Weldable Rust Proofing Primer?

Looking to strip my frame as clean as possible and have some strengthener plates welded on. But, to prevent rust from coming back as much as possible, I'd like to use something on the surface before I have the plates welded on/frame boxed in.

I was told that the Zinc based primers are good for welding through, but I was wondering if anyone has experience using these types of products, how well they keep rust at bay, and if it affects the quality/strength of the welds?

I'd been planning on doing the Eastwood internal frame coating, but I don't want to do that before the welding.

 

Nah man...

I've never heard of anything (besides CLEAN metal) that's good for welding through... Just because it's conductive, that doesn't mean you can weld through it. Anything that's not the metal you're welding to is just an impurity that can adversely affect the weld quality.

Make sure you get rid of all the rust first, then weld. Then coat everything after.

 

@Wyoming09

 

Can you provide an actual product link so we aren’t guessing at what you plan on using?

Zinc is EXTREMELY toxic and burning it happens when welding can cause a condition referred to as “metal fume fever”. That is why you never weld to zinc plated parts without removing the coating first and using lots and lots of ventilation. There are weld through primers available but I personally have not used them nor do I know the safety procedures involved.

 

boxing a frame will hide the rust problem, but won't solve it and may allow it to thrive, actually, as there will be no way to fight rust if it ever comes back.
Boxed frames are great, but their downside is that they rust from the inside out.... because of the moisture that gets trapped in

Anyway if you still want to box it, don't forget to rustproof the inside, not just the outside

 

Any Primer or paint you attempt to weld through just burns off .

So it really does not increase the corrosion protection in the heat effected zone

If your going that route primer and paint primer does not offer real long term protection

Once you understand just what your looking at in your weld puddle you can notice the impurities burning off if you look .

If you live where they use Liquid brine that is just plain brutal makes regular road salt just a minor pain .

The downside to a boxed frame is the inside once it fills with road dirt never really dries away from the arid climates

Allowing for much thinner metal from the drawing board side I guess was a Good idea

 

I'd only do clean metal for welds in this case. You can use flux core MIG or stick with some rust/paint contamination but defeats the purpose of your work here. Grind the contact points weld it up and anything under the plates is sealed. No O2 = no more rusting in that area. Prime and paint over patch pieces. Dont weld anything Zinc...the fumes are nasty toxic.

 

Welding on anything zinc is a no no. Paint it, then grind it clean just on the areas you plan to weld on. Repaint when your finished.

 

Thanks for all the feedback folks!

Would you think putting beads completely around the boxed part or just doing like 1-2” beads intermittently? I think that the thought was to clean the metal as best as possible, then seal it with some sort of rust protection, then do the welding to strengthen. Since the box won’t be touching the inner faces of the C channel rear portion, it wouldn’t be air tight against that face. So, cleaning it up and sealing it before hiding it would protect it for as long as possible. It wouldn’t buy the frame decades, but maybe years... that I am ok with.

 

Use spot welds spaced out every 2-3" to put it in place. Then run a bead around the entire outside seam of the patch metal. No matter what it is like inside if you seal it any deterioration process needing oxygen or moisture stops. Nothing hurt by priming the metal, laying on the patch and marking the edge and then grinding just what you need to affix the patch piece. For that thickness of metal a 1/2" on either side of the edge is plenty enough for bead penetration/strength I would think.

 

That seems reasonable enough! So there’s really no benefit to using something like Bloxide (an aluminum based primer) before welding then? Just doing it up with whatever and then grinding away the area where welds will be. Who knows if a frame will actually end up air tight. And if it does, it seems like it would likely develop some sort of stress or rust would grow back from outside and open it all back up. I’d hope for the best, but plan and prep for the worst.

 

It won't hurt but its not needed. If you are patching the frame then the whole frame needs rust conversion treatment for the areas that are rusty but still sound so do that first after cutting out bad spots.....then just grind to bare metal what is needed to put in the patch pieces.

 

This material is to thin already if your cleaning it up use the discs that remove rust and paint not grinding discs

I have been leaving some good sized round holes in the bottom about 25mm.

Next one is going to be stainless

 

I think these products might suit your needs

steel-it
-or-
SEM weld-thru primer

 

Something like the Eastwood Rust Converter? It seems like that’s for mild surface rust. Mine has moved beyond that to being pitted. I’m going to internal frame encapsulate paint the already boxed in parts... not sure if a converter would work with the more advanced rust and they say those encapsulating formulas and por15 all need to have rust to bind to.

Stainless would be awesome. But are you talking. About those round gray rock had fiberous stripping discs? Those seem optimal. I have a Milwaukee wire disc that’s pretty effective but doesn’t do much surface area.

 

The SEM stuff sounds nice, but I don’t know if there’s and realistic way I’d be able to strip all of my frame down to bare metal. Would it work if I was able to use rust converter? Or does that just leave a different surface compound instead of steel. Maybe an acid wash lol

The steel-it stuff looks pretty legit though! I’m not sure if that’s weld-through? I suppose I could just do the re-stripping of the welding areas. Not clear if this can go over already corroded/rusted surface or if it too needs to be laid down on to clean metal.


Maybe just encapsulator or por15 to coat the rusted soon to be internal areas after cleaning them up as much as possible, while leaving enough rust for the stuff to bond with?

 

I use CGW EZ strip I have no idea if you could find them in your area .

 

I use a strip wheel/wire brush and get off all the loose scale. Pitting does not matter if the area is still structurally sound just get off any loose rust. I really like the POR product...cleaner, converter and paint. It's very hard and durable but it does require a topcoat of paint anywhere UV exposed. It's nice in areas you have access to treat like taking off the bed. I also go back and spray or paint on Corroseal in areas like springs, control arms, etc or small areas of rust that don't need the involved prep and work of POR15. Corroseal is great and converts rust to a paintable black finish.....I never paint over it but you could. I use it on farm equipment every year and that stuff just plain works to convert surface rust. Inside the frame where I cannot get to it good I use Eastwood rust encapsulator with the 360* nozzle and long tube. Ideally the POR product everywhere would be ideal but you just can't access some areas to use it without pulling the frame off. This is what POR15 looks like after application, the cross bar with the spare tire mount was the worst and pitted on top....looks new now: :

 

Yep that’s exactly what I was thinking of in terms of a stripping wheel. Those are excellent.

Wow, nice job on the por15 work! That frame looks beautiful.

With por15, does it need to be taken to clean metal? I thought that it was like an encapsulated that needs to bind to rust.

 

No it does not. With POR15 you only have to remove loose rust and paint. You do need to use their metal prep. It converts any surface rust and prepares anything else to get the POR15 coating. It is worth it for big areas like where I was treating the entire rear frame. In small places I just use Corroseal. Its not as durable as the POR15 but easy. I will take a garden gallon sprayer and ever year or so coat my undercarriage with the Corroseal.