# suggested material for component enclosure?



## dtbaker (Jan 5, 2008)

I am about to layout and wire up my under hood components.... and wanted to discuss what people have used and liked for materials. Something easy to work with, durable, waterproof, etc.

I am assuming that the pieces like pot box, shunt, contactor will be best off in an enclosure... to avoid possible spray of water, and curious fingers from the hordes of interested viewers. 

so.... plastic? what kind? glue-able? 1/4" ? 1/2" ?

I see clear display boxes in museums and stores, but don't know exactly what they are made of, or what to get to glue them together... Is it polycarbonate, or lexan, or what?

My local hardware stores (Lowes and Home Depot) only stock thin sheets of poly and lexan, not even up to 1/4". Where do people recommend getting this stuff? Anyplace online that ships for reasonable fees? Or, do I need to hunt around for a big commercial distributor willing to sell a few pieces retail?


----------



## Bottomfeeder (Jun 13, 2008)

There are many places to get plastics. Those display cases are usually made of acrylic (plexiglas, lucite). You can get raw materials at Home Depot, or online at places like http://www.tapplastics.com, or even http://www.mcmaster.com. I suggest shopping around for just what you want.

You can "glue" acrylic together with solvents such as chloroform, and probably a few others (toluene? acetone?). But you have to have the parts that you are gluing in good contact with each other. If you do it right the joint will be as strong as the acrylic itself.

Why would you want thicker than 1/4"? It only gets expensive and heavy.

Good luck!


----------



## madderscience (Jun 28, 2008)

buy a good quality plastic tool box of the right size, and use that.


----------



## dtbaker (Jan 5, 2008)

madderscience said:


> buy a good quality plastic tool box of the right size, and use that.


not a bad idea, but I kinda want clear for the coolness factor. I found some pretty good polycarb food storage containers with snap lids that might work well, but they tend to have curved walls that would make mounting things on the side hard, and they are so thin I am afraid they would crack when i drill or saw through to put wires.....


----------



## Jimdear2 (Oct 12, 2008)

A suggestion for a quick easy inexpensive container.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=39196

Remove the handles, gut the foam, leave the latches.

Jim


----------



## RKM (Jun 9, 2008)

dtbaker said:


> not a bad idea, but I kinda want clear for the coolness factor. I found some pretty good polycarb food storage containers with snap lids that might work well, but they tend to have curved walls that would make mounting things on the side hard, and they are so thin I am afraid they would crack when i drill or saw through to put wires.....


 
If you want a really good looking box with a transparent, hinged lid, take a look at this link. I would like to use something like this myself. I haven't done any pricing (afraid too!).

Rob

http://www.fiboxusa.com/products/products.php?show=arca


----------



## dtbaker (Jan 5, 2008)

Jimdear2 said:


> A suggestion for a quick easy inexpensive container.
> 
> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=39196
> 
> ...


ooohhh, that is looking better and better... thx for lead on that.
d


----------



## Bottomfeeder (Jun 13, 2008)

There is an art to drilling through acrylic. Usually, you'll be drilling along and right as the hole is finishing you'll hear a snap and there is a nice crack in the acrylic. It's tough to avoid.

I found that it helps to have pre-drill the underside of the acrylic by a bit. Also, it helps to have something else for the drill to go into. Have a spare piece of acrylic underneath what you are drilling into, and hold the piece down very tightly. If the drill maintains a smooth transition from one piece to another, the bit won't grab off a big piece of acrylic at the end of the hole and cause a crack. Also, go slow and use lots of coolant. The drill bit will get extremely hot and the acrylic won't help dissipate the heat like other materials. The interesting thing with acrylic is you can see the material melting and boiling if the drill bit gets too hot.


----------



## RKM (Jun 9, 2008)

Bottomfeeder said:


> There is an art to drilling through acrylic. Usually, you'll be drilling along and right as the hole is finishing you'll hear a snap and there is a nice crack in the acrylic. It's tough to avoid.
> 
> I found that it helps to have pre-drill the underside of the acrylic by a bit. Also, it helps to have something else for the drill to go into. Have a spare piece of acrylic underneath what you are drilling into, and hold the piece down very tightly. If the drill maintains a smooth transition from one piece to another, the bit won't grab off a big piece of acrylic at the end of the hole and cause a crack. Also, go slow and use lots of coolant. The drill bit will get extremely hot and the acrylic won't help dissipate the heat like other materials. The interesting thing with acrylic is you can see the material melting and boiling if the drill bit gets too hot.


 
I avoid acrylic aka plexiglass and use polycarbonate instead (trade names lexan or hyzod). Acrylic is brittle by comparison to polycarb. I've had very good success drilling and cutting polycarb. It's recommended that you should reduce the angle of the drill bit (less acute) and reduce the lead of the cutting edge as well. I have not done this and it works fine.

Rob


----------



## piotrsko (Dec 9, 2007)

I'll use a generic word for materials: plastics

series of comments: you can bend and form most thermoplastics in your home oven set to about 350 degrees,, place a heat proof male mold under the plastic and let it heat soak until you get the desired effect. Then there is pressure forming and vacuum, but........

the best way to drill plastic sheet is to use a DULL drill bit, lots of rpm, and feed very slowly with minimal pressure and a wooden backing plate for break through. the dull bit needs to really heat up and MELT the hole instead of cutting. I also use new bits, but run the drill backwards. swab the inside of the hole with acetone to seal potential cracks. Make the hole one size larger than the attachment because it needs to flop about due to temprature.

where you buy the plastic is where they have the proper glues sometimes in wee little tubes for a couple of bucks


----------



## john818 (Aug 1, 2008)

Showing electronics in a clear box sounds cool, but how concerned do you need to be about heat buildup? How much will ambient temps affect this? Where I am, summers are usually in the 90s to 100s F, so I'm pretty concerned about keeping everything cool.


----------



## dtbaker (Jan 5, 2008)

john818 said:


> Showing electronics in a clear box sounds cool, but how concerned do you need to be about heat buildup? How much will ambient temps affect this? Where I am, summers are usually in the 90s to 100s F, so I'm pretty concerned about keeping everything cool.


I am not planning to put the 'hot' components (controller or dc-dc convertor) in the box... just the shunt, contactor, fuse, interlock relay and heater relay and maybe the pot-box. So far I have settled on .177 thick clear polycarb. I should be able to handle engine bay heat without any problem. I will probably just make the cover from polycarb, and the base plate from thicker polypro I am getting for the battery boxes.

I searched around and was considering cheap attache cases, and cheaper snap-lid food storage containers..... but haven't decided for sure yet.


----------



## gravelydude (Sep 6, 2008)

I used to own a hardware store, and we sold both plexiglass and lexan. Both materials can be drilled, but lexan is definitely tougher, but much more expensive. We routinely cut the acrylics to size, and even drilled it for customers. I always drilled slowly with a wood backer board, preferably no closer than 1/2" from the edge. It glues very well with a product called "plastic welder". I believe that it's made by Devcon. It is a two-part epoxy. If it is applied to clean acrylic, it is impossible to break the bond (the acrylic will break somewhere else.) I would use 1/4" plexiglass for your application, because it is cheaper than double strength lexan, and more rigid. Sounds like a great idea, but you might want to include some vent holes as well. Jusr my 2 cents
JACK


----------



## ZenDaddy (Jul 22, 2008)

I purchased a 12" x 12" x 6" grey plastic oudoor junction box from home depot for I think 13 or 14 bucks. It was easy to work and very clean looking. I did put my dc-dc in it as well as contactor, connection strips, shunt, relays, fuses etc. I did install a fan to keep it all cool but put it and all access holes in a place that would still keep the components clean and dry. I also mounted my underhood cutoff switch so that the lever was outside the box and the terminals were inside. It turned out very clean. The box has a gasketed waterproof lid that attaches with 8 screws and leaves only a clean grey flat surface visible apon first glance.

I also have my inertia cutoff switch in the box with an access hole drilled directly above it so if I have to reset I can without unscrewing the lid. The picture shows the hole I drilled. I have since put a flat black rubber plug in the hole.

If you wanted visible components, a square of lexan or plexi could either replace the lid or you could cut a square out of the lid and glue the clear medium to the inside.

Radio Shack also has a variety of sizes of black plastic "project boxes" for reasonable prices. I wanted something just a bit bigger than their largest.

Add a couple of led's and light that baby up!


----------



## dtbaker (Jan 5, 2008)

ZenDaddy said:


> I purchased a 12" x 12" x 6" grey plastic oudoor junction box from home depot for I think 13 or 14 bucks.



hhhmmm, that sounds great... all I have found so far are the metal ones that are $30 and up, perhaps it is a local stocking issue. I'll look more online before fabricating anything too custom.


----------



## ZenDaddy (Jul 22, 2008)

I looked very briefly at those as well. In my local store the plastic boxes were not anywhere near the display that held items like breaker boxes or metal junction boxes. If I remember right they were by the plastic conduit supplies.

Good luck

Michael


----------



## 1clue (Jul 21, 2008)

RKM said:


> If you want a really good looking box with a transparent, hinged lid, take a look at this link. I would like to use something like this myself. I haven't done any pricing (afraid too!).
> 
> Rob
> 
> http://www.fiboxusa.com/products/products.php?show=arca




RKM,

I can't count the number of years I've been looking for a box like those shown in your link. There are a lot of boxes that come close to what I need, but that link surely has a dozen different ones that would be fine.

THANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOU
THANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOU
THANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOU
THANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOU
THANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOUTHANKYOU


----------



## fugdabug (Jul 14, 2008)

I have found that if you want to cut things like PlexiGlas it is best to 'sandwich' for cutting between two pieces of thin plywood (like 1/4" or 3/16" of Luan board. you can make a template drawing and paste it on the wood and follow that line (with something like a jig-saw or a scrollsaw of coping saw (bandsaw too!).
The use of strips of two sided tape is advised (with the plastic protectant in place on the plastic sheet if using Lexan or PlexiGlas etc..) 

And be mindfull if you are enclosing the controller, contactor, shunt... even the wiring, you want to provide airflow through the container in some way for the heatsink and contactor... heat buildup is a bummer.

Consider access...

Just some thoughts. Hope that they help you.


----------



## DIYguy (Sep 18, 2008)

dtbaker said:


> I am about to layout and wire up my under hood components.... and wanted to discuss what people have used and liked for materials. Something easy to work with, durable, waterproof, etc.
> 
> I am assuming that the pieces like pot box, shunt, contactor will be best off in an enclosure... to avoid possible spray of water, and curious fingers from the hordes of interested viewers.
> 
> ...


If you are going to purchase an enclosure, look for the NEMA 4 rating. Rob (RKM has if right). http://www.cdynamics.com/nema-4.html 

What is your reason for putting the pot box in the under hood enclosure? I'm thinking it would be better mounted at the pedal and running the wires out as opposed to mounting in the enclosure and running a cable.

cheers,
Gary


----------



## dtbaker (Jan 5, 2008)

DIYguy said:


> What is your reason for putting the pot box in the under hood enclosure? I'm thinking it would be better mounted at the pedal and running the wires out as opposed to mounting in the enclosure and running a cable.
> 
> cheers,
> Gary


...only that the accelerator cable, bracket are intact and easy to re-fasten somewhere under the hood rather than figuring out a new linkage jammed under the dash. The pot box doesn't look too susceptible to normal dust/damp so I guess I might just fasten to the firewall and run the WIRES to my enclosure... I have not finalized layout yet.

I dunno, do you have a good idea on a direct mount of pedal-to-potbox?


----------



## CNCRouterman (May 5, 2008)

Machining plastic, acrylic in particular requires good sharp tools and controlled feeds. Drilling "plexi" is best done with the correct tool. Such tools are available from Onsrud tooling, among others. The Onsrud tools use a steep point and a nearly flat rake (the angle of the cutting edge that contacts, and actually cuts the material). Both Plexiglas and polycarbonate can be cut with a table saw or skill saw, but again, sharp tools are important. I use a worm drive skill saw to cut Polycarb on occasion. Both route readily, provided you use the right tools and correct feeds and speeds. Overfeeding the cut, whether drilling or routing in plexiglas will cause stress cracks, which may or may not be readily visible, but they are there. Microfracture of a routed edge can be remedied by flame treatment after the fact, but that may or may not be an option depending on what secondary operations are required for the machined component.

If you carefully observe what happens as you drill with conventional hand tools into/through thin stock, you will notice that as the tool penetrates the far side of the material, it reaches a point where the self-feed-limiting effects of the primary relief angle (that would be the slightly angled grind on the end of the drill that meets the cutting edge) are overwhelmed by the self-feeding tendency of the flute's rake angle, nominally the same as the helix angle of the twist. This is where reducing the cutting edge rake comes into play, it reduces the self-feed tendency to a more manageable level.

It is easy to see than forcing the tool through anything at the advance per revolution rate of the drill helix/twist will cause a lot of material displacement, rather than material removal (where the twist/helix removes the cut chips).
As noted above, acrylic tends towards brittleness, and the displacement, rather than cutting action when the drill grabs and pulls through tends to cause fractures in the Plexiglas, where other materials would just deform and pull the tool through the hole abruptly.

Polycarbonate is much less prone to fracture, and is usually preferred for machine guards to acrylic for that reason. Acrylic is less flexible, ie; stiffer, which can be a preferred characteristic for some applications. Also, both are pricey, but polycarbonate is usually significantly more expensive than acrylic.

We sometimes use a solvent cement by IPS corporation called "WELD-ON" #16. IPS provides various products that you may find usefull. Here is a link to thier site map http://www.ipscorp.com/sitemap.html


----------



## DIYguy (Sep 18, 2008)

dtbaker said:


> ...only that the accelerator cable, bracket are intact and easy to re-fasten somewhere under the hood rather than figuring out a new linkage jammed under the dash. The pot box doesn't look too susceptible to normal dust/damp so I guess I might just fasten to the firewall and run the WIRES to my enclosure... I have not finalized layout yet.
> 
> I dunno, do you have a good idea on a direct mount of pedal-to-potbox?


I have no detail mounting arrangement to offer, I'm not there yet. I do recall seeing a few pics of someone who did it. Also, the Belktronix one is made to mount there. Some suppliers offer these with a pedal as on option also. One reason for mounting inside, that I saw posted was to remove it from any damage from potential impacts and the resultant jamming on that could occur. Just a thought. I'm sure it will work either way.

G


----------

