Yuchan

I decided to compare the 751 and 641 for those who are in the same situation.

751 and 641 both had the same downforce threshhold. Didnt weed at 60, worked at 70g.

Here are both sheets after weeding. They felt the same except the 751 weeds better on tight spaces (because it stretches) while the 641 breaks on small spaces but weeds better on large spaces.



After putting them on tape. They look the same. I had to look back onto my first picture to see which one was which.



And here are two letters on my desk.



This is where I noticed a clear difference.

When applying, the 751 went on in one pass while the 641 tried to come off. I had to squeegee it into submission and then it finally gave up.
Once again, they looked the same, and felt the same once it was on a surface. You can tell when you bend it, but I couldnt care to tell when it was already on something hard like my desk.

When I peeled them off I noticed the big difference.
I realize the 751 has a documented 12% increase in adhesive power, but what I really noticed is this:

It was like peeling a wet piece of paper from the desk, while the 641 was like peeling off a solid plate. It came out in chunks.

The 751 definitely definitely conforms much better. I think the wet paper analogy is perfect.
When I peeled off the 641, I got the classic "pop" and a huge chunk blows away, while with the 751c, It actually has to peel.

edit: I guess there was confusion here. The 641 sticks JUST FINE. But relative to the stuff that costs more than twice as much? It 'pops' off while the 751 sticks damn hard to the glass.

So the bottom line? Yay for conformity and extra stickiness. Is it worth paying 250%? I guess it is for the peace of mind that your decal wont fall off in a few years. (or will it? )

I'm glad I have both the cheapo and something a little higher end, they will both find uses.

 

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theflowerboxx

hhhmmmm.........now I always feel a difference between cast and calendared vinyl. Calendared is thicker and stiffer then cast. Oh and I wouldn't order anything from sign wharehouse. Their customer service is almost the worst I have ever seen.

 

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Yuchan

Quote: Originally Posted by theflowerboxx hhhmmmm.........now I always feel a difference between cast and calendared vinyl. Calendared is thicker and stiffer then cast. Oh and I wouldn't order anything from sign wharehouse. Their customer service is almost the worst I have ever seen.

Yeah, definitely. I wrote that I could 'definitely tell' after putting it on the desk.

Ive heard bad things about signwarehouse like short rolls but last time they gave me free shipping ($15) when an order was late.

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L00T

Quote: Originally Posted by Yuchan 751 does indeed say cast on the back : ) even though signwarehouse says both cast and calandered. Whew, dodged a bullet.

Good for you they send you the casted vinyl and everything is working out well now

 

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BRC

According to the Oracal website the 751 is an 8 Yr cast vinyl and the 641 is a five year calendered vinyl. There is no such thing as cast or calendered, it is one or the other. Where the C comes from I don't know but doing a search on their site shows nothing for a 751c.

As far as the graphics falling off because it is calendered instead of cast, if it is applied correctly it aint gonna happen. Cast is thinner so it is more flexible and conform to uneven surfaces better. There are differences in the manufacturing process which makes the cast perform better. But none of that has to do with the adhesive which is what makes the vinyl stay on. The 641 as an economy vinyl has a water based adhesive where the 751 has a solvent based adhesive. If you look at the 651 you'll find it has the solvent adhesive with the calendered vinyl and works just fine at an affordable price.

If your vinyl comes off the backing in "chunks" you may want to back off on the pressure a little because you may be cutting too deep into the backing causing it to stick and then when it releases it seems like it comes off in chunks.

 

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Yuchan

Quote: Originally Posted by BRC According to the Oracal website the 751 is an 8 Yr cast vinyl and the 641 is a five year calendered vinyl. There is no such thing as cast or calendered, it is one or the other. Where the C comes from I don't know but doing a search on their site shows nothing for a 751c. As far as the graphics falling off because it is calendered instead of cast, if it is applied correctly it aint gonna happen. Cast is thinner so it is more flexible and conform to uneven surfaces better. There are differences in the manufacturing process which makes the cast perform better. But none of that has to do with the adhesive which is what makes the vinyl stay on. The 641 as an economy vinyl has a water based adhesive where the 751 has a solvent based adhesive. If you look at the 651 you'll find it has the solvent adhesive with the calendered vinyl and works just fine at an affordable price. If your vinyl comes off the backing in "chunks" you may want to back off on the pressure a little because you may be cutting too deep into the backing causing it to stick and then when it releases it seems like it comes off in chunks.

Thanks for your words BRC. Of course there is no such thing as "cast and calendered" (i assume thats what you mean) although I guess you could cast it THEN calender it.
Cast OR calendered was the question because signwarehouses website says 7yr cast, and the 751 description page says premium calendered.

You make a good point. I've deleted that part of the post because other people may be thinking the same thing. That topic was in another post : )

In the end, it really doesnt matter.

Quote: As far as the graphics falling off because it is calendered instead of cast, if it is applied correctly it aint gonna happen.

The graphics falling off because its cast vs calandered? I say no such thing. I think you are reading the part where I say "I needed to beat it into submission" and inferring that i'm complaining about the vinyl.
I am not saying it didnt stick. That stuff sticks damn well enough on clean glass. It shouldnt come off too well without a metal tool. But in that particular situation I was comparing to the 751.
I did a light pass on purpose, noted that 751C stuck while the 641 didnt, and documented that.

I am simply comparing 641 to 751C for whoever may be interested.

I explain HOW the difference is noticeable. Not that one falls off and the other doesnt.

Quote: Cast is thinner so it is more flexible and conform to uneven surfaces better. There are differences in the manufacturing process which makes the cast perform better. But none of that has to do with the adhesive which is what makes the vinyl stay on.

Yes, that is correct. The differences include the fact that cast is not stretched, and wont change shape after being cut. I am aware.

Yeah, calendered vs cast does not have a direct impact on adhesive power. but the 751 comes with stronger adhesive, and I was highlighting in my post how the combination of being thinner and having a stronger adhesive effect real world performance.

Quote: "If your vinyl comes off the backing in "chunks" you may want to back off on the pressure a little because you may be cutting too deep into the backing causing it to stick and then when it releases it seems like it comes off in chunks."

I was explaining the process of taking the vinyl off the glass desk (not the backing). Coming off in chunks is a matter of rigidity/adhesive power.
As for the cutting depth/pressure, i noted at the top that at 60g downforce it would not weed and at 70 it would. I used the minimum : )


You see.. I am just trying to help other people who may be curious about a $17 roll of 641 fares vs a $44 roll of 751C (as I was, a few weeks ago).

I wanted to explain the difference between adhesive power/flexibility of the 751C vs 641 in my own words because all we have to go on are

641: adhesive power: 16 N/25 mm, adhesive: polyacrylate permanent, dimensional stability: shrinkage in lenght 0,4 mm max.
751C: adhesive power: 18 N/25 mm, adhesive: solvent polyacrylate permanent, dimensional stability: shrinkage in lenght 0,15 mm max.

which means little to nothing. It only explains that one is better, which everyone knows

I am just trying to help, because I wondered for this information myself when I was looking for a better vinyl. I guess you are too, and I thank you for that.

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