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Hot-cut vs cold-cut

Posted: Fri, Dec 15 2006, 10:52 AM
by Babbman
OK, I've seen discussion on this in a few places and for my own sanity, I would like some opinions here.

When do you hot-cut as opposed to cold-cut?

When I was at UK Sailmakers, they showed me that everything they do is a cold cut just using scissors or an exacto knife. When they make up a sail, they cold-cut all of the pieces and then tape them together with sailmakers double sided tape. Once the pieces are together, they use a zig-zag type of stitch that is about 3 straight stitches for each zig and zag with each straight section being about 1/2" long. For all of their hemming that I got a look at, they basically took a 1/2" strip of ripstop and folded it over the edge and sewed it with a straight stitch.

It seems to me that as long as I hemmed in some fashion, that hot cutting isn't all that necessary. I guess I haven't looked closely enough at my Revs but it seems to me that they just cold cut it all and hem it or lap sew it. The only heat related stuff I remember seeing are the holes in the dacron where the bungee attaches. I'm also pretty sure that they don't hot cut their dacron as that stuff is all fraying on my Revs.

Opinions, attitudes and suggestions please?

Re: Hot-cut Vs Cold-cut

Posted: Fri, Dec 15 2006, 06:50 PM
by Knoted4ever
i was just wondering... when they hot-cut, what kind of tool or instrument is used? i don't currently sew, but i am curious.


p.s.--- i used to like cold-cuts, but now i'm a vegetarian.

Re: Hot-cut vs cold-cut

Posted: Fri, Dec 15 2006, 07:35 PM
by Mike
You can usually get away with cold-cutting everything, although Rev should hot-cut the ends of the LE sleeve.

It's usually recommended that you hot-cut any exposed edges that wont be hemmed. As an experiment I've made some pocket-sleds and left some exposed, cold cut edges. These sleds get a lot of abuse in the summer, as I load them out to kids in the park and they tend run around and drag them as much as fly them. The cold-cut edges eventually fray a little, but not much.

If you have a template that includes seam allowances, it's easier for me to hot-cut around the template (I use a cheap wood-burning tool--about $10 max).
If you look at our Belgian friend's web pages, he hotcuts around a paper pattern. He even uses an official hot-cutter.

If I have a pattern that doesn't have a seam/hem allowance, I trace around the pattern with a pencil. Then I use a quilting ruler (they are great) to add the seam allowance while I cut it out. I then can use the pencil lines as sewing lines.

And finally, my brother had an expensive carbon fiber composite sail blow out soon before embarking on a race from LA to Hawaii. So the sails don't always hold up...

Whenever you are able to get down here, you can try the different methods to see what you like. Meanwhile, a pair of good, sharp scissors will do you.
(later, you can get cutting mats, rolling cutters, big piece of glass, hot cutters, quilting rulers.... what's a hobby if you can't buy cool toys to go with it!)

Re: Hot-cut vs cold-cut

Posted: Fri, Dec 15 2006, 08:41 PM
by Frodos Majik
For myself, I trace out the templates. Then using a quilters ruler I cold cut 1/4in out from the template for inside seams and a 1/2 in out for outside hems. Using either a exacto knife or roller cutting tool.

Then when marrying up two panels, to be sewn together I hot cut them together, rather then using glues or tapes which can gum up on your needle. Then I sew on or as near to the line that I had traced from the template. Just be careful when hot cutting together, make sure you have the panels facing together correctly. Think it through first, would be easier to show rather then to put into words. At least for me it would be. Maybe someone else with more experience could type it out for you.

For the outer hems just fold at 1/4in and fold it again at the 1/4 in, which would equal the 1/2in mark from the template. Then just sew the hole thing down.

So to your question ... Yes and Yes, I use both hot and cold cutting. :blink1:

Thats the way it works for me. :wink: :up: Have FUN!! :mrviolet:

Re: Hot-cut Vs Cold-cut

Posted: Fri, Dec 15 2006, 08:55 PM
by Kite Slayer
Hot cutting can weld edges together, that have to be sewn together. Hot cutters don't need to be sharp, just hot. Hot cutting on a big glass table is just plain fun!

We started hot cutting with a woodburning tool. It had to be used really sloooowly. Now we use a soldering gun. It's a bit faster and easier to handle then the woodburner.

( :poop I did it again! This is going to be nuts with 3 of us on here now!)

TTFN,
Drafnik

Re: Hot-cut vs cold-cut

Posted: Fri, Dec 15 2006, 09:59 PM
by Mike
My woodburner is a little too hot and I had to tame it a bit with a dimmer switch. Mine was from Wal-mart, in the hobby section.

Posted: Fri, Dec 15 2006, 10:23 PM
by BANSHEE
I myself hot cut everything. I started using a hot knife from a hobby store, it really sucked though it actually had an exacto blade on the tip and no room for interchangable tips, then I received a weller pistol style soldering gun and used it for many years. As was said before the blade does not need to be sharp, use a butter knife as an example and that will be perfect. All that's needed is to heat up the current tip and hammer it into shape. I've never been bothered by an over heated cutter you just have to move faster and it's great when cutting multiple layers. The only problem is when it's not hot enough. You can fall asleep waiting for it to cut.

Two good sources for professional hot knives are sail-rite and challenge sail cloth.

Banshee

Re: Hot-cut Vs Cold-cut

Posted: Sat, Dec 16 2006, 12:20 PM
by Knoted4ever
Is there a chance that the kite fabric can catch on fire? i was wondering about sticking a pointed soldering needle close to the leading edge of a couple of dual line kites that i'd like to add Yo-Yo Stoppers to (to put plastic slip-ties through) but i wonder about the possibility of fire.

i bet it would a lot of fun to make a kite for oneself. i better wait until after i retire, though; the last thing that i need is another hobby! :roll:

Re: Hot-cut vs cold-cut

Posted: Sat, Dec 16 2006, 12:50 PM
by Mike
No fire. The nylon and polyester melt and stink, but no flames in my experience.

Re: Hot-cut Vs Cold-cut

Posted: Sun, Dec 17 2006, 01:42 AM
by denverberry
Knoted4ever wrote:~~p.s.--- i used to like cold-cuts, but now i'm a vegetarian.


Me Too!!!

Re: Hot-cut Vs Cold-cut

Posted: Tue, Apr 24 2007, 01:04 AM
by kiteguy
Cold cut only. Except for exposed edges that flap in the wind. The exposed edges of an applique don't seem to be bothered.

As a gift I got one of the hot cutters from Kite Studio (Kitebuilder.com), and it does tend to make me hot cut more often that I ever have. However, I would NEVER expend the money to get one of the hot cutters if I spent my own $$$. If I HAD to hot cut much, using my own limited funds, I would use one of the soldering guns. They heat quickly enough, and are almost as fast as the Engal hot knife from KB.

Re: Hot-cut vs cold-cut

Posted: Tue, Apr 24 2007, 09:52 AM
by Mike
Kiteguy, do you even cold cut applique on banner cloth? That stuff seems to fray just looking at it.

Re: Hot-cut Vs Cold-cut

Posted: Wed, Apr 25 2007, 05:19 PM
by kiteguy
Some do, most don't.

Just straight stitch the applique, cut close to the stitching, and then go around the applique with a wide zigzag spaced very close together. I think it is called a satin stitch. Just make the stitching overlap the edges of the cut part and over the strait stitch.

This said, it is what others do. I don't make things made with banner cloth. Well, I guess really, I did...twice. The first, and last time. Both at once! LOL

Re: Hot-cut Vs Cold-cut

Posted: Sat, Jun 09 2007, 10:08 AM
by outsidetheboxkitestudio
Mylar and poly, no problem with cold cutting. Nylon on the other hand tends to fray out a bit. Dacron, as in LE pocket, is good for the hot cut. The way i do the nose of my kites requires a hot cut as well. Hey Tom, yes i am stalking you... you asked about poking a hole in the LE to add yoyo's. I use a hot needle and very small zip ties. If you slide the needle back and forth to make a small slit, the zip tie fits just right and causes no harm to the LE or sail. Hot cutting can be good but man when i mess up it's not pretty. The cold cut method has it's drawbacks for sure but the misteaks(tm) are not so irreversable for the most part.