“OEM” FJ40 1/2 Door Tutorial (1 Viewer)

[Rock40]

This is simply a “How To” on making a set of custom 1/2 doors using OEM door shells. If you simply can’t stomach the thought of cutting up straight doors, please read no further....

There are quite a few different 1/2 door designs out there, the good, bad and downright ugly. I feel this is the “best” shape which blends nicely with the factory body lines and allows you to use the stock latches, etc.

Here’s the finished shape:

 

[Bluegrass40]

Subscribed

 

[Rock40]

Layout. Start with the best set of doors you can lay your hands on. Finding straight non-rusty doors is becoming harder and harder. Don't let a pet jealous of your passions stare you down...

You can see the cut line scribed through the paint. This is as low as I like to go so that the OEM latches can be used. I eliminate the chrome door handles but retain the soft plastic plug in the top

You 40 series isn’t full of sharp angles and your 1/2 doors shouldn’t be either. This is a repurposed FJ80 air cleaner to make the lower radius

Making the cuts. After marking both sides out and triple checking to make sure things match and are square, I cut them using a high speed speed cutting wheel. Use the thinnest one you can find.

You can see that at some point, a PO added what was likely a goofy aftermarket mirror to the outside of the door skin. I've found that to be pretty common and it's relatively easy to fix. The cut on this one at least eliminates 1 of the 3 holes. The others will be plug welded later.

 

[Rock40]

Finished cuts. Go slow as you only get one chance to do this correctly. The better your cuts are, the less cleanup and prep that will need to be done

Turn the doors upside down and shake out decades worth of accumulated goodies. This one contained a window felt a family of steel washers and likely several pounds of dry sand

Prior to any welding, the surfaces need to be prepped. I used a high speed sander to quickly rip through the paint. An alternative would be media blasting. You can see just how many layers of paint and primer protected this door over the years

CLEAN BARE METAL is crucial for good welds. Don’t skimp on this step. I use a 90 degree air grinder with 3M sanding discs to get up inside the door also.
Now is also the time to square up your cuts if necessary and get everything nice and matched/flat between both sides

 

[Rock40]

Here’s the fix for the remaining old holes from the PO’s mirror install.

I used a piece of 18 gauge sheet metal for backing and media blasted it TOTALLY clean prior to welding.

In regard to welding. The “best” option hands down is TIG, simply because the OEM metal is about 18 gauge and it’s much easier to control the heat input, especially with a variable foot pedal.

I’ve used shielded gas MIG in the past however with .023 wire and that will work but you’ll have to go real slow and you’ll likely burn holes through it from time to time. Doable, but difficult.

All the TIG on these doors was done with a 1/16” 2% thoriated tungsten. Filler rod was added where/when needed.

This is the top cap. It’s 16 gauge, 2” wide and 36” long. It’s cold rolled steel and cut on a brake. I’d advise against using anything hot rolled as the mill scale will screw up your welds and removing the scale prior to welding is a lot of screwing around

I aligned the outside edge of the cap along the outside edge of the door. Keep it absolutely as straight as possible down the length of the door. Carefully tack weld it on both sides

 

[Rock40]

Keeping the cap straight is CRUCIAL here. Slowly tack weld it towards the first radius bend.

If you’re like me, you’ll be wishing for a second set of hands while doing the initial tack welds

For the radius bend, the 16 gauge will bend pretty easily by hand but it won’t bend tight enough to match the bend. I heat the cap (where the bend needs to be) with a simple hand torch. While it’s still hot, I use a piece of flat 1/4” steel bar, lay it over the cap and then smack it lightly with a dead blow hammer. Using the 1/4” bar over the cap will prevent any hammer marks from scoring the nice smooth cap. It shouldn’t take much force to bend the cap down to match the radius. It’s ok to go slow and heat it several times

For the 2nd bend, you should be able to push and bend the cap right down into the radius. If it resists, gently use a ratchet strap wrapped around the door to pull it into position. As you go, continue to lightly tack weld the cap in place down towards the 2nd bend. Tack it on BOTH sides of the door

 

[Rock40]

The rest of the cap should now be laying neatly along the top of the door. Continue to slowly tack weld it in place.

Once it’s firmly down, you can start to slowly weld the whole works.

This is harder than it looks. I’ve found that the Japanese steel wants to melt much more quickly than the cap. Any impurities (and getting rid of all of them is near impossible) are also going to want to burn out. As long as the welds fully penetrate and your not blowing holes in the door you’ll be fine.

The upper and lower corner sections on the doors are almost always cracked from being repeatedly slammed over the years. This door was no exception and the corner here required a lot of time and filler rod to fill the crack and repair a small amount of metal damaged/weakened by rust

Note that the cap extends over the entire door and there’s a significant portion that will need to be cut off. Just weld what needs to be welded, the rest will come off later

 

[Rock40]

Once the door is FULLY welded on both sides, it’s time for a sanding party. The cap (being 2” wide) will have extended over the inner portion of the door. I use a grinder with a pretty aggressive flap disc to rip things down. The 16 gauge will sand off FAST so take it easy.

Using the same flap disc, gently smooth down the welds on both sides of the door. You only want to sand the welds here, NOT the OEM door.

Once the welds are fairly flat, I switch to a 90 degree die grinder with a 3M sanding disc. Carefully continue to sand the welds flatter. You want to match all the inner door radius’s as you go.

Now I switch to a large orbital sander with 120 grit discs. It’ll smooth everything wonderfully and won’t remove too much metal very fast. The idea is removing ALL the high points. In the lower pic, you can see some very minor low spots after sanding which is normal. Those’ll be filled later and will be seamless

Lastly, trim the excess cap on both ends of the door. Then sand it smooth.

 

[Rock40]

Here’s a shot of another low spot on the inner portion revealed during the orbital sanding. This was the result of an old dent in the door

Pic of the inner radius’s and cap sanded to match. Everything is nice, smooth and seamless at this stage

Pic of sanded corners after the removal of the excesss cap

At this stage, the doors are ready for a full sanding or media blast, light filler where needed then primer and paint. Install and enjoy for years to come

 

[crashn]

Very nice job. I agree it takes first class prep work to get a first class finish. Can't wait to see the finished product with the paint job.
You gave a lot of great tips on each step. Excellent work.

 

[69LC]

So when should I expect delivery of these doors?

 

[Rock40]

Very nice job. I agree it takes first class prep work to get a first class finish. Can't wait to see the finished product with the paint job.
You gave a lot of great tips on each step. Excellent work.

Thanks! Unless I'm doing my own project, this is as far as I take it with bodywork. These doors were created for Jason's 66' frame off here: 1966 FJ40 Frame-Off Build (3rd Generation Owner)

 

[Rock40]

So when should I expect delivery of these doors?

Send me a set of shells and I'll send them back.....

 

[Jason Reed]

Nice try @69LC

Jason-

 

[69LC]

@Rock40

Thanks for the offer, but I now have the tig fab skills to repeat what you’ve shown. Thank you for the post of your work.

 

[brooklyn]

Great write up and pictures >> just picked up a pair of doors for this purpose.

 

[74fj40]

Over a decade ago I got a set of late model doors from a cruiser that had been rolled, I think I’m going to finally cut them down and cap them. Have you done any late doors? If so, any tips? The only real concern I have is clearancing the door for the apillar on the cage.

 

[Rock40]

Depending on your cage placement, the doors "should" clear the A pillar. I have a fully Metaltech cage in mine and I don't have any issues.

I've never done a set of late doors but I imagine they are probably quite similar. Possibly a bit more difficult because the inner door is likely more complex given the vinyl inner door piece. Doable I'm sure though.

 

[Hitoy4x4]

I have considered copying your design and making out of fiberglass myself...

 

[scott fasken]

Finished cuts. Go slow as you only get one chance to do this correctly. The better your cuts are, the less cleanup and prep that will need to be done

View attachment 1701496

Turn the doors upside down and shake out decades worth of accumulated goodies. This one contained a window felt a family of steel washers and likely several pounds of dry sand

View attachment 1701497

View attachment 1701498

Prior to any welding, the surfaces need to be prepped. I used a high speed sander to quickly rip through the paint. An alternative would be media blasting. You can see just how many layers of paint and primer protected this door over the years

View attachment 1701499

CLEAN BARE METAL is crucial for good welds. Don’t skimp on this step. I use a 90 degree air grinder with 3M sanding discs to get up inside the door also.
Now is also the time to square up your cuts if necessary and get everything nice and matched/flat between both sides

Dude-- I see flip Flops, where are your safety toe foot ware. Hey don't worry I were them year round in Colorado.

But great job on the doors.