I have a couple of welding questions. Until now I have used extra steel to practice on but for these jobs it is to pricy to have extra parts. In the attached pictures the first one is the side of the box where it meets the roll pan. The side is in primer, the roll pan is not. What would be the best way to weld them together?. Currently they are overlapped. The welding is somewhat new for me so all steps would be helpful. The roll pan has small return edges on it. They can stay or go. Do I need a backing plate. If I cut on piece or the other, do I need to leave a gap? How much?
For the other picture, the plan is to have the stake pocket flush with the back of the box as shown. How do I weld that so it looks like one piece?
Thanks guys, I will post a build thread once I have more done. Doing this slowly as not to mess anything up.

 

With that much overlap you could use structural adhesive and save yourself a lot of time and effort over welding. I use 3M 08116 and have had very good results with it. For instance, this is a pic of the bed on my 56 showing wheel well tubs that were installed using structural adhesive...

 

You may want to do an advanced search for Ax's welding tutorial. It makes a lot of sense.

 

I've never personally used the structural adhesive, but I like the concept and many others have indeed had good success with it, so that idea is certainly worth considering. If you are sure you want to weld it, my advice would be to cut the overlap at the roll pan back until it is only about 3/4" or so and then drill 3/8" holes along the seam at 2 1/2"-3" intervals. Then rosette weld the panels together through the holes. This is a very common panel replacement technique and isn't terribly difficult to learn how to do.

As far as the stake pocket goes, that back edge is going to be tricky to get looking the way you want it to. The way I would weld it would be with standard sheet metal butt weld technique and use a series of tacks in varying areas to avoid heat build up and warpage until the whole thing is welded solid. The issue I think you're going to run into is that you're basically going to be welding right on the edge of both the pocket and the bedside and you'll have problems with one piece or the other blowing out. Even if you get it welded up, grinding and dressing the welds is going to be a nightmare to do without thinning the weld out too much or ending up with an uneven edge. You might be better off welding a piece of light gauge angle to the bedside in the area under the stake pocket and then rosette welding the pocket to the angle. You could then use filler to blend the pocket into the bedside.

I would definitely consider getting some small extra sections of sheet metal and duplicating these types of welds until you're good and comfortable with them. It would suck to wreck new parts at this stage.

 

weldingtipsandtricks.com is a great site with videos for just about every type of welding.

 

I would butt weld the roll pan by running a thin cutoff wheel along the seem with it clamped together, then re-clamping replicating the gap and start tack welding.


As far as the stake pocket, not a big deal either. Again tack welds until complete on the back edge, then dress with grinder and sanding disc. The issue is on the front edge of the stake pocket it. That would be a corner weld which will produce a rounded look. If you don't want that different look at the front of the stake you would have to do something like suggested by (what ever the hell his name is) blue O rage.


On another note I would not suggest applying filler to an edge of a sheet metal piece as it will surly crack, wrecking any fancy paint. I would weld it and grind it back flush.

 

Welding will be a challenge, but on the other hand, if you use a 'panel bond' it wont' fall off. That stuff got used on my 49's box by a former body shop guy and it is impossible to remove.

 

First I would make sure that your roll pan, and all mating surfaces for that matter, are coated with weld-thru primer. Eastwood carries it but I think that Rustoleum has better spray nozzles these days. I believe that the factory used electric spot welders in those locations. So, unless you have a spot welder, you can drill a series of holes through one panel then plug weld through those hole to secure the other panel. Easy enough to grind and fill as necessary.

Charlie's idea about structural adhesive is good providing you have a heated shop and good clamps. Make sure that your fit is good with no gaps or warps. You can always drill ⅛" holes and insert sheet metal screws as necessary in awkward clamping spots. Remove the screws and fill when the adhesive has cured. You still should make sure that all surfaces are primed. As insurance you might want to install 3/16" SS rivets in areas that are hidden like behind the bumper. You will need to use an air rivet gun but they are not expensive - see Amazon.

Also clecos are almost a must in getting a proper fit when the replacement panels do not match up quite right (and it seems that they never do) but they also require drilling holes through both panels in key spots.


3/16" clecos were replaced by SS rivets with structural adhesive between the panels. Rivet heads will be covered by sound insulation so they will not show.



Air rivet gun is a must with 3/16" SS rivets which are very tough.

 

Pete,
I think you mean 3/16" clecos and rivets, that is what you have in your picture, besides that style of riveter (I have one) will not accept nor pull anything over a 1/4".

 

Thanks Dave. You are certainly correct. I'll edit the previous post.

 

Thanks guys for all the tips. I have looked at the welding tips and tricks web site but cannot find anything related or close to what I am doing. Utube search engine and I don't seem to get along as well. For the other side of the stake pocket I was going to tack it and use some caulking seam sealer. I was told it is great and paintable. Looking to make it look like a caulking joint when done. Caulking is something I am very good at.