EDPM Liner Material

[WStayton]

Ok, new (sort of) subject - about which I know essentially nothing and have no preconceived notions, so I'm much less apt to be an argumentative PITA! <grin>

Has anybody actually used/made a liner with EDPM material?

If so, I've got a few questions:

  For my purposes, a width of 16'9" would be ideal.  Of course, NOBODY makes that width - so I've got a few options:

a)  Cut down from wider material, like 20' or 25'.  The only thing wrong with this approach is that it "wastes" what you cut off, and at $.50 a square foot, and being tighter than the bark on a beech tree, I HATE to waste ANYTHING! <smile>

b)  "Splice" up a panel 16'9" from a roll of ten foot wide material.  I have reservations about splicing something that I am buying because it is "entire" and impermeable, but some of the companies do sell materials (glue and/or tape) for making joints, so it IS done - just not sure that it is a good idea, and I will still have some waste, because the piece of 10' wide material that I chop down will have "left-overs".  Also, as a side note, I saw that several vendors say that rolls and/or pieces of any size may have seams in them - not sure what the quality of a factory (presumably) made seam is compared to a "field" (as in ME) made seam, but are factory seams something to be worried about - as in cut the piece so that it doesn't have a, seam, even factoiry in it, or not???

c)  As a last resort, I could change the dimensions of the "box" - this is still in the planning stage, so a change won't really damage much except my ego, after I argued passionately for seams in the box, so that I could make them/it 6' high - of course, if seams in the box are really an issue, I could cut my elongated sides out of a sheet of plywood stood on end, so there wouldn't be a seam/joint in the plywood at all - in fact, that might be preferable, since with that method, maybe I could use exterior instead of marine plywood and save $40 a sheet - I wouldn't feel so bad about wasting a chunk of it then!  <grin>  Oh, and one other issue, though it isn't really a liner issue:  Solar Gary put a "tension ring" on the top and the bottom of his "box" only  BUT he also built his box only 3' feet deep, + / - , I think.  Should I be thinking of having a third "tension ring" around the middle of the box, if it is taller than Solar Gary's?  One problem with having a tension ring around the middle of the tank is that it means that any vertical members would have to be external to this and the whole thing would be kinda like a porcupine with stuff sticking out all over it.  Also, upon reflection, I am wondering if the 1.5" triangular wood reinforcement that Solar Gary put in his tanks is sufficient for a taller tank - it would be a TERRIBLE mess if it split down the corner and dumped 400 gallons of hot water all over everything.  I could glue and screw an upright to the outside of each side of the corner and then glue and screw another V in the space created, thus making everything more than twice as strong as what Solar Gary built but again this makes a "mid" band difficult to achieve.   I was thinking, BTW, that the verticals should be 2 x 6 instead of 2 x 4 as done by Solar Gary, in view of the greater height and hence greater force being generated. Without doing four hundred pages of fourier analysis, anybody see an easy solution?

d)  My 16'9" dimension came from having 5' 11" ID tall sides, 3' 6.5" bottom ID and then 1 x 6 laminated top rail circumferance tension "band".  Would it be acceptable just lap the EDPM material over the edge 3.5", as though it was 2 x 4, and then just have a space at the outside?  I was thinking to clamp the EDPM material using Solar Gary's method of plastic 1" x as the top layer, screwed from the top and sealed with (can't think if the name - stuff that smells like vinegar).  I sorta think that if 3.5" held Solar Gary's tank, it will hold mine, but mine IS going to be taller, so . . .?  This wouldn't really help much in termes of cutting the EDPM material to lessen waste, but I was wondering . . .

e) I saw in a couple of places that EDPM shrank when exposed to high heat - nobody says what is "high heat", of course and the places that I saw where this was mentioned were also selling other materials (that maybe they made more money on?), so I'm not sure if it is something to be worried about, or not.  Solar Gary doesn't mention any thing about any shrinkage when he talks about his tear down one year after completion to insert insulation in the box - but lack of information is not the same as information that there was no shrinking! <grin>  So what's the consensus - is the talk of shrinking just marketing and/or something that only happens at 300F in industrial tanks, or do you think that I should be concerned about it?

f) FWIW, talk of waste is not exactly correct, since I will need one piece for each tank that is as large as the OD of the tank, for the bottom of the cover, so not EVERYTHING cut off of the hunk for the bottom is WASTE.  I'm inclined to make the cover a little larger than the tank, so that I can tack a piece of molding arouund the edge to make the tank-top bottom neater!  Which brings up another issue, Solar Gary just used a chunk of foam with the liner on the bottom and something else on the top, period. There was no framing of any sort, so far as I can tell, and I would think that such a hunk of foam, just sitting there, would be subject to abrasion and trauma and would eventualy be a mess.  Maybe this wasn't such a problem for Solar Gary, since he was burying half of the tank and basically tucking it away where there would be little/no traffic near it, but that won't be the case for me.  I'll be brushing by it to get to the "passenger" side of the engine-generator and also to one side of the battery-bank.  To help insure that I wouldn't have a problem with the foam coming apart at the edge, I was thinking to encase it in a box, where the sides are made of 1" x 6" s and the bottom/top are made of the same 1/8" plywood that I anticipate using on the very outside of the foam in/on the tanks, so there would be something there to secure the molding to - though it could be on the sides or the bottom, there really is no differance - so the cover/box, would only HAVE to be as large as the OD of the tank.  Good idea???  Bad idea???

g) Final item, then I''l shut up!  <smile>  I was thinking that maybe I should attach the tanks to one another, more or less firmly, either after I line them or, possibly, before I line them and then I could have one long piece of EDPM material going down the line of four of them and dipping to line each of them.  Cutting the EDPM material for a one-piece fit would be the original PITA, since I would have to wrestle with the whole 300+ pound piece and have each cut exactly where I need it.  From a standpoint of assembling the piece of material, if I have to do that, it really isn't much of a problem, since it isn't really much  different to glue on four shorter pieces or just one much longer piece, but the dimensions would be CRITICAL, especially when it came to cutting the material so that it fit around the top, or do you think that I should just leave it as a square/rectangle and have folds/pleats in the top?  Also, if the material does, in fact, shrink slightly, this would exacerbate that problem.  However, it would be nice to have the intertank spaces bridged by one piece, making liquid containment easier - I could just cut the inter-tank sides 1.5" or so shorter than the other sides and let the liquid run over the space thus created and not have to worry whether or not a siphon was continuing to work, of course stratifyuing the flow is sort ruled out by  doing that, but it the one oiece liner could be the back-up in case I did have a siphon quit working.  I would much rather have mixed contained water than water on the floor! <grin>  So, what do you think, good idea or bad idea???

Okay, enough from me for now!

As usual, thanx for your comments!

Regardz,

Wayne Stayton

[mike90045]

You can get a factory cut/seamed pond liner from Ag distributors.

[AdeV]

I've just put an EPDM roof on my Portakabin. It's supposedly guaranteed for 20 years, and the oldest installation is 50 years & still going strong. Whilst I haven't subjected it to high heat, it's had some nice sunshine on it, and no issues to report so far...

It is also widely used around these parts as pond liner, although I believe it is a thinner grade than roof grade EPDM (which is a LOT more than 50cents (or even 50 pence...) per square foot...

If I were you, I would use the thicker (roof-grade) stuff for long life, and get a wider piece than you need & cut it down. No matter what anyone says, a seam will ALWAYS be a weak point. Don't think of the offcuts as "waste" - there's bound to be a million & one uses for the stuff (water gasket, perhaps?).

[LowGear]

Take a moment and work with the two basic different materials.  The roof stuff is heavier and really a bear to fold into corners.  The lighter stuff shouldn't have as many chemicals as they might hurt the lifeforms but in a heat storage place you might want chemicals.  Roofs get pretty darn hot so that shouldn't be a problem.

Have you considered that pallet containers that are open at the top like are used at grape and apple harvesting locations?  While water may be pretty heavy the side pressures just aren't that threatening unless someone dives into the pond.

Casey

[mobile_bob]

so you asked

if it were me, and yes at some point it will be me...

i would design around existing material dimensions, so alter you design to make better use of the standard material dimensions

it usually always works out best having done so in my opinion.

bob g

[LowGear]

A rule to live by bob G.

A 32 X 24 (768 sqft) house - shed - workshop may be cheaper to build than a 31 X 23 (713 sqft) when labor is factored in.

Casey

[Ronmar]

so you asked

if it were me, and yes at some point it will be me...

i would design around existing material dimensions, so alter you design to make better use of the standard material dimensions

it usually always works out best having done so in my opinion.

bob g

+1, usually SOP for me:)

[WStayton]

A few notes:

  As far as I can find, EDPM seems to be made in three thicknesses:  0.045, 0.060, and 0.090.  Both 0.045 and 0.060 are offered by many places in a variety of widths.  The 0.090 material is offered only in 10" width, from what I have seen.  That would sort of rule 0.090 material out unless I made a "box" something like 3'4" on an edge.

LowGear:

  About using a "pallet container":  I'm not sure exactly what you're referring to, but the pallet containers that I have seen have been for things like watermelons and apples in the orchard being picked for cider, and personally, I wouldn't trust either one of those with a load of somthing like 3,700 lbs on the side of them, especially when failure would be such a mess to clean up in the immediate vicinity of lots of electricity.  Also, if I am going to use the 16.5' wide material, so as to not have any joints, I think that the "pallet containers" are too big, but I'm not really sure about that! <grin>

  If you are talking about a more substantial "pallet container" of some type, where can I find/take-a-look-at one?

AdeV:

   About roof vs pond use:  Some website don't say anything about end use, some sell it for roofs and some sell it for ponds - near as I can tell, they are all talking about the same stuff.  That is for 0.045 material and 0.060 material.  The 0.090 material is much less available and IS marketed, so far as I can tell, strictly for roofs.  Some places also sell 0.045 and 0.060 material for roofs, so I'm not sure if it is just what you want to use or if there are some definative guidelines as to thickness for roofs, like "more than xxx sq ft, use 0.090, less than that use 0.060".

Everybody seems to agree that user constructed joints are a bad idea, but how about ones that come from the factory, in the material?  Would you cut the piece that you are using so that it doesn't have any factory joints in it, or would you assume that if it came from the factory with a joint, it was "good to go"?

  Also, nobody spoke to trying to fit one piece of material to four tanks, vs cutting a separate piece for each tank.  Having one pice for the whole works is attractive in that I  could make the adjoining side 1" lower than the other two/three and have a safety valve if the lines/pipes between the tanks gets filled up.  Having never worked with the material, myself, I have no idea how big of a PITA it could be to fit one piece to four tanks, but if it wasn't overwhelming, I am inclined to attempt it, on the theory that I could always chop it into individual pieces later, if fitting one piece is to much of a PITA to deal with!  What do YOU think?

About Cost:

  I have found 16.5' material in  0.045 in a 100 foot roll for $0.44 per sq ft while 0.060 material is $0.59 per sq ft.  I'm only going to need something like 1254 sq ft out of the 1650 sq ft roll, but even if I bought the roll and threw the rest (almost 400 sq ft) away, it would still only cost about $0.58/$0.77 per sq ft for what I used.  It seems that buying it in a roll is the best deal financially, since three pieces, (and I need four!) bought by the piece, is almost as much as the whole roll.  The above prices are ex-shipping and the stuff is heavy, 490/660 lbs per roll, so freight WILL be a factor!  The prices I quoted were from a company in Phoenix who's only business seems to be EDPM material and various accourtremont there-of,  I hope that there is somebody nearer Elmira, NY who has/can-get the stuff!!! <grin> I don't suppose Lowe's or Home Depot carry rolls of it in 16.5', do they?

As usual, thanx for the input, so far!

Regardz,

Wayne Stayton

[AdeV]

I put the 0.045" (1.14mm) thick stuff on my roof, and that was plenty thick enough. My sheet was approx 12x30 (feet), and it was a hard lift to get it onto the roof (for weakling me, anyway). Once unfolded & laid flat, it was moderately easy to maneuver around.

Making a box out of it will be an interesting task to say the least... IMHO the easiest way would be to lay the sheet over the hole, and fill it with water (allowing the sheet to sink into place). Personally, I'm not sure I'd attempt 4 tanks from 1 piece; but it does depend on how you're making them. If you can use water pressure to pull the rubber into a tank-shaped mould (which you'd need to retain anyway, because the rubber obviously won't hold a shape), and you can do each tank in a line one after then other, then it SHOULD work... EPDM is easily cut with a sharp knife, or even a pair of carpet scissors, so don't worry about trying & cutting it if you have to.

You shouldn't have any factory joints in the material you buy; the factory make it on giant rolls a certain width. They might cut a width to make 2 narrower rolls, but AFAIK they won't join a piece to make a bigger roll. At any rate, if they do offer a jointed roll, I would consider it the same way as a user-made joint - i.e. when it fails, that's where it'll go.

Material handling... if you've ever touched a wetsuit, the material is very like that, only thicker (actually, it's probably more like a drysuit, but I've never seen one of those). It rolls & folds easily enough, but it's very heavy.

Cost wise, here in the UK the cheapest I could find it is ~60p/sqft (about $1), for the thin stuff. Figures.

[WStayton]

AdeV:

  Thanx for the suggestion!  Maybe if I filled the container slowly I could "fold" the excess material, from stuffing it into a box, and, maybe make it a little neater than just "poke-and-dump".  The way I was thinking to do it was to have the adjoining sides (i.e., the three internal adjoining sides within the row of four of them) 1" lower than the non-adjoining sides, so as I filled a tank, the water would, automatically run into the next tank.  Worst case is I would have to siphon out a bunch of water and clean up the wet material before cutting it and putting it into the tanks individually.

  One note:  Several of the sites that are selling the stuff, but not all of them by a long shot, specifically note that they can not guarantee that it won't have factory seams in it - so it must happen, otherwise I don't think that they would make a specific statement about it.  Though maybe its only a once in a hundered occurance and they just want to cover their backsides.

  Thanks for the idea about using water fill to push the liner material into place - Solar Gary does all of his fitting dry, but that may well be because he didn't think of it either!  I do think it is a participatory "sport" in that you will have to be hands-on while it is filling and insure that the liner folds neatly, otherwise it could be a mess.  I also think, if I'm going to do all four tanks out of one piece, I would almost have to fill the first one, so it was held down, before I could fit the liner in the second one.

  Thanx for the input!

Regardz,

Wayne Stayton

[Lloyd]

Wayne,

You might be the most verbos engineer, I have read.

I also think that the most accurate Engineer's, that i have ever read, WERE Succinct!

I DON'T know IF YOU'RE JUST KICKING TIRES OR just making conversation OUT OF BOARDROM.

it might be ok to save a buck...here and there, But I have never found it profitable to cut every corner.

Everyone of your hair brained schemes has led to great discussion, with the same end..guess that WON'T WORK or MAYBE THERE IS A REASON EVERYONE'S DOING IT A DIFFERENT WAY.

Donn'tget me wrong. I value. You, here as a member, but bring your real senses, as an engineer to the discussion. BE Succinct.

Lloyd

AdeV:

  Thanx for the suggestion!  Maybe if I filled the container slowly I could "fold" the excess material, from stuffing it into a box, and, maybe make it a little neater than just "poke-and-dump".  The way I was thinking to do it was to have the adjoining sides (i.e., the three internal adjoining sides within the row of four of them) 1" lower than the non-adjoining sides, so as I filled a tank, the water would, automatically run into the next tank.  Worst case is I would have to siphon out a bunch of water and clean up the wet material before cutting it and putting it into the tanks individually.

  One note:  Several of the sites that are selling the stuff, but not all of them by a long shot, specifically note that they can not guarantee that it won't have factory seams in it - so it must happen, otherwise I don't think that they would make a specific statement about it.  Though maybe its only a once in a hundered occurance and they just want to cover their backsides.

  Thanks for the idea about using water fill to push the liner material into place - Solar Gary does all of his fitting dry, but that may well be because he didn't think of it either!  I do think it is a participatory "sport" in that you will have to be hands-on while it is filling and insure that the liner folds neatly, otherwise it could be a mess.  I also think, if I'm going to do all four tanks out of one piece, I would almost have to fill the first one, so it was held down, before I could fit the liner in the second one.

  Thanx for the input!

Regardz,

Wayne Stayton

[hal]

Wayne,   I have a large concrete septic tank that I sank in the ground and removed the lid to do the final install.   I used the roofing EPDM membrane.   Think of folding the liner as a big arts and craft project.   Pre-fold the corners inside, get some duct tape to help you.  I had three people plus myself in the tank, in bare feet.   I used duct tape and concrete blocks to hold the edges over the tank.   I started to fill the tank with water and it really flattens out the liner where your corner folds are.

Spend the time with some old bed sheets for a template.   My wife helped sew the old sheets up.   

Good luck..   I'm close to 15 years and running without leaks..

[mbryner]

Welcome Hal.   I used a concrete septic tank, too.  Only 3-4 months up and running so far but no problems.   I didn't use EPDM liner, though, but it was the original plan.   The folding seemed like such a PITA.    Also, I had used EPDM for a pond a few years ago and now have a leak somewhere.    I used R-max foam insulation inside, then silicone paint for sealant.    What kind of temps are you achieving and what are you heating with?   Engine waste heat?   Woodstove?   Solar panels?

Marcus

[cognos]

EDPM is used industrially to line tanks, pits, ponds, whatever... The installers cut it and join it all the time. I've seen it done with a glue alone, glue and heat, or heat alone with a special tool. I've never seen a joint fail. I spent 18 years in a refinery where I watched them build 5 concrete tanks lined with EDPM that were cut and joined with a thick, black glue. Nice, square, form-fitting joints. These tanks held water, sometimes cold, sometimes 160°F or so. They had open tops, and are out in the direct sunlight. Tanks were 10 feet or so deep, 20 feet or so long, and at least 15 feet across. Still good to go today. There are "test drains" around the perimeter of the tank, that drain the area between the liner and the concrete. We would check these drains every now and then for the first year or so.

Tank farms in refineries use gigantic EDPM liners around the bermed areas of the tanks to contain spills. Lots of seams, no problems.

Industrial cooling towers use EDPM liners.

Pig farms use EDPM liners for liquid manure pits - and these can be huge! And they can't leak - the fines involved are big...

I'd have no problem cutting and gluing the joints in a tiny little 4' X 8' X 4' tank. The pressure on the sides at maximum fill - at the bottom - would be under 2 PSI. Just do it carefully, get the right EDPM, the right seam sealer, and buy it from a pro.

If it was me, I'd use the thinnest I could get my hands on - I wouldn't count on the membrane to contribute anything to the structure, except liquid tightness, especially one this small. The right thickness of plywood and 2X4 and X6 framing is more than adequate. Put it on a decent insulated and engineered concrete slab to support the total calculated weight. Any decent DIY store can give the design figures for that. Paint the inside of the plywood with a rubberized basement wall sealing paint, if you want overkill.

[WStayton]

Lloyd:

  Yes, I may be the most verbose engineer that you have ever encountered, but most people DO NOT go away from reading my communications wondering what I "meant" by what I say.  From my point of view, if you are trying to describe something to somebody, it is HARD to give them too much information, unless you are doing something very specialized, like dimensioning a drawing - and, yes, my drawings ALWAYS wind up over-dimensioned!  <grin>

  And, no I am not operating out of "BOARDROM" (not sure if this is supposed to be boardroOm or bOREdom, but I make lots of typos, so I won't throw stones!  <smile), I really do intend to build what I am talking about!  Of course, I could have another stroke tomorrow, and then, all bets are off!

  So I come, finally, to the point of this communication - you highlight a whole messge, from me, and say that I practice UNDOABLE soltions, but you never say what your criticism of this question is.  Do you believe that the whole idea of a wood box lined with a EDPM material is not the best (read: most cost effective) solution or do you have specific issue with something that I propose to do?  In this case, your message is so SUCCINCT, that I don't know what your complaint/criticism was/is!

  Or was this just an example that I generally don't use one word if ten will suufice??

  On factory seams:

   Most people who have expressed an opinion have voted against ANY seam in the material, with one well illustrated exception to this.

  I sort of think that if you are building something where a leak will not be an extreme, major catastrophy, user-built seams are acceptable.  For this application, where the tanks are interconnected and one of them springing a leak could mean the whole 1800 gallon contents of four of them flooding the area and eliminating the cooling water for a possibly running diesel engine, and potentially shorting out lots of electricity, user-built seams are ASKING for problem that doesn't have to be there, so my current thinking is to NOT use seams, of any sort, be it user or manufacturer made, in my project just to make sure that the 0.001 % chance of a calamitous catastrophe is not introduced.  Since it seems that factory seams are uncommon in rolls of product, and since I will only need 60' off of a 100'  roll, Not useing ANY factory seams doesn't really limit me so its dead issue!

As always, thanx for the input - keep 'em coming!

Regardz,

Wayne Stayton