Induction heater recs?

[flyweightnate]

I need to heat a 12" diameter ring about 250F, and don't know if I have the patience to do it with a torch. For various reasons, ovens and oil baths are out, so it's either get a hotter torch, or get an induction heater.

Does anyone have experience with a 1500W induction heater (so i don't need to rewire my garage) that'll fit on something this big? Most bolt breaker types seem to have pre-formed coils... but I'm assuming I could just take a loop of 10AWG solid copper and wrap the part 3-4x and get the same effect, no?

And how long would it take to get a 10lb high alloy ring up to temp?

Thanks - hoping to make a tedious process less tedious, but don't want to throw money at it without results.

[Trbo323]

What torch are you trying to use now?

If this is a one shot thing I would look at local hardware stores/weld shops and see if you can rent a small oxy acetylene setup.

If you need to buy a small oxy acetylene setup can be had for around $400

Sent from my motorola edge 2024 using Tapatalk

[flyweightnate]

Propane - I don't want to heat it *too* fast, to where any one spot starts to oxidize/ discolor. But that's not a terrible idea with a small rosebud and a temperature crayon.

And it's a once- a- month thing, but this month I have enough to do that it's about to get tedious. Especially being slightly neurotic about it.

[Trbo323]

If you have a 20lb propane tank (BBQ tank) you can get different torches for those that will put out much more heat than the little Colman bottles.

I fill propane tanks for a living, there's a lot of weld shops that use propane to preheat parts for welding. So it's a fine solution especially if you are trying to avoid overheating but I bet right now you are just not using enough, it's a flow issue

Sent from my motorola edge 2024 using Tapatalk

[alive]

I’m not saying this out of experience, so I may be totally wrong. But I immediately thought of something like this.

[Grendel]

I was a Field Engineer for Inductotherm Corporation, so I have experience with induction heating and melting equipment. I'm unable to answer your question with the information you've provided. So, going to ask some specific questions:

1. You only need to heat it to 250°F? A 1500W should be plenty of power to heat a 12-inch ring if you can find or make a coil large enough to fit inside, heating aluminum or steel to just 250°F. If anything, heating to only 250°F might be challenging to control.
2. What material is the 12" diameter ring, and what is the diameter of the material that makes the ring? Material matters; you are making a tank circuit, so the XL changes based on material and density.
3. Is the Ring uninterrupted, or can a coil be passed over [around] the ring?
4. What power source are you planning to use, and is it a variable frequency source?
5. Have you just looked for a heat treatment shop in your area? There are numerous small shops across the country, and most are willing to take on small jobs.

You can buy a large single-burner inductive cooktop and possibly get enough induction to heat your ring; you're not asking to couple much energy.

[flyweightnate]

Grendel I'm trying to expand the outer ring of a bearing just enough to take a peek inside.

52100 steel, varying sizes but the ones on my bench are about 1.5" wide and a tapered cross section. It's sitting by itself, nothing in the way.

The reason I want a coil is to focus the energy on the outer ring, and avoid heating the balls and inner ring (which I have a mind to liquid nitro if it becomes a regular occurrence). It'll 'slip' off at 250F, if everything else is reasonably cool.

So it's a power source plus coil question. I'm no electrical engineer. Thus not knowing exactly what questions to ask.

Edit: 15 minutes with a larger torch did the job. Only three more to do today.

I love failure analyses, but they do take some space in the garage.

[Grendel]

Glad you were able to take care of it with a torch. While this is feasible with an induction coil, which is ideal for this application, creating one specifically for this purpose would not be inexpensive. So I assume the three you are looking at are the only ones you anticipate needing done for the foreseeable future? If that is not the case and you will do this routinely, then creating a coil with a variable power supply would make sense. Small ones, such as those for heating fasteners, are relatively cheap and easy to make, but larger coils and supporting power supplies can add up quickly. If you need to do this again, I suggest contacting a heat treatment shop. I have dealt with many over the years, and most would be willing to handle something like this for you for a minimal cost, and usually do it while you are standing there.

[Grendel]

Here is a good link to show you what you would be getting into if you wanted to make an induction coil with a power supply.

[flyweightnate]

I guess i underestimated how quickly something like that would scale up on power consumption. In the production environment they're everywhere... might be a little spendy to buy (or build) for my garage office.

[Grendel]

They are used in a lot of manufacturing applications, mainly for three reasons: 1) Transformer Theory is well understood and relatively easy formulas to figure out what you need, 2) Super high efficiency usually north of 98% if designed and built correctly, and 3) Stupid fast for providing heating. I worked on a 22-metric-ton aluminum furnace designed to reach full melt temperature in 45 minutes from cold start. It was incredibly impressive, and you could feel the energy when it was running at full capacity. I miss working in the industry, particularly for Inductotherm, but the travel was taking a toll on my family life, so I had to give up that career for their sake.

If you ever change your mind about building induction tools, let me know.

[flyweightnate]

Yep, pretty sure I've been around a few of those between the steel and aluminum plants I've visited.
Good to know who to reach out to! Thanks!