They'd know as well as anyone. I would guess the temperature limit on the aluminium alloy specified is probably related to corrosion rather than creep (which would be the other temp. concern) and since it's likely to be greasy rather than salty under the bonnet it would likely be fine.

I think there is a slight over reaction. The alloy selected is what has been recommended. Having spoken to several people tonight I'm confident that the alloy selected will be sufficient.

If there is another option up for sale at similar costs but with better properties then it will be selected and at the very least considered.

Otherwise, the company in concern has done numerous engineering projects including many for performance race engines and they recommended this material so I'm okay with their selection.

In all honesty going by the quality grade of some the metals used in Datsun engines, the alloy used in the inlet manifolds couldn't be any better than what has been selected.

If you have any objections in material selection please PM me and I'll prepare your refund. Having said that, I'm willing to put my neck on the line and insist that this be the material. It is more than sufficient and it is certainly suitable.

I did materials several years ago and haven't touched them since, although I could explain crystal structure, the way metals creep by grain boundary sliding, or something like that. What I couldn't tell you is what is common I'll go have a flick through my materials book anyway. You might want to have a look at capral.

From memory the cast stuff in your manifold has silicon and maybe tungston or manganese or something to stop it cracking. I'll get back in a while. It's all a bit hazy in my memory.

Righto, no word back from the bloke today, I didn't pursue it though. Bit busy with uni.

Sorry guys, the alloy ones are a bit of a balls up, I didn't think to mention it earlier.

I need some suggestions so as I can ask him what material he stocks. Do remember these are for our ancient push-rod motor's so we aren't looking for aircraft quality alloy (unless you are prepared to pay).

So Mark, as a fitter and turner you suggested Alloy 5183?

Lam_daiquiri is a mechanical engineer, he might have some input?

Maybe sikyne, lagwagon or boofhead can suggest a material?

I need some suggestions so when he calls tomorrow and lists his stocked materials I can say, "yep, that's the one! we'll take that instead".

Anyone waiting for last orders the Alloys are still open for additional numbers.

Extreme applications for this alloy are corrosive environments such as salt water or very cold temperatures as its used mainly in cryogenic situations.

It melts at 570 but after some research it corrodes rapidly at temperatures above 65...

Any one have the actual MSDS from an Aussie supplier while I wait for my response.

No offense the internet extracts are good but need something a little more authentic and 'closer to home'.

So this is the stuff boat-builders use? My old man would wrap a spanner around my head if he found out I didn't know the properties of this material


EDIT: e funk that link says it's melting point is 570 celsius, pretty slack threshold if it's not recommended to go over 65C huh? Will see what the supplier says.

Perhaps it doesn't respond well to heat when it is cyclic? It is quite contradictory: 'it is known for exceptional performance in extreme environments ....but not recommended for use in excess of 65degrees', which seems low temp.

"Background
Aluminium 5083 is known for exceptional performance in extreme environments. Aluminium 5083 is highly resistant to attack by both seawater and industrial chemical environments.

Aluminium 5083 also retains exceptional strength after welding. It has the highest strength of the non-heat treatable alloys but is not recommended for use in temperatures in excess of 65°C."

"Mg 4.0-4.9%"
http://www.azom.com/details.asp?ArticleID=2804

Righto well we need to decide pretty soon whether it is okay or not. One says yes, one says no. Supplier says it's suitable.

I have contacted the cutter and he is consulting his supplier for a confirmation on it's suitability, he is also sending the MSDS for that specific material supply line (not something pulled off the net).

Can we have some more opinions?

You mean higher Magnesium content retrorally?

5083 has around 5.0% Mg but only 0.1% Cu.

It pretty much only consists of Al and Mg (plus minute amounts of impurities).

Now 5083 is not the best alloy for this job (inlets)...hate to say it.

It is the strongest non heat treatable alloy but is not recomended in applications exceeding 65*C. However, just for reference - if you were to weld it 5183 is the best filler alloy.