Jump to content
HybridZ

Final started chassis stiffening ...


Recommended Posts

P1010036.JPG

 

Learned a lot in the process. These (both sides) are the first things I've welded other than a whole bunch of practice scraps. Overall it turned out as I expected. Learing that you cant reach the inside edge of the miter since the gun can't fit so they will have to stay unwelded. On the same note need to be careful before you start that you can actually reach the areas needing to be welded as I had to make a few modifications from the initial design. Things like I ended up welding the lower back-up plate to the tube first since you can't get to it afterwords. Also find out real quickly that overhead sucks as it's much harder to get consistent welds - once you get some heat in it your good as long as you can see where your going it's mostly getting starting I still have a hard time with it spitting and popping. Also you'll notice when a little seam sealer / undercoating is between the panels if you stitch weld as it'll pop real good and smoke / burn / small flames. Last tip I found is that for some reason a brass wire wheel seems to work better than anything else I could find for getting to bare metal but you still have to scrape off the undercoating first for which I used a gasket scraper.

 

Now on to the strut tower bars and removing the old framerails. Keep debating weather to stick or seam weld the back-up plates but for now I'm going with stitching them.

 

Cameron

Link to comment
Share on other sites

  • Replies 52
  • Created
  • Last Reply

Top Posters In This Topic

Hi Cameron,

 

You should be able to weld all the way around the tube in the example above. I've done this myself a few times. I generally turn up the shield gas, assuming mig, and pull the gun cover back as far as I can. Then you need to let the stick out increase a ways but you should be able to go all around. If not then the next trick may be to use good ol' gas welding.

 

I've never had luck with just wire wheeling and really prefer a flap wheel for the final cleaning. Did you clean the area with acetone of something similar? If not you may find this helps. I also preheat the weld area with a MAP gas torch. You can see this drive out water vapor and will help with make the weld a little easier.

 

Cary

Link to comment
Share on other sites

You need to clean your plate before you weld it to the car. It has a coating called mill scale on it, and it will weld a lot better if you clean it off. I have some that has a SERIOUSLY tough coating on it, takes forever with a knotted wire wheel so I've changed to a flap sanding disk to get that crap off.

 

Also if you're going to do the whole chassis I suggest you spend a couple days with a propane torch burning the thin layer of undercoating off of the body. I tried a heat gun and a scraper, it sucked. Then tried a wire wheel, it worked but was SLOW. Then got turned onto the torch. You just torch it until the coating starts to bubble, then you can scrape it right off and clean it up with a wire wheel.

 

Overhead welding does suck and that's the main reason I made a rotisserie to put my car on. If you're going to stitch weld the whole thing or even if you're just planning on working underneath a lot, you might seriously consider going that route. I used 3 engine stands and some 1.5" square tube for most of it, a couple 1" square tube for gusseting. It was pretty easy to do and saves SO much hassle...

 

Good luck with it!

Link to comment
Share on other sites

Hi Cameron,

 

You should be able to weld all the way around the tube in the example above. I've done this myself a few times. I generally turn up the shield gas, assuming mig, and pull the gun cover back as far as I can. Then you need to let the stick out increase a ways but you should be able to go all around. ... Did you clean the area with acetone of something similar?

 

Cary

 

Yes it is mig but when I pull the gun back it just 'misfires' and starts popping and just generally making a mess so maybe I just need to practice more. I do clean it with Acetone.

 

You need to clean your plate before you weld it to the car. It has a coating called mill scale on it, and it will weld a lot better if you clean it off. I have some that has a SERIOUSLY tough coating on it, takes forever with a knotted wire wheel so I've changed to a flap sanding disk to get that crap off. ... Overhead welding does suck and that's the main reason I made a rotisserie to put my car on. If you're going to stitch weld the whole thing or even if you're just planning on working underneath a lot, you might seriously consider going that route. Good luck with it!

 

The metal I'm using is very clean to start with - unlike the heavily scaled stuff you get at the hardware store. I'm also not going to stitch weld the whole chassis I was just playing with it up front. When I first tried the overhead weld I thought I would have to build a rotiserie because it just spattered everywhere but I'm getting the hang of it so I think I should be OK. The only other main thing to weld upside down is the subframes but I've found the the rounded edge of the tube makes a real nice place for the weld to hang out when your welding overhead to a flat plate such as I'm doing with the subframe. Since I dont want to cut-up my floors I'm just going with 1x3 tubing attached to the underside. It's the flat plate to flat plate that I'm still not consistent with but I'll get there.

 

Thanks

Cameron

Link to comment
Share on other sites

I can SEE the scale on the plate that you welded, and your weld looks like you welded through scale. It's not a bumpy surface. It's a bluish colored coating, and it's on your plate steel that you're welding. You need to knock it back an inch or so from the edge. If you still don't believe me I can go out and grind some off of my big piece of plate and take a picture to show you. It's there though, and your welds will be A LOT better for getting rid of it.

Link to comment
Share on other sites

Cameron: nice... nice work. cool idea for stiffening without a cage. For mig welding everything has to be CLEAN! clean, did I mention clean? Did somebody else mention it? I agree with workinprogress, sandblasting rocks. But everybody hates it. It makes such a mess, goes everywhere. Nothing works as well. It rocks. It looks like you cleaned the inner fender apron panel rail piece with a grinder. Take that to your plate. Like Jon says, I can still see the coating on it. Flap wheel thingies might work ok, but be a manly man and grind it!! wear googles. It will still weld ok, but the mig works a lot better if it's clean. Oh and what Cary said about pulling the collar back brings up a good point. Don't mig in the wind or breezy day outside or with a fan on you. The shielding gas just blows away. more pics!!

Link to comment
Share on other sites

has to be CCameron: nice... nice work. cool idea for stiffening without a cage. ... Oh and what Cary said about pulling the collar back brings up a good point.

 

Thanks for the kind words. Now you say pull the collar back - mine is as far back as it goes so should I get a longer tip so that it extends out past the collar for this application or do they even make such a thing? My current tip is flush with the collar.

 

Thanks guys for the tips on doing a more thorough job with cleaning as I was thinking cleaning with acetone to the new metal was good enough. Will try grinding the surface down a bit for the next piece.

 

Thanks

Cameron

Link to comment
Share on other sites

  • 4 weeks later...

Here she is in all her glory on jackstands - the LS1 is under the tarp

 

P1010045.JPG

 

Crack I found in subframe right at the base of the firewall. Appeared to have been jacked by a rather small bottle jack on the corner which caused the crack.

 

P10100431.JPG

 

Another misc crack I found.

 

P10100401.JPG

 

Subframe connectors in progress. I found another crack at the base of the firewall in the lip and a spot weld broken but you cant tell from the pic. Lastly is that the doubler plate had rust behind it on both sides so I removed them and now have to decide how to fix - NOTE this one is tricky in that there is no seam sealer so water is free to get between the base plate and the double and you cant see the rust unless you dig in from the top. I would bet that nearly all Z's have this if you look close enough.

 

P10100361.JPG

 

Had to remove the front seat bracket which I was planning to anyway since it pushed the floor down just enough the SFC wouldn't sit flush. There was absolutely no evidence the bracket ever moved just manufacturing tolerances. New favorite tool for cutting metal - air chisel but it really sucks for cutting spot welds as it tends to punch through the wrong side. Cutting the factory subframes off really sucked and took forever and the floor still has too many holes in it.

 

P1010039.JPG

 

I'm finding this to be the biggest piece of crap I own. I can't get a straight cut to save my life.

 

P1010044.JPG

 

I'm starting to omit the year when I say it'll be on the road on May :(

 

Cameron

Link to comment
Share on other sites

...so should I get a longer tip so that it extends out past the collar for this application or do they even make such a thing?

 

They make extended collars that are cone shaped, take the longest you can find and grind it down to the desired open end diameter.

 

For welding overhead, the easiest way I found (I was a welder for 4 years before I flipped out and went into mechanics) is to turn down the heat a little bit so the metal will be less prone to "drip" then you'll want to do a little back and forth movement with the wire, this lets the metal cool a bit as you go a bit further and then you come back over it to fill what's left so you don't have any crevases on each side of your weld. I'm talking about a small movement, here 1/8 at most.

Link to comment
Share on other sites

Some other tricks to weld when you can't see what you are doing:

 

First: when you don't have a clear line of sight to the joint but, can see the back of the panel, what I like to do is to drill a very small hole at each end of the joint then, you go on the other side and you link the 2 holes with a scribe mark. Once this is done, you put the gun on the joint and you, being on the other side, watch for that red dot that the puddle will make on the back side of the panel and you move that red dot along the mark you made trying to keep it straight on the line. Voilà, blind wellding. If the dot becomes glowing red, let go or you'll burn trough.

 

When you can see the joint but you can't get the helmet close enough to see when it's flipped down, I like to take a mirror and put in in the hole instead of trying to cram my head in there. It takes a bit of practice but, if you can shave, you'll be able to pull it off.

Link to comment
Share on other sites

Sometimes I use flux core welding wire so I don't use the gas. That lets me remove the tipshield all together and get in really tight spots... And if you havent already bought an autodarkening helment get one! It is the best thing since the McRib!! Harbor Freight has em for $49 when you catch em on sale...

Link to comment
Share on other sites

Sometimes I use flux core welding wire so I don't use the gas. That lets me remove the tipshield all together and get in really tight spots... And if you havent already bought an autodarkening helment get one! It is the best thing since the McRib!! Harbor Freight has em for $49 when you catch em on sale...

Most licensed welders I know say that flux core is crap... And the flux core

welds I've seen haven't been pretty. Anyway, pretty or not - for welding

that affects structural integrity I'd never use flux core since flux core isn't

recommended when using thicker material than 20 gauge metal.

 

I would assume some 10-12 gauge piping was used for this for example:

http://forums.hybridz.org/attachment.php?attachmentid=1915&d=1166584750

 

 

P10100401.JPG

 

I have that exact crack... Anyone else? :)

 

Your subframe/tension rod connectors are pretty similar to the ones I got:

 

11_G.sized.jpg

Link to comment
Share on other sites

Most licensed welders I know say that flux core is crap...since flux core isn't

recommended when using thicker material than 20 gauge metal...

 

What?

 

I used to work in an agricultural equipment manifacture, they also built Steel structure buildings and for the thick metal it was flux core all the way.

 

To weld REAL flux core, you still need Co2 to get good blending and spreading of the added material and lots of heat usually above 34V.

 

Those little cheap units are designed for the handy men who do small repairs, so they don't have to buy gas and the hassle of dragging a bottle around. They don't make good looking beads but if you're careful you can have good enough results.

Link to comment
Share on other sites

  • 2 weeks later...

I agree with Mike. It looks like you're making progress.

 

I'm jealous...every time I look at my car, I wish I knew how to weld so I can stichweld my frame to stiffen up the chassis.

 

My friend was just explaining to me that you can drill through existing spot welds, re-weld it, and grind down the excess weld to also improve stiffness. Trying to do more research on that process.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...