sheet steel

[Richard V]

Hi,

 

I am trying to source some zinc plated steel for the ongoing chassis repairs, and the future restoration of the body and chassis of my TR4. Looking at the Roger Williams book and the CTM website, it looks like I need 18swg - 1.2mm for the body and 16swg - 1.6mm thick sheet steel for the chassis. These are very reliable sources, but having made a few measurements on the car I don't find the same values. Does anyone have restoration/welding experiance who could let me know what sort of thickness, quantity and type of steel I should be looking for. Please concider that I will be learning to weld at the same time so each part may take a few attempts.....

 

Much appreciated!

 

Richard.

[marko]

Richard,

 

Just a bit of advice from somebody that looks at numerous cars TR's in the UK.

 

If you do a bad job of the welding then you will dramitcally reduce the value of the car if you ever go to re-sell it.

 

For example (and this is my opinion) a decent TR4 with no visible welding or patches will fetch between £8k & £15k retail - depending on condition.

 

If it has nasty patches and holes welded over you are looking at £4k to £6k maximum (from me certainly)

 

If you are doing it to use and don't care what it looks like underneath then don't worry - fire up the welder!

 

Mark

[Richard Crawley]

As Mark says, the quality of your welding will make all the difference to the resale value of your car. Don’t be tempted to patch repair; let in repairs using butt welds & grind off so it’s invisible. You will need a good MIG welder & plenty of practice but it’s possible once you learn the knack. You don’t need a pro MIG but buy the best quality budget/DIY MIG you can afford, fit it with a proper regulator & only use Argon rich gas (BOC Argoshield); forget about no gas welders! It’s then just a case of practice, practice & yet more practice!

 

It was a while ago but, from memory, I think the steel thicknesses quoted sound correct; I have it written down somewhere & could dig it out if necessary but I’m sure Stuart will be able to confirm fairly quickly. Zinc plated steel is obviously protected (until you cut it) but I prefer to use un-plated sheet for repairs for the following reasons;

 

• Zink plated steel can be difficult & will spit, fart & blow everywhere, not ideal for a beginner

• You’ve cut through the Zink plating so there goes your protection,

• You will grind a lot of the plating off when you dress the welds

• Un-plated sheet is far easier to get hold of & a lot cheaper

• You must use etch primer on Zink or the paint will fall off; but you should be using etch primer in any case so you might as well not bother with the Zink plate!

 

Buy a 4ft square sheet of each to start off with & cut it as required; you can get it from a steel stockist, engineering workshop or even a motor factor; a look in your yellow pages will undoubtedly throw up one or all three on an industrial site near you.

[Tr4Tony]

Hi

 

Another good thing to do is to buy (where possible) used panels and cut out the bits you need with any pattenation or tooling already in (such as floors, inner wings, wheels arches etc) ...... this makes a much better job and if you are careful makes an almost invisible repair.

 

Your also putting original metal back into the car ...... one for the concours chaps to debate how much more desirable that is ..... ! ?

 

Regards

 

Tony

[littlejim]

For mine I'm using 1mm (?20G) for the body and 2mm(?14G) for the chassis. I think I miced (?miked) it in a lot of spots to get that, and swotted up in the Williams book.

I'm up in Brisbane at the moment so I can't go and blow the garnet dust off a bit and check.

I'd never MIG welded before, so I used the first bottle of gas practicing on offcuts until I was happy with the results (penetration into the bottom bit for lap joins) by looking at the back of the bit of metal. For the chassis you want to feel confident that the welds will stick. There is a fantastic MIG welding site that has help on the above, mini videos of different welds with sound track so you can get an idea of the corrrect sound when things are right. Unfortunately up here I don't have access to the URL but google might find it for you.

'Flap' discs in the angle grinder are a godsend to rue welders like me.

I used thin cardboard and stiff paper to make the patterns, but later on found thin stiff clear plastic (menu holders from the stationery store) made life easy because you can see where to trace. I use them as visors in my sandblasting hood.

[stuart]

Im with Richard, dont bother to try and buy zinc plated sheets because as a novice welder it will drive you mad trying to work with it and will possibly put you off welding for life! Buy clean sheet steel and keep it somewhere dry. I always use 18SWG (1.2mm) for all your main body repairs and 2mm for your chassis repairs (Rubery Owen actually used something strange like 15 SWG originally)

Original panel sections will help you a lot but always have them blasted or dipped to get rid of any corrosion other wise you will be putting rust back in again.

If you are buying a new welder then try a few before you buy (Your local independent welding supplier will demo you some different ones if you ask) Avoid ones where the wire spool lays flat. You will need a 130 amp or higher to get one with decent wire speed and power control etc and always use a proper welding gas like Argoshield.

Good tip is to buy a couple of angle grinders then you can have one with a grinding wheel and one with a cutting wheel, saves a lot of time messing about climbing out from under just to change discs when you are in the middle of a piece of work Always clean off the area that you have just repaired and have some good zinc based paint like Bondorust or Zinga or Por15 etc to coat over your repairs as you are progressing because areas that have been welded will go rusty very quickly otherwise.

Best of luck and let us know how you are getting on.

Stuart.

[88V8]

Weld-through primer sounds like a good idea, as it leaves no unprotected inclusions to subsequently rust ?

 

Ivor

[Kiwifrog]

It was a while ago but, from memory, I think the steel thicknesses quoted sound correct; I have it written down somewhere & could dig it out if necessary but I’m sure Stuart will be able to confirm fairly quickly. Zinc plated steel is obviously protected (until you cut it) but I prefer to use un-plated sheet for repairs for the following reasons;

 

• Zink plated steel can be difficult & will spit, fart & blow everywhere, not ideal for a beginner

• You’ve cut through the Zink plating so there goes your protection,

• You will grind a lot of the plating off when you dress the welds

• Un-plated sheet is far easier to get hold of & a lot cheaper

• You must use etch primer on Zink or the paint will fall off; but you should be using etch primer in any case so you might as well not bother with the Zink plate!

 

Another reason to add to Richards list is the fumes given off when welding Zinc plated metal are poisonous and can lead to the zinc shakes or "zinc chills" that can be induced by the inhalation of freshly formed zinc oxide formed during the welding of galvanized materials. It will also give you the threepenny bits if you do a lot of welding of a galvanized material without a good mask.

 

Dont ask how I know

 

Cheers Alan

Edited September 17, 2008 by Kiwifrog

[Don Elliott]

Alan - Isn't good red wine the antidote for that ?

[littlejim]

I neglected to mention in my previous post that I used unplated steel, plus weld through primer. (My how to paint book advises to remove all the weld through primer before painting.)

I personally found an electric 'jig' saw the best to cut the shapes with, and backing it with MDF helps avoid it getting bent too much.

For the thinner body sheet I use 0.6mm wire (plus 0.6 mm tip in handpiece and 0.6mm roller in wire feed) For the 2mm metal I use 0.9 (from memory) wire, tip and roller. The settings are in the bottom third of the voltage range on my set.

To patch the inevitable melt throughs in the thin metal I use the lowest voltage setting to fill 'em up. Where ever you can clamp some copper flat behind the spot to be welded do so as it takes away some heat and reduces melt throughs. Not always possible on the body where there are curves rather than flats. After a bit of mucking round I ended up leaving the Argoshield set on 12L/min for everything.

I also have to light the weld area with my 500W work lights, otherwise I usually miss the spot by a few mms. I'd be stonkered without the 'auto darkening' welding helmet. I'd also be stuffed without the trolley I got with my welder.

[Richard V]

I neglected to mention in my previous post that I used unplated steel, plus weld through primer. (My how to paint book advises to remove all the weld through primer before painting.)

I personally found an electric 'jig' saw the best to cut the shapes with, and backing it with MDF helps avoid it getting bent too much.

For the thinner body sheet I use 0.6mm wire (plus 0.6 mm tip in handpiece and 0.6mm roller in wire feed) For the 2mm metal I use 0.9 (from memory) wire, tip and roller. The settings are in the bottom third of the voltage range on my set.

To patch the inevitable melt throughs in the thin metal I use the lowest voltage setting to fill 'em up. Where ever you can clamp some copper flat behind the spot to be welded do so as it takes away some heat and reduces melt throughs. Not always possible on the body where there are curves rather than flats. After a bit of mucking round I ended up leaving the Argoshield set on 12L/min for everything.

I also have to light the weld area with my 500W work lights, otherwise I usually miss the spot by a few mms. I'd be stonkered without the 'auto darkening' welding helmet. I'd also be stuffed without the trolley I got with my welder.

 

Fantastic,

 

Thanks for all the advice, I am actually starting to feel a little bit more confident about this welding. To give you an idea of what Im up against, Ive actually found filler in the main members of my chassis

 

Regarding the primer, I have been sold a weld through primer called "Bloxide" which is an aluminum based primer. It seems to fulfill all the properties of the zinc primer but is safer. Does anyone have experiance with it?

 

Richard.

[littlejim]

Late Final Extra. Memory lapses made me forget to add the following pearl of wisdom. Your welding wire comes in rolls of eleventy twelve metres or such. I get the ones that weigh about 4-5 kilos (I'm guessing, as I said I'm not at home to check) rather than the little bubby ones you can get at the hardware store. The 'pearl' is not to unwrap the wire before you get it mounted on the spindle in the wire feed mechanism.

If you are a fisherman and have had to deal with a 'bird's nest' in nylon line, you'll appreciate that unravelling about a quarter mile of 0.6mm wire after it 'sproings' off the reel keeps you occupied for a fair chunk of welding time.

The voice of experience.

You have to see under the wrap a bit to see which way round to mount the reel. You want to feed from the side furthest from the wire roller/clamp thing. That's the time to be careful. It's sitting there like a coiled cobra waiting to leap up.

 

The 'weld through' primer they sold me has 'copper enamel' written on the tin and looks like copper metal flakes in a carrier medium. It works fine. Just try the wt primer you have on some of your practice pieces and see if it interferes with your efforts or not.

Edited September 17, 2008 by littlejim

[stuart]

Most of the weldthru primers are ok but you need to let them dry well before welding and do need cleaning off at the start point of your weld, after that the heat will do the penetration for you.

Stuart

[Ian Vincent]

I use a 135 amp Clarke welder with BOC argoshield. Its fine for evrything I have needed on my TR3a.

 

I bought an 8ft x 4ft sheet of 20g mild steel from a local stockholder and he charged me £30 including cutting into thirds so that I could fit it in the back of an estate car. Bargain - I still have one piece left after lots of practice bits and having to make one almost complete panel which needed lots of trial and error. I have used galvanised sheet in the past but apart from all the issues detailed above, the galvanising process creates a zinc/iron alloy layer that is much harder than the base steel which makes it hard to cut and bend.

 

I go along with Stuart's advice on angle grinders except I have 3, one for cutting, one for grinding and one with a twist knot wire brush for cleaning things off. They cost about £15 each from Machine Mart and if they packed up tomorrow they don't owe me anything.

 

I use U-spray weld through primer but I also paint everthing with Bondaprimer after I have finished. This seems to work pretty well and I have no evidence (yet!) of rust breaking out.

 

Finally the web site that Jim mentions is http://www.mig-welding.co.uk/ it really is excellent. Look at the section on welding thin material and the technique of using short pulses of current - its an absolutely essential technique for amateurs even though the pros can probably manage without it.

 

Rgds Ian

[Don Elliott]

Richard - Here is a link to a site for welding thin metal. Scroll down to the third photo and watch the video how it's done.

 

http://www.mig-welding.co.uk:80/thin-metal.htm

[Richard V]

Richard - Here is a link to a site for welding thin metal. Scroll down to the third photo and watch the video how it's done.

 

http://www.mig-welding.co.uk:80/thin-metal.htm

 

Thanks Don,

 

I will have a good look at the site and do plenty of practice whilst trying out various primer and paint combinations.

 

Richard.