TL;DR, main points throughout the instructable are in bold text.

It's a bed, it's a bag, it's a shelter, it's a coat. It's the 4th Blarg.

l have been living in the Blarg more and more over the past few years. It was conceived with displaced populations in mind.

The Blarg is meant to reduce weight, number of items and bulk. Some people like the backpacking look to attract more like minded people, this isn't for them. The Blarg maximizes mobility while protecting the user from other people's judgement.

The Blarg is immediately reproduceable, anywhere in the world using locally available materials and minimal equipment. Aside from the ripstop linen and some of the zips, l hand sewed everything while l was traveling around. l don't expect anyone with the resources to expend that much time, you can complete it in one day with ready made materials and a sewing machine.

You are responsible for your own safety. l strive to provide a complete set of relevent information. It is the user/ maker's responsibility to choose sound materials and to ensure construction of the Blarg is sound. Test before you use IRL.

T A B L E . O F . C O N T E N T S

(bold steps are section headers with tables of contents)

step 1: Choose the Main Body Material

step 2: Ripstop linen (self made with specialty materials)

step 3: ripstop nylon (order online or at speciality stores)

step 4: Readymade hammock/ carpet

step 5: Hemp/ jute net + cloth (hemp/ jute cords from hardware stores + your choice of cloth)

step 6: Net + Polyethylene Garden Tarp (hardware stores, shopping bags)

step 7: Prepare Materials

step 8: Straps

step 9: Determining the Dimensions

step 10: Ripstop Linen or "Make Your Own Ripstop"

step 11: Twine for the Net and Making the Net

step 12: Natural Fiber Woven Cloth

step 13: HDPE Tarp or Silnylon (non-breathable cloths)

step 14: Turn the Flat Sheet into a Hammock

step 15: Hammock - Large Fabric/ Tarp

step 16: Hammock - Add Tubes and Hem Edges

step 17: Hammock - Test and Reinforce

step 18: Assembling the Bag from the Shelter

step 19: Assembling - Folding It into the Dimensions of the Bag

step 20: Assembling - Choose and Add Zips

step 21: Assembling - Reinforce Abrasion Areas

step 22: Assembling - Attaching Straps

step 23: Making the Blarg Wearable

step 24: Making It Wearable - Choose Zips

step 25: Making It Wearable - Cutting Arm Holes, Reinforce

step 26: Making It Wearable - Install Zips

step 27: Conclusion

Supplies

You will need to make your own list according to the design you choose.

Main body: A sheet of fabric at least 8 ft x 3.5 ft (2.5 M x 1 M) in area, See steps 1-6: Choose Your Main Body Material and step 9: Determining the Dimensions of Your Material)
2 separating zippers 2 separating zippers the length of the bag dimensions (see steps 19-20).
Usually ~20".
5-10 ft of Webbing, strong cord or rope. Choose something that does not stretch much.Make sure it supports your weight and then some more, minimum 250 lbs.
l'm using Dyneema webbing meant for mountaineering/ climbing. In the past, l've used Dyneema cord, Dyneema rope, hemp webbing and hemp rope. Paracord is not ideal because it stretches.
Strong sewing thread: l use 100nm wet spun linen thread for myself. A heavier weight thread ('heavy duty', 'extra strong', 'top stitch', etc.) from a good manufacturer works well.
Sewing needles with eyes big enough for the thread.
Scissors or a knife.

Optional

buckles/ ladder locks/ D rings
zippers for making it into a wearable (see steps 23-26)
suspender clips or other types of strong snapping clips
sewing machine
conventional sewing thread
2 mm hemp twine or other strong cordage - net + cloth
grommets and grommet tool (and a hammer) - HDPE tarp
flexible, waterproof glue for synthetic materials - HDPE tarp
duct tape - HDPE tarp

Step 1: Choose the Main Body Material

There is a world of materials for you to choose from. Skip to Step 7 if you don't need/ want materials information.

Here are some materials l've used. The 4th Blarg is ripstop linen. If you have time and the resources, it's better to use naturally occurring materials-- moisture not being trapped against your skin is everything. PE tarps are not that, but they are immediately available in most places in the world. The most important thing is that it doesn't fail when you put your weight on it.

Listed in the following order (and where to get it)

step 2: Ripstop linen (self made with specialty materials)
step 3: ripstop nylon (order online or at speciality stores)
step 4: Readymade hammock/ carpet
step 5: Hemp/ jute net + cloth (hemp/ jute cords from hardware stores + your choice of cloth)
step 6: Net + Polyethylene Garden Tarp (hardware stores, shopping bags)

Step 2: Choose the Main Body Material - Ripstop Linen

The 4th Blarg is mainly made of this. Most people will not use this because of the sheer time investment it requires (l spent around 160 hours, l am working on a solution to improve the process.) l use Blarg 4 unwaxed.

A separate Instructable to make ripstop linen is here.

l made ripstop linen manually with:

lightweight painting linen from an art supplies store,
a big spool of 100 nm wetspun linen thread,
a computer tension control sewing machine (the kind that does embroidery, because conventional home and industrial sewing machines are not calibrated to handle threads outside of a small window of specs; the machine is a Bernette Chicago 7 in this case.)

The process is simple but labor intensive. See step 9: Make Your Own Ripstop.

Another goal of the Blarg is to use only naturally occurring materials. There is consumer ripstop cotton for clothes marketed as tactical. But l don't use cotton. Its strength to weight ratio sucks, it dries slow, and l am actively against the socioeconomics of its farming.

There are other naturally occurring materials that can be used, like hemp.

Good points:

moisture wicking
impervious to UV
dries fast
feels sturdy
looks nice

Bad points:

difficult to source
expensive -- for some this is a good point
overall time investment
heavy (Blarg 4 is 2+ lbs/ 1+ kg when empty) while too small as a shelter (surface area is only 8ft x 3 ft, it makes up for it by being a winter coat.)
not water proof, low water resistance unless waxed.

Step 3: Choose the Main Body Material - Ripstop Nylon/ Nylon 66

The uncoated type is popular with hammock manufacturers and DIY. The non-breathable silnylon is the material of choice for a lot of commericial ultralight camping tarps, but not my first choice for various reasons.

Good points:

l've slept in some ultralight hammocks with total confidence even when they had tears.
uncoated type is very light -- a 8.5 ft x 3.5 ft hammock weighs only 6 oz/ 160 g without straps
uncoated type is super small when compressed into a ball
uncoated type dries fast
feels like a commercial outdoor product

Bad points:

not easy to find in retail in most places in the world
very soft as a ground tarp; even with the heavier 60D nylon you will feel rocks/ hard grass poking on your skin
ripstop but not anti-abrasive; silicon coating improves this but adds weight, bulk, and renders the item not breathable
silnylon is not breathable, although uncoated nylon is, but it doesn't wick moisture.
silnylon can stick to itself.
uncoated type breaks down with UV exposure.
not biodegradable

'Tech fabrics'/ 'tactical fabrics' like Gore Tex, Dyneema or aramids are synthetic and suffer from the wet on the inside/ stink issue. Yes, even Gore Tex, it's a 60 year old premium brand. The typical commercial silnylon ultralight tarp is 8 or 9 ft x 5 or 6 ft, weighing 16+ oz (1+ lb, >500 g) along with a drawstring baggie-- that's not big enough. They're made for people who will quickly return to a controlled environment. Shoot for 12 ft x 12 ft so there's room to possibly stand up and allow for rain dripping at the edges of your shelter. That's 144 sq ft vs 54 (or less). It's worth every milligram.

l've found silnylon weight listed as: 30 denier at 31gsm, 40D at 59 gsm, and 60D at 63.5 gsm. When you look at a commercial product like this, 30D actually comes out to around 80 gsm; also this 15D silnylon tarp is 40-45gsm. Sometimes manufacturers provide water column or waterhead ratings.

Step 4: Choose the Main Body Material - Ready Made Hammock Conversion

There are a variety of properties and looks when you choose a ready made hammock, from a light camping hammock to heavy canvas garden hammocks. Blarg 4 was partially made with an ultralight nylon net hammock to save time.

Garden hammocks with spreaders are not good for this. You might be into removing the bars though. South American hammocks (that are not nets) are perfect for this.

Good points:

any hammock without spreaders works
variety of materials and looks
confidence that it will hold your weight
time saving for construction

Bad points:

garden hammocks are heavy and bulky
most are not water proof unless waxed or treated
surface area is not big enough for a shelter, but can make up for this by being a coat

Step 5: Choose the Main Body Material - Net + Your Choice of Cloth

These are charts of tensile / breaking strength of jute and hemp materials, for frame of reference only. **Read the package/ label of the bulk spool/ ask what the strength is.** Finished products have varying properties.*

Ripstop fabric is just a piece of cloth with an embedded net. So consider this as deconstructed ripstop.

The bag is made of the flat sheet of cloth (or a readymade jacket). The most important thing is that it doesn't rip when you put your weight on it, hence the net. This still takes time, but not nearly as much as the ripstop linen.

Cloth

The stuff for making clothes/ bed sheets are not strong enough for hammocks. The solution is to use it along with a net hammock made of strong fibers. Of course, you may be into carrying loads and choose a heavy fabric that you feel confident about, like heavy canvas or even carpet.

An advantage of this strategy is that you can use any readymade flat sheet cloth or finished garment, so you have control over what it looks like, feels like on your skin and weight. l like trouser weight hemp or linen for the summer, the inner bag of the Blarg is a lightweight linen jacket. l do not use cotton. Bed sheets are the most common material of the appropriate size. Whatever you choose, choose something that's good quality and strong enough to withstand some abrasion.

Net

Hemp rope and jute cord are commonly available in hardware stores. You can use paracord or anything else you can get your hands on of course. Use the charts provided here as frames of reference of tensile strength for jute and hemp when choosing your cord.

This site decided to disable tables so the data looks like crap, but l'm typing out the data here so people can text search:

JUTE "tying twine" tensile/ breaking strength (quality vary greatly):
2 ply, 56 kg
3 ply, 84 kg
4 ply, 110 kg
5 ply, 140 kg
6 ply, 170 kg, 2.32 mm diameter

HEMP braided cord:
2.2 mm Ø, 77 lb strain
3.5 mm, 120 lb
4.5mm, 157 lb
5.6mm, 239 lb
6.4mm, 248 lb

HEMP twine
0.6mm; 5/2nm Ø; 10 lb strain
1mm; 2,5/2nm; 20 lb
1.5mm; 2,5/4nm; 48 lb
2.2mm; 0,9/3nm; 100 lb
3mm; 0,4/3nm; 180 lb

3 strand HEMP rope
4mm Ø, 216 lb strain
6mm, 405lb
8mm, 803lb

Good points:

net hammocks are light
variety of properties and looks
You can also use the net hammock by itself.

Bad points:

sheds fibers if using natural fibers to make the net
some people do not like net hammocks
inconsistent quality across different suppliers

Step 6: Choose the Main Body Material - Polypropylene/ Polyethylene Tarp

TL; DR

This is just a variation of net + cloth, but worth its own section because it's highly available. Displaced populations often have access to tarps. HDPE tarps will hold your weight, but are completely unbreathable. Not ideal against the skin. You will need a (multipurpose net) hammock for the hammock part.

Familiar to shoppers, manual workers and displaced populations alike, polytarps

They're made of woven polypropylene (PP) or polyethylene (PE/ HDPE) 'raffia', then laminated with a waterproofing/ UV stabilizing low density PE coating on each side. There are no water column or waterhead ratings because they are completely waterproof and not breathable unless punctured or the LDPE coating has delaminated. The UN provides minimum specs for emergency response units that use tarps and they are part of almost all emergency shelter kits. They can be repurposed when people need to move on from these temporary arrangements.

Heavier varieties (7+ mil, 100+ gsm) can be found in: lumber bags, rain wraps, debris bags, garden ground tarps, permanent outdoor shelters/ shelter kits, wrapped around cargo in transport, footprints for tents...

Lighter varieties, blue tarps in the US (5-6 mil, 50-100 gsm): shopping bags from grocery stores and other chains, big rectangular bags with zippers sold for cheap in Asia and Africa, Ikea bags, sand bags (like for floods)...

l've looked all over for weight capacity ratings for PE tarps. Can't find any. But this product is made from a light duty tarp and is rated for 300lb (137kg), and 1000 kg FIBC (bulk shipping) PE bags are 130-200 gsm. Read: 5 mil/ 50 - 80 gsm/ light duty tarps will hold your weight unless you're a plus size line backer.

Good points:

super common, easy to find anywhere in the world
stays strong in UV
the common 5 mil/ gsm variety weigh and perform similarly as 30D silnylon
Ever since the Ikea bag remake trend a coupla years ago, it's not even considered ugly to wear HDPE tarps or use it on a bag anymore. There are lots of different colors and prints available.
Easy patching with DUCT TAPE

Bad points:

not breathable (yet, you can't make a balloon with it either)
can be noisy
bulky if not carefully folded
LDPE coating delaminates if you put tape on it and rip it off
LDPE coating punctures and delaminates easily
can look fugly (but so can silnylon)
synthetic/ not biodegradable

Step 7: Prepare Materials

Now that you've chosen the material, determine how big you want your maximum surface area and go to the different sections describing their preparation:

step 8: Straps

step 9: Determining the Dimensions

step 10: Ripstop Linen or "Make Your Own Ripstop"

step 11: Twine for the Net and Making the Net

step 12: Natural Fiber Woven Cloth

step 13: HDPE Tarp or Silnylon (non-breathable cloths)

Step 8: Prepare Materials - Straps

You can extract straps from an old backpack. l've also seen webbing with attached ladder locks sold as straps.

Else, to make the straps, you can use rope or webbing then add optional padding.

For the 4th Blarg, l made a thin strap, then padded by rolling a larger piece of extra fabric, the same stuff as the material the Blarg is made from, around the strap. This way, l am storing extra fabric l can use for repairs.

l am using hemp webbing now, works great.

The whole strap should be 35-40 inches long. padded part of the straps should be ~the length of the bag.

Straps can be sewn/ attached directly onto the body of the Blarg or indirectly with buckles/ locks/ D rings.

Step 9: Prepare Materials- Determining the Dimensions of the Main Body

The main factor is how big do you want your tarp shelter to be. Sometimes it's just the size of the tarp you get your hands on.

The secondary factor is whether you want your Blarg to be a coat as well.

Without the secondary factor, you should shoot for an ideal area of 12 ft x 12 ft (4 M x 4 M).

Wait, but what about the dimensions of the hammock? That can actually be pretty flexible, so the dimensions of the tarp shelter take precedence.

If you want it to be a coat, determine how wide that should be.

You can take a coat that you like and measure the width at the widest part. Or you can measure your shoulder width on your back. Multiply that by 2 to get the width of the coat configuration. Multiply that width by factors of 2 for larger total surface areas.

A goal of the Blarg is to protect the user from other people's judgement. Therefore it cannot look like a piece of crap. For some people, in order to feel like they look ok, they might just want to add a logo to it. To those folks, l have to break it to ya'll: obvious counterfeit brand name clothes make you look desperate/ really bad. l like something that looks OK on the bus and at the opera. l choose a double breasted coat. You might want some other type of coat.

Example:

The 4th Blarg is 8 ft x 3 ft. My shoulders are wide for someone born female: 18". It's just wide enough. If l was to increase the surface area, l'd multiple 3 ft x 2 = 6 ft. If l was to increase it again it'd be 6 ft x 2 = 12 ft.

Step 10: Prepare Materials: Main Body Ripstop Linen or "Make Your Own Ripstop"

TL;DR

This method will twist the final fabric a bit, and l do not recommend it because of the sheer amount of time investment. It took me 160 hours total, or 5+ days a week for 4 weeks, sewing perpendicular threads at 45 degree angles to the warp and weft .

l chose Belgian painting linen cloth and artisanal wet spun linen thread.

First, determine the maximum dimensions it can open up to. Most fabrics are no more than 1.5 M/ 5 ft wide, so if you want a piece with both sides longer than that, you will have to combine at least 2 pieces of fabric. Sew them together or use long (a) separating zipper(s). If you need further instruction on how to do this, refer to the "Make Your Own Ripstop" Instructable.

The amount of thread that's needed depends on the final dimensions you want.

Calculating the amount of reinforcing thread:

The formula is L = 2Hrd/e

L is the total length of thread needed (both top and under thread)

d is the length of the shorter side of the fabric

e is the length of the longer side of the fabric

H is the length of the hypotenuse of a right triangle with legs the length of e

r is the number of rows of thread, which is H / distance between each row

For the proof of the math, see the Instructable for Make Your Own Ripstop fabric.

l calculated for a piece of fabric that was 89" X 93.5" (222 cm X 232.5 cm), making a 0.5 cm diagonal grid. It's close enough to a square that l just did calculations for a 89" x 89" area. (It's also because l want threads intersecting at right angles.)

H = √¯(2 * 89²)¯ = 126" or √¯(2 * 222²)¯ = 314 cm

Number of rows? l wanted a 0.5 sq cm grid.

r = 314 cm/  0.5 cm = 628 rows
L = 2 * 314 cm * 628 rows
  = 3948.84 M

Extra bits for thread loss, rounding up to 4000 M.

After these calculations, l halved the area and got 1 spool of 100 nm linen thread that's 2500 M. This also cut the labor hours in half.

The final ripstop linen area of Blarg 4 is 36" X 84" (92 cm x 213 cm) with a 0.2" (5 mm) grid.

L = 2Hrd/e
L = 2 * √¯(2 * 84²)¯ * (√¯(2 * 84²)¯/0.2) * 36 / 84
  = 60480" = 5040 ft

in metric

L = 2 * √¯(2 * 213²)¯ * (√¯(2 * 213²)¯/0.5) * 92 / 213
  = 156768 cm = 1568 M

Ideally, l could have made a loom that can incorporate diagonal threads, which would have used less material and came out with a better final product, but the process of getting space was going to take more time than sitting at the sewing machine for weeks. l have since decided that the loom is not a pragmatic solution, and l am working on a single thread sewing/ thread insertion mechanism, but l have to finish these Blarg 4 instructables first.

For this thread, l needed a computer tension control sewing machine. Regular home sewing machines from the past 60 years are usually not OK for this. You might have access to a really nice vintage machine or something, otherwise, look for a home machine that can do pre-set automatic embroidery. l used the Bernette Chicago 7. A lot of hackerspaces have Brother PE series machines but l haven't tried this thread on them. The threads are still going to break often. Yeah, it's a lot of effin work.

Conventional (polyester or cotton) threads for normal sewing machines will save time and effort, but in that case you're better off just buying ripstop. You can do this with hemp, wool, silk, or whatever you like. Just make sure the tensile strength is high enough. Long strand hemp and linen are strong enough for sure.

Step 11: Prepare Materials: Main Body Cordage for the Net and Making the Net

l'm all about the naturally occurring materials, so l'm using hemp twine. You might just go with paracord. Regardless of the material, you will first have to determine how much twine or cord you need.

How Much Twine/ Cord do You Need?

Decide on the dimensions of the net. l am calculating for a net with dimensions of 8.5 ft x 3.5 ft (250 cm x 120 cm) and 2 sq in/ 5 sq cm holes.

You can figure out the length of each strand and the total amount of cordage with simple calculations.

Each square of the net is flanked by 4 imaginary right triangles with legs that are the same length. Refer to the cover picture.

Find the length of each leg by using the Pythagorean theorem:

2a^2 = 2^2 inches ~ 5^2 cm a = 1.414 inches ~ 3.535 cm

Find the total number of strands needed by dividing the desired width (3.5 ft = 42" = 120cm) by twice the length of the imaginary triangle's leg.

42" / 2 x 1.414" = 30 strands

Figure out how many times each strand will be tied/ form an imaginary right triangle by dividing the total length (8.5 ft = 102 inches ~ 250 cm) by the length of the leg (1.414 inches ~ 3.535 cm).

102"/ 1.414" = 72 segments

Find the length of each strand by multiplying the last product with the length of each hypotenuse (the length of twine between each knot).

72 segments x 2" = 144" or 12 ft or 366cm

If l use the 12 ft strands, the final length of the hammock will be less than 8.5 ft because tying each knot increases the amount of cordage needed, and the two ends should have some extra length so it's easier to work with. l am rounding up 1 ft for 13 ft / 4M each strand.

You can be even more precise with the total amount of cordage needed. The two strands on the edges should be shorter than the rest, they only need to be a little longer than the desired total length of the net. You might also want to include 2 shorter strands, one for each end of the net that are ~the width of the net. But in practice, maybe the person making the net will not keep track of which strand is the side strand and alternate between that and the adjacent strand. So l am still going to calculate the total length as if all strands are the same length.

Total length of twine = number of strands x length of each strand

30 strands x 13 ft/ strand = 390 ft = 130 yds = 119 M

For those using paracord, skip to the end of this step to make the net.

For people using other rope/ twine/ cord, be sure it supports more than your weight.

Natural fiber cordage: refer to the chart in step 5 if the package or label in the store doesn't tell you what the breaking strength is.

If You Can't Find Suitable Natural Fiber Twine

There are 3 scenarios:

You can only find thinner twine that's not strong enough for your weight.
No twine, but you can get rope.
You can't find twine but you have access to fibers.

First scenario: You can only find thinner twine that's not strong enough for your weight.

Twist them together for a stronger line. Refer to the chart in step 5 for the estimated tensile strength.

Second Scenario: No twine, but you can get rope.

You can untwist the rope to extract the individual twines or thinner ropes.The UN emergency shelter kits often come with hemp rope. Where l am located right now, l've only found 10 mm and 8 mm diameter hemp rope at the hardware store and not hemp twine.

The 10 mm Ø hemp rope l have is a twist of 3 thinner ropes, each with 2 even smaller ropes made of 2 strands of twine twisted together. (3 x 2 x 2 = 12 strands) l've cut the rope to the length l want, then untwisted it into 12 individual single twist twines. Each twine is around 2 mm Ø, using the chart from step 5, l can see that they should be rated around 80-90 lb. That should be fine for me, l'm usually ~120 lbs. If you want it to be stronger, just use the smaller ropes instead of individual twine strands.

They will definitely shed fibers when you work with them. When untwisted, the twine will be loose. They often become so loose that they separate into shorter segments, simply twist them back together. You can easily combine short segments into longer pieces of twine.

After the strands are separated, twist the entire length of each twine. Twist it too tight. It takes about 5 minutes per twine. Let them rest for a while (l did overnight) so they retain their physical memory.

Do a good job, your life depends on it.

When making the net, the twine will continue to loosen, just keep twisting them back.

An advantage of using natural fiber cordage is that you can just shorten or lengthen the strands while you make the net.

Having seen the twine separate into fibers, you might have doubts about whether or not it can actually hold me. See for yourself:

Third scenario: you can't find twine but you have access to fibers.

If it's store bought, stick with hemp, jute, or linen. Just run a search for "make cordage" for an avalanche of instructions.

If you want to make cordage from scratch, search for that, and you will find plenty of instructions walking you through selecting, collecting and processing the fibers to making the cord.

Make the net/ hammock following any of these instructions or use some other method.

l made mine from an untwisted rope using square knots. It's smaller than what l calculated for because l am short on time finishing this Instructable.

The little hemp fibers all over the net are actually super flammable, be aware. You can burn them off, it looks cool, but yeah stay safe.

Step 12: Prepare Materials - Main Body Breathable Fabric/ Ready Made Hammock

No further preparation is necessary for a flat sheet or hammock made of natural fibers/ that's breathable unless you want to add a water proofing coating.

If you want to immerse the cloth or paint a coating on it (with stuff like diluted silicone, store bought waterproofing agent, or wood glue, etc), do it and allow to cure completely before sewing.

If you want to wax the surface, wait until after sewing.

For a ready made hammock that has gathered ends, roll the cords/ gathered area up to the line on the fabric where it's flat. Add closures (buttons, safety pins, etc.) that would hold the roll in place. Now it's a flatsheet with 2 chunky ends:

The video here is the actual 4th Blarg.

Step 13: Prepare Materials: Main Body HDPE TARP or Silnylon (Non-Breathable Cloth)

This step prepares a 4 M x 3 M (12 ft X 9 ft) tarp out of 2 tarps half that size (2 M x 3 M), ~80 gsm, 5 mil thick. Final weight should be just under 1 kg (2.2 lbs).l chose camouflage, because people love camo, and l want to show that these things don't have to look super ugly. You need:

thread
sewing needle
duct tape
scissors or a knife

A finished tarp that's more than 2 M x 2 M or 6 ft x 6 ft is probably made from 2 pieces heat bonded together. This is because most looms are less than 2 M wide, the widest ones are just under 3 M. l will compare my tarp's performance to a store bought 4m x 3m tarp at 67 gsm (800g, or ~1.75lbs).

Be aware that you cannot reposition the tape once it comes in to contact with the surface, the LDPE coating will delaminate.

Line up the 2 pieces along 3 M edges.
Cut out the grommets on those edges (not essential).
Duct tape on the open seam on each face. Since this is not intended to be a load bearing seam, l only sewed near the edges before sealing with duct tape.

In the unlikely event that you can only get multiple smaller pieces of HDPE Tarp

It is highly preferable to have big, continuous piece, but maybe you have to do this.

Piece smaller pieces together with a 1 inch overlap until the desired dimensions are reached.
Sew 2-3 straight lines on the overlap ***When sewing, pay attention to the tension of the thread. Do not over tension as this will make the fabric prone to ripping.***
Cover the lines of sewing with duct tape for strength and to prevent leakage.
Follow the steps above to continue preparation

Step 14: Turn the Flat Sheet Into a Hammock

Use this section for hammockfying and/ or making a hammock shelter out of a flat sheet. There are tons of hammock making tutorials as well.

If you made a net hammock in step 10 and don't want to fuss more. Skip to step 17.

step 14: Hammock - Larger Fabric/ Tarp

step 15: Hammock - Add Tubes, Openings and Hem Edges

step 16: Hammock - Insert Rope and Test

Step 15: Hammock - Before Hemming a Piece of Larger Fabric/ Tarp

This step is like the second part of step 12.

For a larger piece of fabric, you may want to add a tube only to part of an edge. Tubes trap moisture in unbreathable materials, so avoid them if possible.

For my 4 M x 3 M tarp, l anticipate using half of the area as the overhead tarp, while the other half will be a hammock/ storage sling/ insulator. For that reason, l added tubes to only half the length of the two 4 M edges, i.e. of the 2 separate pieces the entire area is made of, tubifying the shorter edges of 1 of them.

Fold edges over ~2 inches (5 cm). This is where to fold when hemming.
HDPE tarp edges are folded over once because they come pre-hemmed, all other fabrics, fold the edge in, then fold again to get the hemming fold.
On either side of this fold, cut holes at ~equal distance at all halfway points of the tarp and 4 smack in the middle. (Yellow squares on the cover graphic.)
Reinforce the holes.
Install grommets into the holes only if you have good quality, non-oxidizing grommets.
l could only find crappy iron based grommets locally, they just tear the fabric when stressed. So here are some alternatives to installing grommets in a tarp. l just put duct tape around the holes.
Cut out the corners (red in the cover graphic). To do this, fold one intersecting edge over and cut at the line where the edge lays on the fabric, cut until the line where the other intersecting edge will permanently overlap the fabric. Do the same to the other edge. You will cut out a square with a grommet in it.
You can tape or permanently glue the very edge of the fold into place, leaving a long tube.

Step 16: Hammock - Hem Edges, Add Tubes and Openings for the Rope

Hemming is just folding the fraying edge in, then making it permanent (by sewing taping or gluing.) Most of the time people fold the edge over once more so that the fraying edge is covered before sewing.

The Blarg is just a flat sheet with hemmed edges. 'Tubes' are open ended hemmed edges.

***Fold each edge over only twice.***

You might be tempted to fold it over a few times for a feeling of security; that actually makes the fabric more likely to rip. The line where the fold is sewn on to the main body is most prone to ripping, stitches being too tight on this line makes it worse. Therefore, be sure to keep stitches properly tensioned. This happens to nylon and linen alike. If using a sewing machine, a thicker stack of fabric sewn together also tend to tighten the stitches. Watch out.

It's caused by a combination of (1) abrasion on the threads running in the direction of the force (usually the warp) by the sewing thread and perpendicular threads in the weave (usually the weft); (2) the force of strain shifting along the (warp) threads as the weight pulls on the unreinforced areas of the fabric.

With the above in mind:

For a piece of fabric that's the size of the hammock, hem the 2 edges that are the length of the hammock first.
You can make a thin, regular old hem; but you can also make it big enough for a rope and leave an opening on either end.
Then hem the two ends of the hammock with a fold that's 3 inches/ 7 cm wide. Leave the ends open for a tube. Sew 2-3 lines. The tube should be ~2 inches/ 5 cm wide.
For a piece of large fabric/ tarp, hem the edges with the 2 holes on either side of your hemming fold from the previous step.

Sometimes people want to add a permanent soft shackle, ring or carabiner to the ends of the hammock. It's up to you. l prefer directly inserting a rope only when needed because it allows the sheet to be completely flat.

Step 17: Hammock - Test and Reinforce

Once hemmed, insert rope, set it up between trees, get in and test.

If it tears, those are obvious weak spots, so aside from repairing, reinforce the torn spots.

Step 18: Assembling the Bag From the Shelter

Now we turn the flat sheet into a bag.

step 18: Assembling - Folding It into the Dimensions of the Bag

step 19: Assembling - Add Zippers

step 20: Assembling - Straps, Webbing, Buckles and Loops for Straps

step 21: Assembling - Reinforce Stress Areas

step 22: Assembling - Reinforce Abrasion Areas

Step 19: Assembling - Folding It Into the Dimensions of the Bag

TL; DR

The folding sequence determined in this step is how you will fold the Blarg for the lifetime of its use.

This step presents several folding sequences, but you can design your own based on several key points:

Folding should be as intuitive as possible regardless of the dimensions of the fabric.
It's much easier to fold a piece of fabric in half than thirds or fifths.
You might not think much of it in a controlled environment like your home, but when you need to move quickly, you'll get it. Do all the fussing now when you make the Blarg.
Shoot for a width of ~1.5 ft.
Most backpacks with a rectangular bottom are ~1 ft wide with shorter sides of 3-4 inches. The folded up Blarg bulks up like a pillow case when it's full.
Blarg 3 was usually 16" wide when flat, and can open up to 20". Blarg 4 is usually 13" wide, and can be 10" - 18" (l've cut down on how much stuff l'm carrying).
It doesn't have to be precise, you just need to make it the width that you'd be comfortable carrying.
Once you start using the Blarg, you will also start to see a pattern of how you use it most often. Fold it such that it's most facilitative of the most frequent use.
The final fold should be the long way so that the bottom is closed.
The other sides can be closed with non-permanent closures like zips and clips.

Suggested folding sequence for 12ft x 9 ft fabric, like my HDPE Tarp - there are 2 different fold patterns, you can install zips for both configurations.

Configuration 1 - ergonomic, low profile, but less storage space.

Fold in half along the middle taped seam or fold the 2 halves into the middle seam, 6 ft x 9 ft (2 M x 3 M)
Fold in half the longer way 6 ft x 4.5 ft (2 M x 1.5 M)
Fold the long way in half 3 ft x 4.5 ft (1 M x 1.5 M)
Fold the longer way in half 3 ft x 2.25 ft (1 M x 75 cm)
Fold the shorter way in half 3 ft x 13.5" (1 M x 38 cm)
Fold the longer way in half 18" x 13.5" (50 cm x 38 cm)

Configuration 2 - more storage space but very wide. This configuration will have a roll top. Keep folding in half the longer way until you reach 18" x 27". the following keeps the 2 joined tarps folded separately in the bag so it's easier to use just a half while keeping the other half folded:

Fold the 12'/ 4 M way in half, 6' x 9' (2 M/ 3 M)
Fold the 2 shorter edges into the middle taped seam again, 3' x 9' (1 M x 3 M)
Fold in half at the taped seam, 18" x 9' (50 cm x 3M)
Fold in half the long way, 18" x 4.5'. (50 CM x 1.5 M)
Fold in half the long way again, 18" x 27" (50 cm x 75 cm)

You get the idea: always folding in half. A 12' x 12' (4M x 4M) tarp will fold up to 18" x 18".

The bottom is closed, the sides and the top are open.

For a smaller piece of fabric, like the 4th Blarg:

The fabric area after the ends are rolled up is 7 ft x ~3 ft.
In half lengthwise. 3' x 39"
Fold along a zipper 10 inches in from the edge; l use it as a marker for quick folding, 3' x 26"
Fold the shorter side in half again, the loose folds should be inside. 3' x 13"
Fold in half the long way. Final dimensions:18" x 13". Measurements are approximate because there's bulk.

Step 20: Assembling - Choose and Add Zippers

CHOOSING ZIPS

Get 2 separating (jacket) zippers that are around the length of the sides, usually around 20". The 2 zips do not have to be the same.

Any good quality separating zipper works. Sometimes People online say that metal teeth zippers are the strongest. Nope. it depends primarily on the quality. YKK nylon coil zippers, even as thin as 3 mm chain width, are very reliable and stronger than you need, but watch out for counterfeits. If it feels cheap, don't use it.

If you want more details and data about YKK coil zippers, see step 24.

You can extract zippers from finished jackets.

l prefer using 2 way zippers because l can open the bag both ways when using it as a shoulder bag. But it's not essential.

A 3rd zipper around 15" can be added to the top edge. l find it's not essential. Blargs 1-3 each had a top zipper; l almost never used it. For the 4th Blarg in its backpack configuration, the top is sometimes clipped shut, and one of the lateral sides is always open.

ADDING ZIPS

If your zippers are longer than the sides, just cut them or fold them over to the proper length.

Here's a tutorial on how to shorten zippers.

If the sides are a lot longer than the zippers, you can get/ modify 2 more separating zippers for the rest of the length. A long bag will have a roll top, so prepare 2 longer zippers to the length that will not be rolled, 2 shorter ones to the length of the roll. Plan to install these zippers with the tops toward each other.

While the Blarg is folded, mark where you will attach the zips (4 straight lines). l'm using tape, you can use markers or pencils or chalk.
Unfold.
Install the zips by stitching, stitch 1-3 rows.

Now it's starting to look like a bag.

Step 21: Assembling - Reinforce Abrasion Areas

The bottom 1/3 of the bag gets the most abrasion. Fibers get worn out, and LDPE coatings on tarps might rub off on you. Choose some kind of material, preferably breathable and non-marking, and apply to the area.

You might consider using the extra material as a pocket, in that case you attach on 3 sides instead of all 4.

Step 22: Assembling - Attaching Straps to the Blarg

Where straps are attached, the material needs to be reinforced.

While the bag is folded & zipped, compare it to your back and mark where you want the straps to be. 2 spots on the shoulders, 2 spots at the bottom of the bag.
For a longer bag, first roll the top down until the bag is a suitable length for your back, then mark where you want the strap to attach.
Use a straight edge to determine the horizontal line across the bag where your straps will attach.
Using the marks as guides, measure equal distance along the straight edge from the 2 edges of the bag until approximately where the marks are.
Mark at the equal distanced points, these are the midpoints of the webbing of straps.
Unfold the bag.
Add at least 2 layers of material to where the straps will attach.
There should be extra material around where you will sew
If you are not adding buckles, sew the straps directly onto the bag and you can move on to the next step.
If you have buckles and/ or ladder locks, install loops for them:

Loops for locks & buckles:
1. Sometimes you can get buckles already on webbing loops, less work is better.
2. If you don't have webbing, take some material and cut them into 4 pieces that are ~3 inches/ 7 cm long. The width should be some multiple of the width of the bar on the buckle/ ladder lock.
3. Roll the strips-- l'd do it at least 4 layers-- so that they are the width of the bar on the buckle/ lock.
4. Sew/ glue/ tape to make them permanent.
5. Sew the loops onto the bag where you've put reinforcement material. l like pre-making the loops before attaching but do what you like. If they're not field repair buckles with a removable stud, remember to put the buckles the loop before you sew it on.
6. Install buckle parts to the straps if necessary.
7. Attach straps.
Finally, reinforce the entire width of the bag at the level of the shoulder attachment points.

Step 23: Making the Blarg Wearable

Now that the bag is configured, we can make the Blarg wearable.

There are several possible wearable configurations. Of those, the most popular has to be the coat/ jacket. l will focus on that.

This section requires materials that are not as easy to find. Some people will choose to stop here. If you cannot get very strong zippers, do not attempt.

step 24: Making It Wearable - Choose Zips

step 25: Making It Wearable - Cutting Arm Holes, Reinforce

step 26: Making It Wearable - Install Zips

step 27: Making It Wearable - Reverse Engineering Jacket and Pants

Step 24: Making It Wearable - Choose Zips

Compared to a Blarg that does not become a coat, the required zippers are different here. The specs are more specific.

If you can't get strong closures, do not make arm holes.

But you'll be glad to know that YKK #5 regular coils are super strong, and they are everywhere.

Here's the list of the 12 zips l installed on my 4th Blarg (see the diagram in step 26):

2x #5 two way separating zips (of any kind), half the length of the Blarg - lateral sides
1x #5 double sided (custom) 2 way separating molded plastic teeth zip, half the length of the Blarg
5x #3 separating coil zips, 1/2 the width of the Blarg - hammock ends
2x #3 invisible coil zips - shoulders
2x #10 1 way separating coil zips 10" - 15" - arm holes

YKK regular coil zippers (as opposed to water resistant/ waterproof coils) are the strongest zips you can most easily get your hands on. Lenzip publishes crosswise chain strength for both #5 and #10 coils. l do not generally use other brands/ no brands because their quality control may not be as good. l would not consider other zippers unless l saw their standardized test results. Premium brands like Riri and Lampo are luxury brands, the price is not for strength. Hell, they don't even say their chain crosswise strength.

Zipper numbers indicate the approximate width of the chain in mm.

The following YKK information are from this retailer. l did not get the numbers directly from YKK, they simply redirected me to the JIS standard strength requirements exposited in the YKK catalog. These numbers are significantly higher.

YKK standard coil chain crosswise break strength

#3 58.8 kgf / 129 lbf

#5 107.4 kgf / 236.78 lbf

#8 109 kgf / 240 lbf

#10 140 kgf / 308 lbf

YKK molded plastic ('Vislon') chain crosswise strength

#5 47 kgf/ 103.61 lbf

#8 67 kgf/ 147 lbf

#10 77 kgf/ 169 lbf

From the YKK Conceal brand invisible zip catalog

YKK invisible zippers chain crosswise strength

#3 35 kgf/ 77 lbf

#5 60 kgf/ 132 lbf

Lenzip crosswise pull strength results under ASTM-D 2061 test standards. Note that they do not offer 2 way separating zips for #5 coils.

Coil

#5, 5/8" tape 235 lbf

#5, 3/4" tape 273 lbf

#5, 1" tape 289 lbf

#10, 254 lbf

#10 water resistant, 272.3 lbf

Molded Plastic

#10, 148.4 lbf

#12, 209.7 lbf

#15, 327.6 lbf

Metal

#5, 164 lbf

#10,259 lbf

Step 25: Making It Wearable - Cutting Arm Holes, Reinforcing, Tailoring the Shoulders

The Blarg is meant to protect you from other people's judgement. Looking like this, this or this is unacceptable. These guys might feel like they're just being outdoorsy, but you have to be (1) not from a targeted population and (2) rich to get away with looking this ridiculous.

The illustrations are based on folding the sheet to 3 ft wide. Yours may be a different width depending on your body.

Either take your shoulder measurement or get a jacket that you like.
Tailoring shoulder measurements are taken in a different way from biacromial breadth. The measuring tape lays on the body from one shoulder joint to the other. To illustrate the difference in the two, my shoulder measurement is 17" while my biacromial breadth is 15".
Open the Blarg to a flat sheet.
If your Blarg is made from a large piece of fabric, separate (cut off) a 3 - 4 ft wide piece from the rest of the fabric. You can install long, waterproof zips to join and separate them later.
If the Blarg uses a permanent ring at the ends for the hammock configuration, roll up and stole any scrunchy ends.
Fold the long edges to the mid line.
If you took shoulder measurements:
1. Measure along one of the long folded edges 1.5 - 2.5 inches/ 3.5 - 6.5 cm from the end, this is point A.
  Alternately, mark the point on the folded edge at the same level as where your straps are attached to get point A.
2. From point A, measure away from the nearest end another 10 - 14 inches/ 25-35 cm to get point B.
3. Divide your shoulder measurement by 6 to get length x.
4. Measure length x from the mid line on the short edge. Make marks on both layers. These are points C and D.
5. You might want to:
  open the fold
  draw a line with chalk or baste from point A to C and from A to D.
6. (Fold it back.) Repeat for the other lateral side (if you want 2 arm holes.)
If you are using a jacket you like:
1. Position the jacket such that
  (a) the middle opening of the jacket aligns with the mid line of the folded Blarg,
  (b) where the straps are attached on the Blarg coincides with the shoulder edge of the jacket.
2. Mark where the top of the arm hole on the jacket is laying on the Blarg, this is point A. If it's a little wider than the Blarg, just mark the Blarg at that level at the folded edge.
3. Do the same for the bottom of the arm hole, this is point B.
4. Mark where the collar begins on both layers, these are points C and D.
5. You might want to open the fold, then draw a line with chalk or baste from point A to C and another from point A to D.
6. If you want 2 arm holes, transfer the marks from one lateral side to the other. Do this by folding the Blarg in half at the mid line. Repeat point to point line drawing procedures.
*The diagram is based on my square for ladies'/ normal for men's shoulder measurement, 17" or 43 cm. Yours are likely wider or narrower, and the proportion on the Blarg will be different
Open the Blarg flat again, cut (a) vertical line(s) on the sheet from point A to point B.
Cutting just 1 arm hole reduces the need to cut into the continuous fabric and economizes the 2nd zipper; something to consider.
Cut small pieces of fabric and sew on to each end of the cut, be sure there is about 1 inch/ 2.5 cm of material on either side of the cut. You can do this before you cut the main body to mark the 2 ends of the cut-to-be.

Step 26: Making It Wearable - Install Zips

l salvaged all zippers from finished clothing and outdoor items.

The total number of zips on my 4th Blarg: 12

2x #5 two way separating zips, half the length of the Blarg - lateral edges
1x #5 double sided (custom) 2 way separating molded plastic teeth zip, 1/4 of the length of the Blarg
5x #3 separating coil zips, 1/2 the width of the Blarg - hammock ends*
2x #10 one way separating coil zips 10" - 15" - arm holes
2x #3 invisible coil zips (3cc) - shoulders

#5 two way zips (4) - lateral edges

For each zipper, the two unzipped sides are placed stop end to stop end on each edge.
These 2 can be replaced with 1 double sided custom zip that's the full length of the fabric.

#5 double sided (custom) 2 way molded teeth zip

l invented this zipper type for this use case. It enables each side of a separating zipper to zip itself when folded in half, as well as zip the other side. It's made from existing stock parts: both sides of the zipper have a box at one end and a pin on the other. The 2 sliders are the same. Even though there is no top stop, self locking sliders do not fall out easily.
Requires 2 conventional molded teeth zippers to make (for the parts). They have to be at least 1/2 the length of the intended final length.
This zip can be replaced with 2 zips half of this length-- i.e. they will each be 1/8 the length of the Blarg-- installed stop end to stop end.
Installed adjacent to the edge zips.

#3 separating one way zips (x5) - rolled up hammock ends

These are unnecessary for a Blarg that is not bunched by permanent rings at the ends.
A Blarg with non bunching ends can use these to shorten to the desired length for the coat.
You will need separating zippers. My ends are from the lightest advertised ultralight hammock on the market, and l still cannot get away with non-separating zips.
Installed on either face of the fabric, depending on how you want it to look.
For each zipper, the 2 unzipped sides are placed stop end to stop end.
The zippers join the short edge of the fabric and a line 3-4 inches away. The thicker the material, the more space is required. Too little space will make a puffy roll right at the shoulders and collar.

#3 invisible zips (2) - shoulders

Installed along the marked/ basted lines at the shoulders from the previous step.
Separating zips work better in theory, but are not necessary. Non-separating invisible zips are much more available. That's what l'm using.
Unzip, then placed each side along the marked line, boxes and pins together at the dip of the V.

#10 zips (2) - arm holes

l removed the very bulky zipper pulls, replacing them with light weight fabric cords.
They were longer than the arm hole, so l cut them down to the proper length.
l sewed 3 lines along with some diagonal supporting stitch lines.
l made sure to not make the stitches too tight to avoid ripping.

A video is forthcoming.