[quote="jimmystoys"] Although I will remove all the original paint eventually and spray with epoxy, could I at least treat the patch with epoxy so I could apply some filler? I understand it's better to epoxy the metal to minimize flash rust then apply the filler after. The backside I will clean up and treat right away with epoxy.

Just wondering if anyone had a thought to my query?

I don't understand the question ?

I have applied filler over both metal covered in epoxy and just filler over bare metal both are considered acceptable BUT any more I think doing Filler over epoxy is best.

I have Seen many instances over the years were filler was just applied over bare metal and when the filler is removed many years later the metal is rusty under filler.

Doright wrote:I don't understand the question ?

I have applied filler over both metal covered in epoxy and just filler over bare metal both are considered acceptable BUT any more I think doing Filler over epoxy is best.

I have Seen many instances over the years were filler was just applied over bare metal and when the filler is removed many years later the metal is rusty under filler.

My query/question was that I wanted to replace metal in areas then epoxy and only then apply filler. My understanding is it's better to apply filler over epoxy other than metal because of what you described Dennis. You have answered my question. Thanks again!

After a couple coats of epoxy I let the Epoxy cure out a week or more Then I scuff the Epoxy b4 any Filler work. (Epoxy needs time to do its thing) you could do it sooner BUT....

I am a firm believer of letting the stuff fully cure out the longer the better It gets stronger as it cures. To really get its benefits of using it needs to fully cure out in my opinion before any thing goes on it no better Base to build upon.

Doright wrote:After a couple coats of epoxy I let the Epoxy cure out a week or more Then I scuff the Epoxy b4 any Filler work. (Epoxy needs time to do its thing) you could do it sooner BUT....

I am a firm believer of letting the stuff fully cure out the longer the better It gets stronger as it cures. To really get its benefits of using it needs to fully cure out in my opinion before any thing goes on it no better Base to build upon.

Got it. Thx!

Hi guys. Been awhile. Thought I would update. Still working on my burn through skills lol. Getting better I guess. Here's some pics. Please opinionate, it helps me!
Installed new piece of metal. Started to burn thru on the top right corner but managed to control it with copper backer. This is the result. Hard to get rid of the littles dimples. I try and hammer and dolly but I ain't no expert lol. let me know what you guys think. Thanks. (pics are backwards. Still trying to figure this out)

Middle pic looks to me like one of mine, but you'd have to be happy with the end result.

Seems a little quiet around here. Haven't you guys gotten over Christmas yet? lol.

Seems to run in cycles. Sometimes busy and sometimes not a post for a few days.

Christmas was a bit of a non-event here. I just had the two days off and straight back to work. Most of the rest of Australia went back to work yesterday.

Jim
Its my opinion you have the welder settings very close, and your technique is close AS long as you have zero gap or close to zero. When looking at your beads
I see the good Beads look pretty darn good for a Mig. The Bad ones, look at the Gap wear you Blew through (Do you see why the guys who know say NO GAP now?)

I don't cut out Panels with a cutting wheel, I use a small pneumatic Body saw with a small cutting blade often cutting both the patch and the body to be repaired at the same time to get a perfect fitting patch.

https://www.eastwood.com/pnumatic-metal ... oogle&wv=4

When I gas weld I use a Zero gap and fusion weld only adding rod when I have too.
When I Tig weld I use a zero gap and fusion weld only adding rod when I have too.
When I Mig weld again Zero gap On thin Materials, A repair like this one I would Tig welded OR Gas welded I would have avoided the use of a Mig.
You cant really Hammer and dolly Mig weld bead It will Crack so I Just grind it off.
Stacking Mig weld beads leads to a Porous weld that's why I avoid a Mig for this sort of repair.
If you look at back side of Mig weld bead Generally you'll have penetration BUT it looks pretty nasty I sand/grind it smooth when I can get to it and will coat it and seal it with Epoxy often letting epoxy cure and then coating with thin coat of fiberglass filler to again keep back side sealed from water and air so it doesn't rust again.

When Using a Copper Backer with a Mig:
After you've used it Look at back side of bead look at the bead itself often its very porous with what looks like air bubbles in the bead. (Not good) (I avoid) Not gonna say I don't use a copper backer BUT I keep its use to a very minimum and a Last resort aid.

A better way is to make small tiny patches and weld in rather than filling with your Mig, Yes every one has done it but It looks like Dog poop both on the front and especially the back being very porous which is why it has to be ground down smooth sealed with Epoxy and then sealed with fiberglass.

Prices of small Inverter Tig welders have come down and often much cheaper than a decent Mig welder, Mig is just easier to learn to use its not a better welder! or better welds! Stacking beads with a Mig isn't welding in my opinion it leaves cold spots and air gaps and is very porous which again requires sealing. Every one does it and has been a industry standard for decades doesn't make it right though. Ask any certified welder if their is a Better way if hes honest he will say yes, Gas or Tig.

The Down side of Gas or Tig is the Learning curve, it requires some serious time to learn the skills required to use them! 40-80 hr is not unusual Its a skill which will serve you well for many decades if you bother to devote the time to learn the skill.
I often say to learn Gas welding first then step up to the Tig.
Gas is much cheaper to learn the skills of controlling a Torch and Rod while your learning heat control with Gas.
Then when you jump to Tig here you have to learn to control heat even more adding your foot and Tightening up the control of your Torch keeping your tungsten out of the weld pool while your other hand adds your rod all at same time its a dance.
The real benefit of Tig is heat control and how clean the weld bead is You can pin point your heat to only the weld pool NOT infusing the whole panel with heat warping it it makes an Ultra nice repair when done properly.

Both Gas and Tig weld beads can Be worked with Hammer and dolly without cracking and the panel is easily worked from the heat effected zone with hammer and dolly often no heat warping is encountered with the Tig zero!
Mig weld repairs Not so much often your stuck with a warped panel that cant be worked and your only choice is to fill it with filler. Ya the rust is gone But now you have a 1/4 of filler on your panel because of heat warped panel.

Just the ramblings of a fat old fart