Which steel?

[Vern1]

.040 aluminum race car skin.
Comes in a bunch of colors plus just silver.
Easy to work with, light weight and comes in 4x10 sheets at about $110 per sheet.
The prefinished stuff is painted on both sides so you don't have to worry about rust on inside.
And if you don't paint steel on the back side, it will rust and if not sealed well will leave rust streaks down side of your bus.

We fab Modified and Sport Mod bodies for our race cars so have shear, cutters, hole punches, nippers and a 7' metal brake so it's very easy and fast.

 

[o1marc]

.040 aluminum race car skin.
Comes in a bunch of colors plus just silver.
Easy to work with, light weight and comes in 4x10 sheets at about $110 per sheet.
The prefinished stuff is painted on both sides so you don't have to worry about rust on inside.
And if you don't paint steel on the back side, it will rust and if not sealed well will leave rust streaks down side of your bus.

We fab Modified and Sport Mod bodies for our race cars so have shear, cutters, hole punches, nippers and a 7' metal brake so it's very easy and fast.

I have experience with no only from racing for 18 years, but from repairing trailers last year in Fla. The thin stuff damages very easy, which is why I replaced so much of it. The seems to take abuse pretty well, using a thinner sheet metal would damage easier and need repair more often. The race car you speak of probably had a few panels replaced during the season.

 

[EastCoastCB]

.040 aluminum race car skin.
Comes in a bunch of colors plus just silver.
Easy to work with, light weight and comes in 4x10 sheets at about $110 per sheet.
The prefinished stuff is painted on both sides so you don't have to worry about rust on inside.
And if you don't paint steel on the back side, it will rust and if not sealed well will leave rust streaks down side of your bus.

We fab Modified and Sport Mod bodies for our race cars so have shear, cutters, hole punches, nippers and a 7' metal brake so it's very easy and fast.

What do you do to prevent galvanic corrosion?

 

[o1marc]

What do you do to prevent galvanic corrosion?

On a race car, nothing, they don't stay on long enough for the process to take place. And the whole car gets rescind ever year. That would be a concern using it on a bus. Does it help that both sides are usually painted.

 

[EastCoastCB]

On a race car, nothing, they don't stay on long enough for the process to take place. And the whole car gets rescind ever year. That would be a concern using it on a bus. Does it help that both sides are usually painted.

I wasn't asking about race cars.

 

[plfking]

I wasn't asking about race cars.

He was just letting you know, in case you were planning on replacing all your skins every year.

 

[Vern1]

Greetings,
What do I do about galvanic reactions?
I use the same seam seal tape that bus manufacturers do when they put aluminum window frames, vents, etc. where it mounts to the steel.
Is it perfect? No but works so far.

As for thickness, the stuff they use on manufactured trailers and RVs is not much thicker than a beer can.
If you have ever seen a manufactured travel trailer or RV that has been in an accident you will know what I mean.
They have very thin skin and almost no structure underneath.

The 28 gage aluminum used on most RVs and trailers has no temper and is 1/64" or .0156 - they press ridges into it to give it a semblance of rigidity.
The car skin is 18 gage or 1/25" or .040, has more temper and is pretty rigid if supported properly.

Skin is not structure - the places I used the aluminum is below the floor level as skin and doors for batteries, propane tanks, etc. and above the impact strips to fill in where the windows used to be - windows are not considered structure either.

As for replacing panels on our car, normally we try to run whole season but due to being hit by other cars going 50-90 MPH it's not usually possible.
Let's see how your 1/16" steel looks after it's been hit by something that weighs 2500-3500 pounds doing the speed limit.
Most compact cars weigh around 3500 pounds and a full size car or truck is considerably heavier.


By nature we are non-conformists.
One of the nice things about doing a bus is being able to do it your way to meet your needs.


Just for reference, here is a shot of our car from last season.
It finished second overall for the season and won 2 features.
There was not a straight panel on the car anywhere but the structure underneath is good.

 

[Gustav]

Vern1, I really appreciate the people who use different approaches to a problem. It gives me more choices. Thanks for your detailed explanation.

 

[digdug18]

Are you going to be attaching this via welding or rivets? I ask because welding with a co2 shielding gas on galvanized metal is deadly. It gives off phosphene(spelling?).

16 or 18 will work fine. Either way I’d recommend a seam sealer on the inside to prevent moisture into the interior.

 

[family wagon]

Welding galvanized metal grows more deadly every day...

Per this fact sheet from the Canadian Centre for Occupational Health and Safety:

• phosgene may be created by a reaction between UV light (weld arc) and vapors from chlorinated hydrocarbon degreasing solvents
• phosphine may be created when welding through phosphate rust-inhibiting paints
• "metal fume fever" is a possible health effect from welding through zinc coatings (ie galvanization)

Though all those things can come about during welding, their fact sheet doesn't support the idea that CO2 shield gas plus galvanized coating leads to phosphine nor phosgene. It's the degreasers or paints that can lead to those fumes, and neither a galvanized part nor the CO2 shield gas are required for those reactions.

 

[digdug18]

Welding galvanized metal grows more deadly every day...

Per this fact sheet from the Canadian Centre for Occupational Health and Safety:

• phosgene may be created by a reaction between UV light (weld arc) and vapors from chlorinated hydrocarbon degreasing solvents
• phosphine may be created when welding through phosphate rust-inhibiting paints
• "metal fume fever" is a possible health effect from welding through zinc coatings (ie galvanization)

Though all those things can come about during welding, their fact sheet doesn't support the idea that CO2 shield gas plus galvanized coating leads to phosphine nor phosgene. It's the degreasers or paints that can lead to those fumes, and neither a galvanized part nor the CO2 shield gas are required for those reactions.

I was told about the gas being created in an accredited welding program, that the heating of the galvanized steel, while using a CO2 shielding gas creates phosphine gas. Though it was at a college in the USA, not canada.

So I stick with what I was told by instructors with 30+ years of experience, and more welding certifications than I have.

 

[musigenesis]

My 86 Thomas is all 15-gauge ?
but anyway?
Galvanized will hold a regular paint if you wipe it down good with plain old white vinegar.
That cleans the coating off of the galvanizing and opens its pores so have the paint ready as soon as the vinegar dries especially on a hot day.
And if using full sheets I might could recommend(depending on cutting on bending methods) cleaning and painting the full sheet and then it's just touch ups.
A primer paint on especially cold roll is must have base.
I ain't a painter and never want to be but have been around sheetmetal,sheet steel, and steel for a while and I know that vinegar will save the cost of self-etching primer/paint on galvanized

ARRRGH I hope the vinegar thing works. I built a whole panel that covers where the SCHOOL BUS sign was in the back out of galvanized 26 ga sheet (which I bought accidentally). I primed it after I riveted it on the bus but it looked like it was going on kind of funny, with the paint bubbling a bit.

I really should have researched this before building the whole thing. Fortunately I haven't built the front one yet.

 

[EastCoastCB]

ARRRGH I hope the vinegar thing works. I built a whole panel that covers where the SCHOOL BUS sign was in the back out of galvanized 26 ga sheet (which I bought accidentally). I primed it after I riveted it on the bus but it looked like it was going on kind of funny, with the paint bubbling a bit.

I really should have researched this before building the whole thing. Fortunately I haven't built the front one yet.

You can totally paint galvanized steel. You just have to etch it first with some ospho or something similar.

 

[musigenesis]

You can totally paint galvanized steel. You just have to etch it first with some ospho or something similar.

How long do you leave it on for? I have ospho, also have some Loctite naval jelly which is apparently just ospho with some jelly-type stuff so it adheres better.

 

[o1marc]

How long do you leave it on for? I have ospho, also have some Loctite naval jelly which is apparently just ospho with some jelly-type stuff so it adheres better.

There will be specific directions for use before painting.

 

[musigenesis]

There will be specific directions for use before painting.

But the directions don't specifically cover etching zinc-plated steel, do they?

 

[o1marc]

But the directions don't specifically cover etching zinc-plated steel, do they?

Is it going to give directions for every specific metal, no.



https://home.howstuffworks.com/home-improvement/home-diy/painting/how-to-paint-galvanized-metal.htm

 

[EastCoastCB]

How long do you leave it on for? I have ospho, also have some Loctite naval jelly which is apparently just ospho with some jelly-type stuff so it adheres better.

Apply the ospho, let it sit 24 hrs. rinse and scuff it and its ready for paint.

 

[musigenesis]

Apply the ospho, let it sit 24 hrs. rinse and scuff it and its ready for paint.

Hmm, I wonder what ospho will do to dynatron-550. My problem is that the patch I riveted has something like 60 rivets holding it on now so I need to etch it in place before repainting. The rivets were all "wet" using dynatron-550. Would ospho eat away at that stuff and ruin the seal?

 

[HazMatt-SKO]

Maybe get a fine/medium craft paintbrush, melt some clear, or white, wax, and then paint over the rivets.
After the ospho's sat, before properly painting the panel, take a rag and a Bernzomatic to wipe/melt the wax away.
Mi dos centavos...