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Oracal 751c, looking for advice please?
Posted by Simon Stonuary on 27 February 2009 at 22:20Hi Everyone i`ve got a few merc vans to do over the weekend,usually i use 651 but due to the recess on the sides of these vans i will be using 751.I Have never used this before but seem to remember a few comments on the boards from people saying they prefer not to use 751.I know its down to personal preference but are there any pitfalls to watch out for when using and layering 751
John Childs replied 16 years, 8 months ago 11 Members · 17 Replies -
17 Replies
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Simon
even 751c will probably struggle with the deep recesses on the merc, i always slit them on the recessesKev
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Simon, 751 is ok if fed into recesses, and if the vans are the new shape then you can get away with some stretching, but without seeing the design, hard to say if you will be ok. it does loose colour if stretched, though,
if any doubts I would opt for 851, or other simillar quality castPeter
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Thanks the design is straight across the side panels and doesn`t cross the corners so should be ok , the reason for using the cast was the textured section at the bottom of the recess doesn`t lend itself to good adhesion if using a thicker material
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the reason that the recesses on old sprinters are a problem area is usually down to preparation, the paint is water based and is not as good as solvent based paints at accepting vinyl, especially when stretched,
graphityp sell a mild etch primer, that helps, but if you clean, then clean again, and finally clean with isoprop and avoid stretching, you should be okPeter
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751c is a cast vinyl – so will do what is required here (i.e stretch without shrinking back).
The reason I do not like cast as a good "all rounder" is it is very brittle and tears easily (unlike calendered vinyls).
But I reckon 751c is the ideal choice for this particular application.
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its a misconception that only cast can be used in a recess.
personally I dont rate 751 as a good choice, yes it is a cast, but on the bottom end of a one to ten scale, many calendered vinyls will perform better in recesses,Just my opinion
Peter
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quote Peter Normington:its a misconception that only cast can be used in a recess.
personally I dont rate 751 as a good choice, yes it is a cast, but on the bottom end of a one to ten scale, many calendered vinyls will perform better in recesses,Just my opinion
Peter
Please explain Mr Contrary 😀 😀 😀
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quote Peter Normington:many calendered vinyls will perform better in recesses,
Just my opinion
Peter
Sorry Peter, got to disagree with you there. By the actual manufacturing process, calendered vinyl are no good for recesses.
Polymeric and monomeric materials have a memory effect which is why they pop in recesses. They automatically want to stay flat, so will pop under heat or poor adhesion.
Cast, as you know, can be ‘fooled’ into thinking it has to stay in a recess by heat.
I agree that 751c (as opposed to the old 751) is probably at the bottom end of the scale, even tho its rumoured to be 3M face stock with orafol adhesive.
Personally I’d use 851 if I was staying with Oracal, or 7725 from 3M. 3M180c is also a good choice.
I wouldn’t want any newbie reading this thread to think that it is OK to use a calendered material in a recess though, as when it fails, they’ll ring their supplier and complain, only to be told that you shouldn’t use a Cal vinyl in that situation. Fair enough that our weather is extreme here in terms of heat range, but I’d be surprised if it was any less an issue over there.
The old sprinters should have the recess heated during the cleaning process. Mercedes Benz has told me here the product in the recess has a silicon like material, and the heat will help remove impurities before sticking the material on. I’d use the etch primer tho from experience. Feed the material in as Peter suggests and you’ll have less issues.
Hope that helps 🙂
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quote Peter Normington:its a misconception that only cast can be used in a recess.
personally I dont rate 751 as a good choice, yes it is a cast, but on the bottom end of a one to ten scale, some calendered vinyls will perform better Than 751 in recesses,Just my opinion
Peter
Small correction to my earlier statement, 😳
I use oracle as my main material, and with reference to this particular application it will be fine if fed into the recess, as I said earlier,
but if there is a need to stretch it then I would go for a better cast, or even a top end calendered,Is mac fleet a cast vinyl?
http://www.mactac-europe.com/en/Macmark … t6500.html
Peter contrary
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peter, i have to disagree…
ANY decent calander vinyl being applied PROPERLY "in and out" of recesses e.g. found on old style sprinters and transits will stay put. If its fed in, around and out of the recess correctly with a bit of a heat behind it to help properly adhere the vinyl it wont come back out. not in my experience anyway…
the following picture is certainly NOT the same depth or as severe recesses, but all i have online to show… this CALANDER vinyl was applied about 6 years ago. it wasnt fed in and out, it was stretched in with the aid of heat.
I saw one of these vans yesterday. i sat next to it eating my lunch… i thought "that its now a banger of a van, rust appearing here and there but the vinyl is still perfectly in tact". i can take a picture next week if need be. anyway… my point is, this CALANDER vinyl was Oracal 751.
As you are now aware, a couple of years ago Oracal upgraded 751 to 751c as it is now a CAST. So its performance on the likes of recesses and the like will be far better than it was back then, but still… back then it was extremely good. so in my opinion, Oracal 751c is more than adiquet for the job.
.
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off topic slightly, but asked to do an Avery 800 coloured wrap for a well known radio station, we turned it down as it was cost saving! had trouble with them before supply useless vinyl with it going into recesses.
Also we had a fleet of vans out there which been done over time, all the calendared avery 2000 came apart in receess, we then moved to avery 1900 cast wrap, not a problem yet (except cost)
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Fairplay rob that’s awsome.
I would never risk using heat on a calendered, (main reason i stopped using metamark because they didn’t supply cast.)
J
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Better one this time…
this is "another" example of me using Oracal 751 "CALANDER" before it was changed to a cast vinyl, 751c cast.This vehicle was amongst many the exact same… I still see one of two of these vehicles driving about from time to time and again, the vinyl is still the very same condition.

just giving my opinion/views like you peter but i think i am backing mine with some good evidense to back my thoughts?
Just for the record, I am NOT advising folk that Calendar vinyl should be used in this way. It can, but the vinyl in question must be a good brand and the applicator following the application procedure by the book. in fact, thats not right becauise the book wouldnt tell you to apply over surfaces like this with calander vinyl… but you get the idea yeh? 😉
I am simply posting these post to help prove my point that Oracal 751 and now 751c does what it says on the tin….
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Rob, for the benefit of the newbies on this site, its worth noting that the old 751 was at the very top end of the calendered range, but was still changed by Oracal to a cast to overcome the issues related to cal being used on jobs that really should have had a cast.
End of the day, the rule of thumb is not to use calendered on recessed areas. I’ve used it on shallow recesses too without an issue, but to imply it will work on all recesses is the issue I have, especially on sprinters
I’ve had some of the cast materials ‘pop’ too, but can attribute that to my lack of prep than the material itself.
edit: you added the red text while I was composing my reply 😳
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OK. If this is all personal opinions, here’s mine……
The comment I would make Rob, is that neither of your photos show severe recesses. Looking at the Toyota tailgate, the inside corners of the swage have a very large, gentle radius and this means that there is no weak spot for the vinyl to start lifting. Even the deeper crease running the length of the Escort van has a nice single radius at the bottom, rather than two sharp ones, if you see what I mean. Try doing the same on a Sprinter side panel and the vinyl would be straight out.
I would say that the general rule should be that if you are going over a straight bend, and feed the vinyl in properly, then a calendered is perfectly adequate. However, if the vinyl needs to be stretched in any way, use a cast.
Then, like all general rules, learn where you can break it. That can only be done with experience, familiarity with, and confidence in, the material you are using. You’ve done a good job with calendered 751 Rob, no question, but there are calendered materials I wouldn’t consider for your two examples.
added on edit. As an extension of that last paragraph, maybe the conclusion should be that if you need to ask the question, then you shouldn’t use the material.
Sorry if that sounds patronising Simon, it isn’t meant to be, it’s just an honest attempt to help prevent you making an expensive mistake (which we’ve all done in our time). 🙁
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