Welding a carrier floor

[Tony Smith]

UK, Can, Aus or NZ production?

I know the steel used in the Australian LP Carriers is a local alloy (ABP3) that has very different composition and heat treating to, say, the UK Armour Plate, and as a result the technique and materials (and the quality of the end result) will differ. I believe the NZ steel is also similar to Aus ABP3, and Canadian steel is closer to UK Plate, but may well be different due to the wartime availability of raw materials and production techniques.

But maybe you're working on an NZ LP1 (NZR 6, 21 or 29?? ), which were just Mild Steel and any welding technique will work!

[Andrew Rowe]

Lynn, use mild steel solid core 0.9mm wire with CO2 shielding. This is the most cost effective and best results with no cracking. It will weld any of the armour from any country, and yes use techniques that dissipate the heat from the weld zone, as David has eluded to. One technique is "backstep" welding, where you stop your run from where you last started it , if that makes sense, as it does not allowe heat to keep transferring along the direction of weld. Also use veeing the steel as well for penetration, and gap depending on thickness for sound welds, Cheers Andrew.

[Mike Cecil]

Lynn,

Instructions from the Aust Carrier Workshop Manual for ABP-3 plate repairs.

Mike

[Lynn Eades]

Thank you guys. I will try to follow your accumulated advice. This floor is from a Canadian hull. It is 3mm thick.
As an aside, the NZ Bren has a new floor made from Corten. I am not working on that.
When i tried to weld the div plate from the NZ Bren, it kept cracking, when I used the mig. That was "mild steel" (nothing like mild!) from the ship "Bowen" built in 1901. I ended up using the stick welder, and I can't remember which rods.
Anyhow I'm guessing others have patched a Canadian carrier floor.

[Petr Brezina]

Hi Lynn, I used basic rods 7016 on my British carrier with pretty good results. No preheating, armoured plates to mild steel.
I was surprised how easy it went.

[Phil Waterman]

Originally Posted by Lynn Eades

Thank you guys. I will try to follow your accumulated advice. This floor is from a Canadian hull. It is 3mm thick.
......

Hi Lynn


3 MM seems thin, check my math guys that would be .11811 inches thick that's less than 1/8 of an inch. Floor plates in CMP cab are thicker than that.


I've welded 1/4 inch diamond plate very successfully with Mig welder using CO2 or CO2-Argon with a 110 volt machine. As suggested weld in short sections to prevent warping. If you can find an old brass kick plate I have had very very good luck using them as a heat sink behind the weld to prevent warping. Brass or copper are good because the weld won't stick to them. If you don't have brass plate I've been using scrap copper pipe just slit it and flatten it out.


Another good heat sink trick is wet toilet paper scrunch up and stuck to the steel about an inch from weld.


Before and after pictures of the repair would be interesting.


Cheers Phil

[David Herbert]

I agree with all of Phill's comments but copper works much better than brass because of its higher melting point.

I must admit I thought carrier floor was 6mm but have never cut into it to see.

David

[Lynn Eades]

Sorry guys, I was assuming 3mm. It is actually 4mm.

[RichardT10829]

Pretty much all been covered, I used mig with good argon shielding mix. Weld an inch then move along say 10" before starting the next inch of weld, the aim as already described is to minimise heat soak into the job.

to add another facet to the job, I stretch my welds on long runs such as this....so weld the inch but before it cools flatten the weld with a hammer (dolly will need to be on the other side) this stops the sheet being pulled as the weld shrinks as it cools, in essence you avoid the issues of the two sheets becoming miss aligned and you putting un necessary tension into the sheets.

its a biggie especially welding aluminium, or aircraft skins which are thinner, but personally I advocate irrespective of metal thickness you do it.

best of luck to you buddy.