Underbody paint and cavity wax!

I have been wanting to do the same in my un heated garage. But the weather has put paid to that. I know you can warm the wax up in door, and then transfer to a bucket of hot water whilst using it. But even so I found that after 20 mins the under seal required re heating indoor again it make it brushable. So didn't even try the cavity wax due to the problems I was getting with the under seal.

I've been thinking of getting one of these: www.millarsodablasting.com/index.php?option=com_content&view=article&id=65&Itemid=53

and just blasting the curse word out of the bottom of the car. Then zinc undercoat. Then some kind of POR or other hard wearing paint.

The blasting seems a good way to get a nice clean surface without spending the next 10 years of my life upside down getting rust in my face.

Can anyone point out an obvious flaw in this plan?

^ pot looks a bit pricey, seen them cheaper. My one was £40 s/h but they don't seem to come up s/h very often. Need at least a 3hp comp to drive it.

Paint-wise, I found POR15 OK-ish but not great. Needs a rough surface, falls off smooth ones easily. And chips because it's so hard.

Haven't tried Epoxy Mastic (which I reckon is a re-badged Jotun marine epoxy, and may be cheaper bought that way). But it has had good write ups, and ought to be good if it is a Jotun product in disguise.

Mine will be primer + chassis black. It's so much easier to get a good look at it and know what's going on. Easy to apply, repair, and cheap enough.
Although I'm wondering whether to stonechip the underneath, as well as the arches and inner wings, and then slap some black over that.

in the past I've used Waxoyl and POR15, and havn't found them to be as good as the manufactuers sales literature after a 2 or 3 years on the car.

next time I'm going for Bilt Hamber products including Dynax S50 wax and Electrox primer


www.bilthamber.com/dynaxs50.html
www.bilthamber.com/electrox.html

then to top that off I'll be using U-Pol Gravitex stonechip paint

www.hex.co.uk/tds/upol/gravitex.pdf

need to try and see how I'm going to apply it yet though. says it can be done by brush, shultz gun or sprayed.

Id stay clear of underseal, as it makes a real mess when you try and remove it later, with stonechip and paint its easy enough to remove with a knotted wire brush in an angle grinder

Shop around for the pots though, the sames ones appear under a few names and varying prices. I got a spare bypass hose from Sealey for instance, it's identical to my one.

They can also be made from gas bottles. There's notalot to them at all. The MIG forum has a few home-brewed ones.

Also the ball valves are pretty consumable, but I found a place selling them 40p each, instead of the usual £3ish.