Full Underbody Rust Protection Guide [Seam Sealer, Underseal & Cavity Wax by Dinitrol] BMW E30 | 035

Full Underbody Rust Protection Guide [Seam Sealer, Underseal & Cavity Wax by Dinitrol] BMW E30 | 035
In this BMW E30 build update I do the messy job of applying seam sealer, Dinitrol underseal coating, and cavity wax to the underside of the car, around the floor pans, wheels wells and engine bay. If you're specifically looking for a detailed guide, I did a previous video which was a more in-depth review on the Dinitrol 447 and ML products when I tended to the rear end which you can find here: • Dinitrol 447 Underseal...
Here's what I used in this video:
Ranal Brushable Seam Sealer 1kg: ebay.us/Cget4u
Mipa PU 400 Seam Sealer Cartridge: ebay.us/62SVeH
Dinitrol 447 Grey Underseal x4: ebay.us/FNUGrh
Dinitrol ML 3125 Cavity Wax Brown: ebay.us/EHM15O
150L Compressor: ebay.us/xxiVq8
Schutz Gun with Cavity Nozzle: ebay.us/LWUZej
Troton Epoxy Primer: ebay.us/3M7Kuu
I was hoping to bring forward most of what I'd learned about undersealing cars from my previous experience forward and have an effortless time getting a perfect result. Alas it was just as challenging as last time, but again I learned a lot.
To begin with, I'd got the underside chassis of the car in grey etch primer to prevent flash rusting, especially on the areas I'd taken down to bare metal.
With that thoroughly dry, I applied seam sealer to all the areas that needed it such as seams and areas I'd welded patches in. To do this I started with a can of Ranal Brushable Seam Sealer, the same stuff I'd used on the rear. To be honest, when I purchased this seam sealer I did it because it was the best value brushable and over-paintable seamsealer I could find. But it turned out to be an excellent product I could wholeheartedly recommend. I've used the whole can up now.
When I'd tried on the rear end of the car with a brush I had some frustrations getting the finish to look like a high standard, but this time I used an old card, like a credit card, to apply it almost like a filler. I took a chunk of seam sealer on the card and pressed it into the seam, then smoothed it off. This technique is unorthodox, and I haven't seen it used with seam seal before, but it worked so well I think this will be my default method going forward.
From there I loaded the Mipa PU 400 seam sealer into my caulking gun and applied it to the more intricate areas which required seam sealer to be pumped in deeper. The trick with this one is to allow it 5 minutes to firm up, then smooth it off with a rubber-gloved finger. The Mipa PU 400 was also a pleasure to work with in this way.
Seam sealer can take a long time to properly set, and I'd recommend allowing it to completely dry before applying any top coats to it. I gave mine a few days to completely gas out and dry before I then returned to spray on some durable Troton Epoxy Primer on top of these areas and any areas which were to be masked and not sprayed with underseal. I then allowed this a couple more days to dry.
It was time to get the Dinitrol 447 underseal applied to the car, but first I needed to mask all of the studs and mounting faces, plus the fuel tank and rear end of the car to prevent spoiling the nice paint job I'd done on those previously. I did this with a combination of masking take and masking paper.
With the but 150L compressor charged up to 10bar, I dialled down the output pressure to around 3.5bar for spraying and mounted the first can on under seal on the schutz gun. I then climbed under the car and started spraying undercoat all over the place. I'd learned last time that it comes out very fast and can cause a run if you hold the gun too close, or spray for too long. I also learned that the schutz gun can block up very quickly, in particular between cans of Dinitrol 447. Both lessons did not prevent me repeating the issues.
Going forward I will definitely purchase an additional schutz gun or two, and then hot-swap them rather than getting frustrated and wasting time and products trying to clear the gun back out.
I gave it a week and returned to spray in the Dinitrol ML cavity wax using the cavity extension tube on the schutz gun. All in all the results were excellent and I'm extremely confident in the underside of the car in terms of corrosion protection and its ability to resist rust going forward. As this BMW E30 is likely to be a summer toy going forward, I suspect this is a permanent rust prevention.
For more helpful how-to guides and restorations: www.spannerrash.com/
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[@Hiraeth90]

Absolutely incredible work!!! Can’t wait to see more!!! Learned a lot and can’t wait to do the same with my own e30!

[@SPANNERRASH]

Thanks so much Jordan! 😃 I hope you pick up plenty of tips for your own E30 build, even if some of them are what not to do. 😂

[@eberaladar5530]

Best E30 restoring channel ever! 🙂👍

[@SPANNERRASH]

Thank you, my friend! 😁

[@arroncribbon3809]

Can’t wait to see this car done, amazing job been done so far

[@SPANNERRASH]

Cheers Arron! I'll keep chipping away, we'll get there eventually. 😁

[@paurictighe]

Great project to follow, everything very well explained. 👍👍

[@SPANNERRASH]

Thank you mate, lots more to come on the E30. 😁

[@endeavour2127]

Great video I used play dough to fill the thread holes, worked an absolute treat.

[@SPANNERRASH]

Thank you, and that's very clever I'll make a mental note of that trick! 😁

[@TheNorthernmunky]

Brilliant job as always

[@SPANNERRASH]

Cheers Logan, glad this part is done and dusted now. 👍

[@mariosnikolaou5212]

This car has come up great!

[@SPANNERRASH]

Thank you Marios! I'm really pleased with the result on the underside, it's taken a lot of work to get it to this point. 😄

[@user-hk5mr4fb7w]

Great work, thank you for the video. Cheers

[@SPANNERRASH]

Thank you 😃

[@SXF_turbo]

Putting in the work... wow!

[@SPANNERRASH]

Thanks! It's been some graft just to get to this point! 😄

[@leeyo5494]

thats the best rust job ive ever seen

[@SPANNERRASH]

Thank you, I'm super happy with the results on the underside of this E30. 😃

[@ch54eys54]

Been waiting for this

[@SPANNERRASH]

Hope you enjoy the vid mate. If you're thinking about trying this stuff out, be sure to check the previous vid out from when I did the rear end. 😁

[@yardspeed13]

Outstanding attention to detail 🙌🏼 great tip on the beard protection… I think when I do mine I’ll do exactly what you mentioned… at least 2 guns. Great video

[@SPANNERRASH]

Thank you mate! Yeah I would totally recommend having a second schutz gun on standby. Chaos without. 😆

[@user-qm4vz4bq8s]

ΕΙΣΑΙ ΠΟΛΥ ΚΑΛΟΣ. ΜΠΡΑΒΟ. ΕΥΧΑΡΙΣΤΩ.

[@SPANNERRASH]

Σε ευχαριστώ για τα καλά σου λόγια. Χαίρομαι που σας άρεσε το βίντεο. 👍

[@nickloughrey9841]

Ive done a few cars in my time ....................... well done !

[@SPANNERRASH]

Thank you Nick! 😄 Seemed to go fairly well in the end.

[@andicog]

Best off using Sikaflex 221 or Tiger seal to seam seal, can be piped or brushed easily, use a cut down paint brush, if you want a smoother look you can dip brush into some panel wipe. I've not seen tinned seam sealer used in a bodyshop since the early 90's, it's crap to brush and can crack if it's too thick. 👍

[@SPANNERRASH]

Interesting thanks for the heads up on those. I thought Tiger seal was an adhesive, but I guess the clue is in the name! 😂 The Ranal seam sealer has been good so far, I've pretty much used the tin up between a few jobs and it seems to have done a good job, the only thing I didn't like was how tough it was to get a good finish with a brush. The technique you're describing with the cut-down brush sounds spot on though cheers!

[@andicog]

@@SPANNERRASH Sometimes it's not about getting a neat sealer job but about replicating what the manufacturer did, the Tiger seal can be built up pretty thick if required or brushed neat, it's also great for panel joins such as down the side of a van, pipe in and smooth off with a cloth and panel wipe, you can also seam seal and use paintable stone chip at low pressure over the top to create a spray sealed look. Just make sure everything is dry between processes! 👍

[@MrLense]

Wish I had a garage and all this kit to learn, practice and just do projects on.

[@SPANNERRASH]

Don't wish for it, build it. 😃 But I warn you, when you arrive, you will only wish for the next thing.

[@TheKilli101]

Be very careful- epoxy primer and etch primer react with eachother!!! loving the progress

[@SPANNERRASH]

Cheers and thanks for mentioning that, I actually had no idea they didn't play well. Apparently its the acid in the etch which can upset the epoxy and cause a paint reaction. It seems I've been pretty lucky so far, but I'll be mindful of it going forward! 👍

[@richardknowles1548]

Nice work, giving me inspiration! Plans for the engine?

[@SPANNERRASH]

Thank you Richard, get stuck in pal! I've got an M52B28 engine sat on a stand waiting to go in. It's been sat on that stand for a long time, but hopefully not too much longer now... I'm going for a fun NA car with enough power to enjoy on the road, but not so much you can't keep your foot in. On paper, the M52 24v 6-pot should be exactly what I need. Let's hope it's a good runner. 🤞

[@chrisrawle2967]

Big fan of the credit card spreader

[@SPANNERRASH]

Thanks Chris, not technically how you're supposed to do seam sealer, but I wouldn't go back to the brush now I don't think! 😂

[@Keats.Garage]

Excellent work as always! I'll be sure to remember these videos when I finally get a garage of my own... is there any reason you didn't cavity wax first and then underseal over it all after to avoid getting brown streaks down your underside? 😂

[@SPANNERRASH]

Thanks man! when the time comes, I'd recommend doing some masking to prevent you from spraying it around in a garage unintentionally. My previously clean black toolbox is now speckled grey. 🤣 You'd think I'd have learned my lesson from last time, but I guess it was just long ago enough to forget how annoying it is. Great question regarding the cavity wax, I considered that but I was worried the wax would prevent the underseal from sticking or cause some kind of reaction. I'm not too worried about the brown stains though, it'll all be coated in road grime eventually anyway. 😂

[@georgeclements2742]

Just one for the algorithm. Regards.

[@SPANNERRASH]

@@georgeclements2742 Cheers! 👍

[@Keats.Garage]

@@SPANNERRASH brown stains are better than rust right? ;) I do fully plan to follow in your footsteps once I have a sheltered workspace. I'm currently putting off a thermostat with 2 weeks of rain forcast :(

[@SPANNERRASH]

@@Keats.Garage Couldn't agree more! 😂 Yeah I totally feel your pain working on the drive mate. We're short on time for projects as it is, can't be at the mercy of the weather too.

[@alexouthwaite3740]

Wax before paint is madness

[@SPANNERRASH]

True, I'm not planning to overpaint though, the grey is the underside finish. 😃

[@Choober65]

NOW spray it with a good way like Lanoguard. The problem with underseal is ANY small holes that let moisture in will trap it underneath and then you are back to wsquare one. a GOOD wax (not that shit "waxoyl") over the underseal will help any small bits of damage heal, and FLOOD those box sections with wax to the point of blocking up all holes and filling them completely, leave for a day or so then drain.

[@SPANNERRASH]

Yeah I will probably add an additional sacrificial coating which I top up annually, but as this car is unlikely to ever be driven through a winter again, I think it should out last me!

[@jamiereynolds2950]

Bit of thinners between bottle changes pulled through the gun will stop it clogging

[@SPANNERRASH]

Thanks Jamie, that sounds like a good idea and would avoid it getting to the stage where it's blocked solid. Can't believe how quick it blocks the thing up, and then when it's properly blocked even thinners take a while to get it out. When you're in the thick of it that's pretty infuriating as I'm sure you can attest. One day I will learn. 😂

[@jamiereynolds2950]

@@SPANNERRASH yeah the soon as the stuff gets airborne it dries out quick

[@_________Rema____________]

Are you going to paint the floor car ? Very good project man !

[@SPANNERRASH]

Thank you mate! You mean the interior floor of the car? To be honest I'm leaning towards not doing, the paint under there is in great condition other than the parts I've cut and welded. I was considering adding a bit of sound deadening to it, but only fixing areas that need it and not messing with the rest. Its hidden under the carpet after all so if its not all one uniform colour it wont be the end of the world! 😉

[@ALKUKES]

How do you get away with a no copyright music?

[@SPANNERRASH]

I literally hunt for royalty free music I can use without worrying about copyright strikes. KZbin Audio Library is the best place to start for free stuff. 👍

[@dan44zzt231]

Did the new 447 stick to the original factory underseal ok (once keyed)? I've got a similar situation and really don't want to bare metal the whole underside where it's still sound.

[@SPANNERRASH]

Seemed to stick with no issue at all. So far so good!

[@colagesicht]

Hi, One Question i have is why isnt Rust Protection like this method used more frequently? I mean even if Car manufacturers do something like planned obsolescence and dont care about a cars longevity , why isnt this more popular for Automotive Enthusiast and people who love their car. Is it too expensive to do that or does it have some downsides?

[@SPANNERRASH]

Thats a great question, and I've wondered myself why people don't do this on younger cars as a preventative method before any rust starts. I think the answer simply lies within human nature, we don't like to do work unless we have to. And to be honest, it's been considerable man-hours to get it to this point, on a newer more complex car it would have probably been many more, and harder to reassemble afterwards. I could not have afforded to pay someone else to do this work, even though they'd no doubt be much quicker and more efficient at the task. 😂 Maybe with a newer car, people don't plan to keep them long enough for future rust to be their problem.

[@Ichabod_Jericho]

I’ll never be comfortable with someone just sitting under a car frame like that. Get under, do what you need without bumping into stuff and get out with your life lol

[@SPANNERRASH]

Absolutely, it's worthwhile not becoming complacent with these things, they can kill. I do usually have two additional axle stands under the car but I couldn't get this job done easily with them in place so took them away temporarily. The rear end on wheel stands are pretty much rock solid as though it were on the ground mind, and there's no engine in the front adding pressure to those axle stands. Not to mention I had someone keeping an eye out for me! 😂

[@uamade]

Why cars manufactures do not do this for new cars?

[@SPANNERRASH]

Mostly cost I suspect! Although the factory underseal is pretty good in reality, lasted a long time and still solid in most places. I think if a car is used year-round for most of its life it needs it refreshing eventually - no avoiding it. ☹

[@irondome7334]

cars are designed to last only x amount of years past warranty. Cars are generally a mere form of transportation for 99.5% of the population and thus care little about rust forming 20+ years from now. They'll either be dead, car wrecked, or have sold the car off to another bloke.

[@Benko_DieseL]

DId you put primer?

[@SPANNERRASH]

I would recommend to put epoxy primer underneath this coating.

[@Benko_DieseL]

@@SPANNERRASH Thank you for comenting,i just put epoxy 1k primer on my mk5 golf..Do you think 1k is enough to protect it or i should use 2k epoxy?

[@SPANNERRASH]

@@Benko_DieseL 2k is always better but if you have prepped well and applied Dinitrol well you should find it to be more than adequate and last. 👍

[@stevehodgson3436]

Runs never rust

[@SPANNERRASH]

You're not wrong 🤣

[@dermotmccracken288]

You should never use bricks to hold a car up ,

[@SPANNERRASH]

The blocks are sound, but have been retired since. What's wrong with using them?

[@e30_318is_project]

Here is another way to go about the removable core support, maybe helpfull, just came across it: kzbin.info/www/bejne/eYPGlnd9g8ibrc0

[@SPANNERRASH]

Hey Marco, thanks for sharing that, their way of doing it seemed to work really well, I'm impressed by that. However, I have actually made great progress on the front core support already! It's worked really well. Video coming very soon 😃

[@e30_318is_project]

@@SPANNERRASH good to hear! Looking forward to see what you came up with. When will the next video come online ?

[@SPANNERRASH]

@@e30_318is_project Hopefully it can go live on Monday. 🤞

[@steveelkins52]

Not impressed with the longevity of dinitrol to be honest, seems to wash off

[@SPANNERRASH]

That doesn't sound ideal. Are you using the same 447 stuff I am, and did you prepare your surfaces well before applying it? Mine looks like it wouldn't ever come off even if I wanted it to remove it. 😆

[@drifty1523]

Could you also por 15 the underbody then undercoat the por15 after it drys ? Great job!

[@SPANNERRASH]

Great question! To be honest I've never used POR15 before, but its on my list of things to try. Everyone raves about it and it does look brilliant from what I've seen. I've been told it dries to a glossy hard shell. Maybe this can be sanded to key the surface so it will accept a thick undercoat on top. Although I'd be very cautious as paint reactions can be really annoying. Let me know if you find out either way. 👍

[@drifty1523]

@@SPANNERRASH Thank you for the reply! I will let you know if it works out!