I do not like using the modern conflute hoses on vintage mowers, but sometimes there is no choice because that is all that is available. The old plain rubber snorkels are getting hard to come by in good condition and the prices on auction sites have gone through the roof. I think I saw my last good rubber snorkel at the tip over 12 months ago. I am not prepared to pay nearly $100 for an old rubber hose. I remember when they were getting flogged off on ebay for around 10 bucks each and we thought they were expensive back them.
I am looking for suitable modern replacements.
The dairy industry makes a very good rubber hose in 25 to 32mm diameters, but these are also very expensive and hard to get, unless you know a dairy farmer who is willing to part with his secondhand tubing. Then you may have the problem of mice chewing into the rubber because of the milk residues which are impossible to remove completely. I have searched the internet high and low for plain rubber tubing in the same diameter as the old snorkels, but cannot find a single one anywhere. The world has moved on into flourine, nitrile, and silicon etc.
I am wondering what other restorers may be using as a substitute that looks and behaves similar to the old rubber material? Has anybody tried hydroponic hose? It looks to have a plain but shiny outer surface. But will it keep its shape and not sag and kink off?
This morning I decided to purchase suitable sized hoses in white rubber (black rubber does not seem to be available), black nitrile (seems to be the same stuff as hydroponic tubing), and black silicon. I will trial all 3 and see how they perform.
I get hose and other related fittings from my industrial hose supplier. Although they probably have lower quality stuff available, what I get from them is very durable, it’s often soaked in oil and left out in the weather for years.
Ours is a local company but there are places all over the country that sell industrial and hydraulic hoses. Purple Pig and Enzed used to operate national networks but I think Purple Pig may have folded. Ours keeps many different sizes for different purposes but they also have catalogs with a heap of different hose and fittings with a myriad of different properties and have ordered things in for me.
Some hose can be heat bent and some just collapses, breaks down or loses flexibility after heating. I’ve made up bent hoses for various jobs by filling them with ball bearings to preserve the internal diameter, heating them and bending them to shape around whatever comes to hand to use as a former then leaving them to cool. The temperatures they soften at vary considerably. Some hoses you can get data sheets on that tell you this information, mostly not, so it’s just a matter of experimenting. It can get a bit messy and smelly.
There used to be a service for semi rigid hydraulic hose where you could custom order specific shapes, I haven’t had to do that for years though.
Thanks for the info Ironbark. I'll have to get the name of your hose supplier off you in a PM sometime.
I have seen people use PVC farm polypipe on the cheap, and the great thing is you can get the fittings to make the bend. But I find it a bit rigid. The same goes for radiator hose which has an extra layer of knitted fabric for reinforcement. Okay if you can get a secondhand length of radiator pipe to suit, but still the problem of being a bit too rigid for lawnmower use.
I notice some old mowers like Pope just used a straight length of rubber hose, connected to a cylinder apparatus on the end of the carby, then straight up the handlebars. Seems they just left the hose a bit loose so it could make a natural bend without kinking.
So a one metre length of the rubber hydroponic hose turned up this morning and I would have to say it looks and performs much the same as the original old rubber snorkel hoses. It is a tad stiff and wants to retain its shape on the coil, but that is only to be expected in mid-winter. I would suggest leaving it out in the sun for a while or soaking in some warm water. This hose could be a winner.
Still to trial are nitrile, silicon, and natural white rubber. Stay tuned!
Pic below shows early setup of rubber hose on a Pope mower. No formed bends at all, just straight pipe made to curve up from the carby connection. The main felt filter was housed down in that cylinder affair. The one on the end also had a felt filter of some description but was fairly basic. I've never seen one of the cap ends in the flesh so have no idea what they looked like.
1) "Hydroponic" rubber hose. This is probably Polyethylene Terephthalate-based Natural Rubber Blend (or PET) or maybe a kind of soft Polyvinyl chloride (or Soft PVC)? It is a very good superficial match for the rubber snorkel material of the olden days, and it does have some fuel and grease resistant properties so is perhaps PET rather than PVC. PET is an important engineering thermoplastic polyester because of its good combination of properties, such as good thermal and mechanical properties as well as having excellent chemical resistance, and good optical and barrier properties.
2) Silicon hose. Not recommended, as it tends to kink very easily and becomes very floppy and saggy when hot. It cannot handle contact or proximity to heat, fuel or oil very well.
Still to try are:
1) Nitrile hose. NBR is the polymerization of Acrylonitrile and Butadiene into one large multiple-unit chain. The amount of Acrylonitrile is varied to provide different ranges of oil resistance to the base polymer.
2) white 100% rubber hose.
Other tubing excluded: Polyvinyl chloride or PVC pipe is a solid yet brittle polymer which has limited chemical resistance. Soft PVC tubing generally has little fuel resistance unless chemically treated e.g. "pink tint" PRCVT. Poly Pipe (also known as PE) is derived from the base material HDPE, which has good chemical resistance, is UV stable, and is resistant to cracking, impact and abrasion. Regular PE is generally too rigid for use as a snorkel, however "Soft HDPE" tubing may be worth trying. It is generally black with a thin blue line running the length of the tubing. The blue line might make it a "turn off" for some purist restorers.
I now have the nitrile hose and the 100% rubber hose. The nitrile hose looks similar to the old type of rubber, but appears to be prone to kinking. If left in kinked position for a few days it does not want to unkink. Same goes for the 100% rubber hose. The nitrile product is a bit stiff for my liking, as is the 100% rubber. The nitrile might have the advantage of being resistant to heat and chemicals like petrol and oil. The 100% rubber would have limited resistance and would also be prone to perishing in a relatively short space of time. It is basically the same stuff that pencil erasers are made out of.
CONCLUSION: There can ultimately be only one winner and that is the black hydroponic hose. It looks good, feels good, you can bend it a fair bit without kinking, it is sag resistant, reasonably heat resistant and probably long lasting. For my money that is the replacement hose I would recommend. I am not sure if there are different kinds of rubber used to make hydroponic hoses. In case anyone is interested, this is the one I trialed specifically. https://www.ebay.com.au/itm/265274517759
