rate this weld ?

[Richard.]

If that pipe was 5mm thick or more I would absolutely put a small prep on it. If I wanted to I could fill it flush with one run getting penetration right down and put the second run on top as you suggest only doing which will be a superior joint.

 

[backpurge]

The danger with a small prep is that you fill the prep with molten weld metal rather than fusing into the parent metal. Now if you are talking about a proper T butt, that is a totally different joint type

I witness well over a couple of hundred welder approval tests a year and the majority that fail are MAG welds in the PB position and nearly all the fails are due to lack of root fusion

 

[Welderpaul]

nearly all the fails are due to lack of root fusion

I've heard a couple of testing guys say this.
Its a balancing act to get the right amount of penetration in the root without blowing holes or just laying a cold slug in there that tears apart under test. When i've done mine i have gone slightly down on power with the root to make it a bit more controllable and slightly up on power on the subsequent runs to push the root through a bit.

Mine have always passed

 

[Richard.]

I'm talking plate to pipe (single sided fillet)
I agree a T joint where it can be welded from both sides will be just fine square edged. Personally I would not weld a thick fillet joint from one side without a prep. I would want optimum penetration which a single V will offer. I to make my living in a similar manner.

 

[backpurge]

Richard, as your diagram above illustrates, a fillet weld doesn't have a prep, a T butt or beveled T joint does, 2 totally separate joints which would be approached in totally different ways.

Provided you are using the correct welding machine/consumable combination there is no upper limit to the size of fillet weld you can deposit without the need to bevell, used to regularly do 30mm leg fillet welds on 100mm thick material without ever having a problem but hey lets not turn this into a ******* up the wall contest

 

[Richard.]

Where on the diagram does it show a fillet weld done from one side without a prep.
Plate to pipe would be best done in the form of a single bevel T joint. Please I do know the differences in the joints. The fillet weld in the drawing is welded from both sides.

 

[Richard.]

A pipe on a plate usually can only be welded from one side only. A square edged fillet joint will be welded from both sides if it's to have any strength. If it cannot be welded from both sides then getting good penetration from the one side is key. If the material is thick you will need to bevel the pipe creating a single bevel T joint . This IMO will be a superior weld to a square edge fillet from one side only.

 

[backpurge]

That's the beauty of welding, there is quite often more than one way to skin a cat, must admit I don't agree with what you are saying but that is in no way saying that you are wrong, just a case of agreeing to disagree fella, all the best

 

[Richard.]

Agree to disagree yep. Fair play mate.

 

[dannyp]

altho most methods of skining a cat work best when the cat is allready dead, same goes for welding tecniques they all work better if you clean the crap of first

 

[owas]

At least he doesn't have to worry about warping anything

 

[normspanners]

Where has the discussion of welding plate to pipe come from?
from what I can see there is no pipe involved??
It looks to me as if they have just plated over the original base plate not a good idea because you will have two unpainted plates together so when it laminates it will push the thin base plate off ,
6mm for the bottom of a boat is a little shy anyway, I would say, that will be rubbed away in no time especially if it pushes down in local spots due to lamination , normal thickness is 10mm the one I did was 12mm to help save this problem for longer.

 

[mr migwire]

this is the post in question norm, not the origional post mate.

sadly the destructive power of a numpty is nearl alway massivly underestimatd. i have a photo of the weld that brought that home.

the numpty responsible for this one was useing a murex 400A power sorce. only after seeing it done 1st hand is it possible to accsept that someone can **** up this badly. ( this person has seen a welder before had even been to colledge and done some course and apparently told him he was good )

View attachment 56823

worst bit was if he knew he was been tested or watch he would do it right. at one point even got him to do a load of sampels and bent them round a former in the press to show what differance things make to the weld.( prep power technique )

 

[normspanners]

Sorry I see now I did a little skipping and ignored the posts about the other welds
I think whoever owns that boat has had the wool pull over his eyes, I think it is crazy to weld that plate on, as any kind of a lasting job.

 

[normspanners]

The new plate is 6mm, and the vertical is solid D section.

Also now I see that the vertical is d section basically that is the bottom rubbing strip so they are not actually welding to the sides directly
as the rubbing strip, as it is called, is welded over the side /base interphase join to stop damage to that joint by---- rubbing, on lock walls, piling etc .
In my view it is a total bodge that may get the boat back in the water but for no longer than a year or so

 

[mr migwire]

i think there are a lot of hobby welders on here could probably do a better job than that,

 

[normspanners]

It is a little like putting a repair patch on the outside of your tyre!! it may stop the leak but for how long ??

 

[julianthegypsy]

Where has the discussion of welding plate to pipe come from?
from what I can see there is no pipe involved??
It looks to me as if they have just plated over the original base plate not a good idea because you will have two unpainted plates together so when it laminates it will push the thin base plate off ,
6mm for the bottom of a boat is a little shy anyway, I would say, that will be rubbed away in no time especially if it pushes down in local spots due to lamination , normal thickness is 10mm the one I did was 12mm to help save this problem for longer.

10mm is the standard these days, but it wasn't always so. Overplating is common on older boats, but they don't put more than 5-6mm on top as it would weight the boat down too much. Bodgers just weld around the edges, properly done there should be some plug welds in the middle section too.

 

[normspanners]

don't put more than 5-6mm on top as it would weight the boat down too much

all they need to do is remove some trim ballast to adjust I would not like the bottom of my boat 6mm because of the base rubbing as canals are not maintained very well nowadays and the s**t wear the bottoms out there are a couple of canals up here that are concrete based and the boats only have a few inches of clearance so if the canal hasnt been topped up the boats wear themselves away.

 

[Gritineye]

There's a lot on the web about getting a 'stack of dimes' TIG look with a mig, and how some ignorant bosses/customers are really impressed by the look and now think a normal looking weld is somehow less skilled work.

Could it be that the welder has been infected with this malady?