View Single Post
Old 04-07-2021, 10:39 PM   #35
MP&C
Registered User
 
MP&C's Avatar
 
Join Date: Jan 2013
Location: Leonardtown, MD
Posts: 1,630
Re: Roof patch causing warp / oil canning

First I'd like to say thanks for all the kind words, but I fear you guys overestimate my skills or abilities. I've had quite a bit of metal thrown into the scrap pile, serving as quite the lesson of what not to do. Have also had to strip down a paint job due to overeager application of Ospho by the owner into pitted areas, and me spraying epoxy primer directly over top of it (having no prior experience with Ospho). Sunlight over the course of the first year of car shows reactivated the deposited acid in the pits where it was now outgassing and we had small 1/8 and smaller circles where the epoxy was delaminating above these pits. ..

But I am a rather fast learner, and tend to offer opinions to help others capitalize on my learning curve. So when people start singing praises of using Ospho and other such snake oils, I am quick to offer my insight. Many of the proponents of these products simply are amazed by the minimal amount of work needed (ie: shortcuts) and have recommended product based on this and not much else, as most were still sitting in bare metal in project stage.. Lorne, this is what really get my blood pressure going .. People giving half ass recommendations that haven't finished the job to know the full story yet. Hey, I get it. We humans are lazy, and looking for an easier way, so that's why so many of these short cut products are sold. But that, folks, is why Robert is so damned opinionated..



Quote:
Originally Posted by HAULIN' IT View Post
…...First a question for Robert...Was the tailgate you showed in the video for sure mig welded solid?


Here's the answer from the horse's mouth. Yes, I asked him to clarify once before and this was his response. Names changed to protect the innocent/unknowing. He also spoke of his experience with adhesives, and I am leaving that as well, perhaps you can speak to that based on your experiences....


Quote:
Xxxxxx, question for you if I may.... The video I took of your tailgate I have posted in a couple places in hopes that someone can see the results up front and perhaps choose another method. I do have someone asking more particular questions, as it appears he is one that swears by the flanging and panel adhesive method. So if I could, a couple questions.

Did you attach your flanged repair with a panel bond adhesive or by welding?

If it was welding, was it plug/spot welded and about how far apart, or was it a continuous weld from end to end?

I'm always trying to learn something, hope this finds you in good health.
Thanks, Robert
Quote:
Robert, good to hear from you.

As for the flange repair there was no panel adhesive used and the lip was sand blasted and surface prepped before tacking and then drilled and plug welding approximately every 4 inches,

We went back and moved from one side to the other and did a continuous weld then ground it down.

Having never had any previous knowledge of how to properly make and weld panels this was the only way I was aware of, I know better now.

Thankfully the section still looks the same as when you saw it.

On another note, we used a cheap HF English wheel to make a insert for a 34 Chevy coupe and it turned out pretty good for not having any previous experience with rolling metal, we also had to make and replace all the reinforcement that had been cut out to make a dirt track car we were returning to the street.

The reason I am tell you this is we used the panel adhesive thinking it would minimize vibration between the filled top and the braces, the next weekend when we were ready to start sanding we noticed the panel adhesive drew the top and you could actually see the pattern of the bracing.

We ended up using piano wire to saw back and forth to cut the panel adhesive loose, It took us several weekends to correct the problem but the car was eventually painted black cherry and it turned out perfect.

Hope I answered your questions, that wagon you have been building has set the bar high! Xxxxxx



Quote:
Originally Posted by HAULIN' IT View Post
…...One of the neat things of over 30 years "practicing" auto body repair...you get to try/see how things work out or dont work out. Lorne


Lorne, thanks for adding your experiences here with the adhesives, I agree fully that sometimes another method may be in order, and that is the decision the owner must make in each circumstance. Sometimes you get people that don't want to share with others what didn't work as they don't want to admit "failure", or whatever the reason. I see those as a learning moment, and would feel remiss if I didn't share, especially given the costs today of paint and supplies.




Quote:
Originally Posted by ItWillBeSlow View Post
Should I space it down to allow more room for the bond material to fill the void and not squeeze out?


I do not have personal experience (disclaimer) but what I have read is that any seam should be clamped tightly. I would interpret that as meaning the joint may be stronger as a thin film between the two panels, and not used as a "filler". It may be, based on the roof repair on the 34 Chevy written above, that too much of a gap and the adhesive does it's own shrinking which pulls the area downward.. My thoughts are that the spacer is going to weaken the joint. Perhaps Lorne can share his thoughts on this as well..





.
__________________
Robert

Last edited by MP&C; 04-08-2021 at 08:01 AM.
MP&C is offline   Reply With Quote