Poly Primer

W.A.R. Thanks that makes sense. when to use poly - the way I look at it is if you find yourself priming and blocking and building with urethane primer again and again and again to get it straight then you would have been much farther ahead using poly for the filling duties and final priming with urethane or epoxy for the final cut. IMO there's just so much more chance of shrinkage problems if you're asking a urethane to build more than it should. The comments from people that use polyester glaze regularly but wouldn't touch polyester primer crack me up.
 
If my bodywork is good, I can usually get away with one round of poly and then a reduced coat of 2k for a final prime. urethane scares me on the shrinking aspect and i don't like to do "body work" with it.

Plus with the liquid hardner, I just like the poly because I feel it locks everything down better.

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If my bodywork is good, I can usually get away with one round of poly and then a reduced coat of 2k for a final prime. urethane scares me on the shrinking aspect and i don't like to do "body work" with it.

Plus with the liquid hardner, I just like the poly because I feel it locks everything down better.
 
I know some guys who wont use poly and will stack urethane primer to no end. 3 blocking rounds of urethane with hardly any cure in between. The thing about poly is that it is so much faster than urethane on the curing end. Not saying I wont do maybe 2 apps of urethane over poly if it is like a black car or something, but I'm using the urethane over an already filled and smoothed surface. Just think that makes a huge difference down the road on the hold out of paint jobs...especially in the winter months. We aren't robots and we are dealing with chemicals.

That being said, I also know guys who don't use poly and only urethane primer and their jobs still look great today. So at the end of the day it is user preference and when both of them are used correctly they will produce the same result. I just find it easier and quicker to use the poly. Production is definitely a lot faster while not sacrificing any of the quality. When you have 12 different customers breathing down your neck that helps..LOL
 
I think its a waste of money to burn through all the 2k primer on a big job. 1 gallon of slick sand will cover what 3 gallons of 2k would take to level out.
 
And Im referring to a metal bodied car. I know some guys have different methods for the older vettes and such.

Ive used slick sand on a 59 vette with no issues.
 
I still have some slick sand left over in a quart can. That was my one and only experience spraying poly and it didn't go well. I took several days in the sun for it to harden. Obviously not enough hardener, but luckily it was only on a couple small panels (and I did measure according ot the marks on the tube). I'm defiantly leaning toward giving it another go, working on a '69 Cutlass right now that's a prime candidate.
 
Here is some g2 I shot awhile back.. I remember spraying this at like 6pm before I left work. This was the next morning. Rock solid all the way through. I threw it against the wall and it didnt break.





I used to have all kinds of pucks saved of different 2k's and epoxies.

This was cut in half, it didnt crack.
 
The flexibility and impact resistance of the poly is greatly improved if there's epoxy under and over it, why? I don't know but it does.
 
Bob Hollinshead;42028 said:
The flexibility and impact resistance of the poly also goes way up if there's epoxy under and over it, why? I don't know but it does.
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Hmm, that's kind of disturbing. Any particular examples?
 
I know this thread is over a month old, but I have a question. I just purchased a gallon of slick sand to use on my truck bed cover when the weather breaks. After the sanding is done, whats the proper way to clean the panel before the next coat. I know you don't want to soak filler with w/g remover, but does that apply here? Thanks. Russ
 
I use waterborne and have used solvent based w&g remover on poly primer, never had any issues. Just make sure you give it some evaporation time after it's wiped off.
 
Unless I know that the panel was contaminated by something, I just blow it off and wipe with a clean dry rag at the same time.
 
I have used the Super Build 4:1. 2 coats.. Using the Sata 100 rp w/2.0 tip..over epoxy..If your body work is descent you'll onl need 1 high build euro thane primer and you will be ready for paint. I use solvent w/g before every coat of primer
 
shine;n70978 said:
slicksand at 58 a gal is pretty hard to beat . as for cleaning i use wb clearner .
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I'd like to know where you're getting it for $58 a gallon, I'm paying $100+.
 
last time i bought featherfill g2 i think it was $68-$70 a gal. never bought slicksand since i have never seen it for sale here anywhere.
 
Slicksand is right at $100/gallon now from suppliers in this area. Amazing how popular polyester primers have become over the past 10 years. When G2 first came out I was paying $39/Gallon and that wasn't all that long ago.
 
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