33 replies to this topic

[P91MER]

oxy-cetalene on a car body

That would be quite funny, do the panels get REALLY hot all over, and start to crumple and bend!

never seen it been done before..

Rich

[Jordie]

dad welded my arch on the fiesta due to suspension strut cracking. temp fix, he used oxy acetlyne and burnt through the arch. Got rid of the car eventually, but it did make the mini progress speed up so i cud run that instead.

[Mincento]

a properly deseamed mini looks georgeous and i wanted to do it to mine but have been told by one of my old mates that when he deseamed his which was his daily driver he had all the filler cracking on the joins etc so said that it shouldnt be done on a road going everyday car.

[Ade]

Thanks for the info guys.

As the car will end up having a Z-cars conversion it will have a fairly secure rollcage fitted so strength shouldn't be a worry...(famous last words??) :erm:

I'll be roping my dad in to help with the welding ( he doesn't know it yet :grin: ) He's been welding for best part of 25 years so will hopefully be handy.

Can anyone recommend what filler to use to smooth over the work? I chatted to a guy at Castle Coombe a few weeks back who said "only use a lead based one" as anything else will crack. But have no idea what types are lead based.

Thanks again Ade :cool:

[Al*]

I prefer using all metal aluminum filler but am not sure if it's available in the UK basically it won't absorb mouisture like the bondo filler and thewrefor wont ruast... if i don't use that I've been experimenting with what's called liquid steel....very cool idea and works well... what this liquid steel is is actually a two part mixture thast you mix 2 to 1 one part is the epoxy hardener and the other is very fine bits of ground up metal and the second part of the epoxy mixture....i know it doesn't sound good and i'm doing a terrible job explaining it but it is excellent....tuff as hell, won't absorb moisture and rust, and the coolest part is if you were to run a magnet over a panel that had it on it it would still stick to the magnet due to the metal fillings..... anyways if anyone wants toknow more about it let me know and i'll try and explain it better. ( thus far I've been grinding down all my welds and then filing them with this liquid steel.)

Al

[Ade]

Your not doing too bad a job of explaining it :grin:

I know the stuff you mean and have used it before but I've only ever seen it in small tubes (like a tube of glue size) That could get a bit expensive buying about 800 tubes of the stuff :saywhat:

It is very good stuff though you can cut threads into it when it's dry and all sorts!!

Ade :cool:

[Dan]

If it is done properly (not quickly and definitely not cheaply) then there is no strength problem. I know of deseamed cars that have flown through engineers inspections. The best ones don't use filler to cover the join, get it lead loaded mate. Costs a lot, takes a lot of time and a lot of skill but it will last forever.
Not only does de-seaming a Mini make it look good, but it also makes it noticably faster. The body seams add roughly a square foot to the cross sectional area of the car, and removing them drastically reduces the drag co-efficient of the shell.

[siggy]

Apart from the strenght side of things the big problem is that because of the fit of the panels you need lots of filler. If you look at the roof to side panels you will find that the contour of the body line is not matched.

Siggy

[philster]

Yes, no-gas welders are *******. No better than a filthy arc welder! Also worht nothing that it's not a good idea to use oxy-acetalene on a car body either.

oxy-cetalene on a car body   

That would be quite funny, do the panels get REALLY hot all over, and start to crumple and bend!

never seen it been done before..

We used to use oxy-acetaline when we did grasstracking due to the fact that it is a far superior weld to mig. Yes it can warp panels (especially if you're not very good) but if used carefully it won't. We also made our own fuel tanks which had to be gas welded because mig was not considered a good enough weld.
As for no-gas mig welders being ******* thats probably down to the fact that you've used a mig and then tried a gasless one and couldn't weld with it. The bottom line is they are cheaper to run and as good as any hobby mig (when you've had some practice), a roll of wire is about £2 dearer than for mig but you don't have to buy gas. Also you don't get '*woman of ill repute*' like you do with an arc welder this is a myth, there is a very small amount of flux within the wire so that you can weld smoothly but not enough to cause deposits.

[Ade]

If it is done properly (not quickly and definitely not cheaply) then there is no strength problem. I know of deseamed cars that have flown through engineers inspections. The best ones don't use filler to cover the join, get it lead loaded mate. Costs a lot, takes a lot of time and a lot of skill but it will last forever.
Not only does de-seaming a Mini make it look good, but it also makes it noticably faster. The body seams add roughly a square foot to the cross sectional area of the car, and removing them drastically reduces the drag co-efficient of the shell.

Ok Sorry to be a bit dim here but lead loading????? What is it, how's it done, what's the usual cost etc etc.
I guess it actually uses lead (otherwise it would be an odd name) ,won't it be a tad on the heavy side? I'm asking because I going to be doing some fairly extensive weight reduction. Currently planning Carbon fibre front end, doors, boot lid and dashboard. So don't then want to add a whole bunch of weight by covering the car in lead.

Ade

[tom]

Lead loading fills up dents etc. in the body with lead, rather than filler. It's better because it doesn't crack.

[Woody]

Lead loading fills up dents etc. in the body with lead, rather than filler. It's better because it doesn't crack.

only if it is done corectly !

[Dan]

If you are planning to deseam the body sides only and not the roof then you won't be using more than the thinnest skim of lead. The idea is to get the panel match as good as you can first and then use the lead to blend the join (which is how you are supposed to use filler, not that that stops people putting huge thick lumps in). Most of the lead you add gets shaved back off again anyway. It probably weighs about twice as much as resin fillers, but if it is done properly it is far superior.

And if you're that worried about weight, leave the seams on. The reinforcing plates and yards of welding wire that you use will probably be heavier than the standard seams and covers, but you will gain the aerodynamic improvement so the two effects may cancel each other out!

[TimS]

My shell is completly deseamed.. it was done b4 i got the car so i can help really with the process, just with the looks and problems iv found.
It does give a slight performance ioncrease especially at top end due to less drag as mentioned b4. If you look at the contours of the car a at the rear corner you shal see a lip which takes alot of filler and time to get it right, iv seen a couple of shells that have just missed this and looks rubbish.

if its purley for performance then leaving them on will aid acceleration, taking them off will aid top end, but you will noly be trying to squeese that exctra 0.1 second to 60 out of it

if its for loooks, then its not too bad, takes away some of the origionality, iv had a loilttle problem withn the paint reactinmg with the filler but nothing too bad as its mainly down to the rubbish paint job on the car!

[-Rich]

Hey guys, I'm new to the forum.

I'm in the process of making a classic race Mini into a street car (cough, cough). My mini was de-seamed in the process. It was stripped to a shell and the seam was ground off and MIG welded 6" at a time. The welding process is typical of any sheetmetal welding - don't heat up too large of an section at a time. TIG leaves a nicer looking weld, but the reality is that you're going to grind and fill anyway and MIG will get the job done well.

We sealed the weld with spray, then fiberglassed to create the finished product. That finished project is now 10+ years old and there are no problems. Keep in mind that this is also a race mini, and has seen it's fair share of abuse.

Anyways, pictures are at http://www.poweredby...com/minicooper/

The car has some cheesie window nets int he photos - you can ignore those. I started the conversion to a street car a few weeks ago. Progress is going nicely.
-Rich
(USA resident alien. Moved from the UK 27 years ago)