Welding a rocket launcher

[timddo]

Well i've just got about everything i need to make me own launchers.

1. pipe bender i have
2. stainless welding rods ( gonna arc weld the launchers)
3. 50mm tubes i have


Budget for the launcher will be $200 for 2 by 6 meter pipe in 20mm 2.11 mm wall or OD of 26.67. Prices are from tubesales near jacobs well. Pm if you know a cheaper place

Next is to get some flat stainless steel 40 x 3mm or 40 by 5mm in half a meter 40cm lengths.

Should cost no more than $20 i hope.

I'm intending cutting it up and bending it to the right angles and attemp to weld them. Have tried some welds on scape stainless and it's pretty good.

But if all goes bad ( my backup plan is to take it to a welder to weld the steel together ( should be free as the workplace as an engineering section).

But the question is should i buy 316 or 304. ( 304 cheaper by half price).

All up it should cost me say $270 to build.

[sid_fishes]

tim mate 316 is the only way to go, but i have to say can you send me pics of the outcome please as i would not attemp to arc weld any tube

[adaml1754]

mate I suggest staying away from 304 stainless, as i was told it is mainly for fresh water environments, all we use at work is 316. we also use an acid called pickling paste on the welds it gets rid of the mark left by welding that looks like rust if its left on.

[Hebb]

Mate i think you will have trouble welding that up with arc welder, Stainless workhardens very easy and is prone to cracking under stress and arcwelding will put a lot of heat into metal further reducing its strength. TIG is really the only way to go to get a good strong job. (and very neat too). I welded up some cracks in stainless rocket launcher with stick welder and job turned out ok but they just cracked on weld again. When I had a boilermaker repair it he had to grind every bit of my weld out because he could not tig onto the weld metal the stick had left. Keep your amps real low only use 2mm sticks when welding that pipe as it is very easy to blow holes and make sure you brace it cause theres nothing worse then seeing your prized rod go overboard when weld fails.
darren

[sid_fishes]

tim another thing also , pack the tube/pipe with sand and tape the ends before you bend it, it will stop the bends crushing and looking like shit . cheers ian

[timddo]

thanx's IAN

Will do that sand in the pipe thing, Also about cracking - i thought once you do a good weld it won't crack???????????

I will try a few joins this weekend

[Noelm]

nope, as mentioned, it can certainly crack, and Stainless is quite easy to weld with a "stick" welder, but not so easy on thin wall pipe, especially if the cutting and fitting is a tad ordinary, a lot of Professionals weld Stainless with Oxy, which sounds a bit funny, but it works really well, and as mentioned, it will need to be thouroghly cleaned and "pickled" to prevent "rusty" stainless.

[sid_fishes]

yes it will crack, because of the heat you put into it, and the fact that it is constantly vibrating the welds will fracture in time cheers ian

[ozbee]

pre heat both materials change +and- terminals around and clamp positive earth to pipe this will help the metal flow up towards the tube without blowing . let cool naturally watch eyes for flake pinging as cooling .other wise take to someone with a mig or tig. angle your rod onto the flate plate which i presume is far thicker and lift slightly till it wants to attach it self to the tube.