I ran out of excuses and started welding in my patch panels today. I never did get good enough on the wirefeed welder I bought, so I just reverted to gas welding.

It came back to me - welds are not too bad. What I had forgot was brazing. I have a welding book I bought to learn to use the wirefeed, and was reviewing gas welding when I saw that chapter. Brazing worked very well!

I welded using steel rod on two edges, and brazed the other two. It was so easy. I have an air flange tool so I bent a flange onto the edges I was going to braze. It takes less heat to braze so there is less distortion, and the flange makes me think the joint is stronger.

My welding book claims that brazing is actually stronger than welding.

Now that I have started I hope to have the cab ready to go back on the frame this weekend. I started on the front cab corner so no one could see my first welds. I have to rebuild one lower hinge pillar, plus a hole in the floor, and two inside spots on the back of the cab where it extends below the frame.

There is a couple of spots on the dash that need filled, but those will be easier with the cab installed.

I have been avoiding this job for 6 weeks, hoping it would go away. Now I think it will be one that I will be proud of.

 

Don't you wish all jobs you were holding off on went this well? I have been putting off the same thing; maybe this weekend I'll attempt it also. I do wonder about the flanges though... I wonder what the possibility of water and dirt getting between the flange on the bottom of the floor pan are? Could this cause problems years down the road and actually increase your chances of corrosion? I am assuming of course that you welded or brazedfro the top of the floor...

Vernon

 

Actually, it was a vertical piece on the hinge pillar. The flanged areas were located in an area I did not think I could reach to weld. I intend to use a rust converter over the entire area, front and back, and then seam sealer and rust preventing paint to seal the joint. I am then going to undercoat the heck out of that area, and paint it again.

Someone in the past had replaced the cab support but not the rusty metal around it - it just rotted around the new metal. I don't want that to happen again!

 

***** B, If I may offer a suggestion, make sure you do a very good job prepping the welds for primer and paint as one of the drawbacks to brazing is that if ALL the flux embedded in the seams is not removed, the paint will eventually turn lose. The other disadvantage, as I am sure you know, is excessive heat. On very stiff cab corners warping is not as obvious, but if you get out on flat metal, it will be there. I have heard of old pros using something called a ‘jewelers torch’ to weld and braze body panels with, benefits being that it produces the desired temp but more focused heat.

 

WillyB -

Brazing is an interesting solution. We use brazing at my work often. In some joint styles (enough overlap with a minimum gapped seam) the brazed joint is actually stronger than the parent material.

I am a little surprised you gave up so quick on the MIG welding. Were you using a wire feed with gas? The flux-core wire welding is pretty messy. I just learned to MIG weld last year and love it.

Remember, every weld looks perfect after grinding!

 

Randy's right MIG is pretty easy, don't give up on it yet. Get some practice material and play around with it some. I'm no bodyman or metalworrking whizz but I have read that the MIG weld is a bit more brittle than either gas welding or TIG welding and therefore harder to hammer form after the welding.
Definately stay away from the flux core wire and use a shield gas as its alot cleaner. It does take quite a bit of practice with thinner material.

It seems like whenever I put off a job because I think it going to be terrible or a real pain it turns out to go pretty smoothly when i get into it. Glad to hear it went smooth for you.

Bobby

 

there's a reason brazing isn't used much for body repair, body putty and paint doesn't stick well to brass and will eventually fail. If you must braze, buy some high tensile nickle silver brazing rod instead of brass. It doesn't actually contain any silver so the price is reasonable and it comes in 1/16" diameter, ideal for thin work. It doesn't come flux coated so you'll need a can of powered flux to dip the hot rod into and/or use paste flux brushed onto the area you're going to braze. Start heating slowly to dry the flux then add the rod when the flux melts and turns glassy.
I oxyAc braze gold every day in my business, precious metal "soldering" is actually a brazing process, but I much prefer my MIG for body work. MIG welds are as workable as TIG or torch welding if you use the right wire: ESAB's "easy grind" (that IS the name of the wire, there is no alloy #, it should say easy grind on the spool. Don't accept any substitute!).
To MIG thin stock, tightly clamp a strip of 1/16-1/8" copper or aluminum to the back of the joint. The MIG wire won't stick to the backer strip but it will dissapate the excess heat away from the weld. To weld up holes up to 1/2" diameter flatten the end of a foot long piece of 3/4" copper waterpipe with a vise or hammer and anvil real flat, stick a dowel in the other end for a handle and bend the flattened part like a spatula. Hold the flat part tight against the back of the hole and start welding from the edge of the hole spiraling in to the center. The secret to using a heat sink is to make sure it is pressed tight to the back of where you are going to weld, if there is space between, it's the same as using nothing at all.

 

Thanks, guys. After reading all your comments, especially about paint and filler not sticking to brass, I tried one more time to learn the wirefeed. Spent 6 hours on it today. There is just too much I want to do on my truck that requires welding not to learn mig.

Anyway, discovered that I was trying to weld old Ford sheetmetal to new Ford sheetmetal - they changed it, went to higher strength but thinner steel and it don't weld so good. Practicing on new scrap made it a lot easier. I also think I wasn't cleaning the iron good enough for welding.

The big difference was my photogrey glasses - I am so used to wearing them that I never though about it. Between the new auto-darkening helmet I bought and my photogreys, I could not see the weld pool, or even the pieces I was welding once the arc started.

Welding without my glasses works - I now weld as good with the wirefeed as I do with the gas rig. I got carried away and built a birdhouse to give the old lady - used an old license plate for the roof and a nail for the perch. She likes things like that.

Thanks for the encouragement - I am a mig welder now! I will post pictures of the repair when I am done.

 

Yes, use mild steel sheet for body repair rather than cutting up newer scrap panels the new alloys are so different and most have some sort of rust resistant coating. MIG is very sensitive to dirt and rust be sure to sand the metal clean at least a 1/2" on either side of the joint on both sides and the edges. Dirt and/or rust will cause "volcanos" in the bead. A freshly sanded surface can rust enough just from the humidity overnight to affect the smoothness of the bead. Clean the metal again just before welding.
Try this for better visability: if you hold the torch in your right hand tip the torch ~ 20* from vertical so the tip is pointing to the left towards you at the right end of the joint to be welded. Now run your bead by pushing the tip towards yourself while looking at the bead coming towards you. That way the tip is not blocking your vis and the arc is lighting the joint ahead making it much easier to see where you are going. A flat butt joint is the most difficult to make, outside corners next and inside corners the easiest. Try to plan your work so as to have the least amount of butt joints as possible, welds along or near an edge are much less likely to warp and are easier to clean up. I like to use a fan disk on my angle grinder to clean up most welds, and use a carbide burr in a die grinder for inside corners.
Keep a stock of sheet metal in 10, 16, 18 , and 20 ga. and try to match the thickness of the patch to the thickness of the panel. The metal fabrication shop where I get my metal usually has a lot of smaller cutoffs they consider scrap. I pick up any pieces that are from ~ 4x4" and larger and they either give it to me for free or charge me a couple dollars for a good handfull of pieces. There's also a heavier metals fabricator in town and I get scrap cutoffs from 1/8" and up there. I pick up anything I can possibly use at one time there because the charge is always $5 no matter how much I select.

 

*some great tips ax thanks. here's one for you
if you want to type the symbol for degree hold down the alt key and type0176
20°

 

Thanks, I put it on a post it note by the computer.

 

Back in the old days when we had to gas weld or braze everything I/we found that a good thorough sandblasting made body work stick, have not had a come back for body work lifting off of brazing since

 

Agreed, a lot of folks like to wire brush seams but my experiance is that wire brushing anything tends to shine the metal, closing up what the paint has to stick to.

 

I have used the Brazing rod trick to reduce warpage. I run my own body shop for 6 years, but have done body and paint my entire life. What they say about body repair sticking to a braze is true. I have seen a few pieces of work come back on me. After that, I went back to mild steel and extra putty. It may not be perfect, but done right, it does not crack or come apart.

For the last few years, I have been using a wire feed. This is the difference of day and night. There is however a little trick I did not see mentioned. Do use a Shielding Gas. The trick is, the kind of gas. I know Argon is expensive. $80 per bottle, plus $350 lease for 10 years. What I done is dropped my wire to .028 non flux, then went down to the local Coca-Cola company paid a $50 deposit, then $15 for the gas, and got a bottle of Co2. The regulator I bought from a Beer Supply Vendor. The reason for the Beer Vendor is through any Gas or Auto parts distributor, the Regulator was $80 and up. Through the Beer Vendor, it was only $30.

I can now butt match the panel edges, no overlap, and tack them into place. Then I come back and do a series of 1/2 inch welds so I do not heat warp, then grind it off. In places like door jams and stiff areas, you do not even have to use putty after grinding. You can take a dent on a corner, split it with a Die Grinder cutter, then pull it out, and weld it up again.

The Co2 mixture does give a bit of splatter, but welding with the wire feed is a pleasure it is so easy. Also I can not stress strong enough that prepping the surface by grinding off all contaminates (rust, paint) so it will flow out. Also on metals over 1/8, take a torch and preheat it, and you can weld up to 1/4 thick easy with a small wire feed.

I know there may be some that disagree with this, but it works very well for me.

 

IBeam -

Thanks for the great tips. I am fairly new to MIG welding, but have done some pretty ambitious projects so far, some f it in pretty thin material. I have a lot of work yet to do on the cab mods.

I have a Lincoln Handy MIG (88 amp) and use an argon/CO2 mix and like it fine. I have used the flux core for 1/8" thick stuff because it seems to penetrate better. I don't have a gas torch, but the idea of being able to use my small MIG on heavy sections by preheating is really cool. Thanks again.

Hey, is this forum great, or what?