Seat Foam Cutting with Hot Wire Jig

MEASURE TWICE

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Jul 13, 2010
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You can look up to buy Nichrome wire online and make a hot wire cutter. The Medium Density Foam I have needed to be cut at a precise arc radius curve of 8 inches. It is not for a seat on a motor bike, but some day yes maybe for a motor bike. It is for a pontoon boat.

My motor bike I did use two types of foam but it is not anything but cutting and taped, so it was never really finished very nice. Though it is definitely functional for trail riding as it has no pedals, just pegs instead, and licensed for Off Highway Vehicle stickered.

So, with pontoon at 16" dia that is 8" rad. The jig has adjustment for about a range around 6.5" to 9", but I could make it bigger. Smaller would be something I know how to do but would take a bit more working on.

The kiddie rims of 6" on two side of a platform with angle brackets you see. The two are ganged together with wood. The threaded rod juts out of the valve stem hole, another hole I drilled just the other side for the wood gang to synchronize both rims to move together. The threaded rod has nuts and washers that clamp the Nichrome 80 wire 24 Guage and 27inch length span. The old train transformer wit 15 volts ac had the right temperature and wire did not break when heated with current flowing.

There is flexible wire I scavenged from probably 20 years ago off a waffle iron power cord. Pulled the twin lead in half and sanded clean the strands and twisted to the Nichrome wire ends where I had it strung across the thread rods on the two rims ganged together.

My hand on the ganged wood part with slight pressure while I wore a gas mask and cut some nice arcs. Next to make the seat covers with fabric and zipper to be able to remove foam and clean an rinse out salt water and dry after a day sailing.

More later as I get to it. A few pictures attached.

Cutting the straight cut was a little hap hazard, but I used a fillet knife and it is a little ragged but with the fabric cover probably not even noticeable.

In the past I never thought of this project, but it finds you anyway. Most people would not need a softer seat, but you find when a spine is out of whack you have to adapt so nerves that are being disturbed by bulging disks don’t go even more on the attack. It is just like an electric shock and it is not something you want to have going on if you know ways to prevent it.

MT
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MEASURE TWICE

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Jul 13, 2010
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Have to eventually see about using next thickness gauge wire 22 if it can stay a bent form cutting. I have also thinner in 4 more sizes. I might need to buy thicker if it will not keep the shape. Also a straight cut using sort of like a guillotine or whatever. The fillet knife cutting for straight cut is a bit ragged look.

One other thing I have to wait and see what happens to the area that was cut with the hot wire. The surfaces have a gooey stuff speckled on them. I don't know if it will firm up and just adhere fully to the surfaces and not stay messy. I know I could try washing, rinse, & drying the foam and see what happens. The covers I am to make keep from having the stuff really go anywhere except the inside of the cover. I did not have any publication I read mention the goop?
 

MEASURE TWICE

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Jul 13, 2010
2,600
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Looked at TinSmith on seat made of heavy leather. I am looking at using marine vinyl material. Good videos on making seat and sewing the box construction and also zipper. Around 10 to 20 dollars a yard by 54" standard have seen on Ebay and elsewhere. The breather vents I also looked into, but are ones that keep water out? Maybe test the closed cell foam with water as is mentioned for boat seats. Then maybe if holds air too much, a simple grommet as the small kit including tools are easier to be had for less. I would like stainless steel though.
 

MEASURE TWICE

Well-Known Member
Jul 13, 2010
2,600
858
113
CA
Have to eventually see about using next thickness gauge wire 22 if it can stay a bent form cutting. I have also thinner in 4 more sizes. I might need to buy thicker if it will not keep the shape. Also a straight cut using sort of like a guillotine or whatever. The fillet knife cutting for straight cut is a bit ragged look.

One other thing I have to wait and see what happens to the area that was cut with the hot wire. The surfaces have a gooey stuff speckled on them. I don't know if it will firm up and just adhere fully to the surfaces and not stay messy. I know I could try washing, rinse, & drying the foam and see what happens. The covers I am to make keep from having the stuff really go anywhere except the inside of the cover. I did not have any publication I read mention the goop?
Good news, in about two weeks since the cutting was done, that sticky bit on the foam has gone away.

The vinyl marine light weight fabric I got was not in a roll and has some creases, but will go away after flattening out in the sun. The fabric had a huge amount of odor that would give a headache. It also just needed airing out. The manufacturer to seller to end user probably always has it in wrap that nothing escapes. VOC strong stuff, but OK since aired a couple of days.

Got 16 and 18 size for special sewing machine needles to see which work best. The 102 thread fits the needles and is synthetic polyester strong and waterproof. The new needles are special meant for leather and I'll use them or general purpose ones.

Making some plans out of construction paper or something to get things done right. Good videos on Youtube shown using plans, not so much how to make them. So I figure just measure and get shape right from the foam I have. Then order of transfer and assembly and small v cut marks on edges not showing of fabric to get aliment perfect when you fold.

Cutting I remember using paper forms, called dolls when doing printed circuit board layout to see how components best fit. I may do that to see how to effectively get the least amount of waste when I decide how to cut out panels and have least cut scrap material left over.

I bet there might be a program that scans and tells where to cut, if it is free online use, maybe could use.

MT
 

MEASURE TWICE

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Jul 13, 2010
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I got seat cover material for the foam to make the cushions, but ran into a problem.

My older sewing machine got all frozen sort of from rust or something. It turned ever so hard that the only way was by hand. Not that the motor was weak, it was just never meant to have all that much torque. Oiled it and then after quite a while it moved with the motor well, but jammed a lot the thread. Not that this was unusual for this machine when starting up after not using it for a while, but I usually got it working right. I found some of the controls do not seem to be exact in calibration. Not even that the controls can be calibrated, maybe they can, or something is bent inside needing repair. The stitch length indicator does not go completely to one side of the scale shown. It did squeak a lot before it started to free up so maybe it is damaged to some extent.

Messing with that it ran OK, but the stitches seem to go not exactly straight when I am feeding through straight. Close enough I suppose, so maybe use this machine. I have another that I never used was given to me slightly newer than the former Japanese make, 60's Classic Art Deco Turquoise and Chrome Kingston Synchro-Matic, compared to a 70’s machine, a Singer Touch & Sew Machine with plastic outer case in White.

The thing has also plastic discs with notches that are used to make more than 10 different stitches automatically. A cover is missing I think lost in moving, but I think I can use it without it. This machine does not need any fussing with to get the thing to turn with the motor, but a %^)[email protected] amount of figuring out on how to use it. I did sew using the Kingston some Velcro onto a Windsurf Harness where the hook side of the Velcro was all worn out. It also jammed again and finally broke a needle, but the Velcro was being sewn to some very heavy thicker by like 3 to 5 seat belt thicknesses. I know I should have a special heavy Sail Sewing Machine, but maybe later?

I made it to Sail the NW Wind that came prior to days of rain were now having. Maverick’s for regular Surfing I know was happening just recent too. Just note Tamales Bay by Dillon Beach at the mouth of the bay reaching in to Bodega Bay, the breakers can get big. I went where it was just wind a wind waves. Maverick's by Half Moon Bay was happening. Youtube should have videos.


The Bay Sailing on Tamales Bay was quite good with one other showing up. Inquisitive harbor seal often staring at us when stopped in the shallows for egress or resting & adjusting rigging. The waves are about 30ft at many places along the Pacific Coast here. Maybe some near shore areas could have the kelp thinned by the wave action and I could possibly think on windy but not huge surf days doing the punch through small breakers to get out to sailing. Boating would seem like restricted to another time of year or find myself Bay Sailing, just time with the short daylight hours makes it difficult to do.

Youtube had some nice video too: 8th Dec 2020 Mavericks

 
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Tom from Rubicon

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Apr 4, 2016
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Rubicon, Wisconsin
I got seat cover material for the foam to make the cushions, but ran into a problem.

My older sewing machine got all frozen sort of from rust or something. It turned ever so hard that the only way was by hand. Not that the motor was weak, it was just never meant to have all that much torque. Oiled it and then after quite a while it moved with the motor well, but jammed a lot the thread. Not that this was unusual for this machine when starting up after not using it for a while, but I usually got it working right. I found some of the controls do not seem to be exact in calibration. Not even that the controls can be calibrated, maybe they can, or something is bent inside needing repair. The stitch length indicator does not go completely to one side of the scale shown. It did squeak a lot before it started to free up so maybe it is damaged to some extent.

Messing with that it ran OK, but the stitches seem to go not exactly straight when I am feeding through straight. Close enough I suppose, so maybe use this machine. I have another that I never used was given to me slightly newer than the former Japanese make, 60's Classic Art Deco Turquoise and Chrome Kingston Synchro-Matic, compared to a 70’s machine, a Singer Touch & Sew Machine with plastic outer case in White.

The thing has also plastic discs with notches that are used to make more than 10 different stitches automatically. A cover is missing I think lost in moving, but I think I can use it without it. This machine does not need any fussing with to get the thing to turn with the motor, but a %^)[email protected] amount of figuring out on how to use it. I did sew using the Kingston some Velcro onto a Windsurf Harness where the hook side of the Velcro was all worn out. It also jammed again and finally broke a needle, but the Velcro was being sewn to some very heavy thicker by like 3 to 5 seat belt thicknesses. I know I should have a special heavy Sail Sewing Machine, but maybe later?

I made it to Sail the NW Wind that came prior to days of rain were now having. Maverick’s for regular Surfing I know was happening just recent too. Just note Tamales Bay by Dillon Beach at the mouth of the bay reaching in to Bodega Bay, the breakers can get big. I went where it was just wind a wind waves. Maverick's by Half Moon Bay was happening. Youtube should have videos.


The Bay Sailing on Tamales Bay was quite good with one other showing up. Inquisitive harbor seal often staring at us when stopped in the shallows for egress or resting & adjusting rigging. The waves are about 30ft at many places along the Pacific Coast here. Maybe some near shore areas could have the kelp thinned by the wave action and I could possibly think on windy but not huge surf days doing the punch through small breakers to get out to sailing. Boating would seem like restricted to another time of year or find myself Bay Sailing, just time with the short daylight hours makes it difficult to do.

Youtube had some nice video too: 8th Dec 2020 Mavericks

Thought I saw Jeff Chamberlain's Radon in the vid but his skiff has twin Yam 60's.
Tom
 
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MEASURE TWICE

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I have twin cylinders if that helps, but only 8hp. I found the cover part to the new sewing machine cleaning off a desk!

Will see about how it operates. I should probably get the right sewing machine oil, but I had mineral oil I used.

Maybe I could make a lamp out of the old sewing machine if it won't work well. It is like a boat anchor.
 

MEASURE TWICE

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Jul 13, 2010
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The sewing machine oil is actually mineral oil made from paraffin wax. $8 4oz, $20 qt, $40 gal.

The use of 3 in 1 oil was mentioned some say OK others not. Light oil also TriFlow was also mentioned. Do like food grade no stink oil. Funny one specific trade name sewing machine mineral oil is branded Lily White.

The mineral oil I got that is from supermarket in the pharmacy section. Never had a taste for using this for myself. I only got it for use on a wooden pizza peel. Now I have a second use.

Tuned up the old machine. I found some bent spring and adjusted as best I figured for the top thread tension. A little fine emory cloth to the bottom bottom thread guides. The pressure foot release now also releases top thread tension when lifted as it should. Everything back to square. Top and bottom side test fabric after adjustment. The loose parts mid stream in test stitch on bottom picture no longer showed up when tightening up top thread tension. Fairly even regular stitch.

Stitch width adjustment loosened up and has a full range now.

I lost one part the nut that goes to top thread tension. Some strange metric size. Found one at a shop, but it had an integral scale marking on a bezel. I got out my Demel, mask, face shield, & ear plugs and cut it away. Turning the nut is supposed to turn the scale marking separate by interlocking teeth. I don't really need the scale, but if I want I can try turning the nut at the same time push the scale to move it in unison.

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MEASURE TWICE

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Point Conception is a buffer from the North Winds if I remember right. Ship wreaks there were many that when past the point an in full brunt had many sink. Further problems from at night not seeing jagged reefs.

Much as I know about Point Arguello is that it was defined in CA Fishing License Instructions in the past as a dividing line. Going South of it you needed Ocean Enhancement Stamp added to the license to take fish. Abs were long time ago allowed using SCUBA. It was once 4 Limit. Then 2. Then None.

But in the North for a while till about 2 years ago breath hold diving for abs were allowed in the Northern Area. I remember only much of that from the 90's. Took pictures with UW Film Camera. Now that film is sort of out, maybe eventually get a digital. Mostly just enjoy remembering what I saw on dives.


As for the Machine it was in a Storage Locker for a while. Although rain did not get in, it was not used for a long time. There was a time that snow got tracked inside the locker and melted. It did no good for the thing.

Now to get time to look at the newer old 70's era machine. Instead of an array of plastic disc to change for adding more style stitches, now stuff is digital and have LCD displays.

I tried fixing some sails, but the sleeve for the mast for windsurf sails got me perplexed as how you fix them. I mean some machines have a removable section for sleeves and legs on cloths, and you also have to bunch up sections, but that is just for like less than a foot. I had a guy at a windsurf shop fix where a ripped baton punched through the sleeve. Can't remember how he worked it, but material was old and the sail was toast shortly after anyway.

In a dive shop I bought a custom drysuit once. They have machines that have the needle go partially into a butted neoprene material to sew together. Since needle holes completely though are hard to stop from leaking, the needle then moves horizontally and then up an back out the material after penetrating slightly. Not the average machine can do that.

I think maybe there are machines on a big layout table that only hover from above and maybe use the same way of stitching for professional sail makers. My investing in anything that can handle thicker fabric I may not get much use out of. Sometimes spraying material with silicone spray and using the clutch so that I just turn by hand the flywheel and not use the motor at all.

Thick material at one point pushed the pressure foot up. Neoprene was too thick I was using to sew to nylon fabric as protection for a pack I carry on the water for electronics. When the pressure foot moves up enough it removes a fair amount of top thread tension as it was designed to do. I removed some parts and rearranged them so that I got the thread top thread tension to be in range. Then I just used the compression of the neoprene that I was sewing to push down between the pressure foot deactivated and the surface of the machine and the advance mechanism, wach-a-ma-call-it.

Tomorrow to look at what can be done.
 

MEASURE TWICE

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Got the grease for the gears and oil all around the machine and it is amazing. Learning curve ramping up. If I want other stitches special ziz -zag and hem etc., that is for later as I see it works with this water proof fabric as seen by the test patch with two thickness sewn together.

Now to figure the sequence of assembling the cushions. I know I want to have zipper sewn in one panel first as it would be not possible or come out crummy if I can't lie the material flat without it having extra material of the modified box construction in the way.

There was a need to fix a hinge access panel on the machine, prior owner just used tape when the pin fell. I found 1 left over roll pin just the right size to hammer in place and fixed that. Then trying to put a cover on I replaced I found it difficult. A spring inside I bent to allow the cover to still hold but not be such a bear.

I had the roll pin, as I used them when I needed to secure an extension onto a rim brake shoe. When I spread the drop outs to allow for a belt sheave on my motor bike the clamp action would not reach. I have two extra brake shoes I have with the threaded coupler and extension on them when I wear out the brakes.

No time to be out boating, but if wind sounds to be expected to be above 20mph and not raining windsurfing would be welcome.

Planning on also using special Hypalon compatible cement to attach a few D-ring Patches to tie a few straps to the cushions to keep them temporarily in place while I'm on the water. Later to unzip the cushion take the foam and cushion an clean an dry for next outing.

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MEASURE TWICE

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Getting the wrinkles out from how they folded the material I heard some people left it out in the Sun to flatten out. It is going to rain for 4 days but I have floor heat. It made it easier to handle, but did not fix wrinkles.

I heard using a hair dryer and a rolling pin. Only you can see one place around middle of photo where there is a diagonal crease where I tried and fixed about 1/10 its length with flat spot in the middle. That took the hair dryer on high heat at very close range waving it fast over the one spot. Rolling pin felt was useless.

Thinking damaging the fabric with too much heat like that. I think by having it where the foam inside is compressed a small amount by the covering being slightly smaller will have the wrinkles show less in the fabric cover.

I am also going to try a test piece to see what hot soapy water and rinse and dry flat might do.

Anyway first, I am going to use regular fabric to make one cover and see how it goes before using the red vinyl.

Here are some very useful things learned by watching Youtube on sewing machine use. Simple as holding the upper and lower tail threads taught slightly when starting a stitch. Otherwise loops of spaghetti are formed. Maybe jam. Maybe needle breaks.

The horizontal type top thread feeder, you should look to see which side the spool there is a thin notch cut that is there on many spools to hold the end of thread when storing away. You must face the notch away from the thread feed direction or else it can catch on it and jam up.

Thread spools have labels that are glued on and you should use an edge to clean completely the bits of paper and glue where you cut the paper label to reveal the hole for the spool feed post. Again, else it may jam

This newer for me, but still 50 years old machine winds the lower thread bobbin in the same place it is in normal operation, but button to activate and also other stuff need not mention. It is just interesting how things were advanced through the years.

I’m not sure I like all the flashing led lights on the newer machines, sort of made it distracting to watch videos. If I get one donated, I would probably rewire to be solid on or off leds.

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