Topic of Discussion TOD: Sheet Metal fab
- Thread starter Greg
- Start date
DaveB
Long Jeep Fan
- Location
- Holladay, Utah
OCNORB said:Great tip Dave. Did the horrible looking floors I am wleding in inspire this post??
No, I was just adding to the ideas.
high_roller
www.RideandDriver.com
- Location
- Utah
I agree, those nibblers are great!OCNORB said:
on welding sheet metal, It is all in the welder. I welded all the panels on my derby car with no fill 1/4-3/8 gap at 18V 120in it was a miller suitcase welder and a really nice gas powered miller stick - I wish I owned one, but it is out of my price range .-
The trick I found was to build a little on each side, until they bridge, then strike an arc right in the middle of the "glob" then weld down working side to side until the edge of the pool just barely overlaps the edge of the material, then return to center, so you're not really welding one side to the other, you're welding one side to the bead, then the other side to the bead, then use an over arc pattern for 1/8- 3/16 inch then stop, move 5-8 inches start over again, I welded about 60 feet of panel this way, only it was a derby car I just kept welding the 5-8"s until they were filled, warpage who cares - it's a derby car - right.
Also helps to weld at about a 45* angle on thin stuff if you can seems to make it quite a bit easier.
I've also folded over the edges of the panels and dollied it flat, so you're welding to 2 layers of the same panel it makes it a ton simpler - if you have a welder that doesn't go low enough to weld just one.
The trick I found was to build a little on each side, until they bridge, then strike an arc right in the middle of the "glob" then weld down working side to side until the edge of the pool just barely overlaps the edge of the material, then return to center, so you're not really welding one side to the other, you're welding one side to the bead, then the other side to the bead, then use an over arc pattern for 1/8- 3/16 inch then stop, move 5-8 inches start over again, I welded about 60 feet of panel this way, only it was a derby car I just kept welding the 5-8"s until they were filled, warpage who cares - it's a derby car - right.
Also helps to weld at about a 45* angle on thin stuff if you can seems to make it quite a bit easier.
I've also folded over the edges of the panels and dollied it flat, so you're welding to 2 layers of the same panel it makes it a ton simpler - if you have a welder that doesn't go low enough to weld just one.
jonsegue said:
sometimes a air nibler is the only way to go, if you're cutting into a panel and you don't really know what's behind it (support brace wiring etc), it is a good idea to either use the nibbler, or use a cutoff wheel with lower air pressure and work it back and forth for a long cut, rather then the stab and drag method.
tsm1mt
Registered User
- Location
- Helena, MT
Even though a plasma has a small kerf, the nibblers have no kerf. They also don't burn your paint.
It's also often easier to follow a drawn pattern with the nibblers vs the plasma, since you should be using tinted goggles with the plasma, which makes it hard to see. The heat will melt your chalk or grease pencil, and tints my marker (I don't recall what the soapstone does). The nibbler you just wear goggles/shield and it's easy.
Now, if you made an under or oversized template pattern (vs just a doodle), the plasma can certainly be faster than the nibbler AND come out pretty good, but free-handing a drawn design is a PITA for me with the plasma.
I have air shears, air cut-off, air-nibbler, sawzall, and a Hypertherm 600 plasma.
The nibblers are my favorite for cutting sheetmetal. The sawzall works well sometimes, but the reciprocating action causes issues a lot of the time, too. One of the air-body-saws might help that.
The shears are way down on my list. Sometimes handy for a straight cut, but usually just a PITA. The air-cut-off is also one of my least favorite, mostly for the noise and black dust, but it sure is handy when you need it.
dieslcruisrhead
Registered User
- Location
- Park City & Heber City Utah
Boy this is a good thread, thanks guys..
dieslcruisrhead
Registered User
- Location
- Park City & Heber City Utah
PS has anyone used any of the harbor freight nibblers? POS or OK?
http://da.harborfreight.com/cpisearch/web/search.do?keyword=nibbler&Submit=Go
http://da.harborfreight.com/cpisearch/web/search.do?keyword=nibbler&Submit=Go
tsm1mt
Registered User
- Location
- Helena, MT
I use the 16g air nibbler. Works fine.
My seem old fashion, but I would oxy, since you are welding thin metal. Then this might not be best choice, if you never welded this way. Then again I also had too learn how to fill flaws in fenders with lead also before bondo, at for you local people Trade Tech(I don't know what it is being called anymore).
Alliance4130
New Member
- Location
- SLC, UT
As far as the welding side goes... This may seem common knowledge to some, but I've found that metal prep, and tuning your machine, is 90% of the battle. Having a clean work surface, filler metal, and gas flow is vital.
Also using the right tools/abrasives, to clean off rust/paint or oxidation, (aluminum) so as to not take away clean weldable material from an already thin or corroded surface. i like to use a right angle air grinder -w- a 3" or 2" red scotch brite pad. They whip through paint, or rust, but not good clean metal. Also Acetone for oil/ residue. Also a cool little trick I've found for grinding aluminum, is to spray your abrasives with aluminum Anti-Spatter every 5 min. or so. This prevents the aluminum from sticking to the discs when it melts due to friction. Some people use WD-40 but that can currupt the material. Anti-Spatter Sray is formulated to weld on. Thus, no pits, or black smoke. Plus, you'll get 2-3 times the life out of your stuff man, it rocks.
And as far as Wire Feed tuning, everyone will have there own style, but I preffer lower wire speed, and roller pressure. So that when your using a tack,tack,tack, or stich method, you don't blast through when you don't get a solid ground. (Somtimes due to smoke or spatter from the tack,tack,tacking....)
Also using the right tools/abrasives, to clean off rust/paint or oxidation, (aluminum) so as to not take away clean weldable material from an already thin or corroded surface. i like to use a right angle air grinder -w- a 3" or 2" red scotch brite pad. They whip through paint, or rust, but not good clean metal. Also Acetone for oil/ residue. Also a cool little trick I've found for grinding aluminum, is to spray your abrasives with aluminum Anti-Spatter every 5 min. or so. This prevents the aluminum from sticking to the discs when it melts due to friction. Some people use WD-40 but that can currupt the material. Anti-Spatter Sray is formulated to weld on. Thus, no pits, or black smoke. Plus, you'll get 2-3 times the life out of your stuff man, it rocks.
And as far as Wire Feed tuning, everyone will have there own style, but I preffer lower wire speed, and roller pressure. So that when your using a tack,tack,tack, or stich method, you don't blast through when you don't get a solid ground. (Somtimes due to smoke or spatter from the tack,tack,tacking....)
When i am cutting sheet metal i like to use an air saw , i dont know what they are called for real, but it is like a mini sawsall, (i also use a nice air hose swivel so i can move the saw any way without the hose binding). I put a nice (namebrand) sheetmetal jigsaw blade in it and adjust my air pressure to the thickness of the metal. blades are expensive, but on single layer sheetmetal it cuts like butter, and you can basically control your cut like you are drawing with a sharpie. then use a belt sander on a stand (if the sheet is moveable) to make the edge perfect, or a barrel sander for the edge if it is on the vehicle. I use a 4.5" or 6" .045 cut off wheel on a grinder (with all the proper protection because if you are not experienced with a large cut off wheel it could explode and hurt you bad) for my long straight cuts.
I also agree that the quality of the weld is all in the prep work, get the contaminents off the metal and set your machine right, and if you can weld, you will get a good weld every time.
I also agree that the quality of the weld is all in the prep work, get the contaminents off the metal and set your machine right, and if you can weld, you will get a good weld every time.
turbohaulic
I don't know it just is!
- Location
- Hyde Park, UT
Lots of things contribute to a good weld. But IMO practice is #1, I could not weld good a few years ago if my life depended on it. But now I have a job where I work with sheet metal and weld almost everyday. I recently bought a Lincoln Precision TIG 225 welder for my home, awesome welder. TIG is the hardest of the welding proccesses, but if you can master it and get good with it you can make some pretty sweet welds. And I believe it is easier to control the heat, pluse most have a pulsing feature to cool the weld down as you go. The other thing about welding is make your metal fit as snug and close as possible, if you have gaps you will most likely burn through.
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Metal Twister
New Member
Hey guys, Im brand new here but i do have a bit of experience in the fabrication business. Just some quick back ground, 4 years air force as a flying crewchief. lots of aluminum repairs, 20 years as an outside salesman for a welding supplier in San Diego, 3 years in the shipyard sheet metal shop, 7 years now in the hot rod,sand car, off road business. enough said...
Ok heres a real time saver for you guys on sheet metal rust repair. Like mentioned before by Daveb,
Cut out a replacement patch in the shape you desire. Make sure it is the same contour, and a bit larger than the piece that you are going to replace. Sand off the area that you are going to replace to bare metal. Position the patch onto the body and screw them together using a sheet metal screw or two. Now use your plasma cutter, or saw and cut no more than half way around the patch, making as narrow of cut as close to the patch edge as possible. Now go to the back side and pry the body section away from the patch far enough to wedge a pencil between the two pieces. Return to the front and flush the new patch with the body using edge of a straight edge. Put a couple tacks where its flushed. You can now take the screws out and continue to cut and tack your way around until the old piece falls out the back side. When that happens you should have your new piece flushed in and tacked. Your are now ready for welding.
To prevent any worpage, use .023/.025 e70s6 wire and c25 mig mix with your mig welder. You can use straight co2 but it is a little messy. Start at any location and make a tack weld, (just a couple of seconds not moving the gun). Now go to the oppisite side and do the same thing. Just continue this process untill the whole thing is one solid welded patch. (skip welding) Dont forget to spot weld the hole where the screw was. LOL Just one more tid bitof info, while welding be sure not to get the sheetmetal too hot. An easy rule is that if its to hot to touch, it too hot. So rub your hand around the outside of the patch moving your hand towards the weld, if its to hot to hold your hand on it , let it cool. Take your time and I think you will like the results. If this dosnt make since to you please feel free to contact me and I will try to explain it better. Thanks, and good luck Bob
Ok heres a real time saver for you guys on sheet metal rust repair. Like mentioned before by Daveb,
Cut out a replacement patch in the shape you desire. Make sure it is the same contour, and a bit larger than the piece that you are going to replace. Sand off the area that you are going to replace to bare metal. Position the patch onto the body and screw them together using a sheet metal screw or two. Now use your plasma cutter, or saw and cut no more than half way around the patch, making as narrow of cut as close to the patch edge as possible. Now go to the back side and pry the body section away from the patch far enough to wedge a pencil between the two pieces. Return to the front and flush the new patch with the body using edge of a straight edge. Put a couple tacks where its flushed. You can now take the screws out and continue to cut and tack your way around until the old piece falls out the back side. When that happens you should have your new piece flushed in and tacked. Your are now ready for welding.
To prevent any worpage, use .023/.025 e70s6 wire and c25 mig mix with your mig welder. You can use straight co2 but it is a little messy. Start at any location and make a tack weld, (just a couple of seconds not moving the gun). Now go to the oppisite side and do the same thing. Just continue this process untill the whole thing is one solid welded patch. (skip welding) Dont forget to spot weld the hole where the screw was. LOL Just one more tid bitof info, while welding be sure not to get the sheetmetal too hot. An easy rule is that if its to hot to touch, it too hot. So rub your hand around the outside of the patch moving your hand towards the weld, if its to hot to hold your hand on it , let it cool. Take your time and I think you will like the results. If this dosnt make since to you please feel free to contact me and I will try to explain it better. Thanks, and good luck Bob
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Metal Twister
New Member
Ive used alot of brakes over the years and they all worked just fine. But Im one of those guys that has to tinker,design, and build. I should add a tad bit lazy. LOL I got tired of pulling levers and arms to bend my sheet metal. Plus that the average sheetmetal brake just isnt diverse enough to do the stuff I want to build. As a result I built a sheet metal press brake. I used a hydraulic pump off of a car hoist, the center flap actuators out of an aircraft. a bunch of 12 Inch plate and this is what I came up with. The bottom moves up to bend the metal betweenthe dies. Id love to help any one else who wants to build something like this. I must say its a tool that i use every day, and cant imagine not having one. The max ive bent with it is 3/8" plate. Lots of 1/4" stuff and smaller. Like i said a tad bit lazy, dont look at the grinding that isnt done yet on the cut outs.
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smashmetal
Registered User
- Location
- Syracuse UT.
Good fab points, have seen some of your stuff over at OFN as well. I like how you put stuff together, but since when have crewchiefs done aluminium repairs?
Metal Twister
New Member
Thanks for the kind words---OFN is a great forum as well.
1976 thru 80--- Iceland on EC 121's Super Connies---I was lucky to be one of the last reciep. crew chiefs. Everything else was jet aircraft with specialists for everything. Because these old birds were 52 and 53 models they needed extra care.LOL Iceland was nato at the time. The Air Force was phasing out the EC121's To the bone yards and bringing in the AWACS. There was along time in transission. during that time we had no specialists. The pigs had to fly so we did what ever it took. It seems to me like we had a master sgt. that was an airframe guy that would give some instruction once in awhile and sign it off. But Im not even sure about that anymore. Seem like a thousand years ago. I do remember sending the planes to Homestead where they would inspect further and make changes if required. But I will never forget the rivits, and frozen fingers. lol
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Metal Twister
New Member
Excellent information on the patch panels--took me a few times reading through the description to figure it out, but it's so simple, yet I'd probably never have figured it out on my own. Thanks!
Nice brake too, I'm jealous.
Sorry, I pounded it out when I had a few minutes at lunch today. I will go back and edit it to make it clearer. I hope