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With what little experience I have, I have noticed that weldable primer is not what it’s cracked up to be. I bought this stuff from IMS and could not stop the popping and yucky welds.
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- #923
I’m gonna give them until the end of the week to cure, and then try it again.
Remembered something else. After cutting the passenger front fishplate loose the third time, I noticed that the primer I’d put on the back side had deteriorated and bare steel was showing through. Was out of zinc primer so, in a pinch, I figured I’d try some of the high-temp ceramic engine paint I had lying around. I think I sprayed it and let it sit overnight and all day the next day before tacking on. It may have been several days after that that it got fully welded, and again, no issues. Might be an alternative. Might have to play around with this some more and see what happens.
Remembered something else. After cutting the passenger front fishplate loose the third time, I noticed that the primer I’d put on the back side had deteriorated and bare steel was showing through. Was out of zinc primer so, in a pinch, I figured I’d try some of the high-temp ceramic engine paint I had lying around. I think I sprayed it and let it sit overnight and all day the next day before tacking on. It may have been several days after that that it got fully welded, and again, no issues. Might be an alternative. Might have to play around with this some more and see what happens.
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I am no expert by any means but rust requires iron and oxygen to form/propagate. As long as you are fully welding the fishplates I don’t think you need anything between the frame and the plate.
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- #925
Yeah, was thinking and that. But you know how water is. If there’s any little pinhole, it’ll find a way. Would like to know how many top restoration, resto/mod type shops approach similar jobs.
The fastest way is the way that the shops do it.
I watch these shows like ‘Bitchn Rides’ and they weld all sorts of things up that don’t seem to get any pre or post prep. Granted they then go to paint but the spots I am watching them weld don’t seem accessible to the painters. I wonder.
I watch these shows like ‘Bitchn Rides’ and they weld all sorts of things up that don’t seem to get any pre or post prep. Granted they then go to paint but the spots I am watching them weld don’t seem accessible to the painters. I wonder.
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- #927
Did an experiment. Coated some 3/16” flat stock with this galvanized coating (Bob’s favorite) and let sit for about 2hrs.
Removed the coating where weld would take place. Welded. No off gassing porosity at all.
Not completely apples to apples. This isn’t the same paint I used before.
Removed the coating where weld would take place. Welded. No off gassing porosity at all.
Not completely apples to apples. This isn’t the same paint I used before.
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- #928
So now something else had dawned on me - it could be surface contaminants left over from the old undercoating. I sanded the area down, but don’t recall using any prep cleaner on the frame prior to painting, even though I’ve been religious about that with everything else
- Thread starter
- #929
Got some time in this evening to test my “hypothesis” about the cause for the sh*tty turn the welding took earlier in the week.
The scabs for the rear axle hangers got fully welded, the front shackle hangers were only tacked. I re-cleaned around one of the front scabs with a wire wheel, then wiped it down with some wax/grease remover. Hit it again with a wire wheel that I was sure hadn’t hit any of the undercoating at any point previously. Hit again with wax/grease remover. It was about an 80% improvement. I think 100% would/could be realized if I would have removed the scabs and done a total clean down. But I just don’t have the patience for all that. 20+ inches of good weld is just gonna have to do.
So this scenario brings to mind the earlier conversation about using brake-clean before welding. I’ve personally never done it, but can now see why it would be considered. You want to clean an oily, grease contaminated weld joint, and brake-clean would seem like an obvious choice. I haven’t searched any out yet, but I’m sure there’s a product made specifically for that application.
Reminds me also of the days of TIG welding cracks in pneumatic bulk cement trailers. We only used stainless steel wire wheels that had never touched steel or anything ferrous to do the final clean out of the crack before welding. To do otherwise would imbed impurities into the mother metal and cause the weld to come out like sh*t. I think that’s more or less what happened here.
The scabs for the rear axle hangers got fully welded, the front shackle hangers were only tacked. I re-cleaned around one of the front scabs with a wire wheel, then wiped it down with some wax/grease remover. Hit it again with a wire wheel that I was sure hadn’t hit any of the undercoating at any point previously. Hit again with wax/grease remover. It was about an 80% improvement. I think 100% would/could be realized if I would have removed the scabs and done a total clean down. But I just don’t have the patience for all that. 20+ inches of good weld is just gonna have to do.
So this scenario brings to mind the earlier conversation about using brake-clean before welding. I’ve personally never done it, but can now see why it would be considered. You want to clean an oily, grease contaminated weld joint, and brake-clean would seem like an obvious choice. I haven’t searched any out yet, but I’m sure there’s a product made specifically for that application.
Reminds me also of the days of TIG welding cracks in pneumatic bulk cement trailers. We only used stainless steel wire wheels that had never touched steel or anything ferrous to do the final clean out of the crack before welding. To do otherwise would imbed impurities into the mother metal and cause the weld to come out like sh*t. I think that’s more or less what happened here.
I think the brake clean would be safe IF you let it air dry for a while, but don't take my word for that. I'd do some research first.
Acetone is my cleaner of choice before every weld, I’ve also been known to use lacquer thinner in a bind without ill effects. Never a good idea to grab a can of “chlorinated” brake cleaner sitting on the bench behind you and hose down the entire area before welding.
What about a quick pre-heat with a torch? Your welding on a bare frame, would burn off any residue?Acetone. There you have it
IMHO a proper preheat wouldn't be near hot enough to burn all the contaminates off the surface. As a rule for me on something the thickness of a frame I'll only chase the moisture line with the flame then start welding.
Acetone will remove the contaminates and pretty simple to do especially if you get the little pressurized sprayer.
Amazon product ASIN B002M7MU2A
I've got one of those for light oil, works good!
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- #938
Worked on getting the last fishplates welded on and done today, with the threat of rain in the distance.
Marked out the outline of the plate and used a paint stripping disc on the grinder to remove the paint. Cleaned the bare steel down with acetone. Found the best results when I removed 1/4” - 1/2” of paint from the edges to be welded on the fishplate.
Next step will be to weld the hangers.
Marked out the outline of the plate and used a paint stripping disc on the grinder to remove the paint. Cleaned the bare steel down with acetone. Found the best results when I removed 1/4” - 1/2” of paint from the edges to be welded on the fishplate.
Next step will be to weld the hangers.
- Thread starter
- #939
Easter mimosas and drilling some holes. Haven’t heard any government decree banning drinking and drilling, but the wife may skew an eyebrow if she found out.
Happy Easter my friends!
Happy Easter my friends!
Easter mimosas and drilling some holes. Haven’t heard any government decree banning drinking and drilling, but the wife may skew an eyebrow if she found out.
Happy Easter my friends!
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