keeping a welded frame sturdy?

[kcjaxxnc]

ok im not entirely new to welding however never really had to weld a frame to handle abuse. right now im working on a desert cart to handle various terrain and cant afford for it to break down. im using a manco stinger frame as the center but everything else is reworked. i extended the frame using thick steel pipes from lowes(need a better supplier of tubing also) that matched the width then used steel slugs that fit snug inside the tubing and made 4 rosette welds on each side and welded the center. anyone have any good hints for re working a frame and keeping it sturdy?

 

[Poboy kartman]

Please fill out your profile so we know where you are from. ...

And to the forum!

 

[kcjaxxnc]

lol yeah i just got to that been sick for a bit hence the delay.the pics are before and after i got the idea to do rosette welds and such from a race garage that rebuilds rollcages. however i want to make sure everything is A+ before i even think about putting any final touches on anything. i call it a desert cart/ sand rail whatnot becuase i cant find an appropriate title lol i want it for trails but also may try it on a few dunes ive found.

 

[kcjaxxnc]

not the best welder but my wife wanted to get me one for my birthday with her own money i used to have a miller(dads) but all we could get was a northern 125 flux core. i had to modify the feed and crap to get it to run a consistent bead and not crimp the wire (i miss my gas welder yes i know please dont be too hard on me.*looks up with puppy eyes) and i cant do thinner metal. but needless to say i welded my cars strut mount with a new brace and its held up to my wifes driving since last year so id say it works. i wont go into various excuses ect im no pro honestly but i aspire to be good.

 

[landuse]

One word......gussets

 

[OzFab]

As long as you got a decent bite on the inner layer, I'd say those rosette welds (that's what you call them; I know them as plug welds) should be plenty strong enough...

As far as welding in general, I use 1 simple rule: If you're not sure, turn up the heat & only turn it down when you burn through instantly...

 

[kcjaxxnc]

thnx for your input yeah i learned the term from my dad. hes an excellent welder one of the best in his union. i can only aspire to be as good as him. yeah i got it on high heat due to thicker material. so that boosts my confidence it will hold.

 

[andrewmacc]

With round tube splices: slug the joint, drill the tubes for plug welds, leave a small root gap so it bites into the slug and weld it appropriately hot.

With square and rec/ tubing: bevel, buttweld, and fishplate. Fishplates are plates that are typically shaped like a diamond (ie <>) that are welded over top the buttwelded joint, and help displace load along the plate into the tube. The diamond shape prevents tearing stress. An incorrect way to fishplate would be to have the plate positioned in a way that creates shear stress (ie [] ).

Welding too hot can actually be almost as bad as welding cold. Excessive heat in thin material greatly increases the Heat Affected Zone of the weldment, making it susceptible to material failure beside the weld joint. For example: if you look at some chromoly race chassis's, sometimes you'll stacked TIG welds in a single joint because the HAZ in a chromoly weld joint severely reduces the strength by making the joint too brittle if it hasn't been heat-treated postweld (not in most peoples' budgets), and it'll have cracked multiple times beside the weld joint, and they're just chasing the cracks all the time.

 

[mckutzy]

andrewmacc-
Hey shout out to my local brother.
Not too many from the northern westcoast here. good to see.

 

[supermanotorious]

kc what desert are you talking about?

 

[kcjaxxnc]

i got ya thnx for the post.
i already have the plug welds slug and butt weld done but now per your post i think ill do the fishplates too excellent post .i will keep an eye on the heat. my dad is an excellent welder of 25+ yrs experience however i rarely get to hear from him and hes 850 miles away i wish i could get his help so i wouldn't have to bug yall (not that i dont appreciate the great advice!!) but your help is much appreciated and definitely good info.

 

[kcjaxxnc]

kc what desert are you talking about?

not really desert lol i compared it to a desert cart cuz its where i got my ideas for the build truth be told it will be hitting a few sand dunes and also busco beach most likely. its mainly just build to say i did it i guess lol

 

[andrewmacc]

andrewmacc-
Hey shout out to my local brother.
Not too many from the northern westcoast here. good to see.

Hey! Whereabouts in our rainy province do you live? I'm Lower Mainland in Cloverdale.
Always good to see a fellow local around.



kcjaxx, I only see tube splices in your chassis, no square or rectangular box tube. With the slugs and plug welds done correctly, you should be fine. Fishplates are more of a rectangular and square tubing ordeal, especially with buttwelds. You can sleeve square/rec tubing as well, but most people just fishplate the joints because of the manner in which they're positioned (ie shear, as I mentioned).

Long story short, looks like you had a good gut instinct, and you should be confident in your splices.

 

[kcjaxxnc]

kcjaxx, I only see tube splices in your chassis, no square or rectangular box tube. With the slugs and plug welds done correctly, you should be fine. Fishplates are more of a rectangular and square tubing ordeal, especially with buttwelds. You can sleeve square/rec tubing as well, but most people just fishplate the joints because of the manner in which they're positioned (ie shear, as I mentioned).

Long story short, looks like you had a good gut instinct, and you should be confident in your splices.

well i cant take the credit for that one local race shop showed me that. i get what your saying now. thnx for your help

 

[Scout]

ok im not entirely new to welding however never really had to weld a frame to handle abuse. right now im working on a desert cart to handle various terrain and cant afford for it to break down. im using a manco stinger frame as the center but everything else is reworked. i extended the frame using thick steel pipes from lowes(need a better supplier of tubing also) that matched the width then used steel slugs that fit snug inside the tubing and made 4 rosette welds on each side and welded the center. anyone have any good hints for re working a frame and keeping it sturdy?

Sounds like you are doing it right. Some cross bracing (triangulation) never hurts anything but weight, or you can weld some sheet metal to the bottom to act as a cross brace and a floor pan. It's going to twist some, unless you build rails on the sides.