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Discussion Starter #1
First off, my Marlin sliders have been through hell & back over the last 6 years. They are 1.75" .120 wall HREW round tubing. They have 3/16" thick scab plates welded to the frame with small triangle gussets welded to the tops of the slider legs. I've bent the sliders up to the point the doors don't like to open or close. I need to build a new set that are beefier. The frame is slightly wrinkled around the scab plate area.

I'm thinking of 1/4" 2"x2" square for the slider legs and the main body of the slider. I was going to bend up some new round 1.75" tubing and weld to to the outside of the main body tube. They will be angled up like the current slider.

Here's the current bent up slider




Question 1 - Are square tube slider legs stronger if they are rotated 45 degrees? The diagram shows the slider legs in red.

Question 2 - I know it's easier to weld the scab plates if they are rotated 45 degrees. What about keeping them vertical and added a piece that wraps over the top of the frame?

Question 3 - How do I remove the current scab plates from the frame? They are fulled welded on the perimeter of the scab plate.

Here's my cheezy frame and slider diagram :flipoff4:
 

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Removing the old scab plates just takes a lot of tedious time with a grinder.

Don't know about rotating the tube abd its effect on strenght.

The over the top scab plate will only help if you are able to access the top of the frame to weld them on.
 

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I've always ran square sliders. I usually run then "flat". The set that was on my taco didn't have guesets and bent up (not as much as yours, but still) and I beat the living hell out of them, several slips off of rocks taking the full weight of the taco down on slider. They were 2x2x.120.

The ones I made up for my 85 are 2x2x.25 with gussets. The main rail is 2x3x.25 set at 45*. I haven't beat on them much yet, so can't really comment there, but I have high hopes. The scab plates I made up are like dog houses sort of. think of a square with the top 2 corners cut at 45* to make it easier to weld up under the body. I know it's generally a no-no to weld vertical on frames, but I did it anyways, we'll see if I'm dumb or maybe got lucky. Considering that the slider add's rigidity to the frame, I think that whatever stress I've introduced by welding vertical is mitigated by the slider rail.

I'm no structural engineer, but it seems that rotating the legs at 45* should be stronger due to the bend being at the top/bottom. I have no opinion of the scab plates wrapping over the top. I can't think of why it's bad or good. My taco frame caved in slightly as well, but I think a better scab plate than what I had would have prevented that. Mine was simple angle iron welded on the bottom and most of the way up the side, but not all the way. I think making sure the scab plate reaches both the top and bottom bends in the frame is the key.

As for getting rid of the scab plates, I've had to do this a few times (when I cut off the bent sliders on the taco). Like Ike said, grind it off. Just focus your attention on the edges where the weld is. I was successful at taking a cutoff wheel and carefully cut just inboard of the weld and just as deep as the scab plate (1/4" or whatever). Having done both methods, the cutoff wheel was more work than it needed to be (constantly checking to be sure you didn't go too deep). It's a pain in the ass to grind, but it can be done. Get yourself one of the hard grinding wheels (as opposed to the flap disks), it's slower, but better for this sort of thing.
 

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The above long winded post is brought to you by someone who admittedly isn't an expert, but wanted to explain the ignorant reasoning anyways. :D
 

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One thing just came to me; if you do end up dinging the frame while removing the scab plates, how about re-plating the scab plate area with some 3/16" goodness?

My vote is the diamond-style/tilt/45* approachl looks like it'll hold more weight since the structural rigidity seems to be better dispersed as opposed to having square/flat/90* legs/sliders... but I'm no expert; just my $0.02 and what I may do.

Are you going to sell off those sliders?
 

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Flat legs will be stronger as you're distributing the load better. Rotated will introduce higher stress in the corners of the tube, especially at your welds on the frame.

Rotated looks cooler (IMO)
 

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Discussion Starter #7
Right on, thanks for the advice! I'm thinking of making my scab plates 6-7" wide and running from the top to the bottom of the frame. Currently, they don't run top to bottom and right above the scab plate is where the frame is wrinkled.

I might just reuse these sliders and add a forth leg to them. Since the sliders didn't actually bend, it would save me some time. I can just sawzall them off of the current scab plates, grind the old scabs off and reweld some bigger, thicker plates to the frame. My slider arms are currently gusseted like this

V
O

With two small triangle gussets in a V pattern above the slider leg. I might change that to one large one that extends further out on the leg.
 

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Aaron,

IIRC you have a plasma, no? If so, I've had very good luck "sluffing" the welds with the plasma torch.

Essentially, you rest the torch sideways on the frame so the plasma is coming out parallel to the frame. Then tilt the torch just enough that it starts cutting into the scab plates/welds, and work the torch along so it removes the weld. You have to be careful, because it is easy to make holes.

I've also had luck with Gouging tips on the plasma, which don't cut much at all, but just put a small "gouge" in the metal, sort of like a trough. You run this over the weld several times, and usually you can get a chisel in to break through the slag.

Either way, I suggest putting in a larger scab plate on your new sliders to reinforce the frame there.

I've never had good luck with grinders when you get near the top side of the frame.
 

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Discussion Starter #9
Yes, I've got access to a plasma. I'm scared to burn holes though the frame :lmao: I might look at a gouging tip for it though. Thanks for the idea.

I'm for sure going to make the scab plates larger. In fact, my back bumper on the passenger side is bent bad. I came down on it hard in Moab last year and bent it up 3/4". Looking at my scab plates for the bumper, they are too small as well. I might have to cut the back bumper off on the passenger side. It looks funny that way. Looks like I didn't weld it on straight :lmao::lmao::lmao:
 

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im a little late to this thread but FWIW, having the rotated legs will allow less deflection in them. just properties of static beams. However, like others already said, that will cause pressure points on the scab plates that might cause the welds to fail. so pick what you want, more stress in the welds or more bendage out of the legs lol.
 

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I have been running 2x2 .120 wall square sliders.

Wrap the scabs around the bottom of the frame. L

My scab plates wrap around the underside of the frame and up almost to the top of the frame. I welded them vertical, although i shouldnt have. Should have wrapped around the bottom and then diamond the sides.

My gussets are left over pieces of 2x2 that were cut to fit. They reach almost to the main bar of the slider.

I have five legs though, no frame wrinkeling and they have been beat to crap and still holding up just fine.

I dont have any good picts.


Simply adding more legs with stronger gussets and scabs, will prob help more than replacing the sliders, if they arent bent.
 
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