Hi all,
i have a relatively fresh import V6 type r and want to preserve the underside. can anyone recommend any good products to protect the underbody of the car? i want something that will protect it for years to come and not retain water behind it.

(apologies if this is in the wrong section)

Cheers Jay

 

Hey bud, id recommend the Dinotrol range af products they do a full range of preservatives, good thing about there underseals is they don't dry out and flake off like waxoyl does

 

agreed, dinitrol is the daddy!

The guys at Frost.co.uk are extremely helpful and not justy salesman trying to empty your wallet ..... id recommend giving them a bell.

 

see the dinitrol stuph, I was looking at their site and they have a bunch of different "things" in a can. It's not clear which is the actual underseal to me - what products did you use - I'm thinking its either the 3125 HS, the 4941 or the 3654 does that sound right?

 

Hey there, myself and my friend had a very bad experience with Dinitrol / rejel stuff, where we have followed the instructions and did as the tin stated in a heated garage (spray booth) and after about 4 months the rust started to come throught the underside.

We were a tad puzzled and finally when we did take waxy stuff off and rust proofer with some panel cleaner and solvent we found that rust preventer didnt do the job as there was quite a fair bit of rust that we originally got rid off before applying the product.

In the end had a dispute with rejel which really didnt get anywhere. In short rejel said it was our fault for not applying enough product (although we used as much as was stated on the can and more) Anyway not to be defamotry im sure the stuff works (if used in compious amounts) perhaps the batch we had was bad but what annoyed us the most is the amount of aggro we went through trying to get the issue resolved, which didnt get us anywhere.

In the end we went with usual primer and pain for the underside and to finish off just some hemirite shutz stuff.

So here you go hope that helps.

 

The problem most people have is they expect to be able to buy a can of something that they can slap on and forget. It doesn't exist. Having spent two years under a project car striping it back I can say the following.

To properly do it you need to strip the whole underside off to bare metal. This involves removing every component and a major battle against all the old underseal, paint, rust and mud.

Then for the best adhesion you probably want to shot blast underneath. You need to degrease it with one product, then use another to remove salt. You need to rip out all the old seam sealer. Re seam seal the whole lot.

Then you need to either prime and paint, or powder coat or epoxy mastic the whole underside. Then depending what you have chosen you need to add an impact resistant coating in arches etc. Then maybe a wax product over that. Then inject a lot of cavity wax into every box section and double skin.

Or.... just buy the best product you can afford, clean the underside off with a good steam clean in warm weather. Allow to dry and apply the product as best you can. Then repeat every year or two.

Keep rust away is a constant and in the end impossible to win battle.

 

@FMJ you are spot on. If you need to use your car all year round then you will never keep the rust at bay. Use your car in good weather and not on salty roads over winter your cars chassis and everything else that can rust will last much much longer without going mental on the underseal.

 

I've used Dinitrol products but have recently switched to Bilt Hamber Dynax s50 which is very easy to apply particularly if you heat the cans up beforehand. I just use brush on Waxoyl underseal for the accessible areas, again heated before applying it.

As said above the best way for a car not to rust is don't drive it in the winter, but if you are doing any winter mileage then underseal/wax and regular jet washes underneath are a must.

Another good thing about Bilt Hamber is they're a UK company.

 

do you have a link to the bilt hamber product you used then - is this it?
http://www.bilthamber.com/dynax-s50

I see they do big *** tubs of it, did you spray it on from the can or spray it on with one of those schutz gun?

 

Yep S50 is what I would recommend for cavity's and box sections. But laying the can in warm to hot water for ten minutes before hand is key to getting an even application. Not sure it would be so good for spray on flat surfaces under the car (it does say in the instructions that it is meant for cavitys hence coming with an injection lance). This is the issue, no one product does it all.

 

It's also great for spraying in to all of the hard to reach areas around the arches, strut mountings, fuel tank, prop, behind the inner wings etc. I've really gone to town on mine as it's currently rust free and I want it to stay that way! I'd advice removing the sill covers and injecting it into the sills and spray along the back of the seam and then apply underseal.

Our oven can be set to 40'c and whilst I couldn't possibly recommend you do this, I preheated my cans in the oven but the water method is much safer! (Particularly if your other half doesn't like car stuffs in the house...)

 

Another fan of Bilt Hamber here. I used their rust treatment products during my RA project and on my rusty fords before that. I used the deox rust removing products before applying the dynax wax. I agree that the key to success is all in the prep and unless you have a lift and are able to dismantle the underside, under sealing is always a compromised exercise. The key points for using wax rather than bitumen type sealer's is that it doesn't peel, flap and trap water. My only concern and a question I haven't asked bilt hamber is what effect certain solvent have on their products, wheel cleaner and degreasers etc.


http://www.bilthamber.com/media/down...G-BH13-001.pdf

 

some reading for you... ( test of various treatments)

http://www.auson.se/sites/default/fi...nthly_uk_0.pdf

 

Interesting

 

The way I read it, "rust proofing...or protection".....needs... "redoing,.touching up... maintained", every two, or three years, no matter what you use.

 

OK so has anyone any recommendations for something you can smoosh under the car each summer to give you some level of protection throughout the winter?

 

Personally I think it's a waste of time trying to do that.

First you need to clean all the crap off including mud and salt. To do this you need to car off the ground (not axle stands) to properly wash it. Even then all the parts are in the way of the chassis.

Then you need it to dry properly (hard in this country).

Then you need to mask off bits you don't want to wax. exhaust brakes etc.

Then coat the underneath. But it will be hard to get everywhere with all the parts in the way.

The only half decent way to do it is to pay someone to do this on a lift with proper equipment.

Even then it's not great but the best you will get without taking the more extreme steps I mentioned above.

Just slapping a load of products on a salty muddy underside will do very little. It may even trap the crap in and attract more dirt.

Trust me I spent years doing it the half arsed way before realising how futile it was. Little bits of corrosion can be targeted and treated of course but not whole under body protection.

 

OK - I figured it would stand to reason the car should be cleaned underneath first. So no product is worth applying yourself if you haven't got ramps and such?