Garden Railway Forum

All-

Due to age and dirt, it was time to replace the tubing on the Goodall valves on Major Hitchcock and Janmod. Both were leakers due to dirt/age and the tubing should be replaced periodically.

I found some Tygon (TM) tubing that was thin walled to give me 1/8 ID and 3/16 OD to fit the boiler bungs. Tygon is to be used for fuel line and the like as it is oil/solvent resistant and flexible.

BIG mistake.....

I fired Major Hitchcock and it ran fine for a while until I thought I heard the safety release. It was NOT the safety, but the Tygon tubing developed a hole as it distorted and melted in the loco.

Anyhow, does anyone know what Roundhouse, PPS, Dreamsteam, Accucraft et al use for their Goodall valves?

Thank you!

Hi Garrett,

Just looked up Tygon (TM) tubing and it appears to be available in different materials, PVC, Polyurethane & Silicone.

Not sure what the manufacturers use but I replace mine with silicone tubing used in Radio Control models for clunk lines in fuel tanks. This is the smallest size silicone tubing available which should fit inside your 1/4" boiler inserts without rubbing. Something like this - http://www.ebay.co.uk/itm/White-Silicon ... 6487140212

I clean up the shaft with brasso, blending any burrs on the drilled hole with a small file, and cut the tubing to a length just shorter than the shaft so it is free to move.

Another trick when using a syringe to fill the boiler with water through these Goodall valves is to suck the water out that is left in the top of the valve, otherwise it boils over and drops down onto your burner.

Chris Cairns.

Spule 4:76410 wrote: Anyhow, does anyone know what Roundhouse, PPS, Dreamsteam, Accucraft et al use for their Goodall valves?

As far as I know, Goodall valves require silicone tubing. Not sure if Roundhouse use Goodall valves. The Roundhouse water filler I have has a small Viton ball and a spring.....

If you have an model aeroplane shop in the vicinity, see if they have a suitable size fuel line. That's usually silicone rubber.

Graeme

All-

Thanks for the replies.

OK, I got model airplane and small two stroke fuel line, but wile Tygon is noted for solvent reistance, it is not for temp (or at least the type I have per Chris's findings).  All the tygon we got at work was the same.

Not sure if there is a model airplane shop in Nashville (for a city with an SMA of 1.5 million people, we don't have any decent railway model hobby shops) but I will try on eBay or contact our local industrial hose and gasket company (they found a direct replacement for the hard plastic fuel line for my old Citroen DS) to see what can be found with silicone/heat resistant properties.

EDIT, last month, I did try an airplane shop in Knoxville, TN. I could find the 1/8" ID line, but not with 3/16 OD...to ensure it clears the bung.

Here is the Technical sheet for RH's injectors, yes, while most are the ball spring type, they had a couple models with a Goodall.  

http://www.roundhouse-eng.com/ss07.htm

Thanks again!

Yes I have lost 2 independent model shops in Glasgow in the last few years. The 2nd one closing was annoying as they stocked a lot of Dolls House accessories and I never got around to getting some hinges for my Guards Van kit before they closed.

We do have a chain store model shop Modelzone, but you are limited to buying the standard refill packs (e.g. only need 1 length of brass tubing but it comes in packs of 5).

You need to find a stockist of Du-Bro products as I'm sure their small size silicone tubing will do the job - http://hobby.dubro.com/resources/ecatal ... /00059.htm

Chris Cairns.

Spule 4:76419 wrote: Not sure if there is a model airplane shop in Nashville (for a city with an SMA of 1.5 million people, we don't have any decent railway model hobby shops)

Wouldn't surprise me, the model aeroplane hobby has the same issues as model railways.....

In any case, it sounds like you need thin wall tubing and all the model aeroplane fuel line I've seen is thick wall.

Try a laboratory supply house. An Aust. one lists a wide range of silicone tubing, including thin wall and will sell by the metre.......

The common lab grade of Tygon has a temp rating of about 75C, so no wonder it went pop, even in a Mamod. Lab grade silicone tubing is rated to over 200C, so would even be OK in a high pressure coal burning boiler.

Graeme

Thank you again.

I have discovered (new to me http://www.familyhobbies.net/ ) a large R/C dealer about 20 miles south of here to try.

The sad part is about 5 or so years ago there was a nice little railway hobby shop around the corner, until the owner thought that working for the actual railroad would be better.

GTB:76435 wrote: Wouldn't surprise me, the model aeroplane hobby has the same issues as model railways.....

Even worse I would think. At least Hobby King hasn't started selling model railway stuff yet.

In the UK there are a couple of online suppliers of tubing. I buy from Silex: http://www.silex.co.uk/

Michael

OK....

Thin wall 1/8" - 3mm ID silicone tubing is apparently as rare as a box of dinosaur feathers being carried by Jimmy Hoffa, Elvis and Bigfoot.  Tried, the airplane shops, tried the industrial suppliers (including the one that found me the match for my plastic Citroen DS/ID fuel line of all things), auto parts stores, hardware stores, and even called DuBro HQ up in Chicago, no dice.

I did find thin-ish 3/32 tubing.  It will fit the old Shirley/Sidestreet/West Lawn Goodall valve (3/16" OD) but not the newer IP ones that are 1/8".  Well, it CAN stretch onto the valve, but then it is too large (its 3/16 OD becomes nearly 1/4") to get in the boiler bung.

I did find some online that I will buy.  The problem is the minimum purchase is 10 feet.  


http://www.amazon.com/gp/product/B000FN ... PDKIKX0DER

I guess soon I will be able to rebuild every Mamod/PPS/IP Goodall in the world with 10 feet of the stuff!  :shock:

What I can do the next time I deal with Doug, Chris, Peter, or anyone else in the UK is send a length of it over there that you all can share amongst yourselves as a gift to my UK forum Mamod friends and helpers.

Amazon tubing arrived, installed, tested, all is good.

Well, at least on Major Hitchcock the injector isn't leaking now...note I didn't say the loco was leak free. Have to re-seal the new sight glass, seems to be the trendy thing to do these days.

Spule 4 wrote:Have to re-seal the new sight glass

Yes it appears that somewhere in the old Mamod SL history the specification for the sight glass seal was changed to a thinner 'O' ring which barely allows any compression. Hence you have to use some form of sealant with the 'O' ring in order to get enough compression to form a steam tight seal. Same applies to the MSS replacement 'O' rings as well.

The easiest option is to use the current Mamod oval sight glass seals which are thicker. However you need to visit the Mamod factory to get these on their own, or phone them up to get some sent in the mail.

However we have still not heard if Doug has fixed his leaky boiler yet.

Chris Cairns.

PS - Glad to hear you got the Goodall filler valve sorted out OK.