When and where to use high build primers

[Ronf]

Hello all,
Some quick background. I have been restoring classics and doing body work as a hobbyist for 40+ years. I have completed the bodywork and painted about 15-20 cars over this period. So, I am no professional but still take pride in my work and have progressed through the years to turn out some pretty decent work.
Now to the question. My current project is a 1936 Chevy coupe, when I start a project I always take the car down to bare metal, primer etch, dolly work, filler work(usually with Rage Gold), followed by feather fill and finally hit with 2K primer as a final before moving on to base coat. On my current project I am finishing up the last of the feather fill before I would go on to 2K primer. This time I am thinking about hitting it with a high build primer and guide coat before finishing up with 2K primer. The reason for going with high build primer is to help eliminate those "dimple" spots, usually less than dime size, that I have gotten in this particular build when finishing up the feather fill. By spots I am referring to small high dimple size spots that are barely perceivable. These spots are mainly occurring on the front fenders where there are extreme curves, where the fender shape is literally that of a basketball. I would normally sand the area out to bare metal and shrink it with my stud welder using a shrinking tip followed by filler again. What I'm wondering is if the high build primer can accommodate these dimples? I have never used high build primer, have always worked the metal with dolly, filler and guide coat to pretty much a smooth clean surface, but this extreme curvature is really getting tough to manage.
Thank you to anybody that will enlighten me on these high build primers, I can continue on as I have always done in the past but thought this worth a shot. I'm not looking for short cuts, just something to help me along.

[PainterDave]

primer is not bondo or glaze, that looks like a nice car,

my steps would be this
1 get to bare metal
2 filler and metal work
3 epoxy let flash G2 featherfill
4 block 150
5 fix what needs fixed (at this point it should be min work needing done)
6 epoxy (because you will have bare metal showing) let flash 2K primer
7 block sand
8 interface pad on DA 320 to remove block marks
9 epoxy and paint
10 cut clear 800 and reclear (not a flow coat)

thats my basics but can differ from job to job.

[Len]

I'm a little confused... Are these dimples high spots or low spots and where are they located on the fender?

[baubau]

the reply and procedure listed by PainterDave is textbook, golden rules.....that is how it needs to be done...

RonF, looking at that car and your experience, i think you have done all correctly and the best you could....

now the question is, Could you "cheat" with high build up primer and avoid more metal work/filler?...and Are those dimples high spots that need to be tapped down?

it is very difficult for any of us to give you a proper answer because we need to "feel" the shape of that panel with our hands and then make a subjective decision if high build primer can even it out and does it provide enough "height"/substrate so when you sand it off, it will level off.....


I have used high build primers before and even DTM, direct to metal high build surfacers, to level and smooth less than acceptable body and metal work.....

Give it a shot and see how it goes.....use a sanding block that matches the curvature and level it off, you know what to do ...

[Ronf]

Sorry for the confusion on dimples. These are high spots but only perceived when using guide coat (for the most part) a few will show that can barely be felt when running over the surface with a red shop rag not with the naked hand. Also, they are only difficult to tap out on the front bulbous area of the front fenders(see pic) it's like trying to fill and smooth a basketball. My problem is that I am chasing them. I tap or shrink one down and that area is fine, however when I go back to filler and work that area another one breaks through, so I'm chasing one after another. You have to understand these fenders were for the most part trash when I got the car. Close to 1/4 of all 4 fenders I reproduced from 18ga. for patch panels, they were that far gone. Most people would have probably scraped them and found either another set(good luck finding good 36' chevy front fenders) or went fiberglass. As time is not a factor here I choose to keep the originals. I will continue to work the dimples or should I say chase them, it just got a bit aggravating putting in 2 days on just the front area of one fender. The rest of the car is close to being finished and ready to shoot, I just thought if this is something a high build primer could take care of I would hit the fenders only. I am also going ahead and shooting Evercoats feather fill G2 high build primer on the fenders just to get the experience as I have never used any high build before. Lastly, because I am shooting a tri-coat red I know this needs to be near perfect, so I figure it really can't hurt to use the high build. Thank you to all that have replied, some smart folks here and I really appreciate your input!

[Len]

Yes, the high-build should work well in that situation. I would still guide coat it and sand until the dimples are gone. I haven't tried the G2, I've been using Slick Sand and it does an excellent job but I only use it on large areas that I want perfect.

[tommie.b]

Nice car and yed those fenders are a lot of work to get straight many many hours. I will work the metal with a body file over a dust coat of spray bomb primer to show low and high spots over and over again may have days in one fender and then when close a coat of filler over epoxy. High build 2K or slick sand and work them from there, but like Len and others said should work. Such a nice car don't short cut it.

[PainterDave]

Yes, the high-build should work well in that situation. I would still guide coat it and sand until the dimples are gone. I haven't tried the G2, I've been using Slick Sand and it does an excellent job but I only use it on large areas that I want perfect.

slick sand has a higher mil build than feather fill is the only difference

[Ronf]

Yes, the high-build should work well in that situation. I would still guide coat it and sand until the dimples are gone. I haven't tried the G2, I've been using Slick Sand and it does an excellent job but I only use it on large areas that I want perfect.

Thanks Len for the reply,
Guide coat is pretty much a staple product for me, it's just too easy to use. These projects take a long time, money and energy so I never cut corners. I almost went with the Slick Sand when I started thinking about using a high build primer. As I have never used a HB primer I did a little background research on both the G2 and the Slick Sand. I only chose to go with the G2 because a few people stated it was a bit easier to sand but it doesn't quite build the mil's in terms of coat vs coat. My jobber, whom I talked to this morning when picking up the G2 has used both products and pretty much stated word for word the same advise you have given me, so I can't state enough how much I appreciate you taking the time to help.

[Ronf]

slick sand has a higher mil build than feather fill is the only difference

Painter Dave, that's funny you mentioned this as I dropped by my Jobber this morning to pick up the G2 and he said the exact same thing. He also stated, as have a few others, that it is a bit easier to sand, would you agree with that?

[PainterDave]

Painter Dave, that's funny you mentioned this as I dropped by my Jobber this morning to pick up the G2 and he said the exact same thing. He also stated, as have a few others, that it is a bit easier to sand, would you agree with that?

sand about the same to me, i have no preference really, i use Feather Fill myself.

[baubau]

Slick sand, G2, it will work better thsn HB primer for this...150, 180 grit will help to shape ot fast.m.and you can akways use HB surfacer later....those fenders are strong, sturdy shape, they can withstand extera substrate built uo.m

[Ronf]

Nice car and yed those fenders are a lot of work to get straight many many hours. I will work the metal with a body file over a dust coat of spray bomb primer to show low and high spots over and over again may have days in one fender and then when close a coat of filler over epoxy. High build 2K or slick sand and work them from there, but like Len and others said should work. Such a nice car don't short cut it.

Tommie,
I did work the fenders with a file when I was down to bare metal and doing dolly and lead work. these fenders were really bad(see 1st pic when car was brought home). My fear was how much dolly work needed to be done in terms of stretching the metal. I was trying to do minimal metal shrinking and added to this was the amount of patch panels I had to make for these fenders, I sometimes think I should have just made the fenders from scratch but I really wanted the car to stay original. I never short cut any work that a project needs even if it means striping it all back down to bare metal and starting over, I just wouldn't be satisfied with it in the end. When I pulled this one home my wife said I had finally just lost my mind, to me it's just one more old car saved from the scrap heap. Thank you for sharing your valuable experience, I got into an area I wasn't comfortable with on these front fenders and needed to reach out to the more professional folks, thank you!

[Ronf]

After considering all the advice, instruction and information that y'all gave me, I shot the fenders with G2 Feather Fill, blocked with guide coat and finished with DP50LF primer. I want to take this time to thank each of you for your invaluable professional experience, you serve this forum well by giving professional advice to the hobbyist. I could not be happier with how the front fenders turned out. These fenders were all but trash when I started their restoration (see pics of completed fenders). In 40+ years of restoring old cars I had never used a high build polyester primer and was literally chasing a multitude of little dimples on the front bulbous area of the fenders and this was after I finished all the dolly work and initial coats of filler. Again, thank you all for responding and helping me get through this rough spot in my restoration!

[PainterDave]

looking great, glad you found a soltion