Using hardboard for 3D printer enclosure; what is the temperature rating of hardboard?

5

I am looking for the temperature rating for hardboard. I want to use that as the base for my printer enclosure.

It has proven incredible hard get a ball-park figure from Google.

So, what is the maximum safe temperature for a hardboard panel at long term? (considering a print job can easily take 6 hours).

PS: if you have used a hardboard to build your enclosure, your experience might be helpful.

rufo

Posted 2019-03-03T23:37:04.290

Reputation: 259

You are just wanting to use it as the enclosure? No hot parts should be touching it, right? – Pᴀᴜʟsᴛᴇʀ2 – 2019-03-03T23:52:19.883

@Pᴀᴜʟsᴛᴇʀ2, right. No hot parts in direct contact with it (but close to some stepper motors, like 10-20mm apart). – rufo – 2019-03-04T00:25:15.543

Answers

5

Hardboard is called Masonite here in the States because that is the trade name of the product. If you look up the Material Safety Data Sheet you will see Masonite it states the following (Section 5):

Auto-ignition Temperature (°C): >200 degrees Celsius

In Section 7, it states:

These boards are flammable but difficult to ignite.

Furthermore in Section 10, it states:

Conditions to avoid: Avoid sources of radiant heat and flame; and avoid sparks and sources of ignition in all electrical equipment, including dust extraction equipment. Avoid excessive build up of dust from boards.

The hot end works of printers are neither radiant heat, nor flames, nor sparks. Yes, you'll have a buildup of heat within the working confines of an enclosure, but if you are only using it for a base there should be absolutely no issues. If you were to build an entire enclosure from hardboard, you could put a thermal probe inside with the printer to ensure it doesn't get too hot, but realistically, it will never get hot enough within the enclosure to light the hardboard on fire.

Pᴀᴜʟsᴛᴇʀ2

Posted 2019-03-03T23:37:04.290

Reputation: 2 271

Yes. Thanks. I have to do the thermal probe + smoke detector. The rest of the enclosure is going to be plexiglass (whose glass transaction temperature can start ~85 celsius). I am only printing PLA, so it would be a severe malfunction to bring the inside "ambient" temperature of the enclosure so high. – rufo – 2019-03-04T01:43:09.130

4

Masonite or hardboard is a high-density board without a resin. It is listed at around 200 to 275 °C for its autoignition temperature. Just for comparison, let's look at similar products.

Medium-density fiberboard (MDF) is similar to hardboard but bonded with a resin, offering a smoother surface and is listed at 200 to 275 °C, so pretty close.

The heavier High-density fiberboard variant is listed with about the same temperatures of about 200 to 275 °C.

Oriented Strand Board (OSB) is listed at 200 to 260 °C.

Conclusion

All the materials have very similar autoignition temperatures, so none of them particularly shines over the other. Using a proper fire safety procedure is highly encouraged, even though the ambient temperature in the enclosure should not reach even close to the 200 °C unless the printer has a freak accident and catches fire itself.

  • A smoke detector is a must.
  • Some kind of cooling method that keeps the inside at a temperature down is highly encouraged. A simple temperature activated fan might help in this.
  • Lining the inside of the box with a thicker aluminium or copper tape can help to even out the temperature over the surfaces faster, preventing the formation of hotspots that might otherwise reach dangerous temperatures. Copper tapes are more expensive than Aluminium tapes but have a better heat transfer coefficient.1
  • Including an automatic fire suppression system could be an option.

1 - The RS Catalogue was just chosen for ease of navigation. McMaster Carr does list special heat shielding tape in both thin and aluminium as well as copper and aluminium foil tapes. I am not affiliated to either.

Trish

Posted 2019-03-03T23:37:04.290

Reputation: 15 633

Definite plus for lining the box- if you use aluminum foil, make sure it's "shiny side up" as that will miminize heat transfer to the Masonite sheet. – Carl Witthoft – 2019-03-04T16:16:55.247

@CarlWitthoft I would not use the standard foil but something thicker like real Aluminium tape (RS catalogue for variety of brands and types), that is far thicker

– Trish – 2019-03-04T16:27:13.120