Rust Prevention Where The Sun Don’t Shine

[Sundodger]

The bed supports on my truck has a couple of small sections that need patch panels



Problem is after the welding is done it will be very challenging to paint the inside of the bed support and protect this freshly welded metal from just rusting though



My understanding is weld though “primer” results are mixed at best.



How would you guys coat the backside of this to make sure it doesn’t rust though in short order?

 

[slowtwitch73]

There's some stuff called Frame Saver that is made for bike frames, but I use it on everything. Goes in wet through a weld vent hole or whatever, then evaporates off leaving almost a cosmoline coating on inside.

I'm sure there are other similar products out there.

 

[Sundodger]

There's some stuff called Frame Saver that is made for bike frames, but I use it on everything. Goes in wet through a weld vent hole or whatever, then evaporates off leaving almost a cosmoline coating on inside.

I'm sure there are other similar products out there.

Interesting stuff, how often do you have to reapply? Every year?

It would be ideal to find something that's one and done.

 

[Bighead38]

Cavity Coater - Cavity Wands - Cavity Wax Rust Protection

KBS Cavity Coater is a one-step, super-penetrating corrosion inhibiting coating (CIC) for long term protection on all metal surfaces. KBS Cavity Coater provides a self healing film which renders over 4000+ hrs salt spray protection...over 4 times the protection of conventional cavity waxes.

www.kbs-coatings.com

 

[MushCreek]

That cavity coater looks useful. They don't say how long the flexible tube is, though. I have some 1-1/2" diameter by 8' long steel tubes that will remain open on the ends, and I'm trying to figure out how to rust-proof the inside. I was thinking about making a swab out of cloth or foam to push/pull paint or rust coating through the tube.

 

[slowtwitch73]

Interesting stuff, how often do you have to reapply? Every year?

It would be ideal to find something that's one and done.

They say to reapply every few years. Nature of a bike frame etc, is you can't tell, but I have cut open some frames I treated and the stuff was still in there and not going anywhere. It would have added significant weight (for a bike) if I had re applied. It dries to an oily wax... not easy to remove and pretty hydrophobic.

If it was a small void, the whole space cold probably be filled.

 

[vpd66]

Look into Fluid Film and Woolwax. These are lanolin based spray on corrosion protection. Fluid Film works good in non exposed areas (inside doors, tailgates, and fenders) Woolwax seems to cling better and works better on exposed areas. I use Woolwax on my snow plow truck and it seems to be helping keep the underside rust down. I do touch it up in fall every year.

 

[slowtwitch73]

Eastwood makes a product for this application as well.

I would bet Frame Saver and Cavity Coater are more similar than not.

Frame Saver comes with a typical plastic extension like you see on many lube spray cans. It does seem extra charged though.. it really comes out at high pressure.

 

[Jim greengo]

I was taught to dump stp into seams where moisture collects back in the day.
I've also heard lots of people talk about having good luck with fluid film also.

 

[MBfreak]

Try to find a rust preventer based on > 75 % linseed oil.
It actually expands over many years as it oxidizes, thus creeping in to fill every cavity
Petroleum based products shrink and crack.

In Germany the go to product since around 1990 for high end restorations is " Mike Sanders Rostschutzfett"
Has to be 60 C when sprayed, lasts for a very long time.

Ola

 

[cpttuna]

have you thought of using stainless for this job?

 

[tehach]

We have used HRSCA (high ratio calcium sulfonate) corrosion inhibitor on crevices formed by riveted storage tank lap joints. It's tricky getting the joint clean enough for the penetrating sealer to get all the way inside (flood coating). We've had decent results. One brand name is Termarust but there are others (I am a user and have no vendor affiliation). Might be too complicated and costly for a small job, but calcium sulfonate penetrating sealer is a legitimate method.

 

[Sundodger]

Try to find a rust preventer based on > 75 % linseed oil.
It actually expands over many years as it oxidizes, thus creeping in to fill every cavity
Petroleum based products shrink and crack.

In Germany the go to product since around 1990 for high end restorations is " Mike Sanders Rostschutzfett"
Has to be 60 C when sprayed, lasts for a very long time.

Ola

Thanks for the idea, I will look into Linseed oil options stateside

have you thought of using stainless for this job?

Base metal of the truck bed isn't stainless, so I am stuck with mild steel.

We have used HRSCA (high ratio calcium sulfonate) corrosion inhibitor on crevices formed by riveted storage tank lap joints. It's tricky getting the joint clean enough for the penetrating sealer to get all the way inside (flood coating). We've had decent results. One brand name is Termarust but there are others (I am a user and have no vendor affiliation). Might be too complicated and costly for a small job, but calcium sulfonate penetrating sealer is a legitimate method.

Interesting stuff. I did some quick reading and it seemed they discuss mostly bolted or riveted joints. I am assuming it will not stand the heat of welding?

 

[VR6ix]

Base metal of the truck bed isn't stainless, so I am stuck with mild steel.

That's what 309 filler rod/wire is for, joining mild steel and stainless

I haven't done this, but if you can dam-off all the leak points and flood the cavity with your rust-prevention liquid of choice (something thin like POR-15), that might get the job done.

 

[tehach]

Interesting stuff. I did some quick reading and it seemed they discuss mostly bolted or riveted joints. I am assuming it will not stand the heat of welding?

Yes, it will burn off. Maybe it's possible to leave a port open to flood coat the crevice (with some sort of inhibiting material) after it's welded and then seal the port with polysulfide.