Hot cutter welding

[telemarktim]

I have seen other MYOG commentary about hot cutters for tent making etc. I have progressed from soldering iron cutters to a real hot knife cutter. I am delighted with its ease of use. However, I am even more delighted with its additional functionality as a fabric welder. It is a tool for my DIY tinkering that I should have purchased years ago!


I found that the hot cutter could quickly weld two or three pieces of fabric together while cutting, so that for example, a long tent seam could be quickly prepared for easy sewing of Mock Felled Seams, which some of us 'crap sewers' would otherwise find difficult.


I also found that tie out tabs for the tent could be welded in place, at the same time. This meant that they were ready to be embedded in the tent seams as the two rows of stitching were made without the need to remove the work from the sewing machine. This makes the otherwise difficult sewing of bias grain fabric to straight grain fabric easy as shown in the photos of a sample seam that is started with hot cutting welding below.





The hot cutting/welding works with most synthetic fabrics that we use for MYOG.


The welding is very helpful when preparing Noseeum netting vents and windows for backpacking tents. The pesky stretch of the netting can be controlled by hot cutting/welding that is followed by easy sewing to form a narrow frame of straight grain fabric.




For my full ramble on all the many hot knife cutter welder tricks please my full post:
https://timtinker.com/hot-knife-cutter-and-more/

Tim

[Lamont]

Enjoyed that Tim.
Never used one but seen some vids-I like the way you describe your one in action. Any chance of a wee vid of your hot knife in action?
Didn't see what you paid for it?
If there was a like button I'd hit it right ...now.
Cheers

[telemarktim]

Enjoyed that Tim.
Never used one but seen some vids-I like the way you describe your one in action. Any chance of a wee vid of your hot knife in action?
Didn't see what you paid for it?
If there was a like button I'd hit it right ...now.
Cheers

Thanks, Lamont, Thanks also for the virtual like. It was about $80 and in my opinion, it is very good value for money because I am always mucking around with fabrics to make my DIY gear.
I will do a video for you, but it is so quick and simple that there is not much to see. It looks like nothing has happened (Like the sword fighter who said '"you missed" and then was told to shake his head and say that again). The photos that I took don't really do it justice. The welded edges just look like a single sheet of fabric. Luckily, they behave as a single sheet of fabric as I do the sewing of the trickiest sewn seams. I also would be happy to have any suggestions of other fabrics to test the welding on (like with like or different fabric combinations).
Tim

[Warin]

presently fleebay $84 .. $20 for an extra blade.

I'd think a 'drill speed controller' would set the maximum power nicely. Add a floor 'throttle' and you could have foot control of the cutter.. setting for minimum and maximum could be added... happy tinkering there.

[telemarktim]

presently fleebay $84 .. $20 for an extra blade.

I'd think a 'drill speed controller' would set the maximum power nicely. Add a floor 'throttle' and you could have foot control of the cutter.. setting for minimum and maximum could be added... happy tinkering there.

Hi Warin, The cutter shown has more than enough inbuilt controls (heat settings 1-9 and the on-off trigger). The red colour of the blade gives plenty of feedback about its temperature being in the correct range so that the power trigger can be pulsed on and off when for example a 3M long cut is done in 2*1.5M sections. If I have the radio on at the time the switching of the thermostat talks radio frequency to the radio so that I can even hear what the knife is doing! Even as a compulsive tinkerer, I don't think extra tinkering is needed because it is a magical tool as it is. However, there is plenty of scope for tinkering with the blades. I have already made the cutting edge less sharp so that it glides along the metal backing strip smoothly without scratching. I think this makes the welds stronger. I plan to make a custom blade to do even better welds. Tim

[telemarktim]

Enjoyed that Tim.
Never used one but seen some vids-I like the way you describe your one in action. Any chance of a wee vid of your hot knife in action?
Didn't see what you paid for it?
If there was a like button I'd hit it right ...now.
Cheers

Hi Lamont, Here is your little video. Not much to see. The first piece is two sheets of polyester tent fabric with an extra V-shaped tie-out tab. The edges have been welded together in preparation for sewing a lay flat seam with an integrated tie-out tab. The second section is Noseeum netting welded to polyester. Tim

[Lamont]

Nice work Tim. Another like for you.
Just wondering...Can you pull the jointed items apart easily with your hands after cutting/welding? Waterproof?
Ta

[telemarktim]

Nice work Tim. Another like for you.
Just wondering...Can you pull the jointed items apart easily with your hands after cutting/welding? Waterproof?
Ta

Hi Lamont, It depends on the fabric and the combinations of fabrics. They all hold together well enough to sew seams easily. They can be pulled apart by hand if the forces are applied at one end (like ripping fabric).The polyester/polyester is the strongest so far. The joint in the photo (blue/silver) failed with a 2kg load. Polyester joined blue to blue side held 3-4kg and eventually failed after holding 4kg for 15 seconds.


Yes, the welds are waterproof if the fabric is waterproof. If followed up by sewing for strength, that is all out the window. However, I have been thinking of using a smear of RTV silicone to seal between the layers, after welding, to make a seal by sewing through it while it is curing. No post on that yet.
I am tinkering with the idea of a custom made blade that may increase the weld strength.
There are more details in my website post;
https://bushwalk.com/forum/viewtopic.php?f=53&t=39579
Thanks for the extra virtual like!
Tim

[andrewa]

Thank you. You have inspired me to buy one. Ordered on flea bay….

Should make my boat tonneau project a bit neater, as it will any subsequent projects.

A

[neilmny]

I used a small tipped soldering iron to cut out paired layers (top and bottom panels) of a couple of quilts I made.
The soldering iron also welded the two materials together which made life much easier when sewing the seams.
This gadget looks great and I might just have a gander on ebay and get one as well.

[telemarktim]

Thank you. You have inspired me to buy one. Ordered on flea bay….

Should make my boat tonneau project a bit neater, as it will any subsequent projects.

A

Hi Andrewa, Yes, it should work well for the tonneau. I made a boom tent cover for my yacht before I purchased the hot knife. It would have made the task a lot easier. I expect you will find many other uses. Have a look at the PET bottle welding that the knife can do as described in my full post on the knife.
Tim

[Lamont]

Nice work Tim. Another like for you.
Just wondering...Can you pull the jointed items apart easily with your hands after cutting/welding? Waterproof?
Ta

Hi Lamont, It depends on the fabric and the combinations of fabrics. They all hold together well enough to sew seams easily. They can be pulled apart by hand if the forces are applied at one end (like ripping fabric).The polyester/polyester is the strongest so far. The joint in the photo (blue/silver) failed with a 2kg load. Polyester joined blue to blue side held 3-4kg and eventually failed after holding 4kg for 15 seconds.

Yes, the welds are waterproof if the fabric is waterproof. If followed up by sewing for strength, that is all out the window. However, I have been thinking of using a smear of RTV silicone to seal between the layers, after welding, to make a seal by sewing through it while it is curing. No post on that yet.


I am tinkering (nice work ) with the idea of a custom made blade that may increase the weld strength.

Ta Tim. Great feedback.
I'm interested in the 'weld' as a more permanent(ish) thing. At least really hard to pull apart by hand.
I like the idea of a smear of sil to enhance the seam (in theory) though it sounds like a fair bit of mucking around-then stitching through might (?) still ruin the WP.
I wont (can't) buy one just yet and I'm keen to find out how your next welder/cutter may go.
Ta for taking the time to do these posts etc
Cheers

[andrewa]

Ultimate goal is modifying my older Alpacka packraft to add a tail for stability , and still be able to float! The hot knife is a step closer, I hope.

[Warin]

However, I have been thinking of using a smear of RTV silicone to seal between the layers, after welding, to make a seal by sewing through it while it is curing.

I think it would 'gum up' the needle and thread. Might be better cured? I'm not at the stage of experimenting with that. Think I'll just keep with seam sealing those bits.

[telemarktim]

However, I have been thinking of using a smear of RTV silicone to seal between the layers, after welding, to make a seal by sewing through it while it is curing.

I think it would 'gum up' the needle and thread. Might be better cured? I'm not at the stage of experimenting with that. Think I'll just keep with seam sealing those bits.

Hi Warin. I also was concerned about the silicone rubber gumming up the sewing machine. However, I have been doing this type of sewing for some time now. There has been no problem. With the method that I use, silicone is only on the inside of the seams and has no contact with the sewing machine foot or feed dogs. The needle is kept clean by passing in and out through the fabric and even the eye of the needle is cleaned by the continual passage of the thread around the top of the hole while going in and then around the bottom of the hole as the needle comes out. I still seal the stitches from the outside with diluted silicone rubber after the sewing to make them hydrophobic. If the silicone is allowed to cure fully it still is very easy to sew seams through it. I think it acts as a lubricant in liquid or polymerized form. Tim

[andrewa]

Hot cutter arrived yesterday. Spent today making new boat tonneau using my Paskal weathermax fabric, which really needed to be edge sealed. I didn’t realise a hot cutter was so cheap. Thanks for the original post. I wish I’d bought a hot cutter years ago!

A

[telemarktim]

[quote="andrewa"]Hot cutter arrived yesterday. Spent today making new boat tonneau using my Paskal weathermax fabric, which really needed to be edge sealed. I didn’t realise a hot cutter was so cheap. Thanks for the original post. I wish I’d bought a hot cutter years ago!

A[/quote ]

Hi Andrwa, I am glad that you value the cutter. It sounds as though yours arrived much quicker than mine. I wonder who of us has the most years to regret not having one? Tim

[andrewa]

Well, Tim, I’ve been making gear for almost 40yrs….

A

[telemarktim]

Well, Tim, I’ve been making gear for almost 40yrs….

A

Hi Andrewa, I think I win. I started when I was a student on a commonwealth scholarship. I spent my spare $ on cheap nickle shares and had to make my own bushwalking gear. The gear was good and the shares came good too *200 times. So it has been at least 50 years and I still enjoy doing it, even though I don't really need to. Tim

[Lamont]

Hi Andrewa, I think I win. I started when I was a student on a commonwealth scholarship. So it has been at least 50 years and I still enjoy doing it, even though I don't really need to. Tim

No wonder your blog is so good. Onya Tim.