Help please for a nugget !

[S-Rail]

Evening all , I getting closer to putting the roof on my workshop and that includes some welding , I have someone doing it for me as I cant Stick weld for the preverbial !!

Anyway , I need to weld some mild steel 100 x 50 x 5 box section together , end to end ,all angled work . There are plates to weld on and they are 5mm too .

The question is , what size rods and what type , I have an R-tech 160 tig / Arc unit so have plenty of umph . Sorry if this is a dumb question but trawling the site , I see 2.5 and 3.2 rods are common but would like to get this right as the proviso of a free welder is that I have everything ready and the kettle singing for him .

Thanks in advance for any help

cheers Sam

 

[Bill Edwards]

3.2mm. Either 6013 or 7018, the latter being stronger but not as easy to use, and arguably overkill.

 

[the snooper]

If you have someone coming to do it for you with stuff you've provided, would it not be a good idea to ask them what they recommend seeing as you're buying it ..

Not always I know a guy that had someone weld his car up for him he gave the guy some money to buy rods and although it eventually passed the mot when I was talking to the car owner he said I could have the remains rods quite a lot still.in the box, they were gouging rods I've never had cause to use them so they have been sat on shelf eversince

 

[Spark plug]

If I was doing the job I would use 3.2 7018's.

But as has been said you would be best asking your welder.

 

[HughF]

I'd use a mix of 6011 and 7016

Ask him what size and brand he wants and then buy them.

 

[BrokenBiker]

3.2mm 6013 will do the job providing the welder knows what he is doing, in which case he should know what rods to use...

 

[S-Rail]

Thanks for the help guys , He is a profesional welder , tig primarily but can also Stick , I do trust him with his ability as have spent many an hour with him on site as he worked for my late fatherinlaw and his work is second to none . I was primarily asking as I have a box of 2.5's that I bought too practice with and wandered if I would of been able to use them before I buy more .

To give you an idea of what we are doing I have attached a pic below . There are 4 of these plus end details . The roof it carries is cedar shingles and timber framing so not a heavy structure , except when under snow loading . I will post up some pics when under way , currently working on the frame and clading , I hope to crack on with the roof next weekend as my mate is tied up until then , wish I had mig to hand otherwise I would just crack on with it .

 

[decepticon]

hi ask him what he wants to weld with seems a good idea

your structure seems overly complicated, could you use a bigger box section (add a small haunch if nec) and remove the int'l bracings? would look cleaner underneath.
the tension sections will be complicated to get tensioned.

Keep the thread updated with pics of welds and finished roof


Cheers

Neil

 

[PTvor]

To be honest, if he's a professional welder, I'd expect him to come with the rods of his choice or at least to tell you what to get.

This looks like a fairly costly piece of work in time, effort and money, and the savings from using up a part of a box of electrodes you bought to practice don't really figure in the scheme of things.

 

[Richard.]

I'd use a mix of 6011 and 7016

Ask him what size and brand he wants and then buy them.

Why 6011 for 5mm box. I'd square edge it as its only 5mm. A low hi will have no issues with that square edged.

 

[HughF]

I'd us the 6011 for tacking up and for any iffy fitup. Also, I just like them

I'd square edge the job too.

 

[S-Rail]

Thanks for the continueing guidance , My real answer to the questions of why I am asking is not really down to using a box of uknown rods but as I am the sort of guy that if he is doing me a favour and giving me his time for nothing then the least I can do is have everything ready to go when he arrives . He is a prof in tig and can stick very well but as all things , he is given what he needs for work or it is already specified , and I am asking for my own purposes . The plan was to tig tack it all together and then stick weld it fully . Hopefully if all goes well we should be firing it together this friday coming / next week as he finishes early on a fri and he works sat morning and I with the winter nights being crud it severly limits me to when I can do it and also the fact my plates arent ready until wed which is fine as I have blagged another favour having them by auto plasma and again had to wait until it suited them .

cheers Sam

 

[Richard.]

Ask him what he wants to use.
Looking at the job Id probably go with a box of 3.2 7018's. He might want rutiles though so best to check.

 

[PTvor]

You could probably do it with 3.2mm 6013s and it would be fine. You could use 3.2 mm 7018s which would be best dried in an electric oven just before use.

Since it's important and structural I think I'd go for vac pacs of 7018s to get the full low hydrogen performance.

However your mate is doing the work and you want everything ready when he comes, so you'd best ask him exactly what he wants to use while there's still time to order it. If he's got some particular requirement you may not be able to get it from your local supplier and it will have to be mail ordered.

 

[Richard.]

Yeah if your buying low hi's just get em in a vac pac. Then the first session they can be used without heating them up.