Cutting car Panels with a Plasma Cutter

[DarrenUK]

Hi everyone,
Been hanging around for a while and doing a lot of reading here, must say I'm impressed with some of the quality work going on

I've done quite a bit of mig welding, built a Lotus 7 from scratch some time ago amongst other things, many other things

I'd like to ask if plasma cutters are suitable for cutting out sections of rusty car bodywork for prep with regard to welding in new sections?
Does the plasma cut interfere/contamination with mig welding?

I see some very intricate shapes cut on this forum, is that how peeps are doing it?

Thanks Darren

 

[rtbcomp]

It should be fine, just make sure you cut back into non-rusty steel and clean off any burnt paint residue or zinc plating &c from both sides before welding.

 

[candygt]

Just remember to strip any sound deadening material or waterproof membrane from the other side of the panel just incase. Dont want any fires now

Im afraid thats about the best advice I can offer as I dont actually own a cutter :P

 

[bigbadbugga]

I've been repairing my sisters Fiat Marea (**spits**) and cutting the rot out (**most of the car**) using my plasma.

Makes a real easy job of it, but like has been said be very aware of sound proofing, underseal and fuel lines etc.

 

[DarrenUK]

Thanks Guys, really appreciate the help... one thing, the car in question has been waxoiled and I'm guessing that'll cause some fun

But I have other uses, OK, reasons why I want to convince myself to get one of these ....

 

[wallopadonkey]

where about are you matey?
i'm in llandudno

 

[chunkolini]

Definitely have a go with one, but only if you have access to the funds. All of the work a plasma cuter does can be managed without one, but once you have tried it; it is the thing for the job.

Chunko'.

 

[candygt]

Yup unfortunatley waxoyl is flammable.. however depending on what panels you are replacing you might not even have any of the stuff nearby.

 

[vegplot]

I recently bought a plasma cutter, it's already proved to be exceptionally useful.

 

[SType Mark]

Notwithstanding the wisdom of the excellence of other posts here, my experience of plasma in the marine engineering world is that it is OK to cut the top off a lapped joint or similar if there is an air gap between the two components. (Not many of the ships I have worked on have spot-welded lap joints thought! (Maybe BP use this method for welding their Blow Out Preventers in the US Gulf though! )
If, say, you have a spot welded lap joint, you SHOULD in theory, be able to cut through the top layer and leave the underside untouched. I have not tried this with 0.9mm steel but I guess that if you are cutting away solid rust the plasma won't detect the air gap, (and will probably return to the primary arc and burn out the tip!), which SHOULD be between the steel panels and may blow away both components of the joint. Your project does not seem to indicate that degree of rust though.
I use a 10mm cobalt drill, a very finely sharpened and thinned-down heavy duty wood chisel and a lot of delicate inspection before proceeding. Safest way, especially if you want to retain the 'lace-work' as a pattern! I also have a big mechanical saw blade sharpened to a good edge which sometimes does even better. Good luck!

 

[astro_al]

Do I understand your post correctly, and you're saying it should be possible to plasma the top sheet of two spot welded together? If so, no chance without making a mess of the lower one, or cutting right through it.

Al.

 

[rtbcomp]

Do I understand your post correctly, and you're saying it should be possible to plasma the top sheet of two spot welded together? If so, no chance without making a mess of the lower one, or cutting right through it.

Al.

That's my experience too

 

[DarrenUK]

where about are you matey?
i'm in llandudno

I'm in Blaenau Ffestiniog ... not far ...

 

[wallopadonkey]

i tried to separate two spot welded sheets on the mx5 i am doing and it went through both like butter so no it will not cut the top piece only