Very well put, I think youtube is a great way to share the information. Wish it was around when I started doing this stuff, would have accelerated progress.
Very good ideas here, Ben. I would add an idea that's indirectly related: back in the 90s when doing an Alfa, we were able to locate a special coating from an industrial rust protection company that was sold for use on bridges. Apart from hardening into quite a tough coating, its most important property was how well it *wet* the metal during application. This makes the difference between a coating that gets into all the leftover pores, excluding any atmosphere, and one that just adds a covering layer. I think most paints used in automotive usage are more like the latter. This also was the very best for getting into metal layers, fold-overs etc, as it would pull itself into the joint. The car in question has zero paint lifting since 1996, but admittedly has not got into much rain since then.
Interesting. Sounds a superb paint, I would like an explanation from the automotive paint manufacturers about this. Perhaps there are compromises between how well a paint wets and other desired quality's. Bridges don't exactly need to be polished to a mirror finish for example. Underneath a car though could certainly have a bridge finish without any problem. Your long testing of the paint is the only way to prove it works.
It took me a long time to figure this out, I just thought blasted steel rusted faster for some reason. One of the comments said it was the manipulation of the surface that can cause corrosion to be partially obscured from view. It soon reveals itself if given some time and you can deal with it. I was first alerted to the problem when I saw a blasted bit of steel in an engineering workshop. I said you'll want to paint that quick, he responded by saying it's been here for weeks, no rust. It was new steel not previously corroded and that was the information to question what was going on with the stuff I did. You've got a big channel and a lot of views, will have a look later 👍
Puts into perspective a lot of these mechanical RU-vid channels that sandblast and restore stuff, which looks amazing in the short term, but really makes you wonder how long the stuff they build will last.
Yes, I wonder how many know they are painting over rust. Perhaps good enough for some people but I think if you're going to the massive effort to restore a car why not go that little bit further and make what you do last as long as possible.
My dad and I sandblasted a 1949 chevy and a 1972 VW super beetle. We had to turn down psi for VW. But we blasted from many angles, not str8 on. As soon as we got a fender, we epoxy. The big part was cab. We did inside, epoxy, then taped off and did outside and epoxy. Then we did anot her thin coat of epoxy, then sandals primer, then body work, lil cause we welded in what was needed, then sealer coat of primer, block sanding, primer and then paint. Same with VW. Both still look gr8 and this was done in 94, 95. Paint was acrylic but with ALOT of hardener, then later a scuff and 5 coats of clear with ALOT of hardner.
@@jasonchristopher2977 sounds like you were really thorough with the blasting. You can get all the rust by being thorough but it also depends on the climate where you live and the severity of the rust before you started. Glad it's all still looking good. 👍
@@bensclassicbodywork I have a brake caliper rebuilding business and we blast the calipers with fine steel shot in a tumble blast machine. The worst corroded ones look like the lunar surface after the blasting process. Those are the ones that don’t plate well.
👍 cast steel I find particularly hard to stop the rust after blasting, brake callipers I believe are cast steel ? Immersion is the best way for that in my opinion. Probably not time efficient enough for a business doing it, you would still need to blast the heavy corrosion off and that is of course another process to the job.
Good video and you are absolutely right, but do you have any ideas to the rust off inside frames and so on where you can't get in with the blaster, a few time if it is spot welded I have taken apart the items and then blasting them inside as well then welding them back together after rust protection inside, it takes logn time, so do you have a better solution? Like your stile allways funny to look. Cheers
Hi. The only way to remove rust inside cavity's and paint without taking the panels apart is to immerse. You can have entire body shells immersed in rust remover and then Immersion primed. A company called surface processing in the uk does it, the downside is it's very expensive and sometimes acid that is used to remove the paint and rust can get trapped between the seams and can cause rust. It's not perfect but for the most part as good as you will get. Taking the panels apart like you mention is the second best way but as you say it's very time consuming. I'm sure you will know but cavity wax is your biggest friend to prevent corrosion internally.
Absolutely true. Although a well know brand of so called cavity wax is next to useless. The best that you can buy is UK made, I've known it not to dry out after 25 years, when applied warm with correct equipment it reaches everywhere and creeps well. Formerly " Bodyline by Brown Brothers it is now made by Indasa. Amber or clear - you will not beat it.
I have not tried the Indasa wax, will get some. I've been using dynax s50 from bilt hamber but I haven;t been using it long enough to comment on it's effectiveness. cheers for the info.
Yes. Removing corrosion from aluminium is a different ball game and I haven't managed to crack that one I'm afraid. I can only suggest cutting the corroded aluminium out and welding in new. I know there are some products out there for removing corrosion on aluminium but I haven't found any that do a good job.
What happens when you blast metal, is that the metal starts to move, think of it like ocean waves, one of the waves has covered/folded over a rusty spot, so some of the rust has basically been buried. The process you do is ideal, but is not practical for most people, so a blast followed by a phosphoric acid treatment is usually the best/only option for most people.
🤔 I didn't realise it was, so the metal is mostly covering the corrosion so it's too small to see, then the corrosion starts again due to the disturbance and quickly spreads from the tiny opening ?
If painting with a surface tolerant epoxy primer then those fine bits of rust remaining in pits is not an issue. Bare in mind the blaster may not have "missed it" as such, it may be the blast media is too coarse to get down inside very fine pits.
Hi, I don't think there is a paint in the world that can hold back rust once it's there. I'm yet to find one and epoxy didn't work for me. I found rust that had grown underneath epoxy paint so I blasted it off and started again. You're correct that the size of the media particle has a large bearing on how thorough a job it does. I Haven't tried the very fine grade media to be fair but I reuse media that breaks down to eventually dust. I would have thought this would have a good chance of getting everything, but it very rarely does.
@@bensclassicbodywork Fair enough. I'm sure nothing will hold it back forever. However, I have blasted differential casings, subrames and the like, and although they appear rust free, no doubt some very very fine amounts of rust exist in pits that is not visible. Although, once covered with an epoxy mastic like Jotamastic 87, I have never seen the effects of this, and this is going back years. Unfortunately, blasting can also trap rust such that is not accessible to a remover. Further, rust pits vary in depth, and although you think the remover took it all out, it may lurk at the very bottom. On bodywork its different because it's typically a bodywork epoxy covered with other layers, and there may be issues there. However, pitted metal should really be cut out and replaced anyway. Using rust removers and converters after blasting can also introduce problems with adhesion and wetting of the paint. Further, leaving items for extended times after blasting can lower adhesion. Personally, I have found a thorough blast with clean media, and painted within a 2 hour window, to be very effective.
Understood, the adhesion as you say is best just after blasting, which is actually new Information to me since this video. So the perfect procedure in my opinion is to immerse, then blast and quickly paint. We are talking about ideals and it maybe overkill for a lot of situations. The outside of a car would be an example of needing this much attention. Most people wouldn't have an immersion tank big enough for a compete body but there are gels which I've used to great effect. Repeated blasting will do the job but as you mention trapping rust is a potential issue. As you will be aware just a single bubble in the paint on the outside of a car means trouble. If this happens on a subframe or axle then it really wouldn't matter that much.
I agree. If I ever take rust to bare metal,I,ll use wire wool and small wire brush to work in rust killer after...not the ones that turn black. I use Frost metal ready or jenolite. Then Bonda Primer zinc primer...2 to 3 coats.
@@bensclassicbodywork That Bonda Primer is amazing stuff...and hard to get hold of. Similar to Jenolite Double Act available years ago. Bilt Hambre...amazing company...excellent products.
How would you paint a subframe like that to ensure full coverage and rust prevention with all the nooks and crannies? Is Atom-Mac good enough as final coating or do you have a preferred method?
Hi, If you wanted paint coverage inside you could have it E-coated but I'm going to wax it inside. It's already been powder coated which isn't a bad start.
I've not tried citric acid I'm afraid, there are other company's around the world that sell immersion rust removers. I think it's best to use a tried and tested product. It's not just about finding an acid that will remove rust. I bought some hydrochloric acid to try which does remove rust but it also removes metal and causes rust when the part is removed from the acid. Horrible and dangerous stuff. The deox c is very safe to use and doesn't have any downsides. I'll have a look online for examples of using citric acid.
Hi, No I haven't, not a rust killer/converter. These products I believe only attempted to remove the oxygen to prevent further oxidation. What looks like black and dead rust after applying the product can be scratched into to reveal the active orange rust underneath. In my opinion they don't do anything more than any paint would do. Just my opinions and not backed by any experiments or deep understanding. Rust has to be removed for a lasting job, that much I am confident.
I think there's some truth in the requirement to paint quickly after blasting though too. Here's a video that demonstrates how the surface properties of metal change within a day of blasting. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-x7onZGqrYyY.html.
Wow, thanks for this fantastic video, love the wetting test to establish the adhesion properties. Nice to hear blasting is the best form of mechanical abrasion and interesting to hear that it's effect dissipates over time. Brilliant 👍
