Inspector Scott
Member
I'm interested in hearing the different ways of priming the interior of the push rod tubes and what has worked
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push rod tube priming
- Thread starter Inspector Scott
- Start date
I cut a piece of foam round of the same ID of the tube, attached a string to it that came out of the end. Pushed the foam inside about 2" and filled that portion with primer. Then start pulling the string/foam slowly until it came out of the other end with a container at the bottom to catch all the unused primer.
Several posts on this in the past. I used Ardrox (Dinitrol) AV-8 preservative. Poured it into the tubes with one end capped, then let excess drain.
https://www.chemetall.com/Technical-Files/tds/TDS_00000476_1_GO_EN.pdf.pdf
https://www.chemetall.com/Technical-Files/tds/TDS_00000476_1_GO_EN.pdf.pdf
It is universally a BAD idea to paint ANYTHING internal to the engine. Paint flakes off, clogs critical oil passages, engine seizes, pilot has a BAD day. This idea is 0% benefit / 100% risk. Maybe there are different versions, but recall that my tubes were aluminum.
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I think it's more likely the question relates to the flight control pushrods for aileron and elevator.
wirejock
Well Known Member
Control rod tubes
I think about all you can do is a good clean. A rag tied to a string works pretty well. Soak it with a solvent. Pour some in the open end then pull it though slowly. Lather. Rinse. Repeat. Allow to dry.
Priming
I cut fingers off Nitrile gloves and slipped a finger over one end. Poured in the primer. Slipped another finger over the open end and sloshed back and forth till I was satisfied all the inside was probably covered. Pull the glove off and pour it out into a can.
I think about all you can do is a good clean. A rag tied to a string works pretty well. Soak it with a solvent. Pour some in the open end then pull it though slowly. Lather. Rinse. Repeat. Allow to dry.
Priming
I cut fingers off Nitrile gloves and slipped a finger over one end. Poured in the primer. Slipped another finger over the open end and sloshed back and forth till I was satisfied all the inside was probably covered. Pull the glove off and pour it out into a can.
Boiled Linseed Oil
I tried priming the tubes with spray can primer, but didn't like how much primer it wasted and the spotty coverage it gave. Now I use boiled linseed oil - just plug one end, dump in enough to get good coverage, then let it drain out and dry. Easy and super cheap, plus it lays down a great protective layer. One container will be enough for 100 airplanes.
I tried priming the tubes with spray can primer, but didn't like how much primer it wasted and the spotty coverage it gave. Now I use boiled linseed oil - just plug one end, dump in enough to get good coverage, then let it drain out and dry. Easy and super cheap, plus it lays down a great protective layer. One container will be enough for 100 airplanes.
DanNiendorff
Well Known Member
My process was different depending on steel vs aluminum push rods.
Prep for Aluminum Tube:
1) Acetone wipe/rinse.
2) Alumiprep bath.
3) Alodine bath.
Priming Aluminum Tube:
1) Seal rivet & bolt holes with rescue tape, and plug ends with rubber stoppers
2) Pour in Akzo...slosh and roll
3) Spray exterior of tube with Akzo.
Prep for non-powder coated 4130 Tube:
1) A light sand blasting inside and out. (Inside only if already powder coated from Vans)
2) Flush with solvent (acetone).
Priming 4130 Tube:
1) Powder coat exterior - if not already done (which will also cook any remaining oils out of the interior)
2) Seal up all holes with rescue tape and rubber stoppers
3) Pour in Akzo...slosh and roll
I'm sure this is overkill, but I'm completely OK with that.
Prep for Aluminum Tube:
1) Acetone wipe/rinse.
2) Alumiprep bath.
3) Alodine bath.
Priming Aluminum Tube:
1) Seal rivet & bolt holes with rescue tape, and plug ends with rubber stoppers
2) Pour in Akzo...slosh and roll
3) Spray exterior of tube with Akzo.
Prep for non-powder coated 4130 Tube:
1) A light sand blasting inside and out. (Inside only if already powder coated from Vans)
2) Flush with solvent (acetone).
Priming 4130 Tube:
1) Powder coat exterior - if not already done (which will also cook any remaining oils out of the interior)
2) Seal up all holes with rescue tape and rubber stoppers
3) Pour in Akzo...slosh and roll
I'm sure this is overkill, but I'm completely OK with that.
I prepped the inside of my aluminum pushrods by attaching some scotch brite to the end of a wooden dowel rod long enough to go at least half way into my pushrod. Then I rigged the opposite end so I could chuck it into my cordless drill and spun it while moving it in and out of the tube. Worked really well.
