Butt Joint Question

[JoshStratton]

You know, the only way I know that I am making progress on my project is that questions keep popping into my head the further I go.

I have welded 2 sheets of steel together using a butt joint. I have a large 4 or 5 inch overlap that, while presenting a nice support, is also in the way. Do you normally flip the piece over and weld up the hanging side of the joint, or cut some of it off?



I am going to need to cut a 4 inch hole right in the middle of it and am not quite sure how to handle it.



Oh yeah! I am getting some Blow-through from time-to-time. Can I reduce this by slowing the wire speed just a bit?

[Matt@RFR]

Hey Josh. What's the application?

I am getting some Blow-through from time-to-time. Can I reduce this by slowing the wire speed just a bit?

Yessir. Remember, wire speed directly controls amperage output, while voltage only controls arc length.

[JoshStratton]

I am fabricating a new tail panel for my 79 TA

Thread showing parts

I have the tail lights kind of cut out. The edges are rough and need touched up and the whole thing isnt exactly pretty yet. I have done this whole thing with a metal brake, cut-off disc, dremmel and a roofing hammer. DONT LAUGH! I lost my body hammer when we moved

I will try to take some pics when I get it cleaned up some more.

The hole I need to cut is for the gas filler. I also did the whole thing in 2 pieces because it was easier to build one side and then mirror it for the other. Well, that and the fact that my metal brake is only 36" and this thing is at least 45" long.

[Matt@RFR]

Got it. Yeah, I'd definetely tie up that lap weld. You don't have to weld it solid, but putting, say, a 1/2" weld on both ends would be a good idea.

DONT LAUGH! I lost my body hammer when we moved

What's a body hammer?

Concerning putting that 4" hole through double wall, a hole saw will do it, as well as a jigsaw, and plasma's cutt double wall reasonably well.

If you do it with a jigsaw or equivalent, drill a bunch of holes tangent to your cut line, and then saw inbetween each hole. Lots faster that way.

[JoshStratton]

If you do it with a jigsaw or equivalent, drill a bunch of holes tangent to your cut line, and then saw inbetween each hole. Lots faster that way.

Oooooo great idea!

I wasnt sure how I was going to manage to get it cut out. I have a jig saw, but I was just going to get some more cut-off wheels for my Dremmel.

Ok, so here is ANOTHER question

When I cut the hole out, I know it wont be very smooth. Most of my cuts are kind of rough. How do you smooth something like that out when it is in the middle of a piece and keep it looking like it was punched out all nice and purty-like?

Here is an example of what I mean, sorta.



Those edges inside need cleaned up and they are hard to do. I may get a tail panel from a 69 like Travis (i think) suggested and weld the holes in, but just in case, I would like to figure out how to smooth these down.

[Matt@RFR]

Go to www.mcmaster.com and type look at the top of page 2523. Those stones have a 5/8-11 female thread and they simply screw on to your angle grinder. I've got many, many miles behind those damn things, and they work really well.

Either that, or just use a die grinder with a double cut carbide cutter. The grinding stones are much easier to control though. And faster.

[JoshStratton]

How do you use those and not put little gouges in the steel? I tried using a small one with my Dremmel and it just made little divits everywhere. I tried clamping a piece of hard, thick steel to the edge I wanted to smooth and then grinding down the smaller stuff. That made it look better,but still not clean. They do look much bigger than a dremmel attachment. Is the key to have something with a large surface area?

[Matt@RFR]

Is the key to have something with a large surface area?

Ding ding ding! That, and some power will get you places.

I used a dremel once.

[JoshStratton]

Ding ding ding! That, and some power will get you places.

I used a dremel once.

I really like my dremmel, but it is not very practical for cars. It does help getting into small areas, but I think that is about it.