Xtreme SPL Box Building Techniques

[shizzzon 461]

I want you guys to post things here such as materials and bracing methods used to create the stiffest, non-flex box out there and how it's done.

I'm tryin to find some materials so when i go to tear down my wall that i have something to fall back on.

I've came across this but the comments are up in the air... Some competitors say it's good... others who haven't used it say it won't hold up...

Durock...

I had visioned on using 5 layers of 5\16" thick in between 2 layers of 0.75" MDF = approximately 3" thick total material. Then cross brace it with - 0.75" all-thread.

Now, i'm looking for the stiffest out there...

I had read to pour resin in, on and around each Durock layer wedged in between the MDF to prevent air pockets between each Durock layer.

Do you guys have other suggestions for making a very stiff box?

[Lucky 76 5]

1" threaded rod

[shizzzon 461]

is there such a thing?

Also, speaking of threaded rod, what would u guys consider to be the utmost strongest external\internal brace for allthread?

There should be a way besides just washers to give the allthread a better grab around the sides of a box.

I've seen a 36sqin 1\8" thick aluminum square used but i need to find something VERY strong.

My current wall is being considered using angle iron on the outside and running bolts through it to flat steel on the inside.

[Lucky 76 5]

i saw some 1" threaded at my local hardware store believe it or not lol

[shizzzon 461]

wow! i honestly dont know if anyone with a car would need something that large!

[TechSys 3]

3/4 to 1" square tube welded to make a frame for the enclosure. 2 layers, minimum, of 3/4" MDF for the enclosure. 3/4" all thread for even more bracing.

It'll take one hell of a lot of welding for the sides, top, and back. It'll take even more to do the baffle. I'm talking framing in around the sub holes and joining those together. (picture a pair of sunglasses. Lens frame are the sub holes, nose piece is the joiner).

That will make one hell of a stiff walled enclosure, IF done right.. I have actually thought about buying a welder and doing the Astro this way since the next build will be the last build for the van (going to probably get a crown vic walled)

[djphilly 11]

29oz fiberglass mat. heavy thick stuff. few layers of this stuff along with the right bracing will make it solid

[tommyk90 3]

I try to minimize any internal bracing just so I can get the smoothest airflow possible.

Granted not many people can get away with this because of space constrictions, but the first thing I always do is double up as many panels as I can.

If that's not enough or possible then I go with threaded rod. Least intrusive inside the box and very high strength.

Luckily I can get away with building small setups that get sick nasty loud, so tons of bracing isn't necessary.

[SPLScion 3]

suprised you haven't used concrete yet shizzz....

[shizzzon 461]

I've decided the next thign i'm gonna do after pullin out the wall is to build a 1" steel thick frame for the next build welded but separated as 2 pieces. Like the top half would be welded with 1" square steel tubing and so will the bottom. They are 2 separate pieces. I would then build the inside using 39ply Baltic Birch (3 13ply sheets) then bolt all sheets through to the outer frame using 3\8" thick solid steel plate runs on the inside.

Before building the design itself, i would layer the entire car behind the B pillar with a single sheet of baltic birch or MDF and 2-3 layers of Durock sheeting behind it to create a solid, hard shelled shell in my car to prevent loss of pressure and 0 flex.

This design won't commence til a long time from now anyways.

Now, my current design, i'm VERY limited on space so internal bracing is required to prevent wall flex behind the port...

I'm going to install 1" square wooden dowels EVERYWHERE and see if that helps with pressure. If it doesn't, i'll buy 1.25" ID PVC and split it in half and wrap them around all the dowels to see if the rounded pvc will help air flow around all braces.

Other than that.. it's buyin 6 more batts and goin from 7kw to 24kw and seein how loud i can get...

THEN.... hehe, i'm tearin out the wall.. Goal is to break 160 at the kick first, then at the head. I'm doin 156s in the kick now so i'm sure i can prob get REAL close to a 160 in the kick with my current setup.

[tommyk90 3]

suprised you haven't used concrete yet shizzz....

The problem with concrete is it breaks down over time and can crumble.

Most extreme guys use a resin and sand combo instead, but this is for crazy people who cut the roof open and fill the entire car up with it.

[my97tbird 0]

I want you guys to post things here such as materials and bracing methods used to create the stiffest, non-flex box out there and how it's done.

I'm tryin to find some materials so when i go to tear down my wall that i have something to fall back on.

I've came across this but the comments are up in the air... Some competitors say it's good... others who haven't used it say it won't hold up...

Durock...

I had visioned on using 5 layers of 5\16" thick in between 2 layers of 0.75" MDF = approximately 3" thick total material. Then cross brace it with - 0.75" all-thread.

Now, i'm looking for the stiffest out there...

I had read to pour resin in, on and around each Durock layer wedged in between the MDF to prevent air pockets between each Durock layer.

Do you guys have other suggestions for making a very stiff box?

I am looking to build a box so I would really appreciate it if you could gimme a call at your earliest convience @ (216)314-6000 thank you or just email me with the info you would need to know for you to give my the dimensions and I will email them back to you within the hour after you email me I constintly check my email thanks again for your help

Thanks,

Dave

[rushnrun 14]

I try to minimize any internal bracing just so I can get the smoothest airflow possible.

Granted not many people can get away with this because of space constrictions, but the first thing I always do is double up as many panels as I can.

If that's not enough or possible then I go with threaded rod. Least intrusive inside the box and very high strength.

Luckily I can get away with building small setups that get sick nasty loud, so tons of bracing isn't necessary.

tommy, your box is so small you don't need bracing

I just started using threaded rod... much easier to deal with and a better solution than wood (due to air restrictions) I use 3/8 rod, with 1" fender washers works great so far, I have zero flex on my current box. I try and double up any panel that is larger than 18" in width or length..

[tommyk90 3]

I try to minimize any internal bracing just so I can get the smoothest airflow possible.

Granted not many people can get away with this because of space constrictions, but the first thing I always do is double up as many panels as I can.

If that's not enough or possible then I go with threaded rod. Least intrusive inside the box and very high strength.

Luckily I can get away with building small setups that get sick nasty loud, so tons of bracing isn't necessary.

tommy, your box is so small you don't need bracing

I just started using threaded rod... much easier to deal with and a better solution than wood (due to air restrictions) I use 3/8 rod, with 1" fender washers works great so far, I have zero flex on my current box. I try and double up any panel that is larger than 18" in width or length..

Truth.

Though the 15" box benefitted GREATLY from threaded rod. For some reason the score dropped almost a full db, put 2 pieces of threaded rod in it and the score jumped back up. It was flexing like mad apparently.

Threaded rod didn't help on any of my single 10" boxes though.

[shizzzon 461]

i use only 3\4" rod but i'm crazy too.

[tejcurrent 13]

Any concrete board could help, but if the box flexes at all after a while it can deteriorate. x2 on fiberglass and resin + threaded rod.

[shizzzon 461]

durock plus resin = resin + fiberglass + concrete + 1" welded steel for bracing= Holy !@#$@

[shizzzon 461]

After talking with some people i know and explaining to them what happens to a box when it is exhibited with 155db+, i finally started to get some tips on making our boxes stronger and in the direction of less flex.

Cars like mine have not as much room as other cars do of like size. My car for example is impossible to stack 2 15s on top of each other in a wall... that's not fair, hehe.

So, the point i'm making is in order for someone like me to get a monsterous build in my car, like anyone else, it requires a monsterous build with monsterous bracing techniques.

Most people who are way up there in the competition lanes are using concrete, sand, multi + multi + multi layers of mdf, welded steel frames, 2x4s around the entire enclosure, etc...

While all of these techniques yield great bracing, there are two drawbacks, weight and the ability to undo changes 100% to the car.

Now, i have the task in my car to try and get what i want in my car but be able to come up with bracing tactics that do not require a lot of space being lost in the car. This is where it gets tricky.

How tricky? My current wall is only a SINGLE layer of mdf with a double baffle but with my current bracing techniques, i am able to pull off over 155db in the kick... The rear wall flexes like an earthquake but i get the score done! This is not acceptable when it comes to increasing my score though and other methods, new methods to me, are to be tried.

Before i begin, just put this into your subconscious- Resin is my friend.. resin is my friend... i cannot do anything without my resin

ok, my current wall consists of 3\4" all thread ran through the front baffle in 3 places and through the rear in the center. It runs in other places but this will talk about just the rear wall since it is suffering the most.

I also have flat steel runs on the rear wall bolted through to the other side.. This is NOT helping whatsoever... I was also told if i got some more flat steel and bolted both pieces from inside to outside to each other.. it wouldnt make a single difference either.

1st suggestion - counter-brace the connection by running the inside steel vertical and the outside steel horizontal... This offers more surface area.

While sitting there talking about some other methods.. we finally came across a method that sounds interesting.

We all know that steel square tubing is virtually unflexible since it's bent into a square...

Well, first thought was just to attach this tuning to the inside and outside counter-bracing with bolts but that wouldnt work as well as expected because only where the bolts are is where the brace is effective! Any space between the wood and steel that is not bolted will be able to flex under high pressure.. So how do we overcome such obstacle?

Resin is my friend resin is my friend.

After talking about it for a while, we came up with this solution-

Let's say we have a wall that is 36" tall and 36" wide. We have 1" steel square tubing and a bucket of resin and lots of bolts and washers and nuts.

We will be counter-bracing the steel bars. Inside, vertically installed, will be 4 runs from top to bottom and outside will be 4 horizontal runs from top to bottom. This is how it will look but not the complete process.

(You will need to predrill ALL connection points prior to preparing resin or u may lower the strength of this method when trying to run bolts)

Get some resin and hardner ready(use long pot life)... Apply small amounts at one time, enough for only 1 bar at a time.

Find where u are going to be mounting the bar, make the resin like you normally would, not too too gooey and apply it to the wall section that the steel bar will be placed at. Make sure you place PLENTY of resin in this small area from top to bottom. You want the steel bar to actually rest in it. Once you have enough on there, place the steel bar on this resin and allow the resin to completely fill any pours and gaps between the wood and this steel bar. Now do this to the rest of the internal runs which is 3 left. Once they are all done, go to the outside and run resin over all the marks for horizontal runs and when applying the steel bars to the outside, start running all your bolts through the outer bar, through the wood, through the inner steel bar and out of that. This way, when the resin offically dries and cures, the bolts are now a part of the bonding. The bolts are also to help you not have to hold it while you prepare the other 3 horizontal runs too. Now, once all 8 bars have been set in place and bolts have been ran through, go ahead and tighten the hell out of these bolts. Once they are all tight, now we get some more resin together. Once the new batch is ready, apply this resin over aLL bars and along the sides.

Goal - to ensure that the resin will cure between the wood and steel, and along both sides of the steel to the wood AND to have a nice smooth roll off from all steel bars so there are not sharp edges which could cause turbulence inside.

If you want an even stronger brace, for all steel bars to be used, weld adjacent steel bar runs before applying the bars one at a time(may require more than 1 person to help you work) so that steel bars can be bracing more than 1 wall at a time once all resin is dried and cured. You can also use wood instead of steel of competing in classes that do not allow steel.

This will prevent the wood from flexing away from the inner steel and into the outer steel when done right, when using enough resin.

You can also attach another layer of mdf in front of the steel tubing inside for a perfect flat wall.

Once the resin dries, the material used for bracing will have bonded to the wood at every point possible.

And yes... this will be something i'll be doing soon.

Welcome to competition