There’s many different reasons why somebody might have to hack together their own solution to a problem. It could be to save money, or to save time. Occasionally it’s because the problem is unique enough that there might not be an accepted solution, so you’re on your own to create one. We think the situation that [Raph] recently found himself in was a combination of several of these aspects, which makes his success all the sweeter.
The problem? [Raph] had a pair of foam mattresses from his camper van that needed to be made thinner — each of the three inch (7.62 cm) pieces of foam needed to have one inch (2.5 cm) shaved off as neatly and evenly as possible. Trying to pull that off over the length of a mattress with any kind of manual tools was obviously a no-go, so he built a low-rider foam cutter.
With the mattresses laying on the ground, the idea was to have the cutter simply roll across them. The cutter uses a 45″ (115 cm) long 14 AWG nichrome wire that’s held in tension with a tension arm and bungee cords, which is juiced up with a Volteq HY2050EX 50 V 20 A variable DC power supply. [Raph] determined the current experimentally: the wire failed at 20 A, and cutting speed was too low at 12 A. In the end, 15 A seemed to be the sweet spot.
The actual cutting process was quite slow, with [Raph] finding that the best he could do was about 1/8″ (3 mm) per second on the wider of the two mattresses. While the result was a nice flat cut, he does note that at some point the mattresses started to blister, especially when the current was turned up high. We imagine this won’t be a big deal for a mattress though, as you can simply put that side on the bottom.
In the end, the real problem was the smell. As [Raph] later discovered, polyurethane foam is usually cut mechanically, as cutting it with a hot wire gives off nasty fumes. Luckily he had plenty of ventilation when he was making his cuts, but he notes that the mattresses themselves still have a stink to them a couple days later. Hopefully they’ll finish outgassing before his next camping trip.
As you can imagine, we’ve covered a great number of DIY foam cutters over the years, ranging from the very simple to computerized marvels. But even so, there’s something about the project-specific nature of this cutter that we find charming.
Any good ways to get some soft foam to make a mattress with? The good mattresses always seem to cost a leg but the inexpensive ones are just not good to sleep on.
Surely someone has hacked their sleeping furniture on hackaday?
I feel like I’d need to add a way to automate the process of pulling it through the foam,
Although I’m not sure I’d want to leave it unattended either.
I’ve thought about something for our camper but everything I look into I’d rather not sleep on and breathe the chemicals in anymore. Trying to find a natural fill thin topper has not been successful yet
Your entire house and camper are full of this stuff as is everything in life in a 1st world country. You are wasting time and energy doing this. I get the concern and desire, don’t get me wrong, but I am just being real with you.
What?
They’re called feather beds.
Down toppers, buy a cheap one, it will be plenty thin.
Will get thinner with age.
Old tech, not all that cheap, even cheap version.
There are companies selling pure latex toppers. They are quite comfortable.
This company does some great customisation options, in material and shape, there’s also an emagnets, similarly fairly reasonable. They’ve both been around a while. Ignore the first appearances of the site.
https://www.efoam.co.uk
Friend bought her campervan mattress foam form them, their site is awful but the products are great and their service was good too.
I use Rochford Supply in the US. Each of the 67″x39″ 3″ thick foam pieces used for the van mattress was $125.
That’s quality foam that’ll likely stand up to years of abuse, unlike some of Amazon’s cheap stuff.
Details & link in this post: https://raphvan.blogspot.com/2023/06/bed-platform-20-jun23.html
Video related: https://www.youtube.com/watch?v=faacDjTRz_0
This is how those are made in light industry.
(oooops, posted this reply under the wrong comment below… so reposting here)
Love the skills of many Indian & Asian workers who can do miracles with run down and rickety machines / processes. Definitely inspires me to always look for simpler ways to build my projects.
Reminds me of the video of a guy in India who repaired a 4 cylinder crankfast with just a buzzbox and something that may have been a lathe in a previous life… Right there on the side of the street. And… it worked !
Thanks for the vid.
Seems like this would be a good application of the ultrasonic cutter described recently here on Hackaday…
https://hackaday.com/2025/03/21/high-frequency-food-better-cutting-with-ultrasonics/
Love the skills of many Indian workers who can do miracles with run down and rickety machines / processes. Definitely inspires me to always look for simpler ways to build my projects.
Reminds me of this video of a guy who rebuilt a 4 cylinder crankfast with just a buzzbox and something that was a lathe in previous life. Right there on the side of the street. And… it worked !
Thanks for the vid.
this is 100% a hack and thank you for this. I’ve rigged up some very similar stuff for doing… look I don’t want to get into it… and the fact that several 2x4s are less than $20 has solved many, many problems.
why is no one talking about the precariously balanced power supply?
Honestly it doesn’t seem that precarious to me, sure it’s got what 4 inches hanging off and what looks to be closer to 18 inches on the counter? Considering the display panel is probably the lightest portion, that means an inch-ish of that has even less impact on it. And that bit of a slope is likely because it’s got feet touching on the back but not the front, not because it’s being pulled downward that hard. Snag hazard is the only thing that’d jump out at me. But it looks like most of the rooms space is on the opposite side of the rig, so do your mattress, shut it off, take it down.
Raph here. You nailed it. This psu is extremely butt heavy, so it is extremely stable in that position, even if bumped. Indeed the front feet are over the counter edge.
Thanks for taking the time to answer for me in detail !
Hah thanks for confirming I wasn’t entirely talking out of my rear. I’ve never messed with desktop psus like that like that, so most of that was wild guesses from helping move bulky electronics. When the weight distribution wasn’t fairly even it usually was something that needs more juice and might have a bigger transformer in the back half.
There was an article here, about ultrasonic blades, a few days back.
https://hackaday.com/2025/03/21/high-frequency-food-better-cutting-with-ultrasonics/
Would an ultrasonic blade work reasonably well for this?
A blade of at least couple inches width (4~6″ would nicer!) and some sort of beam or board to suspend the cutter over the foam as a guide/track to move the cutter across the the foam.
Should be a lot less smelly, I would think.
Just have no idea if the ultrasonic produces any amount of dust or particulates that you might be concerned with?