Fibre Washers Vs 'O' rings

tmuir · Fibre Washers Vs 'O' rings

I know most engines come with fibre washers but I personally prefer 'O' rings to use on my SVs and overflow plugs for two reasons.
Firstly I can get O rings cheaply and easily where I live, fibre washers are harder to get.
Secondly I find the O rings seal better without having to lap the bushes on old engines that may of got a bit scuffed from use over the years.

But can anyone tell me which one (atleast in theory) is better and why?
I'll give the one that fibre washers probably have a longer shelf life than O rings but that doesn't bother me as I can always buy new ones at just a few cents each.

flywheel61

Having received many early engines with the 'O' rings perished, and the fibre washers intact (abiet some brittle), I would give the fibre washers the edge. There is also a higher grade of 'O' rings that can be used on SV's, but it will be awhile before I go in search, bcause I've still got around 100 of the ordinary black ones left,

.

The only time I use 'O' rings on SV's, whistles and water filler plugs is when they are on a curved surface, as they seem to provide a better seal,

.

Cheers

Chris

johnreid

I have been making my own washers or gaskets from Teflon, I find that it forms to make a good seal and seems to last almost forever. Just putting the Teflon idea in for another option. I have found that an O ring placed between the body and plunger of a safety valve works quite well though. However I find it difficult to find the smaller O Rings that are required for that purpose.

I have a sheet of .025" Teflon and some inexpensive punches to make the gaskets from.

I suppose I need to make a Gasket page on my Web Site showing how I make them, it is so simple.

mogogear

Make it so John- or here on the resources page...Harbor Freight punches?

johnreid

I will do so in a few days, right now it is a bit difficult as there is a cleaning crew for after fire clean up, they shoul be done with that stage soon,

I use this material
http://cgi.ebay.com/ws/eBayISAPI....eName=STORE:PROMOBOX:NEWLIST#LIST

and the punches were bought on Ebay also, but Harbor Freight would be about the same quality I believe. Roger uses punches he has made from shell casings I believe,

Nick

I use the same stuff as John (I know a few other members do too, because they talked me into it) and I will say it works very well.

Wallace

Tony I've found the orings to work quite well too.

It's mostly what I use.

They seal well and I like that they seal without having to do the s/v or plug up much at all.

That and they are easy to get hold of.

toxx

... I also replaced the washers on my SE3 with o-rings. Works fine!

Les Marsh

I try and replace like for like.

mc_mc

I have melted the (cheap) o-ring I put on a safety valve when I was a bit over enthusiastic with the wicks in my burner (too long).

So theoretically it could of glued it shut which could be dangerous. In fact the reverse happened and it stopped sealing and so there just was a big gush of steam and the engine stopped.

I suspect that putting o-rings on a safety valve also can stretch the spring more and so raise the pressure it blows off at.

But in spite of this I replace all my suspect seals with o-rings as I got a pack of 100 for £1

toxx

CCairns

On the old style Mamod locos, they used a thin fibre washer to seal the steam dome nut. Being thin these are prone to damage from the hex flanges on the nut and can leak, and that is why the boiler insert gets loose due to owners overtightening the nut, and breaking the insert loose in the boiler.

On the MSS locos they use an ordinary black 'O' ring, which does seem to work OK, but these are less tolerant to heat (meths or gas fired) and do badly deform over time. I replaced mine with a thick washer made from a sheet of flexible graphite material.

As you will be aware, the current Mamod washers supplied as spares are those horrible rubber based ones, which do not last long. I prefer to use a thick fibre washer on my safety valves and water top-up valves.

tmuir

So I guess the main points so far are.

Fibre washers last longer
Fibre washers less likely to fail due to excess heat.
'O' rings seem to be cheaper

So I guess its really just a personal choice and both are fine.

johnreid

You are still overlooking Teflon, the stuff is great! I bought a sheet that should last years and make my own. If I was to figure out how many washers that I could get from the sheet I bet it would be the least expensive route also.
I have found other uses for the Teflon and do not regret the day I bought it. I will take some pictures today and make a ste of Gaskets for my Jensen, but to be honest I dont need to as there are Teflon gaskets on it already and they seem to last forever. I do not think that I have needed to replace one yet. In fact, it doesnt seem to melt and works great on my Mamods where the flames seem to want to lick around the boiler.

tmuir

Sorry John didn't mean to exclude teflon gaskets.
I only didn't mention them as I have none and was really trying to find out if there was a reason I SHOULDN"T use 'O' rings.

toxx

johnreid

I bought mine on Ebay, it is an industrial material that I assume would have to be purchased through an industrial supplier, or on Ebay.
You migh do a Google search for a supplier in your area.

toxx

... thanks, John!

IndianaRog

Tom, I bought my teflon sheeting from same guy as John I believe...I remember the seller name on eBay: materialmaster5

He sells reasonably and all sorts of thicknesses and sizes, but the 0.025 inch thick stuff seems to work all around for me.

cheers,
Rog

Nick

I bought it too from him. The only problem was using it on my Jesen 35, it is too thick for some parts on top of the boiler, otherwise it works great.

Bubba

IndianaRog

johnreid

The thing about Teflon is that if it is going against an imperfect surface, often it will conform to the surface and still give you a good seal.
It is a slick surface too, and can be used similarly to a lubricated surface and thus reduce friction.
It comes in all kinds of thicknesses as where I used to work, we used 1/2" and 3/4" thick for various applications.
Be careful when ordering as I believe that some of that which the fellow on Ebay sells has an adhesive on one side, not good for our applications.

Nick

I emailed him about the adhesive. He said he has both, just tell him ahead of time which one you want.