Fillers & Primers

General Discussion. Make yourself at home...read, ask and answer!



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PostPosted: Thu Feb 18, 2021 2:21 pm
Can someone break down the best fillers and if primers can be used to "fill"

Lets say you have an uneven surface, and you want to smooth it all out, is a primer a good idea or just a filler, the thing I'm noticing is ....filler isn't the easiest thing to try and get a nice smooth coat of, brilliant for scratches and bumps! but not so good otherwise, onless i should be using a different filler

I have found primer doesn't safe you all the time from scratches etc, unless you pile it on thick, but is this a recommended method...i would assume not.

my example - sorry no pics available at minute! a panel that has been dented, and smashed with hammer by me (yes i did it on purpose to see if I could repair it) , smashed it back with a hammer, and tried to straighten it as best as possible, but getting it even stevens again isn't that easy! I've applied some filler for the bit dents which is fine, then I tried to use filler as a way to "even the rest out", I assume this is probably just not the best method in general without getting in to panel beating and welding bits on to pull it out straight!

Any advice alwayssss appreciated



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PostPosted: Thu Feb 18, 2021 5:26 pm
i have been useing Upol UP-2253 lately an realy like it its a HEAVY bodied HI BUILD 2 part primer i use Rage ultra filler and just bought a gal. of Rage Extreme to try. as far as flatting a panel its something you just have to learn by experience i commend you for denting up an old panel and trying to fix it that's exacly how to learn. :clap: most people won't take the time and start right on there project and then wonder why it won't do what its suppose to do. i don't work by the hour so i spend a lot of time getting my metal as perfect as i can, it'll save you in the end. with your filler it depends but sometimes its better to put a tight coat on a complete area rather than just filling misl. low spots. you'll then block the filler with 80 grit you'll be able to see the hi and low spots apply your filler primer the first time with about 3 GOOD WET coats really lay it on. then guide coat it and block it with 180 there's so much to it that it would take for ever to go over all of it. just keep asking questions that's how you learn.
Jay D.
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PostPosted: Thu Feb 18, 2021 9:05 pm
Glad you appreciate my crazy ness.i basically bought some average scrap fenders and throw them on the floor as hard as I could. Just to get some damage in to them. Crack. The sort of stuff you would expect from a crash really,

I basically tried to straighten it as best as possible..... Filler...

Then one layer of normal primer. Just more so I could see how bad it was. Sanded off the primer... More filer..... And just gone like that

I did bang on 3 coats of primer heavy! Which I then intended to sand right down again. But wasn't sure if going heavy on primer is a good idea but as you have mentioned it then I'm sure it's not a bad idea then.

It's drying in the garage at moment! Il see how it comes out tomorrow. I imagine a lot more sanding to be done.

Seems the prep... Filler... Primer is about 99% of the work



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PostPosted: Fri Feb 19, 2021 12:12 am
Fabio,

If you have not had a chance to read the many posts on the top of the forum that are in blue, there is a great amount of info that might help answer some of your questions, it sure did for me. Yes the prep is most of the project.
The one thing that I have done as a beginner is to make sure that the metal surface is as smooth as possible before any other work so that you do not have a lot of filler on top of the damage, because the thicker the filler the more chance of it popping off or giving you problems as you paint.

When your beating the panel get a piece of flat smooth steel or if it's a curve some pipe that has the same radius to back up the hammering, or get a starter set of body hammers and dollies, they have payed for them self on my project to take out the dents. Keep hammering so that when you use filler it is no more than 1/8" or less thick, which is what your trying to strive for, thinner is better. From what I read in your post you might spread the filler around but don't work it too much, it's like doing wall board work smooth but not paintable smooth. Then you sand it until it feels and looks smoother, then go at it some more with a guide coat paint and sand until that is gone, then you have a smooth panel.
The primer that the other guys are talking about is what is called a primer filler or high build primer, be sure to NOT use it as a base primer, I did and had to remove it all because by the time I was getting along with the metal work the moisture was through the primer filler [porous] which left rust spots all over the body of the car. I had to media blast it all off and then applied a epoxy primer to seal from moisture then did the body work left with minimal filler. Now I'm getting ready to epoxy prime again to seal the bare metal, then primer filler, guide coat sand that, then paint. So light is at the end of the tunnel. ;)

Keep us posted on your project.

TX
Mr fixit_PDX
Chris :)



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PostPosted: Fri Feb 19, 2021 3:35 am
Hi, well thank you for the base primer comment, as you are right, I used base primer... :/

So looks like all that needs to come off then! ha, but better now than later.

i did leave a nice layer of epoxy primer first thought, which I assume you would act as the sealer...or am i wrong?

question though..... if base primer is porous, and lets water through, what do you do in terms of sealing an area to stop rusting getting through, that's kind of opened up a can of worms for me now about primers.....

So if I have bare metal, I should be using epoxy primer, than can put a layer of base primer on top is that right?



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PostPosted: Fri Feb 19, 2021 1:47 pm
i'm not sure what you mean by base primer? on thing i forgot to mention is that EVERYTIME you buy a paint product GET the product information sheet NOT the msds sheet. this has a lot of valuable info, study it. the one thing you need to look for before you start to take all your primer off, is it a dtm primer,direct to metal that sheet will tell you. epoxy is good under almost anything and yes you can shoot epoxy on the bare metal then shoot your highbuild over it. i like when ever possible is to shoot my epoxy then wile its sill in the sensitive state (recoat time) i will shoot a couple coats of my highbuild. NO sanding required on the epoxy during this time, LOOK on you info sheet it will tell you about the recoat time. you SHOULD be useing HIBUILD PRIMER it will do everything you need to do, it it will fill and most can be used used as a sealer if needed. if your parts are exposed to the elements epoxy the bare metal. if your in a shop then DTM high build should work fine. i have never seen water problems with properly applied 2 part primers, but i don't expose my work to outside aliments or moisture. the epoxy is the way to go it should solve all those problems.
Jay D.
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PostPosted: Fri Feb 19, 2021 2:33 pm
Epoxy primer seals the bare metal and protects it from rust.

Polyester Primer is like spray on body filler and you better read a lot before trying to spray it. It chemically sets just like body filler so spray time is greatly limited.

2k Build primer comes in a variety of quality and "build" thickness per coat.

2k High Build Primer is just what it's name says. Usually takes a 2.0 or bigger tip to spray.

2k Turbo Build Primers are usually high build primers with a bit quicker flash time.

Once all your guide coating and block sanding is done. You can purchase a sealer or spray a reduced coat of epoxy primer to protect the surface from contaminants.

As for filler, there are a few quality brands out there. I use 3M Marson https://sri-supplies.com/marson-platinu ... 01171.html as it reasonably priced and sands decent. You can also add a little Evercoat Plastik Honey to your filler to make it spread easier on skim coats.
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PostPosted: Fri Feb 19, 2021 6:56 pm
fabio1605 wrote:question though..... if base primer is porous, and lets water through, what do you do in terms of sealing an area to stop rusting getting through, that's kind of opened up a can of worms for me now about primers.....


You don't get sole rights to that can, you know.

Everything that 68 said, above, and then complicate it with DTM primers, etch primers, wash primers, plastic and adhesion primers. And then there are 1K and 2K versions of most of these.

Keep it simple. Use an epoxy to coat metal and stop it from corroding. You can thin the same epoxy down and use as a sealer, if you need to. Add a quality high build primer to your kit and leave it at that.
Chris



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PostPosted: Sat Feb 20, 2021 5:50 pm
Ok thanks guys this all makes sense

Very informative as always! :)

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