Rust stains through frek eprimer

JohnJL · 06-27-2015, 04:41 AM

Hi,

I am a novice at bodywork, having done just a couple of projects before.

I am in the process of shaving my gutters and some other bits and have run into an issue. I have been following FH's steps religiously, including the metal conditioning and prep as here: Metal Conditioning And Epoxy Priming 101

I conditioned and prepped, and sprayed 2 coats of eastwood 2K epoxy primer.

THe next morning, there was some rust staining in the primer in a few spots. Pics:

OK, take it easy on my welds. The metal in that area is filled with filler and crap you cant get to on the backside and likes to blow-through. The structure itself is solid but there are some pockets as you see.

The backside of these welds is "blind" but I was planning to run some degreaser, metal conditioner, prep and primer through that area via some gaps and perhaps a strategic access hole drilled here and there where the headliner will cover. That way the welds are fully encapsulated on both sides.

The rust doesn't appear to be "through" the primer, but staining it from the backside.

Whats the course of action here?

THanks

962porsche · 06-27-2015, 06:04 AM

personal allot of what is in the 101 thing I don't agree with .
metal prep is it's uses and most of the time it's just not needed at all .
we use every little of it as most of it is water based water on bare metal think about it ?
with good clean freshly sanded metal wiping with a metal treatment does nothing .
NO it does some thing if you can't wipe it all off and it gets into a seam or between welds it will rust .
the only way your going to get rid of the rust between the welds is to sand blast all the welded seams back down to bare and then spray a coat or two of e-primer back over it .

JohnJL · 06-27-2015, 08:44 AM

How did that f'rek' get in the title?!?!? OOPS!

JohnJL · 06-28-2015, 09:50 AM

Here's what I did:

Materials:
1 qt Wax and Grease remover & pain prep
1 200ml syringe
24" 2mm ID tubing with a "misting tip" that comes with frame interior coating aerosol
1 can Eastwood frame rail internal coating
3" coathanger wire with a loop at the end
rage to pull through the coathanger tip

Procedure:
4 hours to do both sides
Turn the car over 3/4 on the rotisserie so the gutter weld I am working on is the lowest point and all the thinner and paint collects on the inside of the weld. flip the car to do the other side.

Drilled 7 10mm holed in the inner roof panel to allow access for the laquer thinner sprayer to reach the entire length of the inner weld

attached the tube to the syringe and draw in wax remover. thread the tube with the misting tip on it up into the3 roof channel on the inside of the weld and squirt out thinner as I drew it back. Coat the entire inner of the weld so the thinner is running down the channel and through pinholes.

run a rag through the coathanger tip and run the rag up inside the roof along the inner welds.

Repeat the thinner and rags 5x on each side.

dry out with compressed, drieed and filtered air. Check the entire length of the weld is clean.

Spray Eastwood inner frame rail coating all along the inside of the welds. turn the car over a few rotations on the rotisserie to make sure the coating gets everywhere.

I will blast those welds from the outside next saturday and put another coat of 2K epoxy primer on everything.

Any other suggestions?

962porsche · 06-28-2015, 02:16 PM

YOU REALLY NEED TO FINISH WELDING EVERY THING 1ST !
the spaces between the welds and the holes will give you big headaches about a year or two after the body is painted .
it's not going to matter what type of filler your going to use nor primer later on down the road after the car is finished your going to see it come back and bite you right in the butt !

JohnJL · 06-29-2015, 05:16 AM

Hmmm. Not what i wanted to hear but I am listening....

The pinholes are where I "burned through" the material and where there is little or no backside access. How do I patch those up? Do i need to get more backside access and use a copper piece against the pinhole to fill in the metal? Is there another technique? I find trying to fill in the pinholes just makes them bigger.

962porsche · 06-29-2015, 10:14 AM

lower the heat on the welder increase wire speed just a little and used the smallest wire gage you can with your welder .023 .
if you can flatten out a piece of copper tubing at the end and get it up behind the blow out for a backer when you weld it will work .
if not just little welds at the edge of the blow out until it's filled in works .
you also have to weld all the sharp edges were you missed or the body filler will shrink in there too .

JohnJL · 07-01-2015, 12:09 PM

OK, so I spent 6 hours today cutting access holes for the backside of the gutters and re-blasting them on both sides. A nap on the hammock, a beer and I will be back at it with my trusty copper pipe and MIG...

JohnJL · 07-05-2015, 04:02 PM

So I had 4 days to work on her. I took her back out and blasted her clean with glass media on both sides of the gutter seam. I then mig'd her along the inside and outside of the seam. Ground everything back flat, then filled in the pinholes. Did that twice.

Then cleaned her up with degreaser, and 2 coats of 2k epoxy primer, inside and out.

Then 2 sparing layers of Evercoat Metal2metal filler.