Smooth Hood

[Driver_WT]

We plan to remove all of the trim from the hood on the 53 Chevy Truck and then weld up the center seam and fill any holes. Any tips or tricks to ensure a better result?

Thanks.

Wade

[MARTINSR]

All I can say is DON'T COOL THE WELDS!

Brian

[hogfarm]

I'm not a body man.but a friend of mine told me about how body panels on new car are glued in place.he said rather than weld that seam,glue a strip of sheet metal in place. It is hard for an old guy to grasp this method.Can't believe glue is better than weld,but it will not warp

[mongocanfly]

I'm thinking he's wanting to remove the strip and weld the seam leaving a smooth hood...not glue on another strip....but the panel glue they use nowadays is tuff stuff....

[Driver_WT]

Originally Posted by mongocanfly

I'm thinking he's wanting to remove the strip and weld the seam leaving a smooth hood...not glue on another strip....but the panel glue they use nowadays is tuff stuff....

You are right. Based on all of the feedback above, should we be attempting to do the smooth hood by welding this seam?

Thanks.

Wade

[MARTINSR]

Believe it or not, BMW has you do things like "glue" (we would never say "glue" in front of a customer, it would be "bond" LOL) a frame rail or quarter panel on. We just did a 2018 BMW following manufactures guidelines splicing the quarter panel at the rocker, B and C pillars without a single weld! Bonding in a support underneath the seam then "bondoing" over the top with a metal filled "bondo!" There wasn't one single weld, all "glue" and rivets to hold the quarter on.

I have seen the same with a frame rail, we are talking a front frame rail where the bumper bolts, fully bonded without so much as a bolt or rivet.

The "glue" has came a long way!

Brian

[sevt_chevelle]

Bonding a strip of metal to cover the gap I would have to say would be the easiest method but would also create a visible joint line when the glue and various thickness of metal expand and contract at different rates.

I would also say if you weld it,I would cut out the seem and the flange where the rivets go make a patch and butt weld that patch in. Reason being is when you weld, the weld will shrink along with the flange acting like a hinge pulling even more metal out of place. Also, with the flange in place you wont be able to correct any welding damage because of the flange.

[MARTINSR]

I am not suggesting bonding the hood halves together, it may work understand, I am must not suggesting it. But Eric, that "ghost line" for which you speak on the glued line may not exist if the BMW method is followed using metal filled "bondo". I am not kidding you, we just did that 2018 BMW where we bonded the Rocker, B and C pillars. Not a single weld holding that quarter on! That B Pillar is about 6-7 inches across, a backing was bonded in, one that BMW sells with studs on it to bolt it into place with the glue. Once cured, you break off the studs and grind it flat and then fill it with BMW sold metal filled bondo. I looks just like "All-Metal" or "Metal 2 Metal", probably is one of these with a BMW label on it.

This is the exact process we followed.https://www.youtube.com/watch?v=YGC3dFCRgGM

Anyway, we did as they said, grinding away the bonding between the two pieces and then putting their metal filler over it. We will see if the car ever comes back.

Brian

[sevt_chevelle]

Brian, out of curiosity is your shop BMW certified? Last I knew BMW was requiring certs in order to purchase certain parts like rails, quarter panels.

Would BMW even sell their adhesive and "bondo" to shops and guys off the street without BMW certification?

3M adhesives like 8115 and 8116 say no to bonding on exposed edges, for ex bonding a 80% quarter skin on. Fusor had a procedure for bonding butt joints using a backer but even they said ghosting will be visible.

I did a quarter skin on a 68 Buick GS about 20 years ago right when adhesives were hitting the market. 3M rep came in saw the Buick getting fitted for quarters, suggested we use 8115. I remember thinking afterwards, WOW what a game changer. Anyways, the car got painted a gorgeous deep dark blue, sat around a few months getting put back together. Car left the shop to get the interior done and would be returning once finished. Upon returning, the Buick was left outside in the late spring early summer sun for several hours. Car came back inside and that's when someone saw two horizontal lines running down both quarters right where the bonded joint was.

Endless to say, I've learned my lessons multiple times with panel bond. Great stuff when used in the appropriate application, but bonding a strip over a seem on a flimsily arse hood???

[MARTINSR]

LOL, We are NOT BMW certified but they sold us all the parts and we followed the guidelines gotten from BMW.

I sure would think ghosting is possible, but we did just like they said, so if there is, they will be paying for it believe me. We documented the whole process with a lot of photos.

Brian

[mongocanfly]

It would be hard to (tell) someone to have at it....you need to be proficient in welding thin metal....and if you do it right it may take days to accomplish it....be prepared for the worst...you may want to find a old hood to practice on....

https://www.hotrod.com/articles/1001...ding-question/

[mr48chev]

Originally Posted by mongocanfly

It would be hard to (tell) someone to have at it....you need to be proficient in welding thin metal....and if you do it right it may take days to accomplish it....be prepared for the worst...you may want to find a old hood to practice on....

https://www.hotrod.com/articles/1001...ding-question/

There is your answer right there. you need to be extremely proficient at welding light metal. Add to that you have to have huge amounts of patience and be able to put a few small welds on, let it cool naturally, go back and put a few more and repeat time and time again until it is done.

I sold a hood to a guy a couple of years ago to replace the one that his "body man" had warped beyond repair while trying to weld it up with one continual mig weld from one end to the other in one pass. That hood was warped like it had been in a fire.

[sevt_chevelle]

Originally Posted by mr48chev

There is your answer right there. you need to be extremely proficient at welding light metal. Add to that you have to have huge amounts of patience and be able to put a few small welds on, let it cool naturally, go back and put a few more and repeat time and time again until it is done.

I'll add just because your truck/car is at a shop, you have to know what type of work that shop does. I know guys that are fantastic collision production type techs, but give 'em a restoration job and it would be a complete struggle with lack luster results.

I would look into welding the halves together using silicon bronze wire either with a MIG or TIG welder. The beauty about Si-bronze welding is that the level of heat introduced into the metal is far less. Si-bronze wire also flows and grinds very smoothly.

Many vehicle OEM's are requiring Si-bronze welding to take place versus welding with the typical MIG wire.

https://www.millerwelds.com/resource...brazing-basics

https://www.youtube.com/watch?v=CaUkzcdHmws

[MARTINSR]

Originally Posted by sevt_chevelle

I'll add just because your truck/car is at a shop, you have to know what type of work that shop does. I know guys that are fantastic collision production type techs, but give 'em a restoration job and it would be a complete struggle with lack luster results.

I would look into welding the halves together using silicon bronze wire either with a MIG or TIG welder. The beauty about Si-bronze welding is that the level of heat introduced into the metal is far less. Si-bronze wire also flows and grinds very smoothly.

Many vehicle OEM's are requiring Si-bronze welding to take place versus welding with the typical MIG wire.

https://www.millerwelds.com/resource...brazing-basics

https://www.youtube.com/watch?v=CaUkzcdHmws

I don't even want to tell you about the "restoration/hotrod" we did at our shop that does damn good collision work. YEOW what a mess that was! The funniest part, it had WELL OVER 1000 hours in it and we got paid about $17k for the job. The guy who did the body work thought the door skins and repro fenders were going to be like the ones he puts on a year old Honda. LOLOLOL I tried to talk the owner out of it, when I saw the reproduction parts I told him no, don't do it, nope, they didn't listen and they paid for it!

Brian

[Driver_WT]

Thanks for the input guys - greatly appreciated. I will check into the silicon bronze wire.

Has anyone tried removing the trip strip, bolting the hood halves together and then filling the center seam/depression with fiberglas instead of welding?

Thanks.

Wade

[mongocanfly]

https://www.hotrodders.com/forum/wel.../topics/217916

[mongocanfly]

http://67-72chevytrucks.com/vboard/s...d.php?t=662457

[Driver_WT]

Originally Posted by mongocanfly

http://67-72chevytrucks.com/vboard/s...d.php?t=662457

Thanks Greg. The links are awesome, lots to think about. It will be very hard to find a good used hood in my area of Canada, so if we screw it up, I would be looking at buying a new hood - very expensive in Canadian dollars.

[mongocanfly]

There are seamless aftermarket hoods....but that opens a whole other can of worms about it fitting properly...and then the cost...

https://www.ecklerstrucks.com/chevy-...eel-47-53.html

[mongocanfly]

I bet that would eventually crack from hood flex....i wouldnt do it

[MARTINSR]

I am telling you guys, todays "structural" bonding adhesives are doing things like holding frame rails together! I had a car once in the shop that had the quarter bonded on, there wasn't a single weld outside of the C pillar EVERYTHING else was bonded, and it was done very badly. A horrible job, very little grinding, it was really funky.

The car had NOW been rear ended badly, the quarter was hammered, buckled very badly all over, wheel well buckled even. The only places where the bonding broke was at that wheel well, and it was probably only because it was done so poorly.

Here is a little science project my son did with it. Pretty wild to see him now at 21 years old this morning driving off to work.

https://www.hotrodders.com/forum/wel...ct-116090.html

Brian

[MARTINSR]

On that moulding, Mr.48, it's wild how many NOS parts are still out there, I got an NOS hood moulding for my truck a few years ago.

Brian

[msaintg]

go very very slowly. I did not wait for the welds to cool properly when I did my hood and it caused it to warp. I would also suggest doing it with the hood supported (on the truck). I did mine on some saw horses, which caused fitment problems later.

I also pancaked my hood a little bit later in the build. you might want to consider that too while your at it. it softens the lines of the truck a little bit, but it is not noticeable to most people.

[Driver_WT]

Thanks for the info.

One final question - are we looking to achieve a complete end to end weld of the hood seam, or is it ok if is has many tacks along the way but the seam not welded completely end to end?

Wade

[Gippetto]

Regarding welding the seam, each hood half has a pretty large radius.whiere the flanges are formed. Do you fill the entire valley of the seam That would take lots of wire. I was thinking of using a piece of 3/16 diawire and let it form a peak after I skim ir. The rod would be tacked a bit at a time as suggested.
Any thoughts