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This thing just cracks me up :)


Kinarfi
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When you get cracks especially at joints, you should be adding gussets to reinforce the joint. The joint is cracking because it's not supported enough and the stress is consentrating right at the joint, flexing it. It eventually cracks. If you just weld them up, they will crack again at some point. You have to add steel to spread the stress over a larger area of the framework. A good way to do this is to use 90 degree triangular pieces of steel aprox 2 to 3 inches on each of the sides that are at 90 degress from each other and a minimum of 1/8" thich, preferrable 3/16" thick, and weld them into the corners of the broken joint. This should be done after welding up the cracks. If you have for example 2 pieces of tube that cross each other, you would use 4 gussets. If there was a tube running perpendicular to the cross, you would run 8 pieces. You get the idea. Just reinforce the stuffing out of it. The rear swing arms should be boxes with 16 gauge sheet on all open sides. Don't spot i every so often but use continous welds down all sides including finishing the factory welds. Drill holes where there are cross tubes so you can weld to the cross tubes also by welding thru the holes. The swing arms tubular design just flexes and the new design didn't correct the problem. They need to be boxed.

Lenny

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Plus, you need to learn how to weld... ;)

EDIT by Kinarfi - - - - I need a lot of things, Plus, somewhere I said no criticizing or I would delete your post, actually need to learn MIG welding, better, :wacko: but at least the cracks and separations are gone / buried.

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  • 2 months later...

Just one example, other companies make them too. For the price, you can't hardly make them yourself.

http://www.polyperformance.com/shop/Synergy-Suspension-3-x-3-3-Hole-Gusset-p-438.html

I've chased so many cracks, when i take mine apart, I sandblast critical areas to find any cracks, then grind, weld, and gusset the offending area. I also seriusly gusseted all suspension attachment points.

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Another thing on the gussets, don't put them in the center of the tube. Put them on the edge. I use my welding magnets across the tube edges, and then stick the gusset against the magnet, then slide it into place next to the tubing. This ensures the gusset is welded to the tangent line of the tubing, not the center. Gussets in the center can actually cut the tubing in case of an accident.

O-O = bad; O_O = good.

Also, gussets should be set to "pull" the joint. A "push" gusset will bend on impact, so it you have a choice of gusset location, make it "pull".

If you are worried about your welding, the important thing is penetration. The best way to ensure good penetration is prep. Make sure your metal is clean, clean, clean. Get every bit of dirt, paint, and rust off it, then spray it with brake cleaner and wipe it down. Wait for the brake cleaner to dry before you strike a spark. Your welds will look better, and more importantly, get better penetration for more strength.

I sandblast, if the part is small enough, or use a flapper wheel, wire brush, or angle grinder. Even a Dremel tool for small areas. Just get it clean.

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Another thing on the gussets, don't put them in the center of the tube. Put them on the edge. I use my welding magnets across the tube edges, and then stick the gusset against the magnet, then slide it into place next to the tubing. This ensures the gusset is welded to the tangent line of the tubing, not the center. Gussets in the center can actually cut the tubing in case of an accident.

O-O = bad; O_O = good.

Also, gussets should be set to "pull" the joint. A "push" gusset will bend on impact, so it you have a choice of gusset location, make it "pull".

If you are worried about your welding, the important thing is penetration. The best way to ensure good penetration is prep. Make sure your metal is clean, clean, clean. Get every bit of dirt, paint, and rust off it, then spray it with brake cleaner and wipe it down. Wait for the brake cleaner to dry before you strike a spark. Your welds will look better, and more importantly, get better penetration for more strength.

I sandblast, if the part is small enough, or use a flapper wheel, wire brush, or angle grinder. Even a Dremel tool for small areas. Just get it clean.

I also sandblast when ever I can and use the flap wheel which is a God sent in many cases because it doesn't gouge the steel so easy. I'll use any tool that will get into the area to clean it. Clean steel is very inportant as you said. I generally gusset in the middle but I use at least 1/4" thick gussets and a lot of times 3/8". I also put as many gussets on as I can get on. Your point is well taken on getting tangent. If I use a tangent approach, I'll put a plate on each side to sandwich the tubing. You can also weld a heal under the outter points of a centered gusset to keep it from pushing in. When I was manufacturings waterslides, we would put 20" x 3/4" thick round tubing to 50 high to support the flumes. Here we would use eight 3/4" gussets going up the sides about 20" and then weld a 1" square solid bar around the tube at the tips of the gussets. Its all about spreading the stress over a larger area and providing support that is better leveraged in referance to the main junction. A ccouple of things that can help when welding are to use an auto switching helmet to better locate your start point and weld in short beads one after the other. With short beads, if your having trouble setting the amperage high enough to get proper pentration without burning thru or dripping all over the place, 1/4" or 3/8 long beads can help. This is of coursre dependent on steel thickness. Getting older, I'm not as steady as I use to be and this helps especially in difficult to get at spots with out stretched arms. If I can turn it up on the bench, no problem. Just take your time, cleaniyness, setup and getting yourself well positioned can really help.

Lenny

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Start anyplace where two or more tubes come together in the following areas.

1-Under the front,behind the differential. Tubes run to the sides and up. One comming from the rear under the seats and two asre going forward. Seems to be a weak spot. I';ve found cracks there as well as Kinarfi.

2-Thr tubes running from side to side under the seats. I've found cracks on the outter joints where the side to side tubes weld to the side front to rear tubes.

3-The joints all around the front of the rear swing arm pivot points. Both outside and inside joints. Vertical and horzontal. Also tie the tube that the swing arms mount to, to the tube below in. I've torn this tube completely out. It totally broke loose from the frame with the swing arm and rear wheel assembly still hooked to the piece of tube.

4-Also check all your tubes for linear cracks running along the seam of the tubing. I've found cracks as long as 8" under the front of the engine area.

When ever your under yout Trooper, take a flash light and check around. I now do this everytime I work on it, carefully checking the area where I'm working. I found the tubing seam cracks, the side cracks under the seats and the front cracks this way. I caught them before they caused catastrofic failure.

Lenny

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The cracks i found were on my control arms. They had a single push gusset under the shock mount, about the classis location to cause failure. I first straightened the control arms, then gusseted underneath in a pull configuration. I also gusseted the shock mounts on the frame, after i built new shock mounts.

Mine is a 650 Sand Spider with Fox Airshox and limiting straps. I cut the entire frame mounted end of the shocks off and built a new system using triangulation and lightweight gussets. It rides higher, has better travel and smoother ride. My last inspection revealed no new damage, so i just painted them back up and will reinstall when i get home from Mexico.

I understand Lenny, about your gussets, my welding "instructor" was an ag welding guy, more metal is better. When you have about 19.3 BHP it is not always good to add a bunch of weight :) I try to analyze the best place to add a gusset, no larger than 3/16 since the tubing is smaller than that and no point in the gusset being bigger than its surrounding metal. Again, you guys have more HP, mine won't make it to the top of the sand dunes even without a passenger.

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