Weld through primer for stick welding?

Jawon · Mon Mar 09, 2015 2:09 am

I have new replacement panels for my car that will be welded to rusty metal (after cleaning). I've heard the primer on these types of replacement panels are a crapshoot and probably wouldn't survive the heat of a stick welder.

Should I sand down to bare metal and use weld through primer, as opposed to "regular" primer (btw, some areas will be inaccessible after welding)? Or does this situation call for a different approach?

AndersK · Mon Mar 09, 2015 6:07 am

Weld through primer is primarily intended for spotwelding lap joints.
It wont survive the heat close to a full seam. To protect closed areas it is better to spray with products designed for that, like Dinitrol or Tectyl (there are many different products depending your region)

Also weld primer should not be used on surfaces intended for painting. They usually dont mix well with regular paint.

There are etch primers that work well as weld primer too, no worries using regular paint over them.

Ive also noticed that epoxi primer can hold heat quite well, but will burn off close to the weld.

Jawon · Mon Mar 09, 2015 4:15 pm

Thank you. I have so many follow up questions and I may present them here over time, but I'll keep it simple for now...

One of the replacement parts has the black e-coating. I've read the e-coating is weld-throughable with a stick welder, true? I plan to stick weld a few short lap joints and a bunch of "spots" (with the stick welder, not a spot welder).

Also, this part is essentially a tube where the inside will not be accessible after welding. Which rust-prevention products would be good to apply on the inside before welding (ie, can withstand the heat though only the very ends of the tube is where the welding would happen).

Mon Mar 09, 2015 5:26 pm

I'm wondering if anyone has done the experiment... The Ceramic/nickel expensive spatter-spray? How would that perform as a permanent corrosion inhibitor? Or, will it take paint?

Steve S

Superiorwelding · Mon Mar 09, 2015 9:05 pm

Otto Nobedder wrote:I'm wondering if anyone has done the experiment... The Ceramic/nickel expensive spatter-spray? How would that perform as a permanent corrosion inhibitor? Or, will it take paint?

Steve S

Steve,
I can coat a piece with my ceramic anti spatter and set it outside for the next few months and find out. I will take a guess and say it will hold up well. Expensive though.
-Jonathan

Mon Mar 09, 2015 9:55 pm

Jono, please only coat the back and then weld the front. I think that's what the original question was wondering.

AndersK · Tue Mar 10, 2015 4:03 am

Jawon wrote:Thank you. I have so many follow up questions and I may present them here over time, but I'll keep it simple for now...

One of the replacement parts has the black e-coating. I've read the e-coating is weld-throughable with a stick welder, true? I plan to stick weld a few short lap joints and a bunch of "spots" (with the stick welder, not a spot welder).

Also, this part is essentially a tube where the inside will not be accessible after welding. Which rust-prevention products would be good to apply on the inside before welding (ie, can withstand the heat though only the very ends of the tube is where the welding would happen).

I would recommend you remove paint where you will do the welding. Even if I use weld primer I wire brush through the holes where the plug welds will be.

The body coating is some thing you absolutely not want to apply before welding. The heat turns it liquid and it will find your joints in no time after striking the first arc. That is something you apply after welding thru a small hole you plug after with plastic plugs. I have some pics of a recent repair to show thus. That car had been sprayed some months before and they found rust damage that needed to be repaired. Shittiest welding I ever made....

Tue Mar 10, 2015 7:38 pm

weldin mike 27 wrote:Jono, please only coat the back and then weld the front. I think that's what the original question was wondering.

Yep, Mick,

That's what I was getting at... After weld heat, is it still in place and corrosion resistant?

Steve S

Tue Mar 10, 2015 9:00 pm

Great minds think alike, and fools never differ.

Jawon · Tue Mar 10, 2015 10:07 pm

AndersK wrote:The body coating is some thing you absolutely not want to apply before welding. The heat turns it liquid and it will find your joints in no time after striking the first arc. That is something you apply after welding thru a small hole you plug after with plastic plugs.

I plan to use Masterseries and the folks there suggested the same spray-thru-hole-and-plug method. Not sure how that's gonna work, but once I have this product in hand, I think I'll do some tests and figure something out. Thanks for the replies.

Jawon · Tue Mar 10, 2015 10:08 pm

weldin mike 27 wrote:please only coat the back and then weld the front

This is prob what I'll start with and hopefully the tests will show it is good enough, at least further from the welds.

jwright650 · Wed Mar 11, 2015 8:00 am

Stick welding body panels? That should be a good test of your welding abilities.

GreinTime · Wed Mar 11, 2015 8:43 am

Man, were you around when the guy from Europe was stick welding body panels on his old Opel? That was impressive.

Wed Mar 11, 2015 7:58 pm

GreinTime wrote:Man, were you around when the guy from Europe was stick welding body panels on his old Opel? That was impressive.

That was Qwerty12, from Bosnia.

I need to check in on him... Long time no hear.

Steve S

Braehill · Wed Mar 11, 2015 9:47 pm

I miss qwerty12, he was very entertaining, never was able to ship him that helmet because he would have had to drive 150 miles to the closest place that I could ship it to. The shipping would have cost me $112 to ship him a $40 helmet and the gas would have cost him 2 weeks pay. Third world problems for sure.

Len

Thu Mar 12, 2015 12:02 am

That's unreal. Benefits of the European Union right there.

Thu Mar 12, 2015 7:35 pm

Braehill wrote:I miss qwerty12, he was very entertaining, never was able to ship him that helmet because he would have had to drive 150 miles to the closest place that I could ship it to. The shipping would have cost me $112 to ship him a $40 helmet and the gas would have cost him 2 weeks pay. Third world problems for sure.

Len

Jody pulled it off! Qwerty12 got an auto-dark from Jody's collection of "review this" hoods. I didn't ask the shipping details, but Qwerty replied after he received it.

Steve S

Braehill · Thu Mar 12, 2015 8:01 pm

Steve,
That's the first that I've heard that, good stuff right there.

Len

Sent from my iPhone using Tapatalk

Thu Mar 12, 2015 8:15 pm

Len, it was a long while back.

I conspired with Jody, just a bit... Qwerty12 was NOT going to accept any charity, and was insistent on it, so I made a "fair trade" deal, where Qwerty would share a video of "how the hell he welded rusted Opel panels with stick" with Jody as payment for a helmet.

I suspect he caught on that the video was not getting published, and his pride kicked in, but at least he got the hood.

Jody's a good man.

Steve S

Braehill · Thu Mar 12, 2015 8:26 pm

Steve,
Him and I exchanged quite a few PM's with me trying to convince him to accept the "free" helmet before he finally relented. I had quite a chore trying to even find somewhere where I could ship to in Bosnia, I almost shipped it to Serbia and had someone smuggle it to him, but didn't want to get him in trouble. Crazy world we live in.

Len
P.S. I would have loved to see that video.

noddybrian · Fri Mar 13, 2015 3:29 pm

Glad he got a hood in the end - I tried repeatedly to help him but he would not give an address - as he said he had Ebay I went & made an arrangement with a local shop that sells welding stuff on there to " let " him win one at the starting bid of £0.99 - I also had them send him a message that they had some display models that could'nt be sold - he could have one if he paid the post - all he had to do was give an address - if he had I'd left the money for a good one to be sent to him without charge - figured he would'nt send it back & we could say PayPal made a mistake & did'nt charge him ! but after a couple of months of we never heard back from him & never got anywhere to post to - shame some people are so proud - I really wanted to help the guy.

Sat Mar 14, 2015 5:11 pm

Braehill wrote:Steve,
Him and I exchanged quite a few PM's with me trying to convince him to accept the "free" helmet before he finally relented. I had quite a chore trying to even find somewhere where I could ship to in Bosnia, I almost shipped it to Serbia and had someone smuggle it to him, but didn't want to get him in trouble. Crazy world we live in.

Len
P.S. I would have loved to see that video.

I didn't realize you had such a hand in that little conspiracy!

Steve S