'Pushing' Zipper Flaps

[Peppy]

We were having problems with our zipper flaps a bit ago. It took me a lot of thinking to figure out what we were doing wrong. I wonder if anyone else does this, has similar problems, or has another fix....

When we sewed a zipper flap we laid the flap flat on the main top and sewed the zipper to the top. We did this (almost) always on every flap. I tried to mark my lines on the pattern where they would lay on the finished top. Since we always laid the flap flat, sometimes you couldn't do this. A flat flap will lay the seam on the middle of the bar. (on 1" tube the seam will be 1/2" down from the top of the bar) On the back bar of the front section of a camperback the cloth usually only touches the top of the bar then carries on to the camper section. If you lay that flap flat it'll suck down 1/2", changing the shape of the curve of the rain flap leading to wrinkles/sucking in/general ugliness. Some times we would 'push' flaps. Lay the flap flat, then push it back towards the seam and sew it. We had no rhyme or reason to this and only pushed it 1/4". We had no science.

I introduce to you, The Push Gauge! (also know as the Peppy)



The ruler touches the top of the leading bar and the hook hooks on the bar needing the flap.



I have it marked in 1/8" but only ever mark 1/4". I use it to make ticks then join the ticks with the ruler. Here I'm marking 1/2" push.



It seems to me that the optimum place to mark the seam is the last point that the ruler lays flat on the pattern without going over the edge. Seems the rain flap lays better when marked like this. What do you guys/gals think/do?

I then mark the push on the pattern, in this case 1/2". The sewer then lays the flap flat, then subtracts 1/2" and sews it down. (actually she now measures from the seam but same difference.)

This is only for marking seams with a flap. I almost never lay a flap flat anymore. My tops fit nicer than they ever did before in front and behind the bar. I felt like a real dummy making tops for so long without giving flaps a second thought. Oh well, hope it'll help someone else if your not doing something like this already. If anybody's interested I'll detail how I made it.



This is what I was making. A flybridge bimini, enclosure pattern to follow. If it ever stops raining. (I kinda hope it doesn't. I hate flybridges. Pinstripes don't make good scaffolding.)

[JuneC]

When we sewed a zipper flap we laid the flap flat on the main top and sewed the zipper to the top. We did this (almost) always on every flap.

What are you referring to as a "zipper flap"?  You mean the rain flap where a zipper will be attached to the enclosure/camper?  Or the pole pocket? 

I'm not following your post at all here.  I understand what you mean about needing the seam to lie in a certain place on the pole, but pushing/pulling the flap I don't get.  Maybe I need another cup of joe?

June 

[Can-Vas]

Yeah,  I'm kinda lost on what your saying also Peppy...sorry.

There is an excellent article on flaps and patterning in the marinefabricator.com articl from two months ago...

Howard

[regalman190]

Sorry....I'm confused as well.. ??? And I've had a lot of coffee so far!

Howard...that article was great. The flip trace technique works like a charm.. ;D

[fragged8]

hiya
  That flip trace method of marks in the fab mag seems a bit odd to me but then i make few
bimini's

and why do you pattern a rain flap ?? are you making the rain flap in one with the bimini skin and then the push line you are marking is where the pocket is sewn
from the underside ? eliminating the way we do it which is to make a separate rain flap and sew it into the seam between the top skin and the bow pocket.

sounds interesting .. i would like to see some close ups of the sewing and final seam..


Rich

[Peppy]

Sorry all, common language strikes again. Lets try this....here are some cross-sectional drawings of a boat top;



I'm talking about the 'pole pocket' I guess. The flap that holds the bar. All my blather was about where to sew the pocket to the main top.

Rich- I'm patterning the rain flap because I don't do that trick from the fabricator mag, but should probably. I'm sure our tops are built the same, separate rain flap, bimini top, pole pocket.



If you were to lay the pocket flat on the main top and sew it down, the seam will lay on the bar where shown.



This shows (I hope) what I mean about pushing flaps. Clear as mud?

[fragged8]

hiya

If i get it ? then thats the same as I do it .

except I lay the 'Bow pocket' on the top and mark the edge where you've marked the zipper
then from that marked line i make another mark 1/2 back to ease the pocket and make some room for
the bow ..
same as your sewer .. .


patterning with the rain flap as one though is making me think that it could be done  ?
the seam would be thinner and one less process to do ..

[Eric]

I don't adjust my pocket to move seam for flap, bow pocket and seam for flap are always in the same spot. What changes is the curve I cut my rain flap, to get it to shoot out for a camper back or lay down for aft curtain.
Rich you can do bimini and rain flap as one piece, but it looks like hell. I will take a picture of one done that way.
Eric

[Peppy]

Rich- Thats exactly what I'm talking about. But then, how do you locate that seam on your pattern? How do you know where to mark your line? Thats what the gauge does.

When your 'pushing' that flap in 1/2" your not actually making room for the bar, your pushing the seam around the bar so that it would look something like the first picture. I don't think there's any way to actually make room for the bar. Even when you push the flap you can still get the 'cavitation'? of the pocket/main top seam (where that seam sucks down making a trough type thing)

Like in my drawing how I drew the top and pocket making a lowercase 'y' where one leg is straight and the other leg (the pocket) branches off it, on a real life top it's more like a capital 'Y' with the bar sitting in the 'v' part.

Eric- How do you pattern everything behind the rain flap? After the front section is made and installed? All at once?

In my picture the reason I've patterned the rain flap is because I'm going to pattern the enclosure from it later. Usually the rainflap pattern would be part of the backcurtain pattern and attached to the main top. Made like one big paper bag, so to speak. I wonder if it makes this problem unique to me?

[fragged8]

hiya

Unfortunately I don't make enough biminis and convertible tops to to think about the seam placements
a lot of my work is pram hoods here and i make a good job of messing them up  :D

I'd like to make more but i just don't get them .

i'm still a little hazey on moving the seam up and over the bow.

rich

[regalman190]

When I pattern tops, I use blue tape on the bows and mark my seams on the tape exactly where I want them. Then double sided tape, so when you lay clear plastic over it you can trace the seam onto the plastic. As for the flap, I cut it straight, not to the curve, and sew it on. It will lay flat at the middle and tuck in slightly at the bow curves. Fits great.

[Grebo]

I do it the MCTI way.  Front & back poles, top flat on the table, pocket flat on the top & flap flat on the pocket  ???  & sew along the pocket edge.
For any poles in between I 'push' 1/2".  Seems to work good to me  ;)

[fragged8]

hiya

When i've done that the top sucks down in front of the rear bow ?

Rich

[Peppy]

I do it the MCTI way.  Front & back poles, top flat on the table, pocket flat on the top & flap flat on the pocket  ???  & sew along the pocket edge.
For any poles in between I 'push' 1/2".  Seems to work good to me  ;)

It does work good, we did it that way for 20+ years. Actually we didn't push the middle bar flaps and thats pretty much what got me thinking about the whole thing. Because we didn't push those flaps at all (or sometimes a 1/4") they were 'sucked down' ie: the seam was forced to the middle point of the leading edge of the bar. Regardless of where the line was drawn on the pattern. I think thats what you mean Rich?

This is what I'm really trying to get at. The gauge allows you to draw the line on the pattern (or bar for you dotters) in a place that will correspond with the sewing. Reliably without guessing or going by feel.

Because I wasn't drawing my lines exactly where they would end up as a finished top I was getting unexpected things happening on my installed tops. When I drew the line on top of the bar on the pattern, when sewn with the flap laid flat, on the finished top that seam would get squeezed around the radius of the bar 1/2"ish. this caused a bunch of problems;

-In front of the bar it was too tight and creating that 'cavitation' at the pole pocket/main top seam, especially at the either end of the flap. There it would be screaming tight, close to blowing the seam (helped by the fact we didn't shape the flap).

-Behind the bar it caused the rain flap to come from a new radius ,different from the pattern. This smaller radius caused crappy looking wrinkles in any curtain past the rain flap.

-Any curtain attaching to the rain flap was now 1/2" too big since everything ahead of that flap was 1/2" to tight.

The gauge is only for marking any 'load bearing' flaps/pockets. Any flaps for middle bars are marked on the pattern on the top of the bar and when sewn are pushed close to an inch so that they do next to nothing and the seam falls where it wants to go.

I'm sorry if reading this explanation is like brain surgery. I've never really had anybody to explain it to, except the sewer and she doesn't  really understand how a top fits, or care much for that matter. She just wants me to hurry up with the pattern so she has something to do. Thats why I love this board, I can talk about boat topping theory, whether you like it or not!

[JuneC]

Wish now I'd taken pics....  Factory canvas with the bow seam across the top.  The top fit nicely, but you couldn't get at the zipper (tape sewn into the seam) to attach the enclosure.  The teeth were wedged between the rain flap and pole.  Then, when you finally got the enclosure attached and snapped to the windshield, it pulled the pole pocket down and the pocket got all baggy and nasty looking.  The seam was meant to stay on top, but the tension on the enclosure moved the seam around the pole till it just looked bad. 

June