A Couple of Frame Questions Please

[Gerrha]

I am moving slowly along with the complete rebuild of my 97 LC. The frame is off and completely stripped of everything not welded, but now I have a couple questions and hoping for some advice too.

• I am curious about the various unused holes in the frame, notably the 16 rectangular openings along with numerous round holes along the sides of the rails. To me, it is odd that Toyota specifies to cover only 4 of the rectangles and 2 of the round holes with plastic plugs leaving all the others open. Do these have a purpose? I am thinking to plug all of them.
• My original plan was to chemically dip the frame to remove everything down to bare metal and then have it cathodic e-coated. Then, I would have it finished with super-durable polyester powder coating. Now that I am ready to go, I have backed away from this plan for two reasons. First, there are very few places that do the cleaning and the e-coat so I would have to ship the frame to them and shipping is very expensive these days and difficult to do with a frame. Secondly, very few places (I can’t find even one in Houston) understand how to powder coat over e-coat. This is despite the fact that the e-coat industry claims e-coat provides the perfect base for powder coat. I guess that e-coat is so uncommon that powder coaters don’t know much about it. Therefore, I now plan to just have the frame sand-blasted and powder coated locally. But this brings up the question as to what would be best for all of the inner areas of the frame where sand blasting and powder coating cannot reach?
• Finally, is there a consensus on the benefit, or lack of benefit, for undercoating? In theory, you could spray undercoating of some sort in the frame rails, but that might be worse than doing nothing.

 

[Malleus]

What you have identified as "unused" are probably what auto manufacturers refer to as "tooling holes". They're all over the truck, in almost every large part. Manufacturers use holding fixtures during assembly to align various parts and transport individual parts and subassemblies throughout the assembly process. The points of attachment to these fixtures cannot be holes that are used to assemble parts together, or otherwise the parts couldn't be assembled without removing them from the fixtures. After assembly, they're usually left open.

As far as cleaning and coating is concerned, galvanizing is by far the best process. It can be powder coated.

 

[Gerrha]

OK, that makes sense. I guess then that it would not be a problem to cover all of them. My inner frame rails have maybe an inch of sand in some places. Covering the holes would help with that sort of thing and even water ingress.

 

[Malleus]

The first step in galvanizing is an acid wash in a tank, which removes all exterior contaminants. This is one reason galvanizing is the best processs; it's also the most expensive, which is why manufacuturers don't use it.

Some of those holes work as drains; I'd be hesistant to cover them all.

 

[Gerrha]

The holes that I am talking about are all located on the vertical walls of the frame rails so they should not be draining. There are very few holes located on the bottoms for drainage. I will need to lift one end of the frame up several feet in order to flush out all the sand.

 

[rebelcruiser]

"My inner frame rails have maybe an inch of sand in some places."

A friend had a Hilux that accumulated dirt in the low points of the inner rails. The dirt held water after his wheeling trips. The rails rusted in the low spots eventually breaking there.
I cleaned my frame rails out and fluid filmed the inside (and outside). I try to keep sediment from accumulating in the rails but I'm hoping the fluid film will help mitigate any rust potential.

 

[Malleus]

The holes that I am talking about are all located on the vertical walls of the frame rails so they should not be draining. There are very few holes located on the bottoms for drainage. I will need to lift one end of the frame up several feet in order to flush out all the sand.

The tank wash will take care of that.

 

[White Stripe]

Galvanizing the frame should only be around 500 bucks. Fj40 guys do it a lot.

 

[Malleus]

I'd think there would be at least one galvanizing place in the Houston area.

 

[reklund5]

You should absolutely reinforce the steering box and panhard mount areas while it's stripped, stock or not. I like the @Delta VS kit for that

 

[jpoole]

I'd personally lean away from powder coating on the frame and given the effort and expense you are going through to make this right wanted to throw this perspective out for you to consider and research as you proceed. If you prefer powder coating go for it, but there are tradeoffs to all coatings and other options may be easier to live with over the long haul vs. powder coating based on my experience.

 

[80t0ylc]

@Gerrha What is your reason for powder coating the frame? There is a lot of captive nuts in the frame, but besides that, the frame is exposed to a lot of stone and trail damage and IMHO, would be a waste. It cannot be repaired to look original if powder coated. Galvanizing treatment, and you could spray paint it if desired. Much easier to repair with a rattle can. And definitely reinforce around the steering box. That’s been a traditional weak spot. Perfect time to do it.

 

[Gerrha]

I just cleaned out the inner frame rails. The passenger side was not too bad, but the driver's side was bad. About 100 acorns washed out and I had to extract a large wet glob of insulation along with a large load of sand. I think a mouse was in there with a nest and that caused the whole mess.

As to your questions about powder coating. Up until a few days ago, my plan was the cathodic e-coat. From what I have read, that is a really nice way to go. After I dropped that, powder coating became, by default, my secondary option. However, the galvanizing route sounds interesting, and I will look hard at that. For both the front and rear axles, I used two coats of Mastercoat Silver Rust Sealer followed by two coats of their AG111. Those look bullet-proof to my eyes, but we will see.

 

[Gerrha]

You should absolutely reinforce the steering box and panhard mount areas while it's stripped, stock or not. I like the @Delta VS kit for that

I have quite a bit of DeltaVS stuff now, but not for the steering box area. I will definitely check those out. If it requires welding, yikes...

 

[Gerrha]

I have quite a bit of DeltaVS stuff now, but not for the steering box area. I will definitely check those out. If it requires welding, yikes...

Are you talking about this: DeltaVS

DeltaVS Frame Supports - Weld It Yourself Kit​

?

 

[mudgudgeon]

As to your questions about powder coating. Up until a few days ago, my plan was the cathodic e-coat. From what I have read, that is a really nice way to go. After I dropped that, powder coating became, by default, my secondary option. However, the galvanizing route sounds interesting, and I will look hard at that.

Not sure if I'm misunderstanding you when you say 'galvanizing'?
I would be very wary of traditional hot-dipped galvanising a vehicle frame.
The heat involved in hot dipped galvanising is intense ( it's literally dipped into a tank of molten zinc alloy) and will regularly warp heavy structural steel sections. It's standard procedure in construction for galvanised items of structural steel to go back to the workshop for straightenibg after hot dipping.

Heat releases stress & tension trapped from welding processes.
Your vehicle frame was not intended to be hot dipped, I think there's a high likelihood of unintended consequences like warping, twisting etc. I've seen it happen to trailer frames, Not a risk i would take with a car frame.

Also, as pointed out in relation to powder coating, hot dip galvanizing also adds material to every surface, meaning every threaded hole would need to be chased/tapped.
Assemblies that are intended to be galvanised are tapped with oversized tapping tools to account for material build up.


In regards to powder coating, any scratches or chips will expose bare metal underneath. If this rusts, then powdercoating will flake off, exposing more metal

@BILT4ME might have some insight into the galvanizing thing

 

[Malleus]

The repair geek seems to agree with you about Mastercoat, after an 8 month assault test. I was sold on Corroless, until I saw his video. Now I want to try it for my 40.

As far as hot dipping warping steel, I agree it probably would for unbound structural sections, but I'm not sure the same would be true for a frame assembly, since there isn't much except the front/rear horns that are free to move. I guess it would depend on how tight the connections were and how long it was in the tank.

I thought the dipping process was fairly short, and at about 450°F, you'd only risk annealing the steel, if it was hardened at all. Apparently Land Rover, or someone providing parts for them in the UK, supplies galvanized frames.

I'm not sure work hardening from cold bending would cause the same internal stresses conventional heat treatment would, but these frames have been environmentally stress relieved over their lifetime, so maybe there aren't any residuals left. We used to leave really large weldments out in the sun for a couple of weeks to stress relieve and normalize them, and they were pretty stable after that. IIRC, the welding caused more movement than the tanning in the yard.

I would think the galvanizers would be the ones to ask, and that they wouldn't take a job like a frame if they thought there was a chance something would go wrong. I think I remember a place in lower Alabama that specialized in hot dipping power poles, and who also did vehicle frames. I looked through my notes, but I couldn't find them. If I come across them, I'll post an update.

If there was someone within driving distance, I'd be willing to try it; it seems I know someone with a bare frame lying around.

 

[reklund5]

Are you talking about this: DeltaVS

DeltaVS Frame Supports - Weld It Yourself Kit​

?

Yup. Well worth it.

 

[Gerrha]

Thanks everyone for all of your feedback. I have a lot to consider here.

There are quite a few hot-dip galvanizing places in Houston. I was looking at a very large one yesterday. I will make a few inquiries and see what they say. And, I do have an extra frame sitting here that I would truly love to get rid of, but that is another story... I guess if these places say it is a no go for a vehicle frame, I could sandblast the entire thing and use the Mastercoat on it. The thing about the Mastercoat is that both the Silver Rust Sealer and the AG111 go on with a paint brush. The AG111 leaves a thick layer when it dries so you have to put bolts in every threaded location and seal off anywhere else you cannot have that thick layer.

I have already ordered the DeltaVS weld-on brackets and will get those done up by someone that can weld, but I do need to sit down and think about what is going on here and why this location is a common failure point. Is this location where the power steering gear bolts to the frame?

 

[Gerrha]

I just read a bit more about the hot-dip process and it is at 450 oC or almost 850 oF. It sounds like it might not be a good fit for a frame, but I will keep researching.