under body sealunt

hi guys, i want to protect the under side of my disco iv'e got underseal for the chassis and floor but what do you guys use on your axels i thought about hammerite but was told by a local fabricater it will eat into the smallest amount of rust starting holes, your thoughts please

channi said:

i thought about hammerite but was told by a local fabricater it will eat into the smallest amount of rust starting holes

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I'd like to know the chemistry behind that statement... I painted the front axle on my 88 about 8 years (or so) ago with hammerite, and it's fine - yes, there are little patches with some surface rust showing but that's because it's been knocked about a bit over the years.

I would go with paint, a paint that has a high mechanical strength and will stick to metal (or over a suitable primer). Prepare the surface the best you can, ideally - remove, strip, blast then paint - in reality - give it a wash and a good rub with a wire brush, let it dry then paint it.

What's the next line of crap to be offered up then? My money is someone will try to perpetuate the myth that waxoyl prevents rust

I must say, I'm not a fan of other underseals either...

+1 for Hammerite. My boat trailers had liberal coatings of it and it was pretty good. Just don't mix it with other paints or use it on galv stuff or it will peel off.

As long as you treat any rust with Fertan or similar, paint properly with a couple of coats, then add underseal in the form of waxoyl or similar, it should last you a couple of years. Just remove the old waxoyl then and re treat. There's not really a better option save galvanising everything or on an axle you can powdercoat them I suppose if you are flush. My axles are waxoyled and it's kept them tidy underneath.

i dont know the chemistry behind that statement thats why i asked it

cheers ronsealdeath so hammerite should be ok just need to clean it up as much as i can before paiting

I recently done my axles.

Firstly I stripped them back to bare metal. Combination of flap discs and wire brushes done a decent job.

Then welded on my own personal design HD diff pan. (this bit is optional)

Treated all rusty bits (like around the radius arm/trailing arm mounts etc.) with fertan.

Used a zinc phosphate primer. (2 coats) used this stuff.QD Hi Build Zinc Phosphate Metal Primer Paint | www.paints4trade.com

Then gave it 2 coats of black. (bought the black from the same place linked above)

Even after plenty of off road abuse this weekend just gone. The black has chipped off the diff pan admittedly but the primer is still holding on strong. No bare metal and I hit the diff pan hard at one point.

Will just require a touch up and will be like I done it yesterday again

I've never seen an oily bit of metal rust so slap on some used oil every couple of months and it will repel just about everything.

crashbox said:

I've never seen an oily bit of metal rust so slap on some used oil every couple of months and it will repel just about everything.

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Including following motorbikes