newbe welding question-trapped moisture?

[bkreigsr]

unsubscribed

[bluemane500]

bill tack the plates,dnt worry about moisture only grind where your tacking ,one tack on each side in midlle will suffice

[962porsche]

when you are over lapping two or more panels you want to use a weld thru primer . it comes in a spray or brushable . we tend to use SEM's 39786 most of the time . if your thinking of really putting the car on a track you want to do a continues weld around the foot of the bar . as a tech for many racing clubs i would fail any cage or bar if its not done to the rules stated .most rules state to do a continues weld on all pick up points of a cage .

[bluemane500]

its a bolt in cage

[bluemane500]

continuous welds are much more likely to crack and break sheetmetal ,there has to be some give when the car flexes othewise breakage occurs eventually,there are no parts on a car solid welded, why do you think this is? it sounds like a better idea but its totally wrong, im not sure of the rules of nascar or scca but drivers ed cars dont have any such rules to my knowledge,opinions are cheap,take them for there value,, just do your homework, ask the manufactorer of your cage

[962porsche]

a big part of my business is building and prepping race cars . whether its a bolt in cage that you want to weld in or if its a full weld together the feet are still welded to the floor the same way . with a bolt in you would want to plug weld the bolt holes then continues weld the seam around the foot . just because you may want to just do DE with a car you still should build it the way rules state after all its your ass in the car and you would want it to be as safe as it can be . you would not want to hook your 5 point belts to a cage or bar that is welded like that !

[drcoastline]

Originally Posted by bluemane500

continuous welds are much more likely to crack and break sheetmetal ,there has to be some give when the car flexes othewise breakage occurs eventually,there are no parts on a car solid welded, why do you think this is? it sounds like a better idea but its totally wrong, im not sure of the rules of nascar or scca but drivers ed cars dont have any such rules to my knowledge,opinions are cheap,take them for there value,, just do your homework, ask the manufactorer of your cage

Your opinion has been noted.

[Physedfailure]

could also try the racing and autox forum. Some guys prob have had some experience with this there.

[Tim K]

My apologies to the OP for the OT but this could be important.

I'm not clear on what's going on here so correct me if I'm wrong:

There is a weld-in plate with threaded holes which the roll bar bolts to?

If this is the case, I'm thinking I'd rather spread the load out to the surrounding sheet metal and not focus the stress at four tacks holding the plate in place. JMHO.

[962porsche]

i think the biggest thing is there is a person that put a post up that has never installed a bar let alone a cage in a car or has hever run on a track . they made some comment about welding the feet of the bar to the floor using a continues weld around the feet . and that it would crack and brake the sheet metal . i have been a tech for racing clubs and run in the ALMS along with scca , nasa , emra and many other clubs . in no way would a weld like that pass tech !! if it did get past tech you could KILL your self or even kill your instructor ! that i am one also !!! if you want to remove the bar then it has to be a bolt in with a plate under the floor with grade 8.8 bolts holding it in . if you want a weld in bar then you will have to weld it as i stated . i don't like to put people down but from stating what was stated he is putting your life at risk along with others . as for a plug weld you would weld the holes straight thru the hole to the floor . as for the welds even being any good for the bar there is little to no penetration to thows welds . and as for being unsafe with 1000's of LBS of force put on them in a crash don't you think that just 4 little tacks would just rip the sheet metal ? its because your concentrating ALL that force in just 4 little spots . PS i forgot to state this as well ! when it was stated that there are no parts that are solid welded . it is very common to solid weld the seams on race cars ! allespecially rally cars that take a heavy beating ! this is to stop seams from opening up ! just because some one has 30 years in the body biz does not mean they know any thing . i could get into why cars like porsche has there spot welds every 2 inches apart and why cars from japan have them every 3 to 4 inches apart . butthats for an other day .

[bluemane500]

on that note, how much pressure is put on a stabiizer bar ? and how is a stabilizer mtg bracket installed in a 911,surprisingly enough they are spot welded not solid welded around the mount, you can take your information from the horses mouth or his opposite end

[drcoastline]

Originally Posted by bluemane500

on that note, how much pressure is put on a stabiizer bar ? and how is a stabilizer mtg bracket installed in a 911,surprisingly enough they are spot welded not solid welded around the mount, you can take your information from the horses mouth or his opposite end

Hmmmm.

[962porsche]

Originally Posted by bluemane500

on that note, how much pressure is put on a stabiizer bar ? and how is a stabilizer mtg bracket installed in a 911,surprisingly enough they are spot welded not solid welded around the mount, you can take your information from the horses mouth or his opposite end

again i think you know little to nothing about cars and the engineering of why and how they are built !most all of the replys you have made do not hold true to what and how a porsche is built and why its built the way it is . because its apperent you really don't know why the say stabilizer mounting bracket is spot welded from porsche . that is really called an anti roll bar from an engineering stand point ! it has to do with time and cost . now when your building a race car they get stiched welded in . now how would i know that well because i was one of the engineers that worked for 5 of the 7 years at porsche building race cars . O- and the other 2 years i headed up the coating dept. the bottom line is by you stating that 4 little spot welds are more than ok . you can get people KILLED ! AND THATS NO F@$KIN JOKE !!!!! so what you should do is pull your head out of that horses ass and don't claim to know more than you really do and still be so high horsesed about it that you feal the need to try to make a pointless point ! try to rap your head around this ! even thow i know your not a body person ! if there is a crease in a panel and you have to weld a pull plate to it . will it give a better pull if you put allot of little spot welds along the pull plate or just say 3 or 4 spot welds . why does it not tear the metal as ez with alot of welds when it will tear the metal with just a couple ? thow i don't know why i asked you that you would just mud it ! and thats all i have to say to you ! your just not good enough to wast my time on .

[bluemane500]

your probably pulling the crease at an angle,causing your tacks to rip of the metal that was compromised once you started welding,maybe you should of got behind the crease and pushed it out from the rear, the same place you got the info on why the (anti roll bar) was spot weld on, the fact is when they are welded on solid they wind up breaking off, ive only installed about a hundred of them,maybe when you headed up the coating dept you inhaled too much lead, i think it has affected your ability to have a conversation,,and you ought to try polyester on your repairs,mud is prehistoric like a cellette

[drcoastline]

Bluemane500,

I am just a lay person but so much of what you say just doesn't make sense. First anti roll bars are subject to far different stresses then a roll bar. secondly if those anti roll bars are subject to certain stresses they have broken and have torn the mounts free of the metal they were attached to.

There is more then one car in the auto X and racing forum that has had the tack welded seams fully stitch welded to improve chassis stiffness. Perhaps you can explain why this 935 is having all the suspension points and strut towers reinforced with stitch welds if it is not only not necessary but incorrect?









If the suspension is reinforced with stitch welds it only stands to reason that a roll bar would be more then tack welded in place.

[bluemane500]

well the guy was wlding in plates for a bolt in harness bar, the manufacturer sent him pics with the plate spot welded in place, we werent talking about a full blown race car,an i think an anti roll bar has more stress due to the weight of the car,solid welded they break,stitch wlds are a combination of tack welds closer together it is not solid welded, so what dont make sense,, i told him to weld on all four sides of plate,, plenty sufficient as well nuts an bolts which are acceptble for most club racing ,, if someone over kills the welding they can do more harm than good, you think Porsche spot welds to save money? too much heat can compromise steel, ive seen to many issues with solid welding on a race track,,parts and cars need to have some give or things crack

[bluemane500]

i hope answered your question doc a stitch weld intermittently shuts off the welder,, it is not a solid weld,and i also told the man advice was cheap to do his homework,, i dont claim to know everything, i did installs for years for pca club members and no one ever died,also spent hundreds of hours on race tracks with 911s ten years worth i dont talk out of my rear end

[bluemane500]

further more doc before i go to bed all the pics you posted prove my point except for the first one i cant quite tell but i think that is a piece of sheet metal welded in an apron and a hole for a stabilizer bar like a weltmeister, sheetmetal is fine to seal up, but in all the other pics nothing is solid welded, people do it but it doesnt make it right, JMHO I am a factory trained professional not self proclaimed

[962porsche]

the more you write the more your show you really don't know ! the simple fact that with the pick up points on a anti roll bar were it meats the body its only a pivet point . i could see on cars that some people build being of such pore quality that the suspension would move around and brake the pick up points on there anti roll bar . repairing 100's of them ? from what was stated i don't think this guy ever worked on any porsches ! if it was so bad then why do CO's that build roll bars solid weld all there joints ??? its so unsafe that every car on the road spot welds on suspension tabs then runs a weld along the seam were it meats the body . what should be done is some one should get ahold of all the car makers and thell them its wrong .

[drcoastline]

BM500

Correct me if I am wrong but aren't all the areas highlighted in red solid welds?



Again I am only a lay person but it seems to me they are solid welds in those areas because the loads would be greatest at those points and need to be stronger and transfer more energy into the surrounding panel. Less so then say the center section of the tank support in photo #2 of my original post. In addition I believe the larger the area the more the stresses would be transfered. Lets use the following example. If you are treading on thin ice and you try and walk what happens? All of your weight is transfered straight down to your foot and you punch through the ice and fall in. Now if you lay down and spread your arms and legs your weight is transfered over a much larger area reducing the chance of breaking the ice and falling in. I believe the same principal applies. If you use only a few tacks all the stress is concentrated to those areas. I think the likelihood of failure is much greater. Use a solid bead and the stress is transfered across the whole bead and into the surrounding surface.



Notice the additional of the front A arm pick up points. Granted they are tack welded in place but I believe this is because the stresses at this point are not as great as those as say the strut towers that are trying to tear themselves off the car. hence the solid welds.

So to answer your question I don't think the photoos prove your point in the least but do in fact BUST your myth.