Underbody/chassis protection

[Farside]

If there's much bare rusty metal after removing loose flaky paint & rust (like on my 23yr old Disco 2) I'd go with ACF50.
I wait for the warm weather then jet-wash the chassis, & when it's dry a few days later takes about 30 mins to fine-mist-spray it with a £25 Fast Mover HVLP mini spraygun at very low pressure which I keep just for this. A small compressor can easily keep up.
I think I used about 300ml last time.
1litre is ACF50 is around £38. (was £26 when I bought my 2nd bottle 2yrs ago)
Also comes in a spraycan version, not tried that but think it's roughly the same deal without needing a compressor etc.
Just have to reapply every 12 to 18 months or so.
Info on here -
https://learchem.com/products/acf-50.html

Excellent stuff. I found a supplier that will ship to me.

10032 ACF50 Bottle 32oz w/Refill Lear Chemical Research Corporation

Stockist of 10032 ACF50 Bottle 32oz w/Refill from Lear Chemical Research Corporation for supply to General Aviation and Aircraft Maintenance Operators from Airpart Supply Ltd

www.airpart.co.uk

But this stuff looks interesting...

Surface Treatment - Adams Aviation

Surface Treatment - Adams Aviation offers a huge array of products for General and Business Aviation and is widely recognised as having the largest range of aircraft parts directly distributed by a European company.

www.adamsaviation.com

I'm not convinced by ACF50. Its too thin for use on exposed undercarriage. And it's not manufacturer recommended for cavities, though I can see it working in cavities. I have the stuff but use it on unexposed surfaces only.

I became aware of the power of creep when I spilled gallons of veg oil in the back of the Transit in 2002. Ten years later, there was not a peck of rust on the bottoms of the panels, where you'd normally find some.
Arthur's idea of oil and kerosene will also work, but used oil contains a bit of engine acids. How much, I'm not sure but might be enough to cause a problem.

 

[arther dailey]

Excellent stuff. I found a supplier that will ship to me.

10032 ACF50 Bottle 32oz w/Refill Lear Chemical Research Corporation

Stockist of 10032 ACF50 Bottle 32oz w/Refill from Lear Chemical Research Corporation for supply to General Aviation and Aircraft Maintenance Operators from Airpart Supply Ltd

www.airpart.co.uk

But this stuff looks interesting...

Surface Treatment - Adams Aviation

Surface Treatment - Adams Aviation offers a huge array of products for General and Business Aviation and is widely recognised as having the largest range of aircraft parts directly distributed by a European company.

www.adamsaviation.com

I became aware of the power of creep when I spilled gallons of veg oil in the back of the Transit in 2002. Ten years later, there was not a peck of rust on the bottoms of the panels, where you'd normally find some.
Arthur's idea of oil and kerosene will also work, but used oil contains a bit of engine acids. How much, I'm not sure but might be enough to cause a problem.

the other thing I found good was used transmission fluid from my old ferguson tractor , It had gone off colour by ingress of water but it worked well as rust proofer !