I’ve too much time on my hands today (poorly ankle means no riding still) and am filling some time thinking through diy tubeless. I’ve reached a point where I’m after comments on my ideas.

valve and sealing the rim
I’ve done the 20″ bmx tube ghetto before and it works but found getting tyres on a bit of pain and getting them off without using levers impossible…using levers punctured the tube and ruined the ‘split tube rim strip’
so,

I’m thinking seal the rim with electrical insulation tape, it’s tough, sticks in place, thin so getting tyres on is simple, light and at about 3 quid for a 20m roll which, if double wrapped should do 4 of 5 wheels costs about 75 pence a wheel.

for the valve, those rims that are drilled for presta, use the valve from a old tube, or presta valve stems a mate can get from a local motor cycle shop at half the price of stans/mavic valve stems.
For rims drilled for schrader, which I prefer as once the valve core is removed it is easier to get the goo in through the larger stem, agai valves cut from old tubes if they have removable cores and lock nuts (continental tubes I think, like http://www.chainreactioncycles.com/Models.aspx?ModelID=18901) or I think some car valves like this at 1.50 http://cgi.ebay.co.uk/TR-418-CAR-TYRE-LONG-SNAP-TUBELESS-VALVE-/160533997403?_trksid=p4340.m263&_trkparms=algo%3DSIC%26its%3DI%252BC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D15%26pmod%3D220756469910%26ps%3D63%26clkid%3D571312500993578590 and then a hose clip like this http://www.hclfasteners.co.uk/acatalog/Double-Ear-Hose-Clamp-O-Clip.html (currently out of stock on the 9 to 11mm size….which I think is the size I’d need) clamped on the stem to lock the valve in place against the rim.
With those valves and hose clips the valve and rim sealing is about £2.50 a wheel total.

then home made sealant…I’ve been searching forums for the various homebrew recipes and I’ve a couple of questions.

Okay, modelling latex, check, rubber liquid latex about 4.50 a litre on ebay http://cgi.ebay.co.uk/Rubber-Liquid-Latex—1Ltr-Quality–Mould-%2f-Mold-Making_W0QQitemZ230503903250QQcmdZViewItem

particles – rubber dust – attack an old tyre or tube with file or grinder, check. or glitter.

thinner, water or screenwash….screenwash for the ethelene gylcol which evaporates more slowly than water so lasts longer, plus is in antifreeze preventing winter problems. screen wash about 5 quid a gallon.

some ammonia. Ammonia is added to prevent the latex going hard…it’s in copydex and some of the latex paints already. Something like ‘kleenoff household ammonia’ is about 1.50 a pint and I think only a dash is needed. http://www.great4homes.co.uk/products/3620/

Slime? lots of homebrew mixes seem to include slime, I’m wondering why? At about 5 quid for 237ml it’s the expensive ingredient, what does it have in it that the other ingredents don’t do?

Also what sort of ration latex to water/screenwash? some seem to do about 2/1 others about 1/1. I presume 2/1 will clog bigger holes so if you ride a lot of stony areas and get bigger holes in tyres go with a thicker mix?

I reckon 2 parts latex, 1 part water, 1 part screen wash, dash of ammonia, 1/4 part slime, rubber dust works out at about 4 quid a litre, a fifth the price of stans tire sealant. initial outlay 20 quid, 4.25 litres of sealant mixed and loads of screenwash and ammonia left

So any thoughts people? [cue the badger photo]

Neil- Graham D is working on this too and has a load of ideas from one of his US trips. He’s after ammonia too, via me, ‘cos I can get it at 100%. Perhaps give him a bell or ask him via FB?

I know, it was Graham’s stories that set me thinkiing to fill this idle moment. He was bendng my ear for half of the long loop at Nant.

You are a science teacher right?…hence the ammonia. Now…tell me…ammonia, or more correctly ammonium hydroxide in this instance (NH4OH in aqueous solution, not NH3 gas)…..and aluminium….errrr…..its the OH- ions that the aluminium is going to find unpleasant not the NH4+ ions I think but anyway….you don’t need much of this stuff or your going to do your rims a whole world of no good I suspect It’s oven cleaner remember…bye bye anodizing and bye bye the rim over time if used too strong!). Besides you only need an ickle bit to stop the latex from setting, from the copydex safety sheet it is less than 1% by weight of ammonia. wikipediea suggests household ammonia cleaners are about 5 to 10% by weight, commercial products about 30%
So, I’m thinking a ‘dash’ equates to about 100ml of household ammonia in a litre of goo mix….12 or 15 pence worth, Big G doesn’t really need to fret about 100% ammonia I feel….if he does then makes sure he wears gloves and eye protection when changing tyres!!

Super ghetto method
This tape makes it VERY easy.
1 litre of JRA wheel milk lasts ages, if recycled when you change tyres.

Thanks wally, that tape looks good, just the right width and cheap too.

JRA wheel milk does last ages yes, but if a diy mix works then it’s considerably cheaper in the long run…a litre of stans is 20 quid, JRA is about the same I think. 20 quid gets enough ingredients for over 4 litres of homebrew goo.

This is the stuff Stan recommended for his original DIY method (before he started selling rimstrips). A bit wide, but very easy to split off just the width you need.

Many years ago I used some of that along with art latex for my first tubeless setups. Got Eclipse rimstrips when they came out though, and they worked better – currently available very cheap

or were avaialble cheap, that was the last box and they are now out of stock unfortubately.

interesting to know about the tape and that stan used to recommend it. It look very similar to the stuff wally has suggested and wally’s is the perefect width by the look…I have one 19mm wide and 2 x 21mm wide rims that need ghetti sealing and need schrader valves….my other rim is a pukka tubless 819.

aracer, why do you feel eclips was better than diy? did diy not last or harder to set up or something else?

A lot easier to get to seal, as the rimstrip adds a bit of thickness, making it tighter against the bead of the tyre (just fitted a new tyre on my Eclipse strip and it went up with just a track pump). Could probably achieve the same effect with lots of layers of tape, but you’d then end up with no well in the middle making tyre fitting and removal a complete pain (Eclipse strips have a very nice well moulded in). Kind of regretting not buying a spare strip or two at that price before they went.

The tape I linked to only has longitudinal fibres, wally’s has crosswise ones as well – not sure how much difference that makes, but given the relative scarcity of the stuff Stan recommended compared to stuff with fibres both ways I’m guessing there has to be some reason it’s better. Possibly it seals better – though I have a feeling there’s also some issue relating to the adhesive used and how it stands up to the ammonia in the latex (I was fairly sure art latex already has ammonia in).

I have always wondered why the BMX tube ghetto was so popular when this method seemed so simple, and did work just fine.

My worry with the ghetto method using tape is that the tyre is sealing against the rim but the standard tyre bead system does not hold well enough to prevent burping (so UST was invented). Ghetto with a split tube makes this a non-issue as the tyre is sealing against the split tube so if the bead moves the tube goes with it.
I have gone for the Bontrager rim-strips as these are shaped to mimic UST rims and are cheap. Never had a burp.
I use Joe’s sealant but would rally like to start making some home-brew.

I ghettoed my old bontrager rims using the tape method. I used bontrager TLR tyres without any burping issues, just didn’t run them at a low pressure

Burping is always an issue, even with UST, I’ve seen crossmax wheels burp. Higher pressures help.

I see what you mean about seal/profile though….hmmm, I wonder if a wrap of string or something, under a layer of tape, would improve the profile usefully.

Oh hang on…why not seal the rim, then replace the velo rim tape to add some thickness and push the tyre bead up to the rim hook, anyone tried or doing that?

Ambrose, or any other science gurus, I’m after some more peer review. I think I’ve worked out the purpose of the Slime, and may have found a way to replace it with 2 slightly cheaper ingrdients.

Looking at the safety data sheet for Slime reveals that it is a Thixotropic gel/liquid.
Wikipedia tells me thixotropic means it is stable when not agitated but thins and flows when agitated. I think it is this property that helps it to stay a liquid in the tyre/tube and thus flow easiy to a puncture site, but once in the puncture hole it isn’t agitated and sets a bit, plugging the hole.
searching for other thixotropic substances on wikipedia ….I passed quickly over semen (as enjoyable as it might make the ‘brewing of goo’!) and read into …
Silly putty by Crayola. (aka trick putty, bouncing putyy, potty putty) Now science gurus will know that the main ingrediant of silly putty is poly dimethyl siloxane (hydroxy-terminated polymers with boric acid)….hydroxy-terminated polymers with boric acid…that doesn’t sound too hard to make, and indeed it’s not. here is a common diy silly putty recipe http://www.metacafe.com/watch/990009/make_silly_putty_imitation/
you mix adhesive (PVA) with water then stir in some borax, easy! I’ve seen Elmers adhesive on some of the homebrew goo recipes, but not seen anyone add borax or sodium borate, which is the key.
Right now Borax used to be easy to get hold of as it was a household cleaner but a reclassification of the ‘Borates’ group of minerals by the EU means that they will no longer be available as a general cleaner, instead I’m finding Borax Substitute, Sodium Sesquicarbonate, now replaces the product previously known as Borax. It is supposed to have the same properties for cleaning etc but does it work to make silly putty or thixotropix polymers….hope so. right, half a kilo of borax substitute is 1.50 http://www.thegreenstoreonline.co.uk/default.aspx/Page/97/Product/871 and you only need half a table spoon for a couple of cups of silly putty. PVA adhesive is cheap, a fiver for a half litre tub, or 12 quid or so for a gallon, adding 1:1 with water makes silly putty, adding more water would make slime. So I’m changing my recipe for tubeless sealant to
2 parts latex, 1 part water, 1 part screen wash, 2/5 of household ammonia, 1/4 part PVA, 1 tablespoon of borax, rubber dust

works out at about 15 quid a gallon or 3.75 a litre. (not much cheaper than my original recipe using slim, but then I was being stingy on the slime before, should probably have had 2 or 3 times as much)

I reckon add the PVA, ammonia and screenwash to the latex and stir, add the borax and stir, then add the rubber dust and water until you get the desired thickness of goo.

Peer review welcome before I send my paper to the New Scientist 😉

Has anyone used duct tape as rim strip before?

Yes, quite a few, split lengthwise, seems a reasonable option

I would add the Borax as solution rather than as powder. I’m pretty sure last time I made slime at school I used 5% Borax solution and PVA @25% – but I would need to check through some notes and see what I did.

I would consider throwing some glycerol in there as well to stop the crosslinking a bit. Not sure if it would completely stop it though and effect the effectivness of it.

Custard powder is Thixotropic as well

Good point re borax solution Quirrel. Science teacher per’chance? I’m unsure how the borax will affect the pH. as I understand it the ammonia works to prevent the latex polymerising primarily by maintaining an alkaline pH, any idea what the borax will do to the mix?
Ah glycerol…seen that on some homebrew goo recipes, so it keeps the slime thinner?
This is testing my 20 year old memory if A level organic chemistry to its limit :o)

I’m unsure how the borax will affect the pH. as I understand it the ammonia works to prevent the latex polymerising primarily by maintaining an alkaline pH, any idea what the borax will do to the mix?

lol – only on STW will you hear such a phrase used when apparently talking about mountain biking, classic! 🙂

Borax causes crosslinking in the PVA. Glycerol can be used as a plasticizer to allow the cross linked strands to slid over each other.

Too much borax and it just turns rubbery quickly.

http://practicalchemistry.org/experiments/pva-polymer-slime,153,EX.html

Always a good source for chemistry practical work.

He he! I take my biking seriously….just think of this as the goo-brew equivalent of a DIY led light thread!

Right, a dash of glycerol. Thanks for the link, should be handy

Excuse my thickness, but do the amounts have to be accurately measured or is it a bit of this and a dash of that? What I’m getting at is that I can get ammonia/water mix due to me working on refrigeration systems, but it’s hit and miss as to what strength the mix would be. Plus I can get neat glycol too and I think there is a jar of glycerine in the cupboard. Interesting this thread, just need to find some latex now.

Measuring jug will give enough accuracy. It’s for repeatable properties…a bit more or less of any ingredient will alter the final properties a little…thicker or thinner, drying out faster, or not clogging/sealing punctures as fast…I need to experiment. Since every brand of household ammonia and pva etc differs, anyone mixing goo will need to experiment a little, but I hope to get fairly close then add water to thin until happy

Ah ha! I really think I’ve cracked it….well in theory…tests needed to confirm though

From Quirrel’s useful link I know that alkali (ammonia) will keep the slime as slime, and I don’t need to worry about the borax and ammonia reacting.…good. I also know that the borax cross links the PVA polymers by weak hydrogen bonds…. I was slightly worried that the borax might vulcanise the latex too, as vulcanising is just chemical crosslinking of the rubber polymers in a similar fashion but…Wikipedia is a wonderful thing
http://en.wikipedia.org/wiki/Vulcanization
rubber polymers don’t have the OH groups that PVA has, so borax won’t be able to form hydrogen bonds with the latex polymers….I should be safe!

Time to proceed to experimentation! Right, I need to order some latex, some ammonia cleaning solution and some borax…should cost about 8 quid….and check the garage for PVA and screenwash.

Depending on what strength ammonia solution you want, it can be easily made from ammonium nitrate cold packs.

Depends if you want it strong or not.

For how to make your own ammonia.

no only need it about 1% by weight so household ammonia is fine, cheers

^ RIght, then the making it 100% would be overkill and somewhat painful if it gets in your eyes

Fun though

my ebay modelling latex smells like it has ammonia in it already