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Rok Building tips.

Posted: Thu, Jan 11 2007, 06:34 AM
by Babbman
Since it seems that everyone is going to build a Rok of some sort, I thought I would talk a bit about my experiences and try to get some of the problems I ran into out in the open so others wouldn't have to deal with them...

I really liked this project and in the end, the result was very satisfying. But, I did run into a few problems...there has to be better ways to deal with some things. I basically followed Gary's plans for a 6' Rok and scaled it down per Mike's plans for a 3-4-5 Rok. Other than keeping with a similar scale, the most attractive part of Mike's plan is that you can use 1 piece spars.

as for building, that part was pretty easy as long as you pay careful attention to the squareness of the main sail and accuracy of your end piece templates. as for appliqué techniques, that's another thread all together (no pun intended). Where I started to run into problems was assembly of everything...

1) Hemming the complete sail... The double folded hem ended up being easy except for the corners. The basic mitering threads on kitebuilder covered the mitering of square corners but how about the obtuse angles created by a Rok? My first problem here was the fact that at the corners, you have a number of layers and a seam, all in that corner as well as the off angle. There is also the fell seam thread to deal with which makes a bulky and thick corner... Very difficult to fold and hold and it's a large bump for the presser foot to go over... How do you experienced Rok builders deal with these corners while hemming? This was one of the messier parts of my inexperienced sewing job.

2) Dacron patches 1 - These were pretty straight forward for the corners and bridle patches except when sewing on the patches in the middle of the sail. The main problem here was turning the sail to sew on the 1.5" patches and dealing with all the material that must go under the arm of the machine. Do the experienced sewers try to do one continuous sew around the patch or do you sew a side, cut the thread and do the next side? The problem I ran into here trying to do a continuous sew is getting into the corner, turning and then continuing the sew... very difficult to make it all line up.

3) Dacron patches 2 - The patches where the spars cross. Here, I tried to follow Gary's plans as I really liked the look of them and the theory behind them. Making the crossed webbing and sewing it together was pretty easy but because the webbing I used was rather thick, I had problems getting it under the presser foot and having it all stay where I wanted it. My machine tended to push the webbing towards me as I sewed it. Decreasing the presser foot pressure helped but... Sewing this webbing to the dacron patch was simple enough but the same problem especially since dacron is pretty slippery. Finally, the absolute worst part of the entire build process was sewing this completed assembly to the kite. My problem here was that because of the thickness of the assembly, my presser foot could not maintain pressure on both the assemble and the area around it where you needed to sew. 1/2 the presser foot was on the double thickness of webbing and the other half hanging above the sail.dacron area... Every time I tried to sew it, it would shred the thread. Zigzag was the worst... I finally redid the patches and sewed it with straight stitch... I was VERY unhappy at this point as I was turning both the dacron and my 99.9999% completed sail into swiss cheese... Plus, it looks terrible by my anal standards... We need a better way to do this in the future as I will NOT sacrifice my sail and days of work to this assembly again. Suggestions are demanded! :lol:

4) Spar pocket webbing... Mine is shredding at the end cuts of this. Even after hot cutting it... Maybe it's my Hobby Lobby Webbing... maybe I'm just too inexperienced to know how far to go to melt the edge..maybe not any of them. I noticed that Mike cuts his webbing where the spar enters the pocket with 45 deg angles at the corners. Can you guys give some thoughts on this?

5) Spar pocket placement - I figured that these pockets really need to be placed to put the tension on the sail exactly at the corners which put my sewing lines for attaching the webbing just above the sail seam where the top attaches to the main sail... I don't think it's a problem but it just doesn't look very good. Also, at the very end, when adding in Mikes plan for the spar tensioning by burning through the sail, I ended up having to burn directly through the seam because I didn't plan for this.... Thoughts?

6) The button tensioning idea is just plain and completely brilliant.... I love it and it worked excellently.

That's all I can think of and just some of the things I wish I would have known but couldn't have since I had never done this before..

Any other thought, tips and hints would be GREATLY appreciated :thanks:

Re: Rok Building tips.

Posted: Wed, Jan 17 2007, 08:37 PM
by Chris
I like the idea of using webbing to tie the spars together. Looks very neat and profesional; but being a proud member of the 100' kite club, I opted to use shoe laces to tie them together :wink:

Can anyone tell me why the reinforcements are needed on the sail where the spine and spreaders cross? Babbman and I disscussed this last weekend, and couldn't come up with a good answer between the two of us.

I didn't use it..is that a bad thing? :shock:

Re: Rok Building tips.

Posted: Wed, Jan 17 2007, 09:13 PM
by Babbman
the only reasonable answer I can come up with is that there is additional pressure on the sail at that point where the spars cross and the dacron patch would protect that area... I don't even think you really need a dacron patch there... an additional square of ripstop would do the trick...

Re: Rok Building Tips.

Posted: Thu, Jan 18 2007, 11:12 AM
by Draftnik
I've been wondering the same thing...a patch would have more stiches, spread out over a larger area.

Not sure that adds all that much, but probably some added strength. When you patch, are you sewing the sleeve just to the dacron and not to the ripstop also? That would make some sense cause the dacron is stronger then the ripstop and the ripstop would have more stiches and area to absorb the shocks. But I'd think the patch then, would do something funky to the front of the sail.

If you sew the sleeve to the ripstop and the dacron patch, I can't make any sense of it. :? Maybe the strength of the dacron lends itself to the ripstop?

It'll be interesting to compare these roks. I have a New Tech rok too we can look at too at the next club fly.

Re: Rok Building tips.

Posted: Thu, Jan 18 2007, 12:12 PM
by Babbman
here's how Gary Engvall does his 6' Rok...

Image

all the webbing is sewn to the dacron patch. The patch is then sewn to the ripstop... The vertical spar us running under the webbing and is physically sitting on the dacron patch.

I still cannot figure out how he was able to sew the zipzag around the outside of the patch to attach it to the sail though. My presser foot rode up on the webbing and was able to apply no pressure on the dacron only part of the patch so the needle kept ripping the thread... I finally just did a straight stitch to attach mine....

Here's how mine turned out... Keep in mind that I just used some crappy webbing from Walmart... I'll get some real webbing the next time I do this..

[albumimg]428[/albumimg]

Re: Rok Building Tips.

Posted: Fri, Jan 19 2007, 08:51 AM
by Draftnik
Oh! That's a neat set up. Neither of my roks have a connection at the cross points of the spars. The spars have turned white where they bang together, but are holding up fine. I've never wanted to attach a tie to them cause it's just one more thing to mess with during set up.

I don't think there's any significate difference in webbing. Walmarts should be fine.

A zipper foot might get things to work a little better for you, if you have one. Be careful running a zig-zag with it, be sure the needle doesn't strike the foot. It shouldn't, but better safe then sorry. I think you get it to sit on top of the layers and sew across the top and bottom.

I know that my New Tech kite uses what looks like dacron for all the pockets. Maybe it would work better to use dacron for all the layers?

Edit: Gary's changed his plans since I made my rok, he didn't have those vertical pockets on the plans then.

Re: Rok Building Tips.

Posted: Fri, Jan 19 2007, 10:52 AM
by Babbman
Draftnik wrote:Edit: Gary's changed his plans since I made my rok, he didn't have those vertical pockets on the plans then.


can you post a pic and dimensions of your Rok? Chris has been talking about it and I've never seen it!

Re: Rok Building Tips.

Posted: Fri, Jan 19 2007, 11:25 AM
by Draftnik
It's an 8' rok. I believe it's the traditional dimensions. I wanted a kite that could hold a messanger in low winds. Now I wanna make a smaller splat rok for bigger winds.

http://www.kitebuilder.com/forums/viewtopic.php?t=3250

The build thread is over on KB. Don't know that there's any good sewing tips to it, but maybe a few others. Pics on the second last page.

Re: Rok Building tips.

Posted: Fri, Jan 19 2007, 01:10 PM
by Babbman
now how did I miss that thread?....

thanks!

Re: Rok Building tips.

Posted: Thu, Jan 25 2007, 09:17 PM
by Chris
Hey, Babbmann, I found the answer to hemming corners... It's called a quilters corner http://www.kitebuilder.com/forums/viewtopic.php?t=2872 Check out the link :mrgreen:

Re: Rok Building tips.

Posted: Thu, Jan 25 2007, 09:21 PM
by Babbman
Chris wrote:Hey, Babbmann, I found the answer to hemming corners... It's called a quilters corner http://www.kitebuilder.com/forums/viewtopic.php?t=2872 Check out the link :mrgreen:


Yup.. I used this one for hemming the pocket sled... worked great...... my problem was that this demonstrates a square corner perfectly... none of the corners on a Rok are square though!

Re: Rok Building tips.

Posted: Thu, Jan 25 2007, 09:42 PM
by Chris
You're right, I just tried it and the corners won't meet up :(

BUT... If you notch the corner like so...
Image







They don't quite line up, 'cause I just put it together just now...
Image







Very easy to sew through :mrgreen:

Re: Rok Building tips.

Posted: Thu, Jan 25 2007, 09:55 PM
by Babbman
show off... :lol:

But, because of how fantastically anal I am, I want a perfect corner...lol... I learned about this AFTER I built the Rok... Next one will be better... I'll use much better webbing next time also...