On my on going quest to diy just about everything honeyc,omb backing remained an issue.
Old or new automotive radiator cores are one solution which is cheap (scrap value) and effective .
The aluminum ones are available for their scrap value but even new can be cheap .
I hope this helps other economically constrained enthusiasts .
Only caveat on that is some of the older radiators were assembled using lead solder. If it’s copper/brass, it’s probably at least a lead tin alloy. I worked summers at my uncle’s radiator shop. It was lead wheel weights melted and poured into clay molds of welding rod diameter, and that’s what was used as repair rods. Under a hood and with good ventilation, you’re probably GTG. In a room without airflow…that’s up to you.
But, that said, a more modern aluminum radiator…great idea, definitely cheap and sizes can be HUGE!
Perfect. Thanks for that!
I though honeycomb was the sliced bread of a good cutting foundation… However I found it far from what I had envisioned.
I removed my honeycomb and replaced it with a sheet of steel. I have locating hole in it for templates.
Cost me $12 and generally wipes off relatively easily. It’s easy to use a solvent to help clean it up. Anything you cut will produce debris. A video by Russ Sadler points out some of the issues and runs a camera underneath the table so you can see how the air flows (or doesn’t)…
You have to put up with a little bit of Britt humor, but it’s and all of his videos are very good.
Good luck
Good points !
All the ones I have seen are aluminum. They cant be repaired like they once were so they are all in the bin . If they were copper they would be quite valuable .
I have found that having both options breathable, and a flat sheet useful, depends on whats being cut.
I put a flat sheet over the radiator core if needed.
It’s quite a challenge as all these little problems come up . It makes the process satisfying in a sense of achievement . I guess this is part of the attraction to many of us ?
How would you break one?
If you hunt around, you can find steel honeycomb. It’s nice because you can use magnets…
I’d like to know what you can use them for? If you watched the video it’s pretty clear there isn’t much use for them…
Good luck
Hi.
Oh, there’s a plethora of ways.
Swapping aluminium radiators is a very lucrative business for everyone involved, so there’s zero incentive to make them last.
The aluminium tubing tends to corrode rather badly over time especially if any kind of salt is used to fight the slippery road surfaces, since the fins are press fit, and therefore provide any electrolyte that may be present a perfect place to do its damage.
Use a wrong type of coolant/additive(s), and the electrochemical corrosion eats the tubing from inside.
The seals between the core ends and the reservoir ends will eventually fail.
If the core ends are plastic, either welded or integral with the reservoir ends, one of the 100+ O-ring seals will fail sooner rather than later.
The plastic tubing connections will eventually fail since some (all if given enough time) of the plastics used will become brittle with the temperature variation cycles.
Etc, etc.
Unlike the radiators of old, these plastic end aluminium core ones can not be repaired feasibly, the old ones could (and still can) be repaired over and over again with very moderate costs if needed.
Also, from an environmental viewpoint, old radiators can be recycled with great efficiency, with the modern ones the efficiency is somewhere below 50%.
This is IMHO the main reason why I wouldn’t use any of the numerous radiators I happen to have lying around as a honeycomb bed.
The xTool honeycomb for example is steel, and even comes with 4 magnets.
I assume that many others are as well, because there’s similar if not the same magnets in the sales pics.
Second reason is that radiator core is not flat -because it doesn’t need to be- so expect 1mm or so variation over even a moderate work area.
The thin fins will also bend and dent if You look at 'em in a hard way, and if the span between supports is even moderate for an under bed ventilation, middle of the core will droop eventually.
Third is that the fin spacing is so narrow and sometimes the fins are either webbed or angled, that using any kind of a mechanical hold-down is either tricky or even impossible.
Fourth is that radiator cores tend to be thick, and the thinner ones -AC condenser cores for example- are very flexible.
If You @Nikolatesla find a repurposed radiator core useful as a honeycomb substitute, that’s a great thing indeed, but perhaps not an alternative I’d go for.
Regards,
Sam
I was actually wondering how you would break a regular honeycomb bed, not how well radiators stand up… So I guess we got our wires crossed… there.
I don’t have one with any of my other led or fiber machines, so I’m referring to a co2…
I’ve tried them (honeycomb) and found them pretty useless. The one that came with my OMTech, was aluminum, wasn’t even flat and the only reasonable way to clean them it immersion in a bath of solvent…
In the end if you cut something, it will reflect off the honeycomb and leave marks… and the vaporized debris condenses on the inside of the comb.
To fix the reflection, you have to raise the material above the bed… exactly what I do on my metal table.
the fact they severely disrupt how the ventilation evacuates the debris from the system… is minor, compared to an increase of fire danger using one of these.
Russ Sadler mentions in one of his videos that all the laser fires he’s acquainted with were caused by a honeycomb bed. I thought he was being cynical, but I’ve met two other commercial laser people here in Arizona that have lost three machines between them. All were the honeycomb accumulating debris and being ignited by the laser operation…
My steel sheet is easily cleaned, unlike the honeycomb, I use magnets on it and I have the advantage of drilling locating hole in it for templates… It also doesn’t stink when you open the lid.
If you can think of an application that the honeycomb bed actually has an advantage over a steel plate, I’d love to hear about it…
The only thing I’ve found that works as good as sheet steel is a sheet of acrylic… of course, you burn holes and stuff in it so you have to replace it quite frequently. It’s also not very low cost…
You have to use what you are comfortable with…
Good luck… whatever you pick, keep a co2 extinguisher handy… 
Hi.
My bad, we got our thoughts crossed indeed 
.
I’d assume that the lower end of the honey combs, the rigidity and other structural issues will eventually play a part, but I do agree, I can’t see either how a honeycomb bed designed for a laser cutter would break in use.
At least with our low power machines.
In that case I can understand Your feelings towards honeycombs very well.
That was probably originally intended as a honeycomb panel aluminium core, and those are rather flexible for a reason.
And the reason being that a somewhat flexible -in a predictable way- core allows to easily manufacture curved honeycomb panels.
While I do love aluminium as a structural material -except perhaps for welded parts- I don’t see a reason to use aluminium as a laser honeycomb material.
I have a slightly different approach as my ventilation is mainly (ATM solely) from below the honeycomb, so a solid bed wouldn’t work.
As an added benefit, making the ventilation box hermetially sealed at some point, allows the honeycomb to be used as a vacuum bed.
The symmetrical nature and the rigidity of steel also allows the use of hold downs easily.
I will at some point make a “pin bed” with a ~5mm pattern for the really small parts I’m planning to cut.
Exactly, every different bed type has its own advantages and disadvantages, and everyone has their own preferences, there’s really IMO no design that has all the advantages and no disadvantages.
Generally I do wholeheartedly agree, but in the case of xTool PRO, the flame detector is super sensitive, and for some odd reason at least I don’t seem to be able to turn it off, so its extremely unlikely that a xTool PRO would catch fire.
Regards,
Sam
The same reason we buy this stuff from China… it’s cheap.
IMHO, this is even worse with honeycomb. There is little to no flow through a line the size of your kerf. Even with a vacuum it will not allow smooth air flow. You need the air to flow well to remove as much debris from the machine as possible. There are a number of videos out there about moving where the vent is located, for some of these machines.
It it’s not blocked off in the unused areas, that’s where the air flow goes, not where you need it.
It’s pretty simple if you don’t follow me… get under there and watch the air flow… 
It’s not rocket science… Especially if you are running a job. The debris should leave a good trail → exhaust fan. Keep safety in mind, always…
I bought into the great honeycomb bed idea being the sliced bread for laser use… I’ve found it not useful for anything, from cutting/engraving targets to cutting 6mm acrylic… it just doesn’t allow good air flow… I run my machine with the lid up at least an inch or the air doesn’t flow across (and under) the work piece…
One of the reasons I keep asking for suggest where it does work well… still haven’t gotten any…
It’s also the root item in the machine that causes the machine to stink like burn mdf, acrylic or whatever you’ve recently done… mainly because it’s design condenses the output before it can get moving out the vent…
Changing it out has simplified maintenance and material alignment… I’d still like to find a use for it… can’t bring myself to pitch it, hoping one day it will be good for something.
I don’t know how these work, but I’m pretty sure I’ve seen ways to disable them or lower their sensitivity… you’d have to hunt around the site…
In simple terms if it can engrave, it can light a fire… but I understand where you are coming from…
I have a fiber and sometimes the runs are in hours, especially for 3dsliced images (256 passes)… I can’t sit here that long either, but I’m only a few feet outside the door with a smoke detector… It’s focus is super critical… a few mm off and it has no effect on the material… I’m sure under the right condition it can cause a fire.
Again in the end you have to do what makes you comfortable, whatever that may be… that’s just part of being human… 
Take care
