I have this hood that i have made out of 18 gauge sheet metal. It is attached to a perimeter frame made out of 1/8" x 1/2". Now that is is made, i put it on the body and with a new air cleaner i need some clearance. Probably only a half an inch. The air cleaner is only 7" diameter. Is there any way i can make a blister in the steel to clear things. I have very limited tools to work with. The attached image is what im thinking of, something more simple would work. I dont know if i can just beat a form into the hood to strech it or what i can do and still look decent. Any help is appreciated.
the way i would do it is cut a template out of some harder wood oak? like the shape you wanted, clamp it on both sides or drill a few holes and bolt it. then take a body hammer and start beating it out from underneith.
I don't have any pictures right now but I might be able to post some tomorrow but this is how I did it. I took two pieces of 3/4 MDF cut the shape (same size)I wanted out of one of the pieces. Rounded out the opening. I used a router but you could use a rasp or a grinder. I cut a slightly large opening maybe 3/4 all the way around out of the other piece of MDF. I then took a piece of what ever material you want the blister made out of and cut it about 2" bigger than the opening in the MDF. I then drilled holes through all three pieces wood/steel/wool and put alignment pins through all three pieces. I just used steel rod cut in short lengths. Clamped all three pieces together and as mentioned started hammering. I left the top piece of MDF with a little larger opening in it so that I could get better access to thhat side while I was hammering. Once you get it close to where you want it in shape you will need to take it out of the hammerform. What you will find is that the piece will not want to lay flat. In order to fix that you need to either cut off the excess material around the blister or you need to stretch the flat edge either with a stretcher or hammer on dolly until the blister will lay flat. Finally you will need to planish the blister so that it is smooth.
You might want to PM metalshapes. He's a master with metalshaping, and could probably talk you through it using what you've got.
If you don't feel like fabbing something from scratch head out to your local junkyard. There are quite a few cars that you might be able to scavenge something off of that might turn out well. If you don't care about using import metal 90-94 Talon/Eclipse/Lasers have a pretty neat little hood bump that might fit your needs nicely. I was looking for a bulge to graft onto an aluminum hood I'm working on now. A buddy came over today and surprised me with a carbon fiber one that he whipped up in his garage for me though.
Hey, Ya may wanna consider fabbin the blister from another piece of metal, using the above advise on forming, and than cutting out the area necessary to fit the fabbed piece into your hood panel, than weld it into said panel. This method is easier than a wrestling match with a whole hood panel, but will call out all of your welding skills. A semi-crowned hood panel would be much easier to weld, all things being equal. S****ey Devils C.C.
The blister shape reminds me of a bicycle seat, if that'd help/work as a form. How about an airplane cowl blister? I did a quick search at Aircraft Spruce, but didn't find one. Thanks, Kurt
I have more tools now. But when I built the new nose for this car, all I had was 2 Snap On body Hammers, 2 Dollies and a block of wood (about 12X12X 5") I worked for a boss, and he had a Mig, a Tig, and a Torch set ( that helped...) You can do a lot by hammering the steel on the wood block( the wood wasn't shaped, but there was enough spring in it to allow the metal to move and stretch ), not nearly as quick as a shotbag but a bit more controlable. I built it all out of squares ( about 5X5" ) so it was easyer to control the shape, but that also ment a lot more welding, warp, grinding and finish work...
http://s178.photobucket.com/albums/w280/K13-Ian/ Ok here is a link to some pictures. They are in reverse order so I will discribe from last picture to first. 1) This is the smaller MDF form the edges have been radiused and you can see the locating pins in place. 2)This is the larger sized Mdf form also with locating pin holes. I made the holes just barely big enough so that it was tough to put the pins in but it keeps them from falling out when you are hammering. 3)This is the two forms put together with the metal, in this case aluminum sandwiched in between with the locating pins going through all three pieces. I didn't take any pictures while I was doing this so the piece of aluminum is the finished piece that I just propped in the hole. You can see how the top piece of MDF has a hole bigger than the final shape of the blister. Ignore the holes in the piece they are for mounting the piece now that it is done 4)This is a view from the back. Sorry but the finished piece kind of slpped down when I was takng the picture. Obviously when you are hammering the metal will not be this smooth. But as I mentioned I forgot to take picture during the process. 5) The finished piece after planishing. I used a small english wheel and a lot of hand planishing to smooth it out. As I mentioned in my first post you will nee to trim the square sheet of metal you first put into the form to what ever finished size you want. I left about 1/2" to mount with. I did have to stretch that flat edge quite a bit in order to make sure that it was flat. If you were t******* right to the edge of the blister you would not need to do as much of this. 6/7) This is just a picture of what I did with the blister. It's hard to tell but it fills the hole in the hood sides with the blister facing in towards the engine. Hope this helps. If you have any questions please ask.
Use a marker light bucket, or any small light bucket and some sheet metal bent over your knee to make a tear drop shape. weld a 1/2 inch lip in the bottom edge and use rivets to mount it. be smarter than the metal. just think it out.
I hammer stuff like that on a shot bag with teardrop mallets. I REALLY REALLY like the edge K13 got on his using a sort of hammer form though.. It's a major headache to keep the edge even close to that flat when just hammering it freehand.
I would start looking for tree stumps to hollow out and pound into...I also like to use rubber mats /rubber blocks Good luck J.B.
There are several ways that you could do this. One is use a hammer form like mentioned earlier. The other way is to draw in the outside area of the blister. The tricky part would be to determine what the radius is going to be for the blister and this would depend on what tools you have. You would then planish inside the drawn in area (not going outside the lines). By planishing, I mean either using a planishing hammer or with a hammer and dollie. What you are trying to do is stretch the metal inside of your drawn in area. All bets are off, if you hammer outside of your drawn in area. After you are done planishing, the whole panel will be domed. Now lay the panel onto a hard flat surface, with the dome side up. Take a flat piece (this piece could be almost anything, hard wood, metal or plastice) and lay it along the drawn line of the blister and drive it into the the flat hard surface. The area outside where you drew the blister hasn't been stretched, you are really now just changing the arrangement back to flat and the blister is sticking up. If you try this on a s**** piece before trying it on a finished part you should be able to perfect the process that I'm trying to explain.
I appreciate the comments. Im going to see if i can trim off some of the flange on the air cleaner to get it to set lower. I didnt think of that until late last night, and unfortunatly i live a few miles from my car.
Prett easy to stretch a small blister without doing any welding. You could use a ballpeen hammer and some rolled up leather or rubber to absorb the hammer blows. Firm pressure against the hammering is key to keep from pulling your hood out of whack. This will leave a smooth rolled looking transition from the original hood into the blister. To get a nice hard crease around the blister, follow what fordcragar said after you do your stretching. John www.ghiaspecialties.com
Gotta add my two cents worth. The hammerform works great but if you don't take the time to grind or sand a radius in the two pieces to match the curve of the hood you'll have a flat flange on the bilster you'll have to cut off in order to weld to the hood. I'd just hammer out a blister on a shot bag, planish it and weld it in, why build a hammerform if you're gonna cut off the flange. If it was me, I'd shape the hammerforms to match the hood, build the blister out of aluminum and rivit (real rivits, not pop rivits) it to the hood leaving it bare, has an old race car look.
John, Try it on a s**** of metal the way that I suggested. This is a little trick Rick and I learned a at cl*** we took at Clay Cooks. Whatever you use as a block to drive the piece into the flat surface should have a nice square corner on it and that edge should be on the line that you originally drew where you wanted the blister. What you have done is the same as doing it with a hammer form, but without the hammer form. Larry
To add to this... Go to the kitchen section of the local Wally World; see what's there that can be used as a blister. A shallow soup bowl (with mods) will get the finctionality you need at a fraction of the time (and price) of a custom-fabbed blister.
Hi Larry, I understand the concept, and it is a great one. I just think less experienced metal workers have trouble with the idea of having the piece get out of their control as far as the overall contours go. It is easier to grasp stretching the metal in place without deforming the surrounding area. I've had a few students whose eyes glazed over as soon as we went to unintended contour changes in the metal caused by the stretching pulling the whole panel out of whack. It is something that needs to be learned to get very far in metal shaping, but not for making one hood blister.... in my opinion anyway. For those doing more than one project it is a great way to start understanding the difference between rolling, bending, and pulling the metal, which I call contour swapping, (because the roll, pull, or bend changes the contours of the part perpendicular to the roll etc. but not the actual surface area) and stretching or shrinking the metal (changing the surface area), and the way the techniques work with or against each other to make a project work... or confuse the hell out of the less experienced builder. I had a lot of trouble with this concept when I started out. John www.ghiaspecialties.com
John, I understand, this idea was just thrown out as another way to do a blister.[FONT="] [/FONT]
Twenty years ago when Ron and Sue came out with their book, it was the only thing out there on metal shaping. Since then, a lot has been written, video's produced plus there are several internet groups dedicated to this subject it you are looking for information. www.metalshapers.org www.metalmeet.com
I recently saw a couple of pressed tin blisters and forgot to mark where they were. I've searched Ebay but can't find them Does anyone know of a supplier for them? I don't have the skill to make them, so don't suggest that. Cheers
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