How do I tell .005"steel from alum sheet from steel?

[Paul Gibeault]

Gentlemen, I am building some 1 oz. fuel tanks from thin .005 sheet material. I think I have tin & possibly steel. Of course, the tin solders easily with anything. The unknown material will not solder well at all with regular rosin core solder. It will however solder just fine with Sta-Brite silver bearing solder (6% I think) used with it's very strong flux. Would any of you know an easy test to tell me if the unknown material is really steel or something else? Thanks!
Paul Gibeault- Leduc , AB Canada

 

[BaronJ]

Try a magnet !

 

[dnalot]

Your photo looks like it shows a protective material on one side of the sheet, That would make me guess it is Stainless. Sta-Brite works on Stainless.

 

[aka9950202]

Instead of rosen flux try Bakers solder flux. It work for mechanical soldering. Rosen is for electrical or electronic soldering.

Cheers,

Andrew in Melbourne

 

[master53yoda]

aluminum has a fairly low melt point, about 1300F, it normally melts when trying to silver solder, iron is close to 2500F, silver solder flows at about 1100F. If you have a shard of the metal, heat it with a propane torch, if it melts it is aluminum but if all you can do is get it red hot it is some form of steel, if it isn't magnetic but won't melt it is some form of stainless.

You could also look at the sparks coming off when grinding it aluminum doesn't spark much.

Art B

 

[Paul Gibeault]

Thanks guys! You're a wealth of info.

Cheers, Paul

 

[Rocketrob]

That speedpan looks to be a real rip snorter! What engine?

 

[Paul Gibeault]

I have a much milled on latest version (3/4" crankshaft) Nelson 40 (6.5cc) Front Intake Rear Exhaust (FIRE) chromed alum. cylinder (AAC) motor. It weighs ~24 oz. without fuel & from a standing start has hit 160 MPH. It's 'potential' is quite a bit faster I'm thinking....

 

[Rocketrob]

Thanks for the photos - Not a lot of airplane there for a Nelson 40!

 

[Paul Gibeault]

NO there sure isn't! Mine is the most "minimalist" area model there whilst still remaining stable. The acceleration is so quick off the ground the launcher guy has to leave quick as the model will be by in ~ 2 seconds! It pulls an awesome amount on the handle end too. Safety pull test is `63 pounds before every flight. It's last flight can be seen at maac.ca. Look for the Control Line Committee, & it's flight video is there if you have such an interest.

Thanks for the photos - Not a lot of airplane there for a Nelson 40!

 

[Rocketrob]

They don't even give the pilot a pole to brace on? zThe SR-71 rocket is no slouch either!

https://www.maac.ca/en/committees_details.php?committee_id=14

 

[Paul Gibeault]

Thanks Rocket: Unfortunately, the normally solid steel pylon pole had been ripped out of the ground by big 300 lb Joey Mathison on a previous Open Jet speed flight... THAT's what lead to me wandering from center & flying into the safely netting....the F-40 record was SOoooo close. OUCH!!

 

[Rocketrob]

Joey.......