AdministratorSeptember 13, 2020 at 9:43 pm
I have never been a fan of warm pre-stretching. this came about in 2013 because I remember clearly people coming onto my wrap training truck inside Fespa excel London halls and asking have I see the new way to do pre-stretching? there was a buzz about it and some even showed me them doing it on the truck.
I also have seen it demonstrated by 3M in Bracknell headquarters and told them the same, “in theory, yes, but it is fraught with danger and should not be being taught as the way to wrap”.
By that I do not mean “don’t show people” but they, 3M, nor anyone that spoke to about it truly got the overall principle of what was happening. all they saw was a clever way to, as they said, reverse shrinkwrap!
If we take the 3M wrap video above. which is the same way 3M showed me and others present. they stretch and pull down about 30% of the length of the vinyl. Then reverse shrink wrap it.
So you think… “looks impressive and if they say it, it must be right” right?!
1, what about a digital print? do you stretch and distort that to create some stress relief in the hope that “their vinyl” will not fail?
2, What about 3D wrap film, carbon, brushed metal etc. do you stretch and distort that to help prevent the edges lifting?
3, even solid colours. they shouldn’t, but some will colour shift, so become more transparent in the middle of the mirror and darker towards the edges. i.e. wrapping a black car yellow!
4, they are pre-stretching 30% in “one direction” when a wrapping films stretch performance ability is based 360 degrees of stretch. So you are probably overstretching by the recommended amount right away. Yes there will be arguments both sides of the fence but to be trying to teach this as an industry standard is like the blind leading the blind.
about a year and a half ago or so, I saw Justin Pate post online how the Japanese wrapper (can’t spell his name) has invented cold-pre stretch! I quickly replied to him stating that he was wrong! and that UKSG has been teaching cold stretch from around 2012 via my training unit all around the UK. (he did not respond to me)
I am NOT saying now that “I invented it” because I don’t see it as anything more than a technique that anyone that truly understands what’s happening to the vinyl starts to use when they apply it.
I discovered I could easily teach “cold application” (not cold pre-stretch) not long after we created the training room itself. because I had it made specifically with the perfect temperature-controlled room environment, also with the vinyl stored in same. that some (not all) vinyl required little to zero heat to wrap with. only once it became too difficult/complex/demanding areas would heat be used.
When I asked our students to wrap like this, they found it easier and they did not use or overuse the heat gun which is the first thing they normally go to if the vinyl isn’t going to plan. instead, they would lift and manipulate the vinyl cold. which gave them a better understanding of how to handle the vinyl and when heat should/shouldn’t be used.
anyway, I could go on, but my point is, warm pre-stretching is good to know how it is possible to manipulate the vinyl. it is not what I class as a method that should be taught as a standard way to wrap things.