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> Advice on a sleeve for inside the longitudinal
doug_b_928
post Jul 19 2017, 09:02 PM
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It certainly is an interesting idea for stiffening the chassis, assuming the calculations pan out.

In my case, given that I'm not looking to stiffen the car, but certainly wouldn't mind having it stiffer while I'm at it, I do wonder about the extra weight vs. the stiffening if I really don't need it.

@ amfab: very nice work! I particularly like how you are replicating the beads in the bottom of the long. I should have taken the time to do that, but no going back now.
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Curbandgutter
post Jul 19 2017, 09:05 PM
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QUOTE(Rand @ Jul 19 2017, 08:00 PM) *

I don't want to get into calculation games. You'd have to show yours too. If you want to add excess weight, no doubt your answer will be strong. I do know that 1/8" is not necessary.

You're on.
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Rand
post Jul 19 2017, 09:15 PM
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(IMG:style_emoticons/default/biggrin.gif) Fair enough. All this aside, I am really enjoying your build. Could be lighter if you are using 1/8" in the longs... (IMG:style_emoticons/default/poke.gif) but it's truly a standout. I saw someone call you out on FB "it will never see the road." I beg to differ: Watching your work, I know you'll get it done and I can't wait to see it driving.
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amfab
post Jul 19 2017, 09:53 PM
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QUOTE(doug_b_928 @ Jul 19 2017, 08:02 PM) *


@ amfab: very nice work! I particularly like how you are replicating the beads in the bottom of the long. I should have taken the time to do that, but no going back now.


Thanks, I bought a $130 harbor freight bead roller and reinforced it and it works pretty good.
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amfab
post Jul 19 2017, 09:53 PM
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marksteinhilber
post Jul 19 2017, 10:39 PM
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QUOTE(doug_b_928 @ Jul 19 2017, 11:22 AM) *

I'm repairing the passenger long. I've removed the rust and welded in two patches that comprise the bottom 2/3 of the long. To strengthen the long due to the welding I've made a sleeve out of 18 gauge cold rolled (same material as the patches) that is 36" long as pictured below.



The problem is that the 90 degree bend in the sleeve has made it tough to bend to the exact shape of the long for a tight fit. I put clamps on it and then with a hammer and punch beat it at the back (as shown by all of the pock marks). I think if I start welding it at the front and then do the hammer and punch thing as I go along it will probably conform to the long. But, I'm not 100% sure and would hate to have it half welded in and realize that the last 1/3 will not fit tightly. I could also make an 18" relief cut along the bend, bend it to conform, and then weld the sleeve to that shape prior to welding it to the long.

I was going to run a bead on the black lines to make it more stiff, but figured that would make it even harder to make conform to the shape of the long when welding it in. So, I guess another advantage to the relief cut method might be that I could put a couple of beads in the sleeve (though perhaps that might also throw the fitment out of whack and put me back to square one with welding it in being more difficult).

So, my question is, which is the best way to proceed. Take a chance on being able to bend it as I weld, or make the relief cut to fit it prior to welding it in? And, if the latter, should I put a couple of beads on the sleeve?


Use sheet metal screws where you will later do your plug welds to hold the pieces tight together. With all the plug welds or rosettes, the two layers will share the load. Make sure your door gaps are good as you progress, move around with your welding locations. Eventually you remove the screws and finish up welding those locations.
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doug_b_928
post Jul 20 2017, 09:22 AM
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A small relief cut on the horizontal plane seems to have taken care of it.

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amfab
post Jul 20 2017, 10:36 AM
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QUOTE(doug_b_928 @ Jul 20 2017, 08:22 AM) *

A small relief cut on the horizontal plane seems to have taken care of it.


Sweet
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Curbandgutter
post Jul 21 2017, 03:35 PM
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(DISCLAIMER ALERT do this at your own risk. This may or maynot work)

OK I did some calculations based on a 6x4 section .09" thick. This is a close approximation to what we have. I compared apple to apples and was somewhat surprised with how well the current method of strengthening works. i.e., outside reinforcing or inside reinforcing. Since the long is opened up I thought that it would be easy to weld a 4", 1/8" thick flange on the inside of the long at the top and bottom flanges. Well the calculations show that this would be 86% stiffer than an unreinforced long and a long reinforced with a plate welded to the side is 71% stiffer than an unreinforced long. Bottom line the current method of stiffening is really really good! Either Engman or Maddog However, since you have the longs opened up, it would be simple to weld a top and bottom plate 1/8" thick and make as wide as possible. I would also make sure that the vertical section of the long is a continuous piece. For everyone else, if you use the Engman style along with the Maddog......damn that will be really stiff.


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Curbandgutter
post Jul 21 2017, 03:36 PM
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QUOTE(Rand @ Jul 19 2017, 08:15 PM) *

(IMG:style_emoticons/default/biggrin.gif) Fair enough. All this aside, I am really enjoying your build. Could be lighter if you are using 1/8" in the longs... (IMG:style_emoticons/default/poke.gif) but it's truly a standout. I saw someone call you out on FB "it will never see the road." I beg to differ: Watching your work, I know you'll get it done and I can't wait to see it driving.


Thanks Rand (IMG:style_emoticons/default/beerchug.gif) ....man there are a lot of haters on Facebook. I mean really why would anyone want to say something like that?
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bretth
post Jul 21 2017, 03:49 PM
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Very interesting, wish i could follow all of the math. But wouldn't it be better to use the usual Engman type stiffener (or similar to what OP is using) to hopefully more evenly distribute the flexing of the chassis as a whole? Like too much rigidity in one area causing weekness some where else? Debating doing something similar to my own car.

PS the Facebook hater is probably incapable of doing such complicated work so they pin their inadequacies on you. Hate people like that.

Brett
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Curbandgutter
post Jul 21 2017, 04:00 PM
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QUOTE(bretth @ Jul 21 2017, 02:49 PM) *

Very interesting, wish i could follow all of the math. But wouldn't it be better to use the usual Engman type stiffener (or similar to what OP is using) to hopefully more evenly distribute the flexing of the chassis as a whole? Like too much rigidity in one area causing weekness some where else? Debating doing something similar to my own car.

PS the Facebook hater is probably incapable of doing such complicated work so they pin their inadequacies on you. Hate people like that.

Brett


Bretth after doing the math, the Engmann or Maddog area really good alternatives. Since the OP has the long opened up, I though it would be easy to reinforce it with a bottom and top flange.
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doug_b_928
post Jul 21 2017, 05:46 PM
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I think what Brett is saying is that the sleeve I have is kind of like a reverse Engmann (because it's on the inside), and so might be sufficient. But, if I understand correctly, you were suggesting to install my sleeve and then add one strip of 1/8" plate on both horizontal planes. I'm installing the sleeve to strengthen the long because I've welded in patches such that the bottom 2/3 are new metal, so I don't know where that puts me with respect to chassis stiffness as a starting point relative to a new long that has never been cut.

The maximum length of a single piece of plate could only be the distance between the locations where the heater tubes are welded to the long (I'm keeping the heater tubes) on the top side. So, that would be about 25" give or take an inch. Probably 2" wide would be the widest it could be. On the bottom it could run from the heater tube at the front to the back of long (about 35").

I'm still left wondering whether or not it's something I should do. If my sleeve is kind of like an Engmann, even given that it's there to compensate for the welds, perhaps that's strong enough for my needs.... I'm not an engineer and not really sure how to weigh the costs-benefits of adding the plates vs. the downsides (e.g., extra weight).
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Rand
post Jul 24 2017, 05:42 PM
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One long piece like the Engman kit, that fits precisely and tightly against the longs is so much more efficient than hacking 1/8" patches on the inside, which will be way heavier than necessary. But it will be stealthy, I'll give you that. It's a helluva lot more work for less benefit IMHO. Then you have to close it back up. I'm glad your welding skills are solid, because most would twist their chassis out of whack with all of that excess welding.
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rick 918-S
post Jul 24 2017, 07:18 PM
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Ya, 1/8 is not the answer regardless of the math. When you add heat to the equation you introduce a whole new problem. We have had countless guys posting on here with cries of help after they warped the longs to the point where the doors and top no longer function.

The type of heat that would be required to properly bond 1/8" to 18 GA. is a recipe for disaster. The holes in the 1/8 would need an increased size in order to allow the wire to generate enough puddle heat to melt into the 1/8. At that point if your not blowing holes through the factory sheet metal you introducing heat into the 1/8 that expands out further from the spot weld and stays hot longer. allowing the metal to warp.

Doug, Use 18 GA. move the spots around while working and cool the panel as you work. Check the car as you you go to be sure you are not moving the metal. Don't worry about stitch welding the edge of the sleeve.

Long reinforcement is a good Idea where from the inside or the outside. But I can not express enough how important it is to work slowly here. There is always time to do it right the second time.
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amfab
post Jul 24 2017, 07:50 PM
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QUOTE(rick 918-S @ Jul 24 2017, 06:18 PM) *



Long reinforcement is a good Idea where from the inside or the outside. But I can not express enough how important it is to work slowly here. There is always time to do it right the second time.


Fortunately its summer in LA and with my welding jacket I get too hot before the metal gets too hot, so I can't help but work slowly.
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doug_b_928
post Jul 24 2017, 08:22 PM
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Good advice, Rick. I spent all day yesterday welding in the sleeve, so that's pretty slow. I waited for the metal to cool to where it barely felt the slightest bit warm anywhere on the panel before doing another weld (only a few degrees Celsius warmer than the rest if the car). The long still pulled up a bit on the bottom! Door measurements are unchanged but I'll put the door back on the next time I'm at the farm just to make sure. Since yesterday, I've been thinking exactly what Rick is saying... The heat from welding 1/8 to 18g would be really dicey... certainly outside my current welding ability.
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mbseto
post Jul 25 2017, 09:15 AM
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QUOTE(amfab @ Jul 24 2017, 09:50 PM) *

Fortunately its summer in LA and with my welding jacket I get too hot before the metal gets too hot, so I can't help but work slowly.


Back when I learned to weld, we all wore flannel. Hot, but not as hot as leather.
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