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-   -   Need help flange tool/lap welds &cutting straight panels. (http://www.hotrodders.com/forum/need-help-flange-tool-lap-welds-cutting-straight-panels-232364.html)

cutthroatkid 04-29-2013 11:00 PM

Need help flange tool/lap welds &cutting straight panels.
 
Ok fellas when I weld in patch panels&I have yet to have a problem arise that I could not handle.The only main problem that I have is getting the old panel and the new panel cut the exactly the same.I just use a 4 inch cut off wheel on my grinder.Which brings me to my first question I really want a plasma cutter& if I get one could I possibly put my new piece of sheet over the bad area tack this sheet up there and use the plasma cutter to cut both out to have a direct fit?
******************* My next question is I have yet to do a lap joint/weld I a lot of these flange tools and it seems that they may work good for certain jobs.But I don't really get how it works so you make the flange around the panel then I'm guessing behind the cut out hole and pull it forward for it to fit properly.
********* This is what I can figure out the patches in the middle of a pannel you cant get to from the backside then how does it work?What do you do?I really want to learn how to do this as lately metalworking is starting to fascinate me.Now that I have all of my paint tools and most of my body tools,too many wrenches&ratchets.&I just upgraded from a flux core to a gas mig hobart which I am in love with.My plan is to start buying metal fabrication tools as I find deals on em.My main goal is being able to learn how to make my own patch panels.I've always sucked and other things I've tried.But when it comes to paint and body cars and motorcycles I get better by the minute no one showing me nothing....Sorry so long please someone help me understand how to use this flange* tool & learn how to weld nice flush panels that way.Thanks a ton!

Please excuse any typos or terseness: this email was sent from my mobile and I have clumsy fingers.

gearheadslife 04-30-2013 06:32 AM

there is a new tool, called a marker, works wonders..

dogwater 04-30-2013 07:01 AM

I've drilled 1/4 holes into the panel, then cut a strip of sheet metal about 1 1/4 wide, spray it with weld thru primer, use vice grip clamps to hold the strip onto the back side of the panel and leave about 3/4 in. to weld the new panel onto (in other words lining it up from the back side) then weld in the 1/4 holes. Now its flanged. This is how I do all my patch panels,kind of a pain in the *** but its easier to weld the new panel to ( thicker metal). I've even used self tapping screws to hold down the panel to the flange. If you mig weld enough you have to be able to weld in burn thru holes, I've pretty go at that now........ I only butt weld when I really need to.

MARTINSR 04-30-2013 07:41 AM

The trick is to trim your patch panel as big as you want it. Then you fit it, overlaying the surrounding metal, then trim the surrounding metal to fit the patch.

Look at this way, picture putting a patch where there is nothing wrong with your original panel. Picture laying this patch over the bottom of a fender for instance, just laying it over this perfectly good fender. Clamp this patch up tight where it belongs over the bottom of the fender, do you have a picture of this in your head? The patch is covering the bottom of the fender and is held in place by clamps. You now mark the fender right at the top of the patch all the way across. One way is with a very sharp awl, that is what I like to use. So you have this patch clamped to the fender in perfect position and you mark right along the edge of the patch on the fender with your awl, right up against the edge. Remove the patch and cut the fender off BELOW that mark a little bit, say about an eighth inch or less. You then can trim that edge to perfection with a grinder with a fine disc like a 50 grit. You grind that down to perfection until the patch will fit up against the fender as it did before and you have a perfect fit just as you did before, now you weld it.

Another method is to do the same, clamp it in then cut thru both the patch and the fender with a 1/32" cut off disc. This will give you almost as perfect of cut as the previous example. I don't use that method unless I am putting a backing. If you are running a backing behind the seam you are welding you want about a 1/16" to 1/8" gap between the panels so you are welding ON the backing with both panels being welded to it at the edge of the seam.

Ok, so now transfer these same methods to a fender with a rusted hole at the bottom, works exactly the same way. The only difference being you may need to cut the rusted area away before you fit the patch because it is in the way of the patch being clamped in tight. So, this is how I do that, I set the patch into place and mark about where the patch comes on the fender, then cut the fender off below that a good inch or so. This allows me to get all that rusted metal and junk out of the pinch welds and so forth before I do the fitting of the patch. The fitting of the patch goes over that inch or so I left and then after clamping it in there where it belongs, after all the massaging to the patch , the fitting of the fender on the car so I know it's right, after all that I trim the fender to match the patch.

Notice the most important part in these two examples, that the panel is clamped in PROPERLY where it is going to be. Not sort of there, not "good enough until later" not anything but PERFECT as you will be leaving it. With it clamped in there perfect is the only way to mark and make the cut. Anything less than clamped in there perfect is going to cause you trouble. If this patch needs some massaging to make fit better as every repro part needs, you do that BEFORE you weld it in. You do that BEFORE you cut the final cut. You clamp it in after you KNOW you are ready for that final cut.

Brian

tech69 04-30-2013 07:50 AM

without writing a book here, make sure there's nothing in the way causing it to line up incorrectly and scribe. Then cut it on the scribe. sometimes you have to cut out an area you already plan on cutting out to let it lay right before scribing.

tech69 04-30-2013 08:16 AM

an easy way to do small slightly complicated patches is lay a piece directly on top and screw it in. The hole in the bottom panel will be cut out anyways. Then you can get a round plastic mallet and hammer it into shape, using the shape of the metal you are going to cut out. Then scribe it. Cut it out then weld in your new piece. No, it's not rocket science but it doesn't have to be. I don't get all anal about making it 1000% perfect. I just have good techniques. Want to know how many times I have had to cut out a patch after the first one didn't work? Probably 1-3 times in the last 5 years. The only concern is the patch being flush and the gap not being too big where I need to lower the amps of the welder, sacrificing penetration.

cutthroatkid 04-30-2013 06:26 PM

Quote:

Originally Posted by MARTINSR (Post 1671352)
The trick is to trim your patch panel as big as you want it. Then you fit it, overlaying the surrounding metal, then trim the surrounding metal to fit the patch.

Look at this way, picture putting a patch where there is nothing wrong with your original panel. Picture laying this patch over the bottom of a fender for instance, just laying it over this perfectly good fender. Clamp this patch up tight where it belongs over the bottom of the fender, do you have a picture of this in your head? The patch is covering the bottom of the fender and is held in place by clamps. You now mark the fender right at the top of the patch all the way across. One way is with a very sharp awl, that is what I like to use. So you have this patch clamped to the fender in perfect position and you mark right along the edge of the patch on the fender with your awl, right up against the edge. Remove the patch and cut the fender off BELOW that mark a little bit, say about an eighth inch or less. You then can trim that edge to perfection with a grinder with a fine disc like a 50 grit. You grind that down to perfection until the patch will fit up against the fender as it did before and you have a perfect fit just as you did before, now you weld it.

Another method is to do the same, clamp it in then cut thru both the patch and the fender with a 1/32" cut off disc. This will give you almost as perfect of cut as the previous example. I don't use that method unless I am putting a backing. If you are running a backing behind the seam you are welding you want about a 1/16" to 1/8" gap between the panels so you are welding ON the backing with both panels being welded to it at the edge of the seam.

Ok, so now transfer these same methods to a fender with a rusted hole at the bottom, works exactly the same way. The only difference being you may need to cut the rusted area away before you fit the patch because it is in the way of the patch being clamped in tight. So, this is how I do that, I set the patch into place and mark about where the patch comes on the fender, then cut the fender off below that a good inch or so. This allows me to get all that rusted metal and junk out of the pinch welds and so forth before I do the fitting of the patch. The fitting of the patch goes over that inch or so I left and then after clamping it in there where it belongs, after all the massaging to the patch , the fitting of the fender on the car so I know it's right, after all that I trim the fender to match the patch.

Notice the most important part in these two examples, that the panel is clamped in PROPERLY where it is going to be. Not sort of there, not "good enough until later" not anything but PERFECT as you will be leaving it. With it clamped in there perfect is the only way to mark and make the cut. Anything less than clamped in there perfect is going to cause you trouble. If this patch needs some massaging to make fit better as every repro part needs, you do that BEFORE you weld it in. You do that BEFORE you cut the final cut. You clamp it in after you KNOW you are ready for that final cut.

Brian

First off thanks everyone except the ******r.Can you please explain more to me about backing behind a weld?Also I'm guessing there's no way to flange a weld if you can get to the panel from the backside?

tech69 04-30-2013 06:59 PM

lay your piece on top, scribe your line on the panel hanging, then cut 1/2" below the scribe mark. Flange and mock up. You might have to grind here and there to get certain areas tucked down on the flanged area. When it's in mock up use a marker and mark exactly what needs to be taken down, then grind it down til the mark is gone. Once that is done bevel your edge just a hair and re-mock. Don't bevel enough to make it burn thru but just enough to get a nice fat bead in there and to help transition. Also helps to have a long screwdriver to forcefully hold down the edge while tacking. You do this all around so it doesn't walk on you and you don't have to hold it down anymore. Then turn up your welder and build off your beads with a little overlap. This will allow you to keep it hot without warping and to get the molt into the cracks.

MARTINSR 04-30-2013 08:18 PM

The other way is a butt weld with backing. What this is simply is putting a strip of metal behind the seam that you are going to weld. This is very common where you have no access like in a rocker for instance. You make a strip of metal about an inch to an inch and a half or so and you fit it behind the panel with it hanging out half the width of the strip for your next panel to lay over it. You punch a few small holes along your seam to hold that strip with plug welds. You get the panels right up to within a 1/16" to an 1/8" apart laying over that backing. You clamp it in place and when welding you hit the wire down on that backing starting your arc there then with the weld coming up onto the the two panels.

It's very common to when doing this in collision repair to have your new panel that you are cutting to size and you have that piece you cut off to use as backing. So you have this backing that is already bent to the shape of the panel like a rocker. You simply cut it off perfectly so size so that the piece you are cutting off is your backing. :D

Here is one in aluminum.

http://www.i-car.com/graphics/about_...ize/fig_05.jpg

Brian

deadbodyman 05-01-2013 06:07 AM

Do your best to never use a backing strip the exposed top edge will hold moisture like a cup and rot out the panel prematurely.,..yes ite easier but you know what they say about the ez route....
in spots like a rocker with no access simply use strong magnets to hold the new patch in place and flush...
most all your smaller seams will be butts. always flange the original panel never the patch .flanging the patch will leave the top of the seam exposed (like the weld strip) holding water and moisture...
if your patch has four sides that need welding,a you shouldnt flange all four sides ...flange the top and sides but the bottom needs to be butted to avoid the upside down flange that holds water....
never depend on seam sealer ...

MARTINSR 05-01-2013 08:00 AM

I am with you Mike, flanges and backing or butt are all options and they all can be the perfect way to do a particular splice.

I have pointed out before but every single body is held together with lap and pinch welds. There are hundreds of these welds on every single body so as far as rust and moisture collectors, the entire body is held together with them before you even start. So I don't worry about that, simply seal it properly and you have at least as good as the rest of the body.

It is true that many manufacturers guidelines are now eliminating backing and going to butt welds.

As a balance between what is the "bestest" way being with skills, with expectations on that particular job, etc. A butt weld with backing or butt weld or flange weld could be the "perfect" way to do it.

Brian

tech69 05-01-2013 08:07 AM

a butt weld with back is the easiest way but also the least quality of methods. Sounds like he wants to learn so I'd suggest he practice his open butt welds starting with small squares for rust or whatever. Then he can hone into his skills and then do it on bigger stuff if he chooses. For now, I'd suggest a flanger. It's a lot of work though to flange but worth it.

tech69 05-01-2013 10:12 AM

here's a hinge pocket where it's flanged up top but an open butt weld everywhere else. If you look close the edges are beveled where it lays over the flange. Flanging helps stuff stay straight and adds strength.
http://i1183.photobucket.com/albums/...ps80b66a23.jpg

Here's another one. If I did this today I would probably open butt weld it but I'm sure the flange helped keep everything lined up nice.
http://i1183.photobucket.com/albums/...ps6a6b1f8e.jpg

gearheadslife 05-01-2013 10:25 AM

Quote:

Originally Posted by cutthroatkid (Post 1671540)
First off thanks everyone except the ******r.Can you please explain more to me about backing behind a weld?Also I'm guessing there's no way to flange a weld if you can get to the panel from the backside?

the bet way 99% of the time is make a template, either with paper or cardboard and A MARKER..
wasn't being funny, it's the way it's been done for years

tech69 05-01-2013 10:30 AM

I think it depends on the situation. if it's a big complicated piece than a template is a way to go. If it's just a small patch you cut it out, file the edges, then use a sharpie to trace it. Thing is, not all patches are gonna come out nicely in one piece.

So that brings me to another option...just laying metal on top and scribing around the metal. This way always leaves a perfect fit and worked well for me the last time I used it, which was on a 55 rocker. The shape would be a little bit of work to do yourself so I just laid the piece on top, used a forgiving and soft hammer face to shape it into the old, then scribed and cut it out. it was a piece of cake. Those are my three main go to's. It makes it easy, but yeah, a template works well.


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