What metal do I need

[miles and jules]

Hi guys...my first post

Just got some sheet metal today that is 1.2mm thick. I asked the guy if he had any that didnt rust...so he said this zinc/steel sheeting didnt and that it wasnt a zinc coating either but a mix.

So I am wanting to know what this is properly called. I'm wanting to know so i can try and track down some 6.5mm tubing in it.....also if you have any suggestions of where to track this down, that would be cool ...we are in brisbane-ipswich area

Thanks
Miles

[Metal Head]

Hi guys...my first post

Just got some sheet metal today that is 1.2mm thick. I asked the guy if he had any that didnt rust...so he said this zinc/steel sheeting didnt and that it wasnt a zinc coating either but a mix.

So I am wanting to know what this is properly called. I'm wanting to know so i can try and track down some 6.5mm tubing in it.....also if you have any suggestions of where to track this down, that would be cool ...we are in brisbane-ipswich area

Thanks
Miles

Hi Miles,

Any chance of a picture(s)?

[Wood Butcher]

Well there's
-Zinc anneal
-Zincalume
-Galvabond

You won't get 6.5mm tubing in any sort of those. You may get it Copper or Stainless

[miles and jules]

Hi...wow that wa quick ... thanks for the replies.....I cant send a picture as the metal is at our shed....

We could probably go to 8mm tubeing would that be possible in one of these metals
-Zinc anneal
-Zincalume
-Galvabond

I think it might be zink anneal......it was about $50 for a 2.4mx1.2 m sheet. Copper is problematic as it reacts with latex foam(which will be covering the metal.....I guess we could seal it with epoxie or something.

Stainless is a bit of a nightmare to work with for us...we need to tap it aswell. Aluminium is not tough enough. What else could we use?

[Wood Butcher]

I don't think you'll get anything that size in steel. What about Aluminium?

[miles and jules]

Hi ...Yeah we tried alluminim today(are there different grades of aluminium?)...but we need to tap it and put a screw in it and it just threads when we tighten it. So we are really after any mild steel-like tube that we can tap easily that doesnt rust and isnt copper.

It would be really great if we could get tube in this same zinc stuff we have in the sheeting.

These guys look like they have small sizes in stainless http://www.spec-net.com.au/links/link141.htm

[Wood Butcher]

I haven't seen galvinised tubing that small in any of the trade catalogues that I have.

If you can divulge what application you are wanting to use it in then maybe the collective knowledge here may be able to give you a bit more advice

[Sterob]

There are heaps of grades of Aluminum. Google it and you will find them, mainly in the 6000 series, but I think there is also at least one grade in 7000 series. ( I got some to make a top triple tree for a motorcycle)

[Andy Mac]

Welcome Miles, hope you enjoy yourself around here.:)
I'm a bit confused about what you're trying to do...tap a thread down the guts of the tube, or on the outside; or tap a hole you've drilled into the tube?
Sounds like you might be breaching any rust-proof plating anyway, by adding a screw or bolt. Can you use pop rivets or something, so there isn't the chance of cross threading? They are removable if need be.
Otherwise is there any chance of finding what you need in plain old mild steel then coating it somehow?

Cheers,

[miles and jules]

Hi Andy
Yeah we are taping a hole in the side of the pipe so we can turn a screw and lock aluminum wire inside the tube by turning a screw on the outside. The thing with this zinc sheeting we got today is that they recon it wont rust even where we cut it. So it seems like it isnt a coating but its all rust proof.....Which is cool for us. It would be cool if we could get it in tubing. We will give the same place where we got it (hands steel)a call and see if they have it in tubeing but i think they said they only have it in sheeting. yeah...We might have to try mild steel especially if we can get it in the right size.

[DJ’s Timber]

What size is this screw? You might be better off brazing a bush onto the tube then drilling and tapping a thread. Any tubing in that size will have a very thin wall thickness and you will most likely strip the thread after a couple of times of loosening and tightening it.

[joe greiner]

Tapping a hole in the pipe wall is an additional constraint on your choices. For best performance, the pipe wall should be about the same as the thickness of a nut for the same size screw. I don't think you'll find a combination of such a wall thickness with your proposed pipe diameter. Such a material would be called a "hollow round bar" - likely available in limited materials, and still maybe not in your needed combination.

How does the sheet metal get into the act? Pipe attached to the sheet? Pipe stabilizes Al wire? A possible solution could be to attach small Al blocks of appropriate thickness to the sheet via pop rivets; hole for wire parallel to sheet. Blocks located close enough to preclude wire buckling. Threaded hole in Al block perpendicular to wire. Use stainless steel screws. For best purchase of SS screws in Al, make pilot hole for threading at root diameter of screw thread (i.e. 100% engagement), not normal tap drill for such taps in similar materials (usually only about 65%). Note I'm only guessing about your application.

Joe

[miles and jules]

Hi
we tapped the 1.3mm thick sheeting we got today and it was definatly tough enough for what we need, so as long as its no thinner it will be fine to tap. the screw size is 3mm. We tried a 6.5mm tube in aluminum and it was perfect size but as soon as we tightened it and unscrewed it a few times the thread was gone. So if we could just get it in something like the zinc/steel sheet we got today only in a tube we would be happy.

[DJ’s Timber]

Why not give stainless a go, it's not all that hard to tap especially at that thickness. You just need to use plenty of lube and back the tap out after every half turn to crack the swarf.

[miles and jules]

Hi
Yeah there is a place on the way down the coast that sells stainless at this size so we might have to give that a go.

Thanks
Miles

[NCArcher]

Not sure what you are attempting to make but you cannot get zinc/steel tube in the size you want.
The sheet you have is most certainly 'coated' and will rust where cut if left untreated assuming it is exposed to the elements.

[miles and jules]

Here is what we want to do I hope i sent this diagram correctly. The plastic buffer is to cushen the wire when it is moved. The wire gets replased when it snaps.

thanks
miles

[Ashore]

Hi ...Yeah we tried alluminim today(are there different grades of aluminium?)...but we need to tap it and put a screw in it and it just threads when we tighten it. So we are really after any mild steel-like tube that we can tap easily that doesnt rust and isnt copper.

It would be really great if we could get tube in this same zinc stuff we have in the sheeting.

These guys look like they have small sizes in stainless http://www.spec-net.com.au/links/link141.htm

Try aluminium rivits rather than screws gives a better result drill straight through the tube and wire but double the wire first or tripple it whatever the tube size will hold
Rivits are easy to remove and replace simply drill out the head

Rgds

[miles and jules]

Hi
We need to use a screw as the wire needs to be replaced often. The screw needs to be tightened to lock the wire in position. Then loosened once the wire has snapped then replaced and retightened.

Thanks
Miles

[journeyman Mick]

Miles,
what about using the aluminium tube and putting a helicoil thread insert in to make the thread last? See here (http://www.engineproblem.com.au/helicoil.htm) for an overview of the procedure.

Mick

[joe greiner]

How about pinching the tube from outside? Should be enough elastic rebound to allow removal of the wire.

Joe

[miles and jules]

Hi Mick
I like ths sound of that ....where would I get one of these inserts small enough though. Maybe a hobby shop?

[miles and jules]

Hi
Actually a similar technique could be to use a t-nut inside the aluminium tube if i could get one small enough. then epoxie it into position with the t on the inside..... then when i tighten the screw against the wire the t wont be able to pull through the aluminium. i guess this will depend if they make them this small. If they dont I could always tap a small sliver of the zinc/steel then insert that in the tube.

What do you recon?

[ANTHONY62]

Noticed you are from Brisbane. You could try some of the Aerospace fastening systems available, ie RIVNUTS. They work by simply drilling a suitable hole in the tube or whatever and inserting a rivnut into the hole and actioning off like a rivet. The tail expands and secures itself like a rivet, however the centre is theaded allowing the insertion of a compatable screw- very easy process, only thing is you require the tooling to action the fastener off.

There are a number of Aerospace repair facilities around Brisbane- Archerfield and Brisbane Airport to name a few.

[Wood Butcher]

Anthony, I never thought of using rivnuts. You can alos get them from truck bodybuilders. I know that they are used to mount external fairings etc.

[Cowbz]

Have you thought about automotive fuel or brake line (steel not rubber)

[Master Splinter]

If you are worried about it rusting - remember galvanic corrosion (http://www.bluescopesteel.com.au/go/howto/avoid-incompatible-metals)!

If you end up making it out of a heap of dissimilar materials, you may end up with something that corrodes faster than plain old steel.

Stainless steel only likes to be with stainless; zinc coated (zincalume) metals dont like copper, lead, stainless and chromeplate.

Do it in mild steel and paint it. Easy to get in most sizes, thick wall so you can tap it with confidence, and cheap. Yeah, it can rust - you can probably make half a dozen of them for the price of one fancy stainless one and consider them consumable.

Or remove the idea of tapping it for repeated removal - put the screw all the way through, bend the wire as a loop before you push the wire down the tube, catch the screw with your wire loop, and twist the end of the wire to make it secure. Repeat as the wire breaks (although that sounds like a weak point if it is breaking!)

[miles and jules]

Hi guys...thanks for all the info!
Wow RIVNUTS sound perfect....that way i can keep the aluminium tube(so its light weight) Do you know any shops that carry them in bris? I'll google them.

The galvonic corrosion sounds like a bit of a worry....These armatures that we are building probably only need to stay strong for a couple of years...do you think that will effect if we used RIVNUTS with aluminium tube...i guess it would depend on what the rivnuts were made from)

thanks again'
Miles

[miles and jules]

I wonder how small you can get the rivnuts...... we wanted to use 3mm alan key screws to hold the wire in place.

[miles and jules]

Maybe we could just tap a stainless/aluminium rivet .......aslong as it still had enough thickness in the rivet on either side.

[journeyman Mick]

Miles,
how much weather/moisture will the finished object be subject to? This will determine whether galvanic corrosion will be an issue.

Mick

[Wood Butcher]

According to this website http://www.aerobolt.com.au/Products/Inserts/Inserts.shtml#AL you can get rivnuts with a M3 insert.
and they also have the tools to suit as well http://www.aerobolt.com.au/Products/Tools/Tools.shtml#toolsinserts

[miles and jules]

Hi guys
Think I will have to go with stainles due to the small amount of room inside the tube. I did a test today with a rivet and it unfortunatly filled up the tube with itself. If I just tap the stainless it will probably save a heap of problems....It woks out about $10-$15 per meter.

[Billy Bignutz]

How about making a small collet that fits around the tube and is threaded and the screw goes through a hole drilled in the side of the aluminium or whatever tube you use. Does that make sense?. If you can't make a collet then perhaps rip the guts out of a large electrical connecter (brass may react with whatever metal you use though). The screw would be then in a solid piece of metal, the collet would be located by the fact that the screw goes through a hole in the tube and the wire in the tube would be pinched against the other side of the tube which in itself is supported by the collet. Simple!!

By the way they say that the 1.2mm zincalume sheeting woun't rust when cut because it has enough zinc in the coating to self heal over the very thin edge in the same way that anything that is galvanized does when it suffers minor damage.

Good luck

Bill

[Billy Bignutz]

How about a collet that fits around the tube and has a threaded hole in it to take the screw. If you then drill a small hole in the side of the tube the screw will pass from the collet and through the wall of the tube and pinch the wire against the other wall which is supported in turn by the other side of the collet - if this makes sense. if you can't make a collet then rip the guts out of a large electrical connecter of the appropriate size - brass though so it may cause corrosion problems with the aluminium if in a damp situation.

By the way they say the 1.2mm zincalume sheeting won't corrode when cut because there is enough zinc in the sheet coating to 'self heal' over the thin cut edge in the same way that hot dipped galvanized metal will self heal over slight damage.

Good luck

Bill

[KevinR100]

My first post - wow baby...
Maybe you are a bit too young in that you believe salesmen or people who are trying to palm you off. Zinc alum. not rusting where it is cut/screwed etc. yeah...
The best way to get answers to problems is to photograph the idea/plan etc. & upload them to a place such as 'ImageShack' & then you can put 'thumbnails' or .url links to your pictures to explain what you need.
Personally I think that stainless steel is the way to go (unless you need heaps of it). If the area to be tapped is too weak then, as has been mentioned, a build up of metal (just silver solder a scrap to the area) is required. The main thing with using s/s is that you use sharp drills (about 30 degs.) & cutting tools. One day when you get around to using TIG you will find s/s is great to work with. btw marine grade alum. is quite strong - the normal grey rubbish is ultra weak.

kev

edit: billy - you get extra points fot double posting? he he

[journeyman Mick]

Kev,
I'm old and ugly enough that salespeople don't try to palm me off.:p Zincalume is "self healing". The coating will migrate to cover and protect cut edges or scratches. Obviously not suited to extreme applications like marine environments but it does work, I've seen it over the years and it is covered by a warranty. If you have information or evidence to the contrary please share it.

Mick

[KevinR100]

Kev,
I'm old and ugly enough that salespeople don't try to palm me off.:p Zincalume is "self healing". The coating will migrate to cover and protect cut edges or scratches. Obviously not suited to extreme applications like marine environments but it does work, I've seen it over the years and it is covered by a warranty. If you have information or evidence to the contrary please share it.

Mick

Hi Mick,
Unfortunately I am much older & ugly than you - sales personnel either don't see me or run the other way...
I get what you mean about zincalume but I have spent most of my life in coastal areas. Even the copper ground rusted off my meter box one day... Plus a lot of my applications were for marine environments. Also, being an ex stainless & alloy fabricator, I have a soft spot for 316 grade stainless.
I did not intend to ruffle feathers so early on here - sorry.
My main reason for joining is that I would like to buy a lathe & mill for work & pleasure that I am about to do. I have well & truely lost touch in just what I should buy. I have spent about the last 20 years on being a computer um err expert instead of machining...
kev

[journeyman Mick]

Kevin,
no feathers really ruffled, welcome to the madhouse!

Mick

[simso]

Hi, Im not really still to sure what your trying to achieve but have looked at your supplied photo. Small tube with large wall thickness is almost impsosible to find, rivnuts in an m3 may be available from the states but here in australia Ive never managed to get under an m6, also could imagine when you pull up an m3 it would rip destroy the tool installing it. Ive broken a few tool inserts pulling up m6's also for info an m6 needs a hole drilled 9.5 to fit the rivnut in. Best option would be to get some light weight gal tubing and weld a nut onto the outside so that way you have your strength for clamping down with, if the life span of the item is a few years then it really doesnt matter what you make it out of provided its not in a marine enviroment
Steve

[Barry_White]

Miles

The automotive industry uses steel tubing in small sizes for fuel lines etc. Also the hydraulic industry does.

You could perhaps try a truck spare parts place and buy a replacement fuel line or a hydraulic place.

[Woodlee]

Hi ...Yeah we tried alluminim today(are there different grades of aluminium?)...but we need to tap it and put a screw in it and it just threads when we tighten it. So we are really after any mild steel-like tube that we can tap easily that doesnt rust and isnt copper.

It would be really great if we could get tube in this same zinc stuff we have in the sheeting.

These guys look like they have small sizes in stainless http://www.spec-net.com.au/links/link141.htm


For zinc coated steel tubing try a hydraulic supplier ,some of the hydraulic steel tubing is either zinc coated or cadmium plated.