Are rust convertors good or useless?

[duffman]

I'm currently restoring an old classic and a lot of metal work to do. However looking at places I can't get at but has a bit of rust inside, e.g. sills, chassis rails and any other crevices. I'm cleaning down anything I can and painting but what about the bits I can't get at. I was thinking of spraying rust converter in through holes with a 360 nozzle. Is he jenolite rust converter worth a try? Cheers

 

[Haz87]

The aerosol Jenolite is more an encapsulation of the rust, starving it of air (or more moisture etc). It doesn't tend to turn things black like the brush on types though I think it is advertised as doing some kind of "converting".
If you're confident its just surface rust, then the Jenolite isn't a bad shout.

Ultimately all the options only treat or cover the surface. Anything below that surface will continue to be rust...

 

[Shedendman]

Ask the question "what does a rust convertor do"?
Well it doesn't convert it back to metal thats for sure,all it does is convert iron oxides into a protective chemical barrier,like a primer as such
Its what you put on over this afterwards that counts,basically your slowly the corrosion down and preventing it from getting worse,its still gonna be rust either way,remove as much of it as you can by replacing or cleaning then protect
I wont comment about which is best etc as they come in many flavors,and everyone will their fave/best one

 

[Ross365]

I think that a good question to ask is whether the manufacturer approves to the use of his paint on top of the rust converter. I'm pretty sure that there are combinations of different products that don't work well together. You could go down the route of looking for a company that sells both a converter and a paint as part of a "system".

I've bought and used Jenolite's tradition product which has been out for decades, but I'm wary of some their more recent stuff.

 

[bert]

Not being able to fully get to surface rust inside box sections is why I have all the cars I do chemically dipped before I start welding. Once metalwork is complete it goes back for dipping and e coating

 

[charlysays]

Just use a generous helping of a good cavity wax like dynax UC in there when all the other work is done. I bet the rust will never become an issue especially if the wax is reapplied now and again.

 

[bert]

In my experience cavity wax over the top of rust does absolutely nothing to stop it. All it does is make it very hard to weld the car without turning it into a fire.

I've just done some repairs to a karmann beetle that had been absolutely plastered with waxoyl everywhere and it's just as rotten as one that hadn't been waxoyled.

 

[JOEPRO]

I guess completely inaccessible areas may benefit from rust converters. But for anything else I have tried 6 ot 8 of the "best" ones and find they all fail after a couple of months with rust breaking through again.

Another option would be a rust encapsultor type product like POR15 when applied correctly it is very strong stuff and rust does not break through again in my experience. POR15 with proper decreasing steps etc then cavity wax is what I would do.

 

[Cobbler]

Where I worked years ago, we had a builder customer that bought a nice A60 I think it was. He blocked the drain hole in the sills, cut an access patch in the top & filled the sill with Synthaprufe (builders waterproofing tar) & left it over night before draining it out. I would love to know how that fared over the years.

 

[Gareth J]

They treat surface rust and give a good surface pre painting. But I'd try not to hung up on surface rust - think about how long a sheet of unprotected 1mm ms will last in your workshop; surface goes rusty then that's about it for a generation or so.

In a car, what happens is there is a constant supply of water and minerals from road dirt that, it it can get into unprotected areas, causes steel to rot. That's what it's important to focus on stopping. Stopping water ingress, ensuring drainage works etc

 

[MetalMonkey]

There are many different types of rust treatments. The ones like the traditional jenolite are usually a phosphoric acid based product with 11 herbs and spices.
Basic phosphoric acid is cheaper and does much the same job, neutralising the surface of the rust and providing a good substrate for primer as stated.

It won’t work magic, the rust will still be there and if its loose and flaky it will achieve nothing as once it flakes off and reveals new metal it will continue to rust.
In such cases, mechanically removing as much rust as possible is the key to success.
What they are handy for is dealing with pitted metal where you have rust specs at the bottom of pits which are hard to remove.

If the inside of these sections is clean and dry and just surface rusty, then treatment is probably worthwhile, following it up with some sort of cavity wax – dinitrol make some good products for this.

These converters don’t work over fresh metal or any sort of coating, and just leave a sticky residue IME
If the sections are painted/coated/dipped/waxed already and you just have odd spots of corrosion then spraying jenolite over everything is going to be a waste and may actually stop you applying some form of corrosion prevention coating.

 

[arther dailey]

hmmm, looking at doing chassis on mitsi when weather warms , so what is recomended for closed section box ? excuse me for poaching op.

 

[Roger440]

There are many different types of rust treatments. The ones like the traditional jenolite are usually a phosphoric acid based product with 11 herbs and spices.
Basic phosphoric acid is cheaper and does much the same job, neutralising the surface of the rust and providing a good substrate for primer as stated.

It won’t work magic, the rust will still be there and if its loose and flaky it will achieve nothing as once it flakes off and reveals new metal it will continue to rust.
In such cases, mechanically removing as much rust as possible is the key to success.
What they are handy for is dealing with pitted metal where you have rust specs at the bottom of pits which are hard to remove.

If the inside of these sections is clean and dry and just surface rusty, then treatment is probably worthwhile, following it up with some sort of cavity wax – dinitrol make some good products for this.

These converters don’t work over fresh metal or any sort of coating, and just leave a sticky residue IME
If the sections are painted/coated/dipped/waxed already and you just have odd spots of corrosion then spraying jenolite over everything is going to be a waste and may actually stop you applying some form of corrosion prevention coating.

I wont use a convertor in a box section for the reasons you state, they dont work or adhere to clean or painted metals.

I have, for over 30 years, used a cavity wax after ive cleaned out as best possible, over whatever rust, dirt, paint etc is there. Worked for me. I still have some of those cars. Bilt hamber S-50 is my favourite. Sometimes with an infrared lamp to warm the panels for max penetration into seams.

What i absolutely wont do is chemical dip. Ive seen too many cars years later with acid leaching out of seams. If/when that heppens, there is nothing that can be done.

One has to make a choice.

 

[bricol]

I use Noxudol 700 in mine - seems to be doing well so far a few years into outside storage and daily use.

 

[Mark 5]

In my experience any rust spots/areas are twice, three times the size of what can be seen.

 

[marlinspike]

I've found Hydrate 80 pretty good. I think the thing is to treat it as a last resort after you've got every last bit of rust out that you can. I only use it in pitted rust or areas I can't get to to derust 100%.

 

[arther dailey]

nutarust 661 ?any one used it?

 

[Bobtail4x4]

I have a gallon of fertan, a bit in a pump spray thing goes a long way,