'Rufus Maximus' - Build Thread

[mat in tn]

I'm guessing the argument may have gone "it's not like the air is not ending up in the same cab anyway". I do like the air at least directed in the proper directions. the big ones for me are the areas with the open cell foam as gaskets. between the lower and upper duct for defrost. and then the ones where the dash vents fit the duct.
whether it was open cell or closed cell by design, after thirty years of heat cycles (seasons) its open cell at best, if it's not dust.

[Danny G]

It's the same deal that happens in offices where you see dirt plastered to try ceiling near vents. Basically you are sucking the dirt from your floor mats and carpet into your ducts and face lol.

ArdWrknTrk said Gary may have the terminal part numbers so that puts me back on track for the ford box.

I just need to sort a dang alternator out now

[Danny G]

Took it easy today spent time getting out spare room organized and ensuring my parts were protected bagged, tagged an organized. Now I'm hanging out in the living room trying to distract myself.and get this last set of ducts cleaned up. It's the big one. It looks like these rivets are going to need to be drilled out to access the blend door and repair it.



With that said I did discover an easy way to check these vacuum actuators is simply depress the lever. If it shoots air out the pipe then it's in good shape.

[mat in tn]

I do not drill out these rivets! instead, I only remove the rivets at the blend door itself. the folding plastic "hinge" seam is what breaks leaving the mount. this mount strip has a metal support on the inside.

[Danny G]

Sounds good.

Talking about broken plastic. This hot stapler is one of the best investments I have made for everything from toys to car parts. I even fixed a crack in my shop vac frame.

Couple of wave fasteners to set the two broken pieces.



Then a combination of 0.6mm staples to stitch it together. It's completely rock solid.



All on the outside of the sealing area less one on this corner. Next to cut the tails

[Danny G]

You definitely need some solid flush cutters or some transverse flus cutters to get these as flush as possible and not destroy your tool.



Next trying to use a plastic welding iron to smooth this out.

[Danny G]

Smoothing out the plastic that volcanoes up back over the staples helps reinforce the joint even more.

I need to take a few mini files to clean up any tail left behind them a bit of fine sandpaper to clean up the look of the plastic. No plastic was added as part of this repair.

[Danny G]

Smells bad man .. but this panel that was burned up from a fire inside the AC evap coil area is now whole again.

Combo of hot stapler and plastic welder.




The gap will this hole was to melt the existing plastic back into place. You will see over the pictures it be melted down, then a wire screen embedded in the back. This part takes two hands. One hand holding cold needle nose pliers and the other the iron. You want to sink the wire mesh into the existing material. Kinda like rebar in concrete. Therefore the plastic must be allowed to cool. Enter  needle nose pliers. Heat it up the plastics come through and hold.it with the needle nose. Wash rinse repeat. When that's done run the iron over to smooth the material into the mesh.

After that the rest of the plastic bubble can be melted down, smoothed out and forced into the mesh.  The side where the bubble was pushing out has no added material. The back where the mesh was added has some added plastic.

When all is said and done, you don't have to leave it like this. Some sanding and buffing and it will smooth out more like normal plastic.











Even decided to rebuild this ridge.

[ArdWrknTrk]

Forgive my ignorance but what kind of plastic is this, polypro?

[Danny G]

Not 100% sure what Ford made these out of. Plastic welding rods come in all types. PP, PE, TPE, PU, ABS, PC and Nylon.

[Danny G]

mat in tn wrote

I do not drill out these rivets! instead, I only remove the rivets at the blend door itself. the folding plastic "hinge" seam is what breaks leaving the mount. this mount strip has a metal support on the inside.

Soooo...... I drilled out the rivets. A sharp, lubed cobalt 3/16 bit on the tail side made quick work with no spinning.

Reason behind it.

1) Replacing them with bolts or plastic trim fasteners means easy repairs in the futureif needed
2) I can now replace the degraded foam
3) I can replace the degraded butyl seal
4) easier access to the damaged door so I can fix it and so I can put new foam on it as well.
5) it's been really hard to clean the inside of this duct 😂 would have been much faster if I did that first.

Also those fender washer nut things, WD40 and a pair of needle nose and twist back and forth with upwards pressure and they come off pretty quick.

[ArdWrknTrk]

Well the door panels and kicks are ABS almost certainly
Acrylic, nylon, polycarbonate and polyester are definitely out
PE & PP can be a little challenging to distinguish from each other.
Usually TG is the easiest way, though technology is getting better every day.

[Danny G]

I have a cracked pillar on the other truck I kept the pieces to and I am thinking I can hot stapler that from the back then the seam should be clean or small enough that a coat of paint hides it. Worse case prime and texture then paint.

I tried ages ago to fix a dash mount with abs and epoxy.

The hard plastic trim and dash is probably ABS. Can check with acetone. This is most likely why they crack.The black plastic ducts and the door panels are most likely some form of PVC. You don't want to use ABS where there is fire/heat, fuel, oil or where it needs to flex.

[ArdWrknTrk]

Seemed too 'waxy' for PVC.
A drop of 2 of methylene chloride would definitely tell you.

Maybe my '87 is completely different from a an '86 AC truck?

[Danny G]

I've been pondering this door yesterday.


Firstly obviously this was covered in foam that was heat embossed to the plastic. The notch on the edge makes me feel like it was actually a sleeve.

Secondly is the hinge repair. This hinge fails because of plastic fatigue, temp swings plus constantly flexing is bad. But there are no physical hinges like Ford used on literally every other door.

I don't want to use a piano hinge. So after much thought I decided I wanted to use a fiber reinforced rubber product. Silicone or neoprene rubber(not foam) fits the bill. I went with the latter. It remains flexible in extreme temperatures, is resistant to automotive fluids and is durable enough to be used in motor belts etc.

The plan will be to bond it to the plastic with both adhesive and physical retention to form a hinge. Then cover the entire door in a new layer of foam.

[ArdWrknTrk]

Chris Huske 3D prints a repair hinge for these.
He & his partner took the time to make sure the geometry is correct.
You can see it in the marketplace.

[85lebaront2]

I cheated on Darth, he has a 1996 inside duct which has a more normal pivoting door.

[Danny G]

There is a thought.

Does it have the metal bar through the middle like the others?

[Danny G]

Lat night delivery.

I got my resistors today. They are 100W wire wound resistors with aluminum heat sinks. I think this is a fair compromise for the resistance wires in the design and safer IE it can get hot but not going to have a wire catch on fire and shut the system down.



I was unable to find a single resistor that met the 720 to 810 mOhm range so I figure I will pin and solder these then most likely mount them directly to the fender near the future fuse box. That gives it a bit more heat sink as well.

[85lebaront2]

Ok, what are the resistors for? You need to be careful mounting anything that gets hot to the inner fenders, they are plastic.