Bear's New Mixing Block

[Frank]

Frank,

Kindly open Kevin's mixing block for the dual injector and take a pic w/ a ruler . I wish to see if any modifications were made.The original had two distinct and sharp angles that i was not fond of for sure. I'll get a pic of the two single injectors on the mixing block later and post it for you. Order some Chemionics medium from Bear's- no smell, very little smoke and is a bit thinner/more flexible then the rest of the medium plastisol brands (3) I have injected.Very little settling in the bottom of the 2 1/2 gallon container that is easily shaken ed up in a minute or two.

Al

P.S. I mentioned the plastisol fumes and Pyrex use for safety reasons,not to criticize your successful method of two color injecting.

http://www.madsci.org/posts/archives/2000-06/961600694.Ch.r.html

Thanks for the advice on the chemionics( I just got mine 2 days ago) And am looking forward to trying it. You definatly have a differant climate than me in CA. I can still pour in my garage with the door open in the dead of winter and still do now. As for smell I have worked in an auto body shop for 30 years now so my sense of smell is gone. I am in smell all day long. You are in an enclosed shop and need the exhaust fan. That being said I am guessing alot of your heat is going out too. I was thinking about getting something like a smoke eater fan. We have one at work that is nothing more than a giant hepa filter that cleans the air within the shop without an exhaust on the outside. The channels still have the angles you talk about but I still have had no issue with them in fact most of the time when i clean out the block it is more like a straw even with the angles.Frank

sorry forgot the ruler

Edited December 23, 2010 by Frank

[smallmouthaholic]

Thanks for the advice on the chemionics( I just got mine 2 days ago) And am looking forward to trying it. You definatly have a differant climate than me in CA. I can still pour in my garage with the door open in the dead of winter and still do now. As for smell I have worked in an auto body shop for 30 years now so my sense of smell is gone. I am in smell all day long. You are in an enclosed shop and need the exhaust fan. That being said I am guessing alot of your heat is going out too. I was thinking about getting something like a smoke eater fan. We have one at work that is nothing more than a giant hepa filter that cleans the air within the shop without an exhaust on the outside. The channels still have the angles you talk about but I still have had no issue with them in fact most of the time when i clean out the block it is more like a straw even with the angles.Frank

sorry forgot the ruler

Frank-

What's the distance between the center of each injection port? personally,I'd prefer a straight line from the bottom of the injection port to the bottom of the block. Too many angles allow the plastic to solidify quicker and cause you to push harder on the injector. The mods I made to bear's made it work easier w/ less effort

Al

Edited December 23, 2010 by smallmouthaholic

[gone2long]

MrBilky,

Please see above, I admitted to my mistake.

Tim

All's good when I started to post the phone rang and when I got back and posted you had corrected the situation, I was scratching my head on that one

[Frank]

Frank-

What's the distance between the center of each injection port? personally,I'd prefer a straight line from the bottom of the injection port to the bottom of the block. Too many angles allow the plastic to solidify quicker and cause you to push harder on the injector. The mods I made to bear's made it work easier w/ less effort

Al

[/quote)

The distance between the two sprues is .065 with the openings .250 and the outside is .61. I am sure the numbers you have are pretty much the same as me and Bear already talked about it. You know there is not much play here if you have a 5/8 hole to work with. And if angles really have anything to do with plastic cooling then why is there a 90 deg port on tube molds and many others. I just had a discussion with Jason at CCM about this subject. He could not tell me why it is done that way. I have had more issues with a 90 deg port than any other design. Issue being you have a real good chance of getting an air bubble in the top of your bait. I also think it swirls more when it changes direction not saying it does not look good but I can see the differance. One thing that I do think is differant on the injectors though is the hole size in the end, Bears I think is the biggest one out there. That does not matter if you restrick it to .250 with the block. Frank

[rhahn427]

TTDuckman,

I broke out my 21 year old digital pyrometer and put the equipment back in the toaster oven. There is a fine line between broil/bake and 400 degrees. Regardless ,both the upper and lower heating elements glowed for 10 minutes.I could barely hold onto the molds w/ the hot-melt gloves which are good to 450-500 degrees

Pyrometer / Infrared

1- 6oz. injector 275 / 103

2-4 cavity stk mold 285 / 110

3- Blending Block 291 / 107

There is obviously a problem w/ the digital infrared thermometer and I don't believe the pyrometer is accurate either. The infrared thermometer read the palm of my hand @ 97.1 , the pyrometer said it was 87 degrees( should be 98.1)-yet the completely inaccurate temp. reading of the equipment listed above. The pyrometer has not be calibrated in 21 years and therefor I'm sending it back for an up date calibration. The fact that I could feel instant,hot heat through the gloves( which made me release the object ) strongly suggests the temps are in the 450+ degree range .

I didn't intentionally post false data early this morning for the initial readings (which are way off base and totally inaccurate). My bad for which I truly apologize to all who rightfully questioned these ridiculous temperature numbers. A new infrared thermometer will be ordered and hopefully the factory(which is still in business) can calibrate my old Pyrometer.

Again,my humble apologies to rhahn, TBaits and TTDuckman for my inaccurate data posted.

Ahhh ........ now that sounds more like it ....... no apologies necessary ........ glad you figured it out ........

[pirkfan]

OK I watched my video again and see the temp gun I think you are missing the decimal point. Frank

I think the problem is the emissivity of aluminum which is very low.

Emissivity is the ability of an object to emit or absorb

energy. Perfect emitters have an emissivity of 1, emitting

100% of incident energy. An object with an emissivity of

0.8 will absorb 80% and reflect 20% of the incident energy.

Emissivity may vary with temperature and spectral

response (wavelength). Infrared thermometers will have

difficulty taking accurate temperature measurements of

shiny metal surfaces unless they can adjust for emissivity.

Infrared thermometers calibrated for the emissivity of plastics won't get an accurate reading from shiny metals. There are correction factors for various emissivity levels for different materials to calculate the true temperature

[smallmouthaholic]

I think the problem is the emissivity of aluminum which is very low.

Emissivity is the ability of an object to emit or absorb

energy. Perfect emitters have an emissivity of 1, emitting

100% of incident energy. An object with an emissivity of

0.8 will absorb 80% and reflect 20% of the incident energy.

Emissivity may vary with temperature and spectral

response (wavelength). Infrared thermometers will have

difficulty taking accurate temperature measurements of

shiny metal surfaces unless they can adjust for emissivity.

Infrared thermometers calibrated for the emissivity of plastics won't get an accurate reading from shiny metals. There are correction factors for various emissivity levels for different materials to calculate the true temperature

Thank you- I guess that explains the completely inaccurate readings from my inexpensive, non-adjustable, infrared thermometer.

I checked my digital pyrometer against a lazer beam ,infrared thermometer @ my automotive repair shop. It was consistently inaccurate by 20-35 degrees

on 3 different comparison test but when I switched to an immersion probe-it read 200+ degrees higher then the infrared comparing the output of a heat gun.I'll be in touch w/ the manufacturer to see if the calibration can be checked and re-set.

[smallmouthaholic]

Pirkfan,

I just ordered a AQA 4344 IR-Temp Laser Thermometer ($89.00 + shipping) which Offers Variable Emissivity, Three-Point Calibration and Pinpoint Targeting.Thanks again for you valuable technical info on emissivity. Now I'll feel confident in accurate temperature measurements of various targets.

Al

[wchilton]

I've had trouble getting my infrared temperature meter to get a good reading on shiny (aluminum) surfaces. I had a couple of aluminum blocks sitting on top of a laboratory hotplate. Hotplate temp was 360 F but the aluminum read as high as 1200 F. I'm not sure if it's the shiny surface or what. Also, you gotta be careful with heating in any oven that does not have accurate temperature control...like regular kitchen oven or toaster ovens. You can set the temp to 400 F or so but the element heats up a lot hotter than that and if the object you're heating is near the element it can get much hotter than the temp you set the oven for.

W