Foam Pit

$$Noble$$

$$Noble$$

Likes Dirt
i remember on nitro's circut when travis took us on a trip around his joint. and he explaned that each foam cost $1 and there is 10 thousand peices of foam and if you do the calculations 1*10 000 = plus the 1 take 3 add 4 for good measure and that equals about $676.49c...... put a stack of old tyres underneath the foam to help circulation and more softness. you will need some sort of pully system to full the bikes out to.
 
henryg

henryg

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yeah ive never done it but pullys seems a little excessive to me. if u have spring mattereses or tyres as a ground layer it should be fairly stable to walk on/pass bikes across.

The crate idea under the pit is a great one.

i looked on some vids and the really big ones seem to be about 6 foot deep.
 
single-track-mind

single-track-mind

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How about using an old above ground pool ? you know those low rent ones everyone had in the '80s should be able to find someone who wants to give one away or cheap on ebay
 
Bretty.

Bretty.

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For the bottom layer use pallets instead of tyres, they will provide better support and water won't collect up in them. Oh and at least 2 layers of mattress (spring, then foam) ontop of that, I can't stress enough how important this is - as after a while the foam will compact and hitting the hard floor beneath is not pleasant! Then of course, as much foam blocks as you can get, the more the merrier! Not sure about sides though, as long as the foam doesn't blow away though, it should be good.

It may help to search the Pinkbike photo database too, heaps of good foam pit ideas for ya.
 
Barrett

Barrett

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stprider said:
Yeah i know, what would be one of the cheapest ways in building one?
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Grand is a bit rich, all tho i could see more than that being spent. Think for a 5m long x 4m wide and 6 foot high on 3 sides and 4 foot across the front pit, it cost me about $550.

$400 in wood including kicker and $100 for the cover and liner and the rest in batten screws.

We lined it with corrugated iron that was free( Phills a plumber)

24 innerspring mattresses both double and single, including a queen sized mattress to throw your bike on. these line the floor and walls, imo it is essential to line the sides as riders often hit to wall quiet hard.

The foam and mattresses were collected from hard rubbish, chech all the foam and mattresses for bed bugs i cant stress this enough rat bait is all so a must to keep the snakes out and obviously the rats.

if you have any more questions feel free to ask me.
regards Barrett
 
dan-492

dan-492

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$$Noble$$ said:
you will need some sort of pully system to full the bikes out to.
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yeah mate you would for moto's, not mtb;s though.

i suggest using pallets as a cheap, sturdy design. they offer great ventilation and would be very steady when joined-not flimsy. if you joined them with seperate lengths of timber and nailed them across the fronts of pallets they would stand on their own as they are about 200mm wide when standing on edge. as suggested earlier i would also put down a waterproof base sheet or tarp to stop water soaking up from ground.
finally a cover of some sort is a must. wet, mouldy foam after rain doesnt sound real appeaing to me:p

edit: for the height mate, i would build the box about two pallets high, at least at the back and sides. this will put depth at around 6ft. u might need to brace it from the ground though. you could also use pallets on top of base layer as a floor, then matrresses on top of them. that way it wont hurt to hit the bottom.
 
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B

Biogenesis

Likes Bikes
stoff said:
Hope that was a joke.

The easiest way will be to frame up stud walls (consider using treated pine to get a better life out of it) and clad it with Marine Ply.
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And I hope marine ply was a joke. Firstly, marine ply uses exactly the same type A phenolic adhesive as exterior grade ply, it's special in that it does not contain knots and other defects which would degrade it's structural integrity (ie, it's A-A grade, exterior tends to be A-C*).

What you actually want is plywood treated to at least H3 (termites and rot). Same for the framing timber, which should be H4 or H5 (termites, and underground rot) if it is to be in contact with soil.

Unfortunately treated plywood is very difficult to find, so I'd suggest using H4 treated framing timber with an exterior grade ply cladding which you then paint.

Also, slope the base at least 1 in 100 to allow water to flow into one corner, which should be drained into a rock pit of around 500x500x500mm in size, depending on the size of the foam pit. Basically assume a big downpour, calculate the volume of water that would enter the foam pit, then make the rock pit big enough to fit all of it, assuming about 50% of the volume is occupied by rock.

So for a 4mx4m foam pit, assuming 10mm of rain, gives 0.16 cubic meters. 500mm square is 0.125 cubic meters.



*Plywood quality grading goes from A to D, A being a practically "perfect" finish (no knots etc) and D being a finish which is covered in knots, cracks, bits that were filled with putty etc.
 
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nspud

nspud

Squid
the bottom is most important

i have a foam pit made out of pallets, its perfect. i also put a row of pallets on the ground down each side then lifted the outer edge of the pallets up about a foot to make the bottom like a boat shape. the boat shape bottom helps ventalation. but the main reason is for safty, if you get the line wrong comming in or just end up close to the edges of the pit it will deflect you back into the center of the pit as there is no as much foam support arround the sides and could throw you into the side walls.

it also makes it easyer to get out because its shallower and you use less foam.

i will post up picks soon of the one i am selling. 0414 308 006
 
downhiller_1

downhiller_1

Likes Bikes and Dirt
if you live close to rampfest you can use theirs

but if you want to build the walls i strongly recommend using the traditional framing technique... extra supports are advised
 
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