I’m going to make a start prepping the underneath of my nc this weekend ready to under seal it and was just wandering if there’s any good guides to follow. Thanks
Thanks guys I’ll have a good read through these
To do it properly you really need to wash the underside and have it thoroughly dry before starting as otherwise you will tend to be coating over salt and road muck with any wax products. This is for the areas that arent easy to check or access like perforated subframe and brace members. Ideally you would want to do this in warmer summer weather when the products will flow and creep better.
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Thanks mk375
Reg,This is a project Ive also undertaken over the last couple of months.
Is any previous underseal present ? If so as mine has I yesterday used my Vax steamer to clean the underside. the steam was good enough and I used no detergents.
For the suspension arms I opted to use a wire brush fitted to my pistol drill with pretty good results.
Rear subframe was buffed with 4" flapper discs to pretty good effect.
Ive ordered Dinitrol for the main section of underbody.
The suspension arms were coated with ‘Buzzweld’ products…rust encapsulator and W.A.R and will be further coated with several passes of Motip anti gravel.
I as others have, advise you to remove chassis braces as the unseen surface will be rusted, especially the rear subframe braces. These braces are almost £52 each so its worth saving them.
Beneath the rear crash bar is unpainted from factory and will also be rusty.
Bottom of boot needed some attention also after removing heat shield.
I also found rust under the rear deck plates.
Not sure age of your car , mine is an 06.
Few pics of my efforts.
Been on a while, but I need to be thorough as Im treating her to a respray in near future.
Thanks pale rider you’ve gone wild there mate good work 
. I’m fairly lucky mines one of the last mk 3.75s on a 15 plate so its in pretty good condition underneath so just a clean down treat any areas I find then underseal. I’ve got the mx5 dinitrol kit with the cavity wax etc and luck to have access to a ramp when I want which is great . Good work there mate
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My Dinitrol turned up today 
cavity wax and underseal… working though until weekend so its on back burner.
Unfortunately for me its axle stands, on my back and probably a black sticky face when I emerge 
Yes me to, probably start Friday afternoon. I remember doing that with my old 200sx years ago its satisfying once it’s done though isn’t it .