Cost of pipe couplings for DIY fuel polisher

[Lomax]

Hi all,

I'm trying to build my own fuel polisher, using Chinese Racor 500FG clones. I've got all the main components (strainer, filters & fuel pump), but I'm having great difficulty sourcing the required pipe couplings to plumb it all together. I never expected this to be such an expensive problem, but then I'm not really a plumber. For example, the strainer has 3/4" NPTT ports, which I'd like to reduce to a more common 1/2" BSPP - but having looked for hours the best I can find is £7.50 each for two brass reducing bushes from 3/4" BSPT to 1/2" BSPP*. An M18 to 10mm hosetail costs £15 (needed for fuel pump input). Etc. I've spent around £80 for the main components, but at such prices I'm looking at another £100 for the pipe couplings. This cannot be right, can it?


*) From what I understand 3/4" BSPT should seal in 3/4" NPTT, if I use some pipe sealant.

 

[snowbird30ds]

Some npt threads are the same thing as bsp but not all, thread angle is also different 55degs vs 60degs.
It's often the fittings that rachet the cost up.

 

[Lomax]

Some npt threads are the same thing as bsp but not all, thread angle is also different 55degs vs 60degs.

Yes, I did look this up and while not recommended 1/2"and 3/4" NPTT and BSPT should mate. It will probably require some sealant to get a good seal, but the strainer body is nylon so maybe not in this case.

It's often the fittings that rachet the cost up.

I was expecting some cost of course, but I am now getting severe sticker shock. I don't think even £100 will cover it. Part of the problem is that the fuel pump and filters have metric threads, which is quite rare.

 

[Boater Sam]

Iron fittings will be much cheaper than brass.

 

[Laysula]

Did you not get any hose tails with your racor? I just used a length of 6mm copper pipe with a plastic 6mm hose pushed on , hose then into the racor, hose out of the racor to electric pump using the pipe that came with it and then a long length of pvc hose back to the filler cap to the tank.. Cost me £25 for the racor, £13 for the pump £5 or so for the pvc hose and a couple of quid for the copper pipe. In addition I used the cheapest filter inserts I could buy for the initial polish to get rid of the big bits and then later a better quality one to give it a final polish.

 

[snowbird30ds]

A set of bsp taps may make things cheaper.

 

[Lomax]

Thanks guys! I'm battling on... Here are a couple of baskets I've been working on, from thehosemaster.co.uk and tameson.co.uk:






It comes to £45.55, which is bad, but not quite as bad as it was looking at one stage. I'm unsure if 10mm copper pipe is sufficient though? I don't want to go to 12mm, because it's a rare diameter, and 15mm seems total overkill! It would also increase the cost... The piece of 10mm I have on my desk has a 7mm i/d, which is actually slightly larger than the 6.5mm i/d of the hose tails that came with the filters. I just wish I could order all the bits from a single supplier, but there always ends up being some bits they don't have

Did you not get any hose tails with your racor? I just used a length of 6mm copper pipe with a plastic 6mm hose pushed on

I did get hose tails with the filters, but they are for 10mm i/d hose.

 

[Laysula]

I did get hose tails with the filters, but they are for 10mm i/d hose.

Just checked mine. Yes they are 10mm hose tails but I was mistaken with my hose sizes. I used 3/8 copper pipe and 8mm pvc hose which stretched over the hose tail. Just plain cheap clear hose, not the reinforced stuff. You don't need anything special as long as your system is airtight. Your only going to use it in a locker for a couple of hours at a time under your own supervision.

 

[Lomax]

Updated baskets, to include fuel hose, and input/output ends. For the latter, I opted to take the idea from @Laysula, and use compression fittings with bits of 10mm copper pipe instead of hose tails - this actually worked out cheaper. Total is now £80. I'm pretty sure these are all the bits I will need, apart from some hose clamps (got those) and a fixing bracket for the fuel pump (will make one myself). Awaiting your verdict on using 10mm copper pipe with zinc-plated steel cutting ring fittings before I order.

 

[LadyInBed]

I was once told that 'plastic' pipe was the way to go, to reduce the likelihood of stress fractures, having once suffered from one.

 

[Laysula]

That's a lot of copper pipe. I only used a foot or so as a wand to make sure I got to the bottom of the tank. Do you not have a plumbers merchant near you that would cut you a bit off?

 

[Lomax]

That's a lot of copper pipe. I only used a foot or so as a wand to make sure I got to the bottom of the tank. Do you not have a plumbers merchant near you that would cut you a bit off?

My tank already has a ball valve drain at the lowest point, which is quite handy. The copper pipe and cutting ring compression fittings are for connecting together the components of the fuel polisher. This works out cheaper than hose tails + adapters + hose + hose clamps, and will make for a neater and more compact installation. You may be right that I won't use that much though; I'll just get the one metre for now. That said, I am unsure whether 10mm o/d copper pipe is sufficiently large, and whether galvanised steel cutting ring compression fittings are suitable for the application?

I was once told that 'plastic' pipe was the way to go, to reduce the likelihood of stress fractures, having once suffered from one.

This is only for a fuel polisher, which will be mounted on it's own panel. It is not connected to the engine.

 

[Lomax]

Don't you just love it when you leave your computer for an hour and this happens:



I have spent hours trying to get all the bits together! Luckily I do have the screengrabs, so I don't have to start from scratch...

 

[Laysula]

How big is your tank? mine is 130L.

 

[Laysula]

My system is similar to this.

 

[Lomax]

How big is your tank? mine is 130L.

By measuring its dimensions it would appear to be 500L (10cm³ = 1L).

My system is similar to this.

The dip stick method certainly has its benefits, allowing you to hoover up sludge from those parts of the tank you can reach with it. Unfortunately the deck filling point is offset on mine, so I cannot use one. Nor do I have an accessible inspection hatch, because the tank sits just 4" below the aft deck. Fortunately, this means the bottom of the tank is readily accessible, and it has a permanently attached ball valve with hose tail in one corner. It is relatively easy to ensure this is the lowest point by moving heavy objects/people around

Because I plan to have the polisher permanently installed I opted to go for a slightly more elaborate set-up; first a 150 micron stainless strainer, then a 30 micron 500FG, followed by a 10 micron 500FG. My pump is similiar to yours, rated at 250L/hour. This will of course come last in the chain.