Sustained high temperatures

[letterman7]

Ok, sort of got into a lively discussion on an automotive forum about the use of vinyl in an engine compartment as decoration. Essentially, the owner of this particular car wanted to wrap his air intake with a carbon fiber wrap vinyl and was wondering on the life span. I thought it would be fine, seeing how sign vinyls react on some of the black cars and trucks I've lettered over the years. Yes, there have been failures (Avery) but for the most part, especially on squad cars, the sign vinyl has held up fine. I know there is a difference between a sign vinyl and a wrap vinyl, but I would think the basics would be very similar with similar life spans. Anyway, one of the forum know-it-alls who says that he's some sort of R&D engineer for the printing industry and has "extensively tested vinyl films" says that the vinyl will fail in a short time. So... my question to the group is - what is the highest temperature object you've personally applied vinyl to and had it survive past, lets say, a year?

Personally, I had (since removed) vinyl on my black box trailer that sits outside every day. I haven't measured the surface temp of the aluminum in the summer sun, but I think I would be close in saying that it would push 180° or more during the day - and the vinyl lasted for many years that way.

With the owner of said automobile the engineer mentioned heat soak from the engine is what kills the vinyl (outgassing and resulting shrinkage) since the heat from a typical engine could exceed 275° for quite a while. I don't buy it..

R

 

[Gino]

Can't give you any statistics, but vinyl will basically cook off a hood if there isn't sufficient insulation underneath. According to where this vinyl is gonna go, I doubt it will hold up.

 

[Fred Weiss]

I was talking to this customer the other day and I asked him how the below job had held up for him. It's an Edge print with a clear UV overprint and cut white Gerber/3M 220 HP vinyl. He told me it looked great when he traded the vehicle in ... six years after I installed it. I've never actually measured it, but the surface temperature on tinted glass in the summer here is beyond hot to the touch. It's hot enough to burn you. A guesstimate would be between 175°F and 200°F.

Looking up the spec sheet, the Service Temperature Range for Gerber/3M 220 is quoted at -40°F to 225°F. Whether or not the temperature under the hood goes above that would determine whether or not you could expect it to last. Also consider that vinyl is a thermo-plastic and will melt as well as catch fire at higher temperatures.

 

[letterman7]

The vinyl would be going on the air intake housing, so away from a combustible source. I agree, Gino, I've seen vinyl cook off a hood before as well - but I think we need to take into consideration the horizontal exterior exposure to that as well. Fred... yes, that's what I experience with black cars and trailers here. Just want to see what other installers have to say.

 

[rjssigns]

I've made custom valve cover decal and they hold up. Years back there were all sorts of decals on the cars air cleaner housing. Go to a car show and look at some of the old stuff that's still hangin' on.

 

[SellersSign&Design]

I use sign vinyl on my custom metal fire helmet shields. They are put into extremely high temperature environments, and I haven't had a failure yet. I have had some slightly bubble or shrink, but then again that was when it got hot enough to blister the paint on the actual helmet.

 

[letterman7]

I've made custom valve cover decal and they hold up. Years back there were all sorts of decals on the cars air cleaner housing. Go to a car show and look at some of the old stuff that's still hangin' on.

True, but that's when the decals were paper based and not vinyl.

Sellers; let's not hope that happens too often - for the firefighter's sake. Yes, short term it would be fine, but that would be repeated heating and cooling cycles from the operation of the vehicle. Still.. high temps are high temps.

 

[Gino]

Basically, depending upon the particular vehicle we're talking about, there are varying factors which enter in and can change the temperatures from time to time inside the engine compartment. For instance, going up and down hills will make almost any vehicle hotter under the hood. The condition of the engine [maintained or not] also contributes. The temperatures can reach anywhere from 350º to 500º or 600º. After a vehicle's engine is turned off, the temperature rises further more..... much further because the cooling systems are basically turned off, except for maybe a fan, which doesn't do much. The temps can easily go even higher than 600º.

I'd approach this very cautiously and before charging for something, ask the guy to let you put some vinyl on it and check back in a month. Then he can decide if it will tolerate it or not. If this is a show car, then just make him many decals and let him replace them as he sees fit.

 

[rjssigns]

Underhood temps get no where near 500 to 600 degrees F unless you are directly touching an exhaust manifold.

http://www.mvfri.org/Contracts/Final Reports/R04-13v01 Underhood Temperatures 1.pdf

Check some of the traces on the graphs.

I also drag race and it is routine to "run the valves" after a couple passes after heat cycling components. We wait a few minutes, pull the valve covers and get to work. Toasty warm, that's about it..and oily.

Engine blocks, heads, and oil are all water cooled. That's the reason why you can paint a block the exact same color as the body of the vehicle. Discoloration will be minimal if any and only occur at the point where the exhaust manifold/header flange meets the block.

 

[letterman7]

Oh, I'm not doing the job, Gino, just arguing as I am wont to do with guys that say they have experience in the field but no actual practical application experience. Bench testing and real world are two different things... and I think the other feller is a bench tester. For what it's worth, the vehicle in question is a sand rail out west with an open frame. The poster wanted to wrap the fan shroud in a carbon fiber. I have old VW's. Even in an enclosed engine bay the shroud rarely got more than warm to the touch, even after an engine shutdown.

 

[Gino]

Underhood temps get no where near 500 to 600 degrees F unless you are directly touching an exhaust manifold.

http://www.mvfri.org/Contracts/Final Reports/R04-13v01 Underhood Temperatures 1.pdf

Check come of the traces on the graphs.

I also drag race and it is routine to "run the valves" after a couple passes after heat cycling components. We wait a few minutes, pull the valve covers and get to work. Toasty warm, that's about it..and oily.

Engine blocks, heads, and oil are all water cooled. That's the reason why you can paint a block the exact same color as the body of the vehicle. Discoloration will be minimal if any and only occur at the point where the exhaust manifold/header flange meets the block.

That's the same chart and test I used. What is page #17 about ??

 

[rjssigns]

That's the same chart and test I used. What is page #17 about ??

From what I gather it has to do with the volatile compounds in things like brake fluid and engine oil reaching the flash state.

Although I do have trouble believing the claim regarding auto-ignition of anti-freeze. I've been around a lot of catastrophic engine failures and never saw anti-freeze on fire. Makes a heck of a white cloud though.(smells horrible too) Engine oil is another story as is trans fluid. Although those fires are generally infrequent.

Flash points on most oils are right around 400 degrees F, and unless it gets directly on the exhaust it's not going to touch off. Again in most instances, like anti-freeze, it will make a huge white or grayish white cloud. Affectionately known as Death Smoke.

For a fire show watch a nitrous car backfire and while doing so shear the fuel lines. Some of those go like the head of a match. Like this: https://www.youtube.com/watch?v=--PE6eXlA-I

Always hate to see any of that. So much blood, sweat and cubic dollars go into our rides.