Introduction: Broken Plastic Buckle on a Nylon Strap

Picture of Broken Plastic Buckle on a Nylon Strap

I use a backpack when I commute to meetings on my bicycle. A few days ago I stooped down to pick up something and the extra stress on the backpack straps caused the plastic ladder lock buckle to snap. The rest of the backpack is in good condition. Backpacks are only one item that uses nylon straps with adjustable buckles.

This Instructable will provide two solutions to a broken ladder lock buckle. One is for those who can weld and one for those who cannot. The welded version will show how to make your own ladder lock buckles. The non-welded version will show you how to use "D" rings, either those you purchase or those you fashion yourself.

If you make the "D" ring version, you will need "D" rings you purchase and a hacksaw or a Dremel tool with a cutting wheel. 

If you make the ladder lock buckle version, you will need a hacksaw, a grinder, a vise, a hammer, and a wire feed welder.

Step 1: Stitching

Picture of Stitching

I wanted to fix my backpack without cutting the stitching on any of the nylon straps. My wife says it is not difficult to make new stitches. But, I am trying to avoid that and leave the original stitching undisturbed. That means I will make a ladder lock buckle that begins by feeding part of it through the nylon strap loop sewn to the backpack. Shown is the beginning of the welded version. The next steps will describe using "D" rings for the non-welded version. Then I will explain how to make the welded ladder lock buckle. The ladder lock buckle will be easy to release with one finger. The "D" ring, non-welded version will be easier for most people to manufacture at home, even if a little more difficult to release.

Step 2: Non-welded Version

Picture of Non-welded Version

It is possible to buy "D" rings about the same size as the width of the nylon strapping. Although there is an on-line link in the previous sentence, look for them in women's fabric stores and in generic hardware stores. Cut about 1/8 inch from the center of the straight side on each. See the photo. Slip the nylon loop through the opening you make in the straight side. Two "D" rings are needed for each nylon loop. While this works very well, the straps may not release as easily or as quickly as they do with a ladder lock buckle. But, this makes a quick and effective solution. 

The photo shows two "D" rings I made. See the next steps for more details.

Step 3: Making "D" Rings

Picture of Making "D" Rings

If you wish, you can make your own "D" rings from rod. Bend a half circle in the rod using a piece of pipe. (The diameter of the pipe should be about the width of the nylon strap.) Bend the ends sharply. Leave an opening where they meet. Slip the nylon strap through the opening you made in each ring. Thread the strap under the bottom ring and the upper ring. Loop the strap around the upper ring and under the bottom ring. Pull tight. 

Step 4: Protect the Strap Loop

Picture of Protect the Strap Loop

In the welded version some welding will need to be done on the ladder lock while it is on the backpack. The nylon from which the backpack is made will melt with too much heat. The nylon needs to be protected.

Cut strips of paper, fold them over, make a roll, and insert the rolled paper into the nylon strap loop. Use four or more thicknesses of paper. These strips of paper will insulate the nylon strapping from welding heat in the rod used to make the ladder lock. The paper can remain inside the nylon strap loop forever. 

Step 5: Protect the Nylon From Weld Spatter

Picture of Protect the Nylon From Weld Spatter

Weld spatter will burn holes in the nylon backpack. Surgeons cover bodies with sheets that leave a hole where the surgeon wants to operate. I made something like that to fit around the nylon strap loop, using scraps of sheet steel. (First and third photo) I also bent a "U"-shaped piece to cover the nylon strap where it comes through the hole in the protective cover. (Second photo) This "U"-shaped piece goes into place first. Then the cover for the field slips over it. (Third photo)

Step 6: Bend 1/8 Inch Rod

Picture of Bend 1/8 Inch Rod

I used some 1/8 inch steel rod that had been part of the mesh used to reinforce concrete. A friend built a garage and gave me stubs of wire about five inches long after breaking them off from the finished concrete foundation. Bend a piece of the wire so the space between the two halves is the width of the strap. Insert it into the nylon loop so it is surrounded by the paper from the last step.

Step 7: Buckle Design and Strap Pathway

Picture of Buckle Design and Strap Pathway

This shows a profile view of the strap (red line) in its pathway through the ladder lock buckle. The gray portions show cross sections of the parts. The black area is the 1/8 inch rod from the previous step. The green areas are welds. The relative positions of the different parts are important to causing the strap to bind and release well. As much as possible, the orientation of the parts follows those of the original ladder lock buckle.

Step 8:

Picture of

Cut a piece of 1/2 inch strap iron so it is as long as the strap is wide. Grind one long edge to 45 degrees.

Step 9: Begin Welding

Picture of Begin Welding

Position the strap iron and tack weld it in place. When welding on the ladder lock buckles, keep a wet sponge nearby to cool the steel before excess heat can soften the nylon strapping. This is mostly a precaution. The paper strips from step 4 should be adequate to protect from excess heat.

Step 10: The Rest of the Ladder Lock

Picture of The Rest of the Ladder Lock

Weld a 1/8 inch rod across the ladder lock frame. Cut excess from each side. Grind smooth. Be careful about the shower of sparks from a grinding wheel or a cutting wheel on a Dremel. A concentration of sparks can burn a hole in the nylon backpack. Make the spacing approximate that on the original plastic ladder lock buckle. See the finished ladder lock buckle in the second photo.

Step 11: Pull and Release

Picture of Pull and Release

The first photo shows how to pull the nylon strap to tighten it. The second photo shows how to push upward on the ladder lock buckle to release the strap. This works well with the backpack. It is easier to put the backpack on and take it off if the straps are loose. But, the backpack fits better, especially while riding a bicycle, if the straps are snug. Fortunately, backpack buckles are located at the front and side of the rib cage on each side, making the strap ends and the buckles easy to reach and manipulate. There is an advantage to the ladder lock buckles in that they can be operated easily with one hand. "D" rings are more likely to require two hands, especially for releasing them.


DanielC349 (author)2016-03-24

Thanks for the Idea and comments. While I don't have a welder I saw something in the comments that may work for me and would be easy to rig up. I have a tent that sets up in the back of the truck and on of the buckles like this is broken. I hooks to the bottom of the bed on the outside and you tighten it down to keep it in place. It would take an industrial sewing machine to stitch the nylon. We are looking for one for my mother to sew leather. On of her friends has one, but its a far drive to her and I'd hate to ask. Never thought about using D-rings like a helmet. I do have an old helmet or two that I don't use any more. I may just rig something up. The only issue that it runs down the side of the truck against the paint. It may just have to make a little shroud for so it does not scratch.

godson1952 (author)2016-03-22

Looks like the 'D' rings on the motorcycle helmet.Then to make ends solid i'd use (j-b weld) it hardens really well.Specially with a hair drier to heat it up.Good idea even though. ;-)

Phil B (author)godson19522016-03-22


JoshuaTerrell (author)2011-09-04

I like your workaround for not cutting and resewing by simply welding the buckle in place. It seems impractical, but then there must be some people who are willing to weld and not sew so this is a useful guide, and a good intro to ladder lock design as well.

Phil B (author)JoshuaTerrell2011-09-04

People with welders look for every excuse to use them. What can I say?

finton (author)Phil B2013-05-07

And sometimes they're just the thing you need! I was mowing the lawn yesterday and the blade mount broke - it was only held together with four tack welds. A new unit costs NZ$25 + labour. Blow that! Out with the old Young's arc welder...
Mower won't start 'cos I filled the cylinder with engine oil while tipping it sideways, but that's another story.
The pics show the repaired mount in place on the blade and the whole thing fitted back on the mower. If it ever stops raining again, I'll let you know how it goes.

Phil B (author)finton2013-05-08

Congratulations on your repair. We do not currently have a lawnmower, but I think all of us have learned the hard way about oil running into the engine cylinder when tipped the wrong way. If you weld should break, you can analyse the situation and do it again so it is stronger than the first time. Thank you for looking and for commenting.

JoshuaTerrell (author)Phil B2011-09-05

I too am guilty of this.

nartyteek (author)JoshuaTerrell2011-09-04

I sew, but you really can't beat that factory stitching with a home machine and I've broken many needles trying to get through tough material.

Phil B (author)nartyteek2011-09-04

I agree. My wife volunteered to sew the nylon strap for me. But, I would want a nylon strap sewn on one of those industrial strength machines like they use in places that do shoe repair and more. I grew up in a farming area and the man who did shoe repair sometimes sewed bridles and harnesses for horses. Those machines are beyond the machine my wife has and uses.

Avatar_I_Am (author)2011-10-03

I kave a BIG box of backpaks, straps, loops, buckles, clips, etc., because I fully intend[ed] on repairing or mutating them into something useable.

Worst case: While in Georgia [U.S.A.] I had an occurance of one or both of my own Dogs being upset with me and chewing through 3 of the 4 seat belts. Coat hanger, rivits, hammer, pliers, screwdriver, and a propane torch got us back on the road safely, in just a few hours.

Nice job with the welding!

Phil B (author)Avatar_I_Am2011-10-03

Thank you for your comment. My welds are not always pretty, but so far, they have held.

brocks411 (author)2011-09-04

A great solution to a very annoying problem! I had the exact same thing happen to me, but I used a carabiner as an impromptu fix.

Phil B (author)brocks4112011-09-04

The carabiner would give you a metal loop. Did you tie the strap to the carabiner with a knot?

JakeBlanton (author)Phil B2011-09-07

I don't think I would use a carabiner. I think a shackle would be a better piece of hardware for this. Something like one of these:

brocks411 (author)JakeBlanton2011-09-07

Thanks for that, nice idea. The problem was the lack of equipment I had with me (I was abroad) which meant I had to improvise.

Phil B (author)brocks4112011-09-07

We had a hair dryer quit on us when we were staying overnight in Amsterdam. I did what I could with a screwdriver on a utility knife, but the circuit breaker plug was a goner. We were flying back home to the USA the next day, so we toughed it out for the next couple of days.

brocks411 (author)Phil B2011-09-08

I suppose a towel would've helped too :)

Bodging things is definitely an important life skill!

brocks411 (author)Phil B2011-09-05

Well due to the way the buckle broke (the middle rung snapped out) I was able to loop the strap around it and back through the buckle- the carabiner being too big to be pulled through with it. It worked given the fact I was abroad in Moldova and needed an instant fix, although a longer term solution like yours would be better!

NitroRustlerDriver (author)2011-09-08

Nice work on making the buckle.

For those of you who do not have a welder, metal buckles are available from various suppliers. Here is one here: (author)2011-09-04

Well that's as irritating as all get out.
I threw out a backpack I'd had for years after I trod on the buckle while overseas and broke it. If I'd thought of the 2 D-ring approach I could have been up and running again quickly.
It wasn't an expensive backpack and I have others so it wasn't a great loss. Still irritating though.

Thank-you for a great idea.

JakeBlanton (author)metric.nz2011-09-07

In my experience, it has not been the hardware that broke on my backpacks, but rather the stitching or fabric ripping loose -- usually up near the top when you carry it with just one strap over your shoulder. Sometimes, it's the zipper that breaks. Unfortunately, no companies make heavy duty metal zippered backpacks. I would like to see the same type of heavy duty brass zippers that used to be used in Levi jeans or maybe the even heavier ones that are used in the classic type motorcycle jackets.

Phil B (author)metric.nz2011-09-04

Perhaps you have heard the adage that we get old too soon and smart too late. I think we have all discarded something we later learned could have been brought back for another useful life.

JakeBlanton (author)2011-09-07

My high school daughter went through 3 backpacks within the first month of classes 2 years ago. I searched around and finally found a backpack that could survive all the stuff that she puts in there. Check out the ones from Maxpedtion. They are sewn very well and made of very thick nylon. They're a bit more expensive than your typical school backpack, but they last a long time.

glitteringsky (author)2011-09-06

Wow I never thought I'd say this but you are as nuts as I am. LOL. I have an industrial heavy duty singer for coats and bag etc. I also save all kinds of metal rings and D rings and buckles etc and have bought lots of them over the years for things I used to make and sell.
I am also someone who soldered my daughters cracked metal tip on her cowboy boots back together. And I LOVE those popular mechanics issues! esp vintage/antique articles. I've met my match in you! This is exactly like something I WOULD DO!! LOL! Good stuff Phil. I feel less alone! :D

Phil B (author)glitteringsky2011-09-07

Thanks. Take a look at some of the other stuff I have posted on this site. You will feel even more like we may have been separated at birth. Over the years when my friends saw something I did, they just smiled, shook their heads, and walked away.

glitteringsky (author)Phil B2011-09-07

Yeah most of my friends in my life have said "Wow Karen, your something else!" I always take it as a compliment. Thanks for posting your fine work Phil. I'm inspired!

Phil B (author)glitteringsky2011-09-07

Thanks, Karen. Instructables like mine are what you get 50 years later from guys who did not care much for sports and were not interested in girls until well after high school.

a2e (author)2011-09-06

One step closer to unbreakable backpack.
It is a shame the amount of money we spend on cool backpacks that break at the least opportune moment.

Phil B (author)a2e2011-09-07

I get a certain pleasure from having something that is supposed to be cool, but includes a home fix that looks a little crude and yet is stronger and better than the original. My backpack shown in this Instructable was even a super cheap one, not one of the really cool ones with a good brand label and extra features. Its big appeal for me is that it includes a reflector on the back for extra safety when riding a bicycle after dark.

hjjusa (author)2011-09-05

Couldn't you just weld the buckle while off the backpack, cut an eith inch slot in it and slip it on the strap as per the D rings?

Phil B (author)hjjusa2011-09-07

Good idea. I did not think of that until a couple of days ago. The heavier the rod used to make the buckles, the less likely it would ever bend at the opening.

pfred2 (author)2011-09-04

That metal buckle looks hardcore. I hope no one picks you up for carrying a lethal weapon! Faced with a similar problem I'd have likely looked for a replacement buckle and sewed. I'll admit it I have one of these:

A manly sewing awl.

Phil B (author)pfred22011-09-04

I have seen those awls advertised in various magazines since forever. I always wondered how well they work.

Beemer10 (author)Phil B2011-09-05

If you follow the instructions, they work great! I've done quite a few harness and horse cover repairs with mine. Need to be careful not to put too much sidewards pressure on the needles: they are brittle and will snap. It is certainly slower than an industrial sewing machine, but ideal for work in a paddock when youdon't want to cart a cover back to the barn.

pfred2 (author)Beemer102011-09-05

Yeah I have to get into a rhythm with it and if the material is really tough I'll pre-drill the holes.

pfred2 (author)Phil B2011-09-04

I think the big trick is getting the tension just right with them too much it is hard to move the thing too little and threads come out sloppy. Like anything it takes some getting used to. Once you get going though it is pretty cut and dried. Sort of neat how it is made with the slot in the needle for the thread. It works a lot like a sewing machine except it is manual and there is no machine.

Phil B (author)pfred22011-09-04

Thanks. (author)Phil B2011-09-04

I've had one for years and used it extensively at one point.
They're slow and it takes practise to make a neat job, as with any manual skill., but they definitely work.

Phil B (author)metric.nz2011-09-04

Thanks for the evaluation. I wondered about how difficult it is to get a neat job. Wood and metal stay where I put them, but anything that requires stitching seems to run away from my fingers.

emerson.john (author)2011-09-04

I once broke what appears to be the same buckle on my pack. I am sure the manufacturer makes them that way, and sells new packs by doing so. I found a replacement buckle on a yard sale pack that was full of holes and otherwise not worth saving - cost $.50. I took it to a shoe repair store and he stitched it on for $2.00. His machine stitching looked better than the factory, and he used heavier thread.

I like the D-ring solution, too. Works great on helmets, you get used to them.

If I had a welder, I would always be on the lookout for reasons to use it! This is yet another clever solution (2, really) from Phil B.

Phil B (author)emerson.john2011-09-04

I hoped someone might be able to use this Instructable, but had no idea I would get responses from so many about broken plastic buckles on backpacks, etc. Helmets for bicycles and other things would be another very good application.

I went for many decades without a welder and am very grateful to have one now. If you have not seen it, check my Instructable on Learning to Weld, especially Step 19 on some ways to make your own stick welder with "junk" parts. By applying the method in this Instructable, it would be possible to use a stick welder and some 1/16 inch electrodes to make the ladder lock buckle shown here. 

It is sad to watch, but in recent months monetary inflation has done terrible things to the price of welders.

soul_eater (author)2011-09-03

Nice job, I usually put 2 D rings like some belts but some time they dont hold very tight the strap

Phil B (author)soul_eater2011-09-03

Thank you for your comment.

rimar2000 (author)2011-09-03

Great, Phil, you have to be brave to do that job!

One suggestion: when you need to make bends at an angle more or less closed on a heavy rod, you can do with the grinder a recess in either the inner or outer of the angle. This greatly facilitates the work, and usually requires no further strengthen it. In this case, yes, because that buckle makes a bit of force. A touch of welding is generally enough.

Phil B (author)rimar20002011-09-03

Thank you, Osvaldo. The rod I used is only 2.3mm. in diameter. After thinking about this job more, I would advise most home hobbyists to buy "D" rings and cut an opening in the straight side so the "D" rings can be slipped into the nylon strap loop.

Ranie-K (author)2011-09-03

If you would want to avoid welding, could you sew a small loop attached to the buckle and attach that loop to the loop on the backpack using a split-ring/key-ring?

ehudwill (author)2011-09-02

Nicely done.

Phil B (author)ehudwill2011-09-02

Thank you. I hope you never need it, but if you do, I hope you can use it.

About This Instructable




Bio: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying ... More »
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