Welding Practice

[estamato]

Hello all,

I have been following this forum for a while but just recently have started my project.

I have a 68 camaro and want to stick in my 335/35/18 tires that i bought for super cheap from tire rack a while back thanks to this forum.

I want to extend the wheel wells 3in like veryone else. have read all the post and believe I have the concept down pact,

I just purchased a Lincoln Mig pack 15 230V/175A mig welder which I believe and have read should be more than enough for what my project will probably require.

My question is if I want to practice welding a similar material and thickness what should I use and where can I get it.

My thought was going to a scrap yard and looking for similar metal to fool around with any thoughts should I even practice? Of coarse I should I know the answer to that.

Regards

Elias

[derekf]

Hi Elias, welcome to the board.

Absolutely you should practice. You might also think about (I haven't done it yet, but I've thought about) asking local body shops for the bent-up bits they took off the cars.

Do you have a local community college with a welding class?

[estamato]

Iam sure there are some welding classes around here but with a new born not sure I can dedicate my self to going to every class and would hate to miss any that I pay for.

I do have a friend that is a welder by trade, problem is he builds paper press roll type of machines there are huge take up his whole shop when he is building one. Not that he is not a good welder but his machine is probably too big for thin metal like I want to do, plus wouldn't a guy that works on body panels all day like a body guy be better at this type of work. Does it even matter?? A welder is a welder no? I think the answer to that would be no but I could be wrong.

I was thinking of practicing my welds at home with my machine this way I practice with my own beast then bring my welds to this guy so he can take a peek and tell me if they are ok or not and what to look for, untill I get it right then after lots of practice do it on my car..

What do you tihnk?

[Matt@RFR]

Welding sheetmetal is a completely different animal than welding thicker plate. Your fit up has to be perfect! Filling gaps in sheetmetal will allways result in much warpage.

The real trick to sheetmetal is taking your time. It's more tacking than welding: Tack here, move a ways away, tack there, repeat. Do NOT use a wet rag to cool a hot tack! You can use a wet rag on the surrounding area to keep the heat down though.

As a side note, the theory of big MIG's not doing well on sheetmetal is just downright funny to me. Look at the bottom end amp ratings on all of Miller's Mig's and power sources. The same applies to TIG's too. If nothing else, the "bigger" the machine, the better it does everything .

My Miller 251 does a helluva job on 18ga WITH .035 WIRE! I'd imagine it would do quite well if I fealt the need to switch to smaller wire for sheetmetal.

[Andrew McBride]

Matt,

I gotta question? What is wrong with putting a wet cloth onto the hot welds?
That is the way I have been doing all my metal work and haven't had any warped panels, maybe I am lucky.

Andrew

[Matt@RFR]

Oh, I think it's more bad in theory than anything, since, by the time you drop your gun, flip your hood up, grab a rag and slap it on, the tack is allready cool enough to not do any damage.

The theory is that weld material shrinks as it cools, which causes warpage. The faster it cools, the more pronounced the shrinkage becomes.

I proved this to myself years ago when building big big tanks:

If the tank was big enough to need more than one plate for the wrapper, I'd have to weld two plates together (butt welds), then roll that into the round wrapper. Well, mild steel plate is not square, straight, or anything else from the factory, so I had to burn the sides to fit, and would allways come up with gaps.

So I tack'd as much of the seem as I could, and where I had gaps, I'd run a weld right up to where the gap was, stop, throw all my **** off and dump a 5 gallon bucket of water on it....and watched the gap close!!! Lesson learned.

Example of a big tank: 30,000 gallons, 30-something feet tall and something like 15' in diameter. Fun stuff! Bottom wrapper was 1/4" plate, middle and top wrappers were 3/16".

[MuscleRodz]

Quenching a weld also hardens it. If it cools too fast in certain alloys especially 4130 will make the weld so hard it will become brittle and break on impact. You do not want to temper (harden) a weld in most applications, especially rollbars.

Mike

[estamato]

So what I should be doing on sheet metal than is tacking instead of welding...

Sorry I already know this is a newbie question and I hope you guys dont get too upset at me, but for these wheel wells how far apart should my tacs be?? 6in 3in..

I am not in a hurry and would prefer to do a good job instead of a rush job so if every 6 in gives less warp then better and should I use a wet rag on this type of metal or will it make the weld weak? I guess the wheel well is comprised of just regular steel, I am not sure..

[parsonsj]

To amplify what Mike said, MIG welds are hard enough without adding to it by quenching. Quenching nearby is OK, but I would never directly quench a weld, especially one that you intend to grind later.

jp

[Ralph LoGrasso]

Are you planning on using DSE's deep tubs? If you are, pick up some 16 ga. sheetmetal at your local steel supply and practice welding with that. I'm almost positive DSE's tubs are 16 ga., but they might be 18. Then, pick up some 1/8" steel plate. (I used 1018 cold rolled steel) and practice welding on that a bit, the 1/8 is what you will be using for boxing the frame rail and all of the close outs. This is the most difficult part of the job, IMHO because the frame rails are sheetmetal and they're not as thick as the 1/8" plate. Because of this, you have to becareful to get penetration but at the same time not burn through the sheetmetal frame rails. It's not too difficult though. Mini-tubbing a first gen is not an extremely difficult task, and as long as you're not replacing anything (outer wheel houses, quarter panels) at the same time, it's fairly straightforward. Most of the work is the cutting and grinding, and a good amount of the welds are spot welds. Good luck!! You can see some of my mini-tub pictures here:

http://www.infamouscamaro.com/Ralphs%2068.htm

The picture quality isn't the best and there are only a few pictures, I was having camera problems at the time and most of the pictures didn't come out right, and the ones that did, still weren't good.

[estamato]

well I know everyone uses the DSE tubs I will probably use them too, but I was thinking what does everyone do with the old ones?

I was thinking of trying to add the 3in to the existing ones and see how it goes... If I mess them up oh well order DSE.

Great pics I will add them to my collection. If there is one thing I can't get enough of is mini tub pics on first gen.

I think I have what I need so far thanks all, just waiting to see if someone replies to the question about the DSE tubs thickness of metal. I am sure someone will answer everyone has used DSE tubs...

Thanks for the help!

[69bigblock]

I've just recently finished a welding class last week. It was 13 weeks 1 night a week 3 hrs a day . We actually did 4 nights of mig, I new mig wasn't that hard but I just needed to watch and get the whole concept thing down..

[Ralph LoGrasso]

Per the info on Detroit Speed's site, the deep tubs are 18 ga.

www.detroitspeed.com

[RobM]

if i decide to tub im deffinatly going to expand th stock wells, its wayyyy cheeper and can come out just as nice. how ever you have to do full length welds when patching the gap. This takes alittle more welding skill though

[nkopper]

I wanted to learn fabrication while working on this Camaro, so I'm widening the factory tubs and saving a bunch of $$ over the DSE tubs. If your time is valuable, this might not be the best option. I'm currently practicing on 18 guage and 1/8" steel I picked up from a scrap metal place in town. I bought about 90 pounds at 15 cents per pound. I'm also learning how to adjust my Millermatic 135 for different thicknesses of steel. On the thin stuff, I have the best luck welding about an inch to an inch and a half then moving about 6" down and doing the same. Welding any more than an inch and a half at a time leads to serious warpage if I'm not careful. When I finally feel comfortable enough to do the real thing, it's gonna take a while to fully weld the 3" strip into the inner fenders! I should be a fairly decent welder by the time I'm done, though.

Nathan

[Matt@RFR]

Just a word of warning...if the pieces of 18ga you're practicing on are fairly small, warpage will show up much much worse on full size body panels...especially when the perimeter of the panel is attached (restrained) to something else.

[estamato]

Hey Matt,
From what I am reading on every thread you are the man to talk to about welding.. Perhaps when I start the project I will drop you an e-amil with progress and perhaps questions If I have any if that's ok with you? I don't think I will be rushing this so don't worry about me filling your inbox.

P.S. Too bad your so far away!!!!

[Matt@RFR]

I'd be happy to help.

[Milow68]

Matt IS THE MAN

[Matt@RFR]

Brad, your statement proves that you're crazy...no need for the smilie.

:rolleyes5