RHS Door Frame Repairs

10/25/2021

The door frame was soaked multiple times in rust 911 to remove the rust pitting. A major life event delayed my follow through on this, but it seems we are back on track. After multiple wire wheel treatments followed by more soaking the frame was wiped down with Ospho and allowed to dry. This puts an Iron Phosphate coating on the metal and protects it from further oxidation. The coating is gray and can be removed with additional wire wheeling but some paints (NOT most epoxy paints) can spray right over top. The chemical reason for this incompatibility is that the phosphoric acid is acidic, and epoxy paints are initiated with a base, so if there is any excess acid, the acid neutralizes the base before it can initiate paint curing (polymerization).

Some pretty serious pitting in the corners, but it is still pretty solid metal. The flange is another story and will require complete replacement.

As noted in these photos, the majority of the frame is in quite good shape so definitely a solid piece to start with.


REPAIR

I decided to start repairs by removing the hinge brackets as it was clear there was sandwich rust between them and the frame. The spot weld locations are noted above, along with one spot in the middle. I used a 1/4″ spot weld drill bit to drill these out, being careful to stop as soon as I saw rust in the hole, signifying that I had drilled through the first layer of sheet metal. The two end pieces had a heavy tack weld holding them on to the inner flange of the frame.

I decided to remove these one at a time to minimize the risk of twisting the door when I reassembled. So the top one first.

I wire wheeled most of the rust and then since I could just get the frame into my blast cabinet I took a shot a cleaning it up that way. It worked partially, but I can’t move the gun or the door much so it wasn’t perfect.

The last of the rust in the pits was removed with Ospho and a wire brush. The Ospho converts the rust in the exposed part of the pit, but doesn’t quickly penetrate, so letting it sit a few minutes followed by wired brushing the black iron phosphate to reveal more rust, and rewetting a few times does a pretty good job of cleaning out the pits. Here it is all cleaned out. I basically did the same thing with the bracket and now have two clean bits to prime and  plug (rosette) weld together. That is for this week and weekend. Time to break out the welder…


October 31, 2021

Today I started re-welding the upper hinge bracket. Since the spot welds were drilled out only through the first layer of sheet metal, it was easy to line up the bracket to where it was originally mounted. In the end I chose to mount it just a bit off of so as to ensure that the play in the cage nut would allow the hinge bolt the full range of motion within the pass through hole. I want as much adjustability in the hinge as possible going into the door frame assembly.

With most of the plug welding complete on the upper bracket I removed the lower bracket. Lather, Rinse, Repeat…


11/4/2021

After soaking the affected area with Ospho soaked paper towels overnight and plenty of wire brushing the pitted rust came out nice and clean.

The top right corner of this photo is a folded piece of sheet metal, but unfortunately I couldn’t properly clean the sandwich rust. Decided to drill the spot welds and disassemble to clean it up.

The square flap under this angled piece was cut out and a new piece fabricated. Time to hone up my TIG welding skills. But first, soak in Rust 911 to remove the rust I came here to remove.


11/6/2021

After soaking in Rust911 to get the rust out of the corner area, I cleaned it, wire wheeled it, and TIG welded a replacement flap for the under piece of the corner sandwich. I could tell this was the first time TIG welding in a while, but I figured better to suck on this piece than on the door panel.

When I drilled out the spot welds for this corner piece it became quite floppy, so to make sure I had the angle right, I reinserted it into the door skin, in effect, making it a jig to establish the “squareness” of the door, even though its not really square at all. From everything I could measure this worked like a champ.

With both brackets in, the corner reworked, I just need to dress the spot welds, add a bead weld along the corner angle piece, and get it ready for the next step, replacing the lower corroded outboard flange.


11/20/2021

Next on the list was to repair the lower flange. The forward section was marked and cut out with a thin cutting (Dremel) disk. The replacement was test fitted, and filed (over and over) until it fit right prior to tack welding into place.

Here it is fully stitch welded prior to dressing it up. My priority here was to make sure the mounting flange was clean, spot weld free and made a smooth transition from section to section.


11/21/2021

Work on replacing the flanges continues. The second longer stretch was done with the TIG welder. It puts down a lot less excess metal so the cleanup is much quicker, even if the welding is slower. I have some door panel tig welding to do so this was my practice run for what is coming up.

I didn’t spend much time cleaning up these welds, I just wanted to do a quick grind to knock them down a bit.

I inserted the frame into the old door skin to check alignment and fit. I left the two flange repairs a bit long and these don’t quite fit right in the space allowed, but still pretty close. I wrote down the size of the flange at various intervals, and so when I grind it down to that original dimension it should fit fine.

I was a bit surprised to see as much waviness in the lower flange as I did. Makes me wonder how I’ll control the precise fold position once I weld in a new lower section and the reference points for the fold are lost.  I guess as long as it isn’t too big, I can always add a bit more material to get the gaps right later.

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