when you peak a hood; do you weld the 2 halves together first? I assume, yes.?. working on a '54 Chevy.... Also, is TIG or MIG preferred?
There should be a lot of threads on welding the two halves together and many will mention peaking. I remember reading a bunch before doing mine. (no peak for me) I believe MIG and gas were the two preferred methods but I could be wrong. Once this I DO know is go SUPER slow. As in weld - jump - weld - cool - repeat. These hood WILL warp if you heat them to much. good luck, Carl
I used 3/16" round rod on the hood of my '55 Cadillac...and the trunk as well...and used a Mig...go slow and jump around on it... The entire build...??? Go here for 40 plus pages with pix: http://www.jalopyjournal.com/forum/showthread.php?t=329070&highlight=the+best+55+caddy+build R-
No matter how careful you are, expect some warpage. Another method to consider is to separate the two halves, clean the adjoining flanges to bare metal and use 3M or SEM Panel Bonding Adhesive, along with some screws in the flanges to hold them in place while the adhesive sets up. I'd leave them for reinforcement. I welded the seam, very carefully, on my '54 GMC hood, and kept the warpage to a minimum, and worked it out, but if I had it to do over, I'd try the adhesive method. For the peak I sheared some strips of 20ga sheet and ran them through my bead roller to create a 'peaked' strip to attach to the hood. This required more than one strip because it took a little practice, and some fabricated guides clamped to my beadroller, to keep the strips straight as the rolling process wanted to twist them. The strips were narrowed to fit in the little 'trough' at the seam and I used panel adhesive to attach it and did mig the ends at front and rear......belt and suspenders. Turned out very nicely........ Ray
TIG MIG or gas. All will work, it's more about what your best at. I'd rate this modification as one of the more difficult. DO NOT USE Panel adhesive. I don't know where you guys get your info but this is NOT what it's designed for.
panel adhesive? why not just use paste... like you used to eat in 1st grade. it won't work either, but it will be easier to remove.
I think those of you who are bad rapping panel adhesvise should explain your objections very specifically, rather than just a blanket condemnation of the product. Are you experienced with it's use, or just reacting to it not being 'old tech'? From my experience, which spans about 15 years, though infrequently used, is that it works very well for it's intended purposes. I would like to hear your experiences..... As for prefering to use a 'rod' for the bead......I have to ask ....why? A rod is a 360 degree round shape, as you well, know, but when used to form a bead on a body panel you will not be using more than, if as much as, 180 degrees of it's shape before the fillet begins fairing the rod into the body panel. The bead I rolled, described in a prior post, was as I recall a 3/8" round bead. The depth of which is controlled by the number of times it is run through the dies. It has a 'natural' fillet and a flange that aids in attachment, whether welding or "pasteing". That thinner material at the flange will weld far more easily to the panel with much less heat (and warpage) than a solid rod. You could use a piece of tubing to solve part of that problem, but still have no easy attachment surface. The fact that Chev and GMC truck hoods have a depression running down the hood at the seam makes the flange very easy to blend into the hood surface. Using a rod or tube will require a lot of filler, either lead (and it's attendant heat/potential warpage) or plastic body filler. How that trumps my method is not immediately obvious to me, but I am willing to listen. Ray
I don't believe that panel adhesive will provide a sufficient bond for the two halves of the hood- nor are the edges perfectly flat/straight. There's no way that'll hold. Panel glue has it's place. This ain't it.
Beadrolling a "patch" into the centre and welding it in place would have been the cooler, better way to do it- but that's beyond my skill. Instead, I used 1/4" round- and it sat in the groove really nicely, exposing ... I'd say the top 65% of the rod. Welded it very slowly and carefully in place, then ground my welds down and filled the seam with plastic body filler (lead, also, is beyond my abilities... next time, perhaps). I like the way mine came out, though.
Well Ray, it all boils down to an old school method of using what you got...besides, I don't have the fucntionality of building a peak with sheet metal...it'd simply take me way too many times to get something to work and fit and look like it was supposed to be that way... Besides, even tho round rod is round, by the time I Migged the rod to the hood...it was mostly filled the way I envisioned a hood peak should be...all I did was grind it smooth and skim it with bondo...probably much the same way you took care of the peak you made... And it pretty much looks just like DavidB's hood peak...would I try it with a metal patch...??? NOPE...the round rod worked for me and I'd do it again the same way... R-
Like tinbender said, got rate right up to the top of difficult mods. Number one problem is the flange that bolts the 2 halves together, a little to much heat and the flange pulls down and is near impossible to get it back. Wish I had a dollar for every hood a guy welded and then brought to me to "fix". Trouble is it is real hard to know what is too much heat till it sucks down and your hood is fubar . I cut the flange out just past the recess ( take out the flange and recess)and replace it with a strip of 18 gauge hammer welded in, sometimes with a peak, sometimes flat. I do 12/18 " at a time, I don't cut the hood sides apart then try to line them back up. The benefit is you no longer have the flange to fight, what warpage you get can be worked out easily. As a bonus the hood looks much cleaner underside, something that might not matter to you but I was usually working on "show cars". FWIW I originally gas welded but switch to tig when I got one. IMHO never/ never mig on a seam in middle of that big of a panel, just asking for it to crack down the road, too hard of a weld.
Alternate method; We did a sectioned 39 Olds a few years back. Made some dies to fit in the bead roller and made a strip with the profile we wanted and then cut it in to the two hood halves to make a one piece hood.
Tinbender.....thanks for your detailed reply. The limited times I have used panel adhesive has been for the recommended purposes, such as you describe. For instance, installing a roof panel on a roll-over Jeep Cherokee several years ago. When I repair rusted and/or damaged panels I typically butt weld and metal finish. All that said, it just seemed (seamed?) to me that this hood bead thing was a 'natural' for using the adhesive. I have considered the possibility of the 'witness lines' you mention showing up sometime along the way. I am hoping that the thin layer of plastic body filler that actually covers the small seams where the bead strip lays in the hood trough will eliminate that problem. Maybe it won't and I either have to accept the result or build another hood. I do agree the most "professional" method, as ELpolacko and Metalman refer to, is to cut out the butted flanges and weld in a strip to join the hood halves into one unbroken expanse of sheet metal. While I admire that skill and devotion, this time, at least, it was more work than I wanted to do. Ray
I peaked only the front of mine and flowed it into the top that I welded the 2 halves togeather. Wanted to peak the entire hood but was afraid of being able to keep the peak straight for that long of a distance. Jump around a lot with your welds and grinding. It took me 4 nites to weld and grind this one. I warped the last one so badly grinding it down it was beyond saving. Good luck with your project, and have fun with it!
No- I treated the 1/4" rod as "filler material" and welded it solidly to both halves. Your mileage may very, I was a peaking virgin at that point. However, it's held up really well over the past 2 years, exposed to the elements and constantly being opened and closed... I love those peaked fenders in that other thread, I was thinking of doing that with my rear fenders. By the way, I don't know if you can use brakeline- I personally wouldn't...
I know this is a very old thread but I am planning to do this exact thing, weld a rod. I noticed you have some stitch welding, do you have to fill in the gaps between the stiches with weld also? Could you fill in the rest with body filler? Your peak is very clean and smooth. Exactly what I'm looking for.
So did start tacking it and it ended up warping a bit in the flat area. lol. I can't find the comment here but I read that the rod shrinks due to the heat so I'm thinking of putting cuts in the rod around the weld to relieve it. At this point whatever I do is a hail mary attempt to save it. This is the my first time doing this and I'm already thinking I need to get another hood.
Welding does indeed shrink the parent material. For sheet metal, standard procedure is to weld in 1/4" segments, skipping around, allowing the previously welded areas to cool enough to touch, correcting warping as you go. You can make, and it is a totally acceptable procedure to make relief cuts to alleviate strain.
Many thanks! One more question in regards to how to actually achieve the peak. Is it typical to fill in the weld and leave the round section as the peak or do people grind down the welds and rod on both sides to achieve a peak? I guess this could be a preference thing.
That's up to you. I am all function, and have little in the way of aesthetic taste. I leave that up to the artists.
The Jalopy Journal
