Comment by Stratoscope | Hacker News Reader

Comment by Stratoscope | Hacker News Reader

This is cool! I can buy a $30 Black & Decker toaster oven and turn it into a reflow oven.

There are a few worrisome steps, like this section:

> Ceramic fibers are very fine and sharp. They don't penetrate though thick skin, but can irritate thin tissue like eyes, nostrils and lungs. If you exercise precautions you won't have any problems. The blanket has amazing insulating properties, and the top of your oven will be barely warm during a reflow.

> Things to keep in mind:

• Unwrap the ceramic fiber blanket just before you use it - not earlier.

• Clean up your workspace immediately after applying the blanket and closing the oven

• If possible, wear a face mask (we recommend using N95 masks)

• Wear shoes. Our preference is flip-flops that we can easily wash afterwards

• Take care not to touch your eyes, lips or ears

• Keep the area free of drinks, and use the restroom (toilet) before starting

• Work in a draft-free environment. Don't use fans

• Make slow movements to minimize dust

• Make sure you have all your tools and parts close by (you need to close up the oven too)

• Make sure pets, kids and neglected spouses don't come into your work area

• Immediately after working with the blanket you should take a shower and wash your clothing

> Scared? Don't be. Ceramic fiber is easy to work with as long as you take a few precautions.

OK! I am not scared at all.

I do have to wonder about the cost effectiveness, at least for myself. It sounds like a solid couple of days work to make this thing.

Suppose I were looking for a ready-to-go reflow oven at some kind of reasonable price. Where would I start? Any recommendations?

I don't think the ceramic fiber blanket is necessary. I made my own reflow oven (PID temperature controlled) and was surprised to find that my roommate was able to reflow a PCB with his completely unmodified toaster, just popping the PCB in and bringing it up to the right temperature. Obviously it didn't follow the temperature curve like mine did, but the end result wasn't really different, at least for our hobbyist uses.

Suppose I were looking for a ready-to-go reflow oven at some kind of reasonable price. Where would I start? Any recommendations?

Here's the rub... there are relatively inexpensive, COTS reflow ovens out there[1], and they do work - more or less. The problem is that many people find them to be more on the "less" side of that spectrum, without putting considerable work into upgrades and mods anyway. And once you take a cheap T962 off the shelf and start modding it, you might start to ask "why not just build my own from a toaster oven?"

The toaster oven conversion winds up being cheaper, or - at worst - a wash, from a price standpoint. And many people find that they get better results from the converted ovens than they do from a T962.

Unfortunately, the next "hop" up in quality in terms of commercial ovens winds up being a pretty big jump price wise.

I haven't tried this myself yet, but I have a friend who has both a T962 and a conversion oven (made from a Black and Decker convection oven, so a little pricier than the model cited in TFA), and he only actually uses his converted oven. I trust his opinion a lot, so if/when I decide to get a reflow oven, I'm leaning hard towards doing this.

[1]: https://www.amazon.com/Happybuy-Soldering-Machine-Infrared-A...

I've also had less screwups using the regular toaster oven instead of T962. I suspect that's because T962 uses IR heaters instead of convection.

I've regularly had slightly charred or even molten connectors on boards reflown with T962. The most extreme case was broken inner layer traces (on a board with black soldermask, which apparently had a bit too much moisture inside- the board layers visibly popped).

An interesting side note- large LEDs don't like being reflown in IR ovens. The lens on large LEDs also works in reverse- it happily damages the bond wires by focusing incoming IR radiation to a point.

I've also had less screwups using the regular toaster oven instead of T962. I suspect that's because T962 uses IR heaters instead of convection.

I suspect so. Especially if one follows the advice of adding an extra heating element to their converted oven. It's not just about having more raw heating power, it's about having the heat coming from multiple places, so you get more even heating.

I have one of those (T-962) at home, and I am pretty happy with it.

I keep thinking about buying one, but for now I've convinced myself that the amount of SMD work I do is small enough that I can rely on either hand soldering under magnification, or using my hot air rework station.

Most of what I do prototype wise is still through-hole, or the larger SMT packages (SOIC, etc.)... the only reason I'd use one of the smaller packages would be if the component I need is only available in that package. Unfortunately, that's becoming more and more the case.

Anyway, if I need a component that's a real fine pitch QFP or something, I'd just hot air solder it to a breakout board, and then jumper it in... unless it's something where that little bit of extra capacitance would screw something up, or where EMI would be an issue. But I'm a hobbyist, so that stuff isn't usually an issue here.

It's extremely irreponsible of this author to not list a respirator as a requirement for handling ceramic fiber, given that the audience is likely to be unfamiliar with the materials.

That "if possible" is terrible advice. If you're working with a ceramic fiber blanket, always wear a respirator. And the fibers will continue to hang in the air afterward, just like asbestos.

High temperature turns the fibers from irritants into carcinogens like asbestos. The suggestion to build one of these things with an uncoated ceramic fiber blanket is horribly negligent.

High temperature turns the fibers from irritants into carcinogens like asbestos.

Well, high temperature in this case being above 1800 F/1000 C, over 4 times the operating temperature of these ovens.

I built one of these about a year ago. I spent about 5 hours on it, over a little more than 2 days (some things need to dry or set up before going to the next step).

To reflow a small board (or 3) on an extreme budget, use a frying pan and an infrared thermometer. Not super accurate, but if your board is on a piece of foil you can pull it out before it overheats so your components don't cook.

I handled the ceramic fiber part by working in a room with a powerful vent fan that exits far from people, taping my cuffs to my gloves, and staying upwind of the insulation. I cleaned the room as soon as I was done. It only took a few minutes and the top cover goes on as soon as you get the insulation in place.

You can buy pre-built Controleo3 ovens, but you can probably get a used industrial oven for about the same price as the prebuilt kit. I guess it depends on what you consider a reasonable price, and whether you know people who like building things from a box of parts.

I've worked with fiberglass insulation before, is this stuff significantly worse?

I thought the worst thing that could happen to you with fiberglass would be to inhale the fibers. Isn't a mask and gloves enough?

> This is cool! I can buy a $30 Black & Decker toaster oven and turn it into a reflow oven

$20 at Bed Bath & Beyond [1].

[1] https://www.bedbathandbeyond.com/store/product/black-decker-...

Maybe $16 with one of my lifetime supply of 20% off coupons!

This gives me an excuse to share the Three Secrets of Bed Bath & Beyond in-store coupons:

1. Even though the coupons have an expiration date printed on them, they do not expire. Keep your old ones and use them when you want.

2. You can use more than one coupon in a single visit. You can't stack them on one item, but if you have N coupons you can use them on N items.

3. If you forget to bring a coupon to the store, you can come back within 30 days with your receipt and a coupon and they will refund the discount amount.

None of this applies to online purchases, only in-store.

Seems like it would be physically quite similar to asbestos. I wonder if it's comparable.

AliExpress expect to pay maybe US$140ish plus shipping

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