth fwiw....

Also I block a bare steel panel to see what I have and what I need, fill, block, fill, block, then when I "think" its flat hit with 2k.

Also I spray 3 coats at a time.
 
I mixed up the 2K. After looking at how thick it is, and tiring my arm out just stirring it, I decided that I would start with the 2.2 tip and forego trying the smaller one. Glad I did. Sprayed beautifully. I only got 2 wet coats out of the 24 ounces I mixed up.
 
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