MGB: Puddle Welds?

Okay you welding experts, explain please. It has been six or seven years since I tried to weld what may be called a puddle weld. The two pieces to be welded are overlapped and drilled completely through with a 5/16" bit (Not sure on the size. Seems large to me) Then I was told to place the wire in the hole start welding and move out to the center of the hole. Stop when the hole is filled. OR is puddle welding the same except the under piece is not drilled and you weld the top piece to the bottom by filling the hole with a puddle?

Not to be a smart arse, but have you tried a web search? More info out there than you could ever hope for. Google reports 910,000 web pages related to the term, and the very first one is titled "How to MIG Weld a Puddle Joint"! ;)

Puddle weld, drill only the top layer and fill the hole.
Plug weld, drill thru both then weld the hole closed

[quote=bk]
Puddle weld, drill only the top layer and fill the hole.
Plug weld, drill thru both then weld the hole closed[/quote]

Thanks Bill. That answers my question. EXCEPT, I decided to do what Steve recommended. I googled plug weld and it turns out that a plug weld is when the top layer is drilled and the bottom layer is not. So perhaps "puddle weld" is just slang for plug weld.

I'm glad I did look it up [size=x-large]so I apologize to Steve for my curt answer[/size]. Now what is the proper procedure to weld a hole shut when you can't back it up with another piece of metal?

[quote="Steve S"]
Not to be a smart arse, but have you tried a web search? More info out there than you could ever hope for. Google reports 910,000 web pages related to the term, and the very first one is titled "How to MIG Weld a Puddle Joint"! ;)[/quote]

Well I was just trying to keep it in the MG community. That's why we have this forum. Probably all the questions posted here could be googled instead, but what fun is that? That kind of response makes a person reluctant to ask questions here.

Yeh, would not be much of a community forum, if every question was answered with...

GO GOOGLE IT OR USE THE SEARCH FUNCTION.

To weld a thru-hole closed, weld the edges of the hole. Point the gun to get at the 'side' of the hole (i.e., the gun won't be perpendicular to the surface/hole, it'll be as close to parallel as you can get it). Hold the trigger for a second, then move the gun a bit, put another weld there. Edges weld quickly, so you won't need to hold the trigger down long. Continue around the hole until it's closed. This works well for holes that are too small to put a patch into.

And yeah, I've always thought 'plug' and 'puddle' welding were the same thing.

[quote=comart45]That kind of response makes a person reluctant to ask questions here.[/quote]

Many people post here so much that they forget that there are better places for finding some kinds of info. In the past, I've seen web searches recommended and the poster appreciating the reminder. I even pointed out that I wasn't trying to be smart about it.

I didn't realize that you were intentionally asking MGB owners about welding, so I responded with the best resource I could think of. I thought I was being helpful, sorry.

A good practice when you are doing this is to have a piece of copper or some sort of heat sink on the back side of these welds. Use copper if you have a holw straight thru.

You want to make sure that you get real good penetration into the bottom piece of metal, otherwise, they will not hold.

If you're doing the floor pans, its best to have only the top drilled, that way you don't have to grind both sides of the metal a gazillion and a half times.

Wow, I like that large type option, really gets the point across, I'm gonna have to take advantage of that on some of my rather smart ass remarks!

B

Steve S.....No problem. I took your response in the wrong way. I did google plug welds and got some nice pictures as an extra bonus. [size=x-large]You were and are being helpful.[/size]

Thanks Steve Lyle and Brian.

Whoa, that's some big text! Kinda scared me! :D

Plug & Puddle are the same in Australia too, only difference is being 'down under' we drill the bottom panel and weld from underneath!!

All I'll add to the above wisdom is use the lowest speed and current you can to work aronds the hole and take your time. You can crank things up once the edges are sound. Copper backing works very well if you can get behind the weld. Keeps the back side nice and smnooth.

Tony

The way I do a plug weld is to start around the edge, with a slower wire feed. Once the weld is closed all the way around, I'll turn the wire feed up a notch to build metal and then fill in the center with a quick spiral motion.

Also for larger holes I got a 1" round copper pipe, about 10 inches long and smashed one end flat and slightly curved to back the hole.

FWIW....... When using a plug weld I have a copper bar that I clamp over one side of the holes. Then fill the hole with weld. The weld will not stick to the copper and leaves a nice appearance. Most times I camfer the hole on both sides so that the plug is shaped like a rivet.

Cool. Thanks guys.

So I'm curious now - I know nothing about welding, so...

What kind of body work would require a plug weld or a puddle weld?

Thanks

So I'm curious now - I know nothing about welding, so...

What kind of body work would require a plug weld or a puddle weld?

Thanks



--------------------------------------------------------------------------------


Whenever you're replacing a panel and have to 'mimic' a factory spot weld, you can use a plug/puddle weld to do it. Most of us hobbyists don't have the equipment to do spot welds the way the factory did them (which are most of the welds the factory did on the car). Or when welding on a patch. In the latter case the type of weld you do will depend on how you're fitting the patch - if the patch overlaps the part it's joining to, you generally use plug welds. If the patch doesn't overlap, you use butt (edge/edge) welds. I've put in patches where I've done both - overlapping some sections, and edge-fitting other areas.

I use a chamfered plug weld in areas where I can get my copper bar in place such as rocker assemblies. Puddle welds have worked well for me when installing floor panels and other areas that I cannot get my copper bar in place.