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Heater Blend Door - Alternate Design

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ckuske

Heater Blend Door - Alternate Design

Administrator

Hi Everyone,

I recently had my dash apart as part of the restoration (still in progress) I'm working on, and I noted my Heater Blend Door had separated from its hinges. This explained why only my defroster worked and not my vents. Anyway, I shared my tale of woe to a coworker who recently started using a 3D printer. He offered to print me a replacement part with some improvements to boot. After a few iterations, I believe we have something that is ready for beta testing. If someone would like to install this and try it out, we can offer a free copy to that person. Feel free to send me a private message or reply to this thread.

I still have to work out a few details (like attaching foam to both sides of the door) but the main purpose of this post is to have a fit check done on someone else's truck. A sample size of one does not mean it works everywhere.

The main advantage to this design is that the hinge will not break and separate from the door like the original door design, where only a very thin bead of plastic joined the two pieces together. This design also uses clips and nuts to fasten the door instead of rivets. I drilled out the rivets on my plenum and am using the original screws on the top and bottom holes, and new hardware that allows for larger holes where the rivets used to be.

The assembly is printed in ABS plastic which should be able to handle the temperature range needed, but real-life testing is yet to be done. We do not have a price in mind yet, but the goal is to be reasonably priced emphasizing that this is meant to be something that won't need to be touched again, is a better design, and is ready-made for installation with a minimum of fuss.

I've attached some pictures below, any and all feedback is welcome! Hopefully this is something that can provide some utility to others out there. I will post updates here as well if that is OK as we fine-tune things.

Thanks,
Chris

Chris

'84 F-150 XL 2WD Flareside, 302 w/ AOD transmission, Motorcraft 2150 feedback carb w/ CA Emissions, EEC-IV w/TFI, factory A/C, Tilt Column, Borgeson/Bluetop Steering, Speed Control - Info about me and my truck - My project thread

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

That's cool, Chris! Looks like it'll last forever.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

kramttocs

Re: Heater Blend Door - Alternate Design

Administrator

In reply to this post by ckuske

Very, VERY nice!
A lot of people print ABS parts (if they can get it to print right

) for engine bay use so you should be good here.

Scott
'Camano' 1986 F250 Supercab XLT Lariat 460/C6
'Chanute' 1980 F350 C&C 400/NP 435 - Gin Pole

But there ain't nothin' wrong with the radio

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

Thanks guys, I think it's pretty spiffy. I think it will hold up nicely and it has some advantages over existing solutions. The offer stands above for me to send a free one to the next unlucky person that needs to fix their blend door to verify fit/function in another truck. After that if everything works, if you guys could offer this to anyone as a possible solution I'd appreciate it! (if you're so inclined) I'll probably post to FTE as well a little while down the road...

And yes Scott, the ABS is harder to print! My friend says its harder to get things to stick to the build plate while printing.

confetti

Re: Heater Blend Door - Alternate Design

This looks like it would last forever

This afternoon I pulled the blower motor and cleaned out a mouse house. I noticed the blower door “hinges” looked frail and a little rusty.

I was wondering how I would fix it if it breaks. Maybe I’ll try one of these out in the future!

•1985 F-150 300 motor auto a/c (“survivor” ..in rejuvenation)
•Parts truck 1981 F-150 300 motor bronco manual

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

Here are some new pics after foam has been applied. I might double up on the foam on the front after testing (can't do it at the moment, long story involving multiple mishaps with getting stuff shipped to me...)

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

Yeah, it looks like the foam might be a bit thin. Is the foam on the door actually touching the housing?

Gary, AKA "Gary fellow": Profile

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

This post was updated on .

Hi Gary,

Yeah, I made a guess on the thickness but I was wrong.

It’s surprisingly difficult to find foam in sheets that is 1/8” thick or less, and not neoprene. I figure neoprene won’t smell great heated…. Weatherstripping foam is great, but it’s in coils or narrow rolls 1 or 2” wide. The door is 8”x4.5”. I know exactly what I’m looking for but my Google-fu is failing me. I’m really looking for what I think is called “charcoal foam” but in thin sheets. (And reasonably priced)

The foam is 2mm thick with adhesive backing. With 4mm, it’s close but didn’t touch the whole way around. This is one of the things I need to test when I can get heat going again - feel for blow by.

i think 1/4” is probably a better place to start. I have some more work to do in this area…

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

I remember going through this on BB's door. Never did find "the right stuff", and wound up using weatherstripping. Not saying it works well, just that it worked. But I didn't do any leakage tests.

So if you find "the right stuff" let's document it.

Gary, AKA "Gary fellow": Profile

salans7

Re: Heater Blend Door - Alternate Design

I found the "right stuff" when I purchased the a/c box sealing kit from DMT, shown below. The center sections of the foam gaskets were left intact when the kit was shipped to me, I assume to protect the gaskets and keep them from folding. I removed the center sections from each gasket and was able to use those to seal my doors. In my opinion, they were all about the right thickness, and they seem to seal well to the box.

https://www.detroitmuscletechnologies.com/ford-80-86-pickup-truck-f150-f250-bronco-ac-heater-box-rebuild-seal-kit/

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

Thanks Shaun,

I actually have the same kit, I didn’t think of this! Worth a shot, you are correct that the foam in that kit would be ideal.

That being said, I got some different foam in the mail and it looks to be on the money, but I need to see how it fits in the truck.

While it’s clear I’m not going to sell a boatload of these by any means, I need to find a source to buy supplies for more.

Thanks!

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

I found some material that looks to work well! I test fit it and it does the trick. I still need to do my "leak" test but I'm pretty confident that will work. This is open cell 1/4" foam that's actually for an A/C filter...

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

So "open cell" doesn't mean it'll allow air to move from cell to cell, creating a leak? I assumed you'd need closed cell foam, but I don't know.

Gary, AKA "Gary fellow": Profile

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

This post was updated on .

Good question Gary - I hadn't really thought about it because the open cell looked like what was on my original door. In a bit of a panic (haha) I Googled it, and it seems both types are acceptable for creating an air seal:

http://retrofoamofmichigan.com/blog/open-vs-closed-cell-foam-insulation

More will be revealed after I test it out installed. Shaun’s suggestion is a good one, I have that foam and can try that next. I just have to figure out how to source it if needed.

Of course I could just use one inch wide weatherstripping around the perimeter and “call it good” but I’m trying for something a little more professional. We will see if that is attainable.

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

That link didn't work for me, but I did some searching and found this: https://www.retrofoamofmichigan.com/blog/open-vs-closed-cell-foam-insulation. However, that site is confusing.

Anyway, I think it'll work.

Gary, AKA "Gary fellow": Profile

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

I did a very scientific test of holding the foam to my mouth and forcing air through it. So far, it checks out.

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

By "checks out", I assume you mean the air didn't go through. Good!

Gary, AKA "Gary fellow": Profile

ckuske

Re: Heater Blend Door - Alternate Design

Administrator

I installed it, and it turns out there is too big a gap between the face of the door and the plenum allowing too much wind to sneak by. So, another revision will be coming out. Trying to get it just right...

Gary Lewis

Re: Heater Blend Door - Alternate Design

Administrator

Keep at it until it is right.

Gary, AKA "Gary fellow": Profile

James191145

Re: Heater Blend Door - Alternate Design

In reply to this post by ckuske

Did you ever come up with a design that works good?

"Brother Charles" 1984 F-250 6.9IDI 4x4 BWT19
"Lacy" 1984 F-250 6.9IDI 4x4 ZF5
"Tommy" 1985 F-250 4x4 300ci ZF5

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