by metalworker0 » Mon Oct 18, 2021 2:22 pm
The next stages are difficult to describe, they have not been done yet because of the rain. this outer sill is what people will look at ..so its important that you get it right ..or the whole job will look a co%k.
When you eventually do the second cut on the vans remaining sill, you will then then install a backing plate. (more descriptions of that when i get to that stage)
Why - (this is what they don't tell you on youtube)...because the metal is very thin and dictates this, welding without a backing plate will result in you turning the current down on the welder to avoid burning holes, this results in lack of penetration...and when you grind the weld down flush afterwards ..you'll end up with a very thin week area, that could be tin foil thickness that does not have a strong weld..and will probably crack at the seam with the slightest knock.
Fist picture: showing positioning of sill and magnets keeping both surfaces on a plane with each other. - note how the bottom flange now springs out - don't worry about this.
Second picture: shows weld in place, ..put most of the seams along the top at this stage ..do not attempt to clamp the bottom in place. the gap will grow larger at the bottom because the weld seams will contract the metal as they cool down.
Third picture shows bow - exaggerated in the pictures to get the point across. ..as you clamp the bottom flange in place - this bow which is less than 0.5mm will work to your advantage when you grind the weld down ..it will stop you undercutting the panel either side of the weld ...also remember the weld has small pits either side of it ......anyway taking notice of how things move and distort during welding ..you can pre- plan how you want things to turn out ..not have the job dictate to you as you go along . when i say bow this is a corrective bow that will hopefully put any small amount of distortion right and you;ll end up with with hopefully a perfect looking job
This does not always work out right ..and what I'm trying to convey to you ..is how i want it to happen .....it worked at 100 percent on the other side . and I hope it works out for you .
Doing it this way will result in a better stronger job with absolute minimum of filler
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