Roof patch causing warp / oil canning

[HAULIN' IT]

For the situation you are in, I would use some metal adhesive (Fusor 208 would be my choice) to put the piece(s) in & limit your "effected" area. Over the years I've done several antenna/light holes in ex-police vehicles, ect. with no issues.

A round "backer" slipped in, half under the original skin & half to sit the patch on will allow for a better/flatter finish. You'll want to do it in two stages, put in the backer...let it dry, then install the filler piece. This way you can work through the hole to hold the backer in place until it dries

I'm sure you have realized now that it would have been best a week ago to ask: "How would you guys go about filling this 1" round hole in this roof?", but hey...thats what makes it all a challenge. Lorne

[ItWillBeSlow]

Originally Posted by HAULIN' IT

For the situation you are in, I would use some metal adhesive (Fusor 208 would be my choice) to put the piece(s) in & limit your "effected" area. Over the years I've done several antenna/light holes in ex-police vehicles, ect. with no issues.

A round "backer" slipped in, half under the original skin & half to sit the patch on will allow for a better/flatter finish. You'll want to do it in two stages, put in the backer...let it dry, then install the filler piece. This way you can work through the hole to hold the backer in place until it dries

I'm sure you have realized now that it would have been best a week ago to ask: "How would you guys go about filling this 1" round hole in this roof?", but hey...thats what makes it all a challenge. Lorne

Can you elaborate more on the purpose of the backer? Is this to help absorb heat, or support the patch before it goes in? I dont understand how it would help the shrinkage, if that is the root cause of the issue here.

Originally Posted by HAULIN' IT

I'm sure you have realized now that it would have been best a week ago to ask: "How would you guys go about filling this 1" round hole in this roof?", but hey...thats what makes it all a challenge. Lorne

Definitely agree with this statement. However I have already done cab corners, rockers, floor patches, pillars, cab supports on this truck. This is my first rodeo obviously but I was looking at this hole as one of my last "easy" metal work tasks.... (wrong!).

[HAULIN' IT]

Originally Posted by ItWillBeSlow

Can you elaborate more on the purpose of the backer? Is this to help absorb heat, or support the patch before it goes in? I dont understand how it would help the shrinkage, if that is the root cause of the issue here.


Definitely agree with this statement. However I have already done cab corners, rockers, floor patches, pillars, cab supports on this truck. This is my first rodeo obviously but I was looking at this hole as one of my last "easy" metal work tasks.... (wrong!).

Im thinking you misunderstood what I have suggested. What I was referring to is to use a metal bonding adhesive & glue the piece in...not doing any welding at all. That way you can't/won't have any warping issues. The backer is to sit the patch on so it fits flush with the original Roof
I look at it this way, years ago someone made a mess by drilling the hole & then tightening down the antenna, raising up the area around it with the little bar/foot (Im guessing was the reason for you to cut the bigger hole?)...you didnt help matters by welding in the square cornered patch. Without cutting some inner cab away to properly work the weld area, the whole thing is going to be a compromise at best. The middle of a Roof (or Hood) is NOT the place to learn/practice...get something stuck in there to keep the water out & move on.
You may see a "ghost line" around you patch under certain light being the sun heat will be beating on it some, but the outcome for the situation (no access, somewhat limited tools & knowledge) I feel its the best answer. Like I said earlier, Ive done several antenna holes (Roof & Trunks) just like what you had starting out without a problem. A couple I just tapped down a bit & glued a piece on top. NOT Robert-like, but for a 6 or 8 year old ex-police car...it works real well
If its something you have interest in, I can go into detail of how to prep the parts, ect for the best results. My intentions are not to be-little your efforts or ability, just being a realist with the situation. Lorne

[MP&C]

Originally Posted by HAULIN' IT

…...NOT Robert-like.....

Point taken Lorne, most just go ahead and say anal retentive.

Sometimes we do what we have to do. In this case as long as the truck is stock height nobody should see any ghost lines..

[HAULIN' IT]

THAT is my point! I love to follow along to your posts & have some pretty good skills...I think that is why I appreciate what guys like you can do. Sometimes the vehicle design, time, tools & skills should just lead in another direction for some folks.
Get it done & enjoy the truck is my thoughts. If the worst/most noticeable spot on the whole truck is that ghost line on the roof...the man did a mighty fine job for his first rodeo! Just my Thoughts, Lorne

[72c20customcamper]

This guy has some great videos and explains everything in great detail without getting to technical

https://youtu.be/_u31t13QO6A

[ItWillBeSlow]

Originally Posted by 72c20customcamper

This guy has some great videos and explains everything in great detail without getting to technical

https://youtu.be/_u31t13QO6A

This is a cool video and interesting technique. It seems theoretically I could follow this same procedure and reduce the warp risk. The only notable drawback or risk may be that I am currently planning a smaller patch (3.25" circle) and may not have the easy manipulation/flexibility of patch to push the patch back into the hole after back-cutting at the 45 degree, compared to the larger square he is using in this video. I would have to tack 4 times on the circle, and then cut one quadrant at a time to push this section back flush prior to tacking it in flush. I hope that makes sense - basically I am saying my patch is less flexible. I am curious what others on this thread may think of this technique.

[ItWillBeSlow]

Originally Posted by HAULIN' IT

Im thinking you misunderstood what I have suggested. What I was referring to is to use a metal bonding adhesive & glue the piece in...not doing any welding at all. That way you can't/won't have any warping issues. The backer is to sit the patch on so it fits flush with the original Roof
I look at it this way, years ago someone made a mess by drilling the hole & then tightening down the antenna, raising up the area around it with the little bar/foot (Im guessing was the reason for you to cut the bigger hole?)...you didnt help matters by welding in the square cornered patch. Without cutting some inner cab away to properly work the weld area, the whole thing is going to be a compromise at best. The middle of a Roof (or Hood) is NOT the place to learn/practice...get something stuck in there to keep the water out & move on.
You may see a "ghost line" around you patch under certain light being the sun heat will be beating on it some, but the outcome for the situation (no access, somewhat limited tools & knowledge) I feel its the best answer. Like I said earlier, Ive done several antenna holes (Roof & Trunks) just like what you had starting out without a problem. A couple I just tapped down a bit & glued a piece on top. NOT Robert-like, but for a 6 or 8 year old ex-police car...it works real well
If its something you have interest in, I can go into detail of how to prep the parts, ect for the best results. My intentions are not to be-little your efforts or ability, just being a realist with the situation. Lorne

Thanks, I did misunderstand your initial post about using the metal bond, I was thinking this was for backer-only and not the actual install of the patch. you are also correct that I cut a larger square (d'oh!) due to the dimple around the original antenna hole. I could have gotten away with a 1.5"circle if I hadn't stacked mistakes to this point.

I have not looked into the metal adhesive up to this point, and havent heard of it to be honest (did I say I was ignorant yet?). I must say I am a bit skeptical of a product like this but do like the idea of avoiding this issue altogether. Is there a drawback to the metal adhesive? is there a risk this bond will break in 10 years and I will have a major issue? I do need to look into this in more detail.

One additional option I thought about was to take hybrid approach to the recommendations so far: I could cut this circular patch as precise as possible and weld in as clean and slow as possible and cross fingers/hope/pray there is no warping. If there is warping, I could cut a square out of the inside roof liner to get a dolly behind it if needed and properly correct the warping. I could then metal adhesive the roof patch back in place, and put a headliner in the truck to cover the patch since there are some grooves in this metal here I could never clean up to look 100%.

I'm still mulling this over and thinking through the advice so far before taking any action - please keep comments and advice coming, thanks everyone for the help.