Seam welding

[99redgst]

Well after searching and finding there has not been a single thread dealing strictly with this topic, I thought I would start one.I have recently gained intrest in this topic since my car is currently stripped(motor, trans, interior) and I have a MIG welder in the garage not seeing much action lately. Also I have plenty of time until I am ready to assemble the car. Most people that have done this to their car all agree it makes a noticeable improvement in handling. The only people that I have seen call it a waste of time are people that have never done it. So on to the technical part of it. Is it even possable for me to get the chassis square doing this in my garage, or is there special equipment that is absolutely necessary? I've seen one guy say that you need the car on a rotisserie to do it properly. I don't want to stiffen the chassis and then end up with a crooked chassis. What is the best technique for welding it, equal amount of weld and gap, such as a two inch weld then a two inch gap before the next weld? So I guess I would like to hear for anyone who has done this to their car or anyone with a good amount real knowledge on the subject. I would like this thread to stay on topic so it will become a good resource for anyone looking for info in the future.

 

[Turbo Shogun]

You should PM "zephyr_8", one of the users on this site. He says he's done it and it makes a big difference, apparently.

 

[99redgst]

You should PM "zephyr_8", one of the users on this site. He says he's done it and it makes a big difference, apparently.

Well I would actually prefer him to post in here. He may be able to answer my questions but it won't help anyone in the future. It would be nice to have one thread dedicated to this topic with as much info as possable.I know this isn't the most popular subject but I am sure I am not the only one intrested in this. I know there has to be a couple people here that have done this to their DSM or other car.

 

[zephyr_8]

Sorry, I would have posted earlier but my internet has been down all week. I cant answer many of your questions now. I will tomorrow(its 2 in the morning). It does make quite a difference in the way the car acts. The way I did it isnt the necessarily the best way or the correct way, but it was/is the best way I could come up with to do it and works very well so far for me. If you want to look for more information try looking to see what the rally guys have done. I couldn't find much information before I did it either. It seems to not be a very common thing to do at all, my car is the first street/daily driven car I have heard of thats seam welded(doesnt mean I'm the only one, just that I haven't heard of anyone else driving theres). There have been a few people asking me questions, but as far as I know no one has done it. I'll give you more info when I have time.

 

[zephyr_8]

Ok to answer your questions....
I wouldn't worry to much about getting the chassis square, as long as you started out with a car that isnt bent up, it should be fine. You won't be welding a solid seam so it shouldn't pull the chassis. The reason you would want a rotisserie to do it is because that will be the absolute best way to do it. Then you can weld the back side of some seams, and get to others you wouldn't have access to. But that is looking at things from a "ultimate" point of view. Just as there is a "perfect" way to figure out where to weld. You take the car, pretty much stress it, and then weld the parts that are weak...which would be great if you have the tools(i can't remember off the top of my head what they are, but think big frame bench type thing, needless to say I didn't use one).
When I welded the chassis, I had my car sitting in a shop, on the floor, with most of its weight(like engine and supsenion on it) I welded the seams that had seam sealer, mainly because I didn't have time to take out the windows. I didn't want to bust the windows out by welding right next to them. I stitch welded it all, just weld a spot, wait for it to stop glowing, then weld right next to it. I did this all around the car. It isn't the "perfect" way to do it, but it is the only way I could come up with to do it. I didn't want leaks either, so welding the seams completly seamed like the best way to me. It has stiffened the car up tremendously but I do expect to crack the welds within a few years. I expect the chassis to slowly lose its strength, but I don't think it will happen quickly.
Oh as far as your Mig, i recommend a 220. A 110 might work, but there is a lot of crap behind the metal you can't get out(seam sealer in between the layers of metal, undercoating, oil, you name it) that makes welding it hard. I couldn't even get a bead started with a Tig, it just burned away. If you want to know the settings I used I can tell you, but it would probably be better if you come up with them yourself. If you need more answers, ask away. It would be great to see another car seam welded, I love mine, and definetly recommend it. Even if the way I did it wasn't perfect, it made an amazing difference.

 

[zephyr_8]

Well...you wanted information so heres an older detailed post on this

Sorry I don't have pictures and I don't think it would come out well in pictures. I can tell you what I did though, 1. 3 other guys helped me chip all the seam sealer out, we used sledgehammers and chisels, it took us 1 1/2-2 days(but i took all the insulation out too). 2. I took a electric grinder with a wire wheel and grinded down the remaining seam sealer. 3. I then took a dremel and grinded down more seam sealer that I didn't originally get too. at this point I am at 3-4 days of work. 4. I grabbed a tig welder and attempted to weld it(the weld was too contaiminated from all the seam sealer behind the metal). 5. I then grabbed a mig welder and started to weld the seams. I did stitch welds across all of the seams I grinded to bare metal. I welded all the seams in the interior that had seam sealer on them. The front floor, the seam behind the seats, the rockers, the trunk,across the front and back of the trunk, the sides all the way from under the dash to the back, all of it. (there are many more seams in a car, more than I want to think about but I did the ones I thought would add the most stiffness) The only ones I didn't do are the ones under the hood and the ones next to the glass. All in all about 20-30 feet of weld It took me a week and a half-2 weeks to do all of it. I did it in class(i go to school for this kinda stuff) I was working 8 hour days. And I started with a stripped interior. And the ecu and modules were miles away(if you do this you MUST take them out) I still haven't found all the electrical stuff I fried. I'm pretty sure I blew some fuses but I may have other problems. It did stiffen it up alot though. I can hear the difference just closing the doors. I don't know its effect on handling yet. Because I can't get the car to start. It has an electrical issue. If you still want to do it, I'll tell you more, just send me a pm or something.
I am working on it all weekend so I'll tell you its affect later if you want.

(the car runs now, this was back in march I think, actually it runs great, I just drove it 800 miles two days ago)

 

[99redgst]

Great info! This is the info I was looking for. Thanks for taking the time to post this stuff. This is all the convincing that I needed, I will be starting this project shortly. I'll try to take some pics along the way.

 

[zephyr_8]

oh a couple other things, Make sure you mask off your windows on the inside, because all the weld berries will lodge themselves in the windows otherwise(trust me). Just use masking paper/newspaper/paper bags whatever you got. and make sure you have a fire extinguisher around, because you WILL set it on fire. No if/ands/buts about it. Most of the fires I had were small and didnt require a fire extinguisher. I just hit them out with my gloves most of the time. Just a precaution though.

 

[92awddsm]

I have also seam welded but it was the same time I installled my roll cage. I, on the other hand, had engine and transmission removed and the car on jackstands during this time. I can vouch for the extinguisher because I went through 3 of them. I probably went a little overboard for my setup but my engine was being built at the same time so it was just easier and why not go ovberboard, right? I welded everything on the inside and some on the bottomside but that didnt last long because of the undercoating. My suggestion is to heat all seams with a mapp gas or o/a torch before welding because it will burn all of the seam sealer out before hand and make welding alot easier.

I can say that my car is a lot more stable in turns and just overall but remember, I installled a cage at the same time so my results are somwhat inconclusive for this thread. Regardless, I wouldnt hesitate to do it again.

 

[zephyr_8]

The torch thing sounds like a great idea... i feel kinda dumb for not thinking of that. Thanks. Oh and I have a cage too, but its a 4 point so i doubt it adds much strength although I'm sure it helps the rear portion.

 

[92awddsm]

The torch thing sounds like a great idea... i feel kinda dumb for not thinking of that. Thanks. Oh and I have a cage too, but its a 4 point so i doubt it adds much strength although I'm sure it helps the rear portion.

Mine is an 8 pt so the front and rear are tied together pretty good. I thought of the torch after burning through the first seam and catching fire. The torching made for clean seams and nice, smooth welds. It can be done without it but was a lot quicker and easier with it.