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Jud - s/v Sputnik

Diesel heater valve - fabrication repair - diesel-resistant epoxy?

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(Cross-posted to Fix-It Anarchy (here), but thought I’d post here too since lots of knowledgeable folks congregate in these parts...may not see it there.  Curious if anyone has any insight.)

Anyone know anything about basic diesel heater fuel metering valves?  No spare internal parts for the valve assembly, or easily-fitted spare whole valve assemblies are available from the manufacturer (Dickinson).  (They do sell a replacement valve for another type/brand of heater but it would take some re-plumbing to get it to fit on my heater, a different brand.)

My idea is to make a new float for the needle valve in the fuel metering valve.  I have my old fuel valve - pic below.  It sat with diesel in it for years, and the float, made of a shitty, inappropriate  composite material, absorbed diesel and stopped working (doesn’t float to adjust the needle valve).

Looking at it, I was thinking I could easily fabricate a new float (carefully cut off the old plastic) if I knew a composite that floats in diesel and doesn’t absorb it.

Then I realized I might be able to simply mill/router/carve one from a small block of wood and then lightly epoxy saturate and coat it to repel diesel.  (But only some epoxies will work??)

Elaborate, maybe, but I want a very easy to install spare fuel valve for my heater...which are no longer available.  I figure it’s worth a try to make something if I have the right materials to start with.

Any thoughts?  Seems like it would work - I think it’s about using the right kind of epoxy that won’t absorb diesel?  I’m kicking myself for not buying a spare fuel valve assembly two years ago when I got the current one that’s on the heater now (to replace this unit that got saturated/ruined)!!

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What model heater is it? I have an Alaska model.

FWIW I think any polyethylene plastic should be diesel resistant.

FKT

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7 minutes ago, Fah Kiew Tu said:

What model heater is it? I have an Alaska model.

FWIW I think any polyethylene plastic should be diesel resistant.

FKT

Well, therein lies the problem :-)

My heater is a Sigmar (Sig Marine) - a guy who was at Dickinson years ago left to start his own heater company.  I bought one of these years ago because they had more BTU output than the similar Dickinson Newport.  I think Dickinson later bought up the company, but supported the heaters with parts and service.

Fast forward years later, I laid up the boat and didn’t drain the fuel from heater.  Valve float float got ruined.  I bought a replacement valve assembly two winters ago from Dickinson.  Now, Dickinson no longer sells the original Sig Marine spare valves (they used to).  They’re phasing them out.  I can, however, use the similar Dickinson Newport valve, they said - unfortunately, it’s not “plug and play” as a replacement spare with my heater, requiring some diesel line re-plumbing to work as a spare...which Id like to avoid. 
 

So - if I can make a simple float and get this one working again, that would be ideal!  I’ll try polyethylene.  Question is, will it float in diesel?

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1 minute ago, Jud - s/v Sputnik said:

Well, therein lies the problem :-)

My heater is a Sigmar (Sig Marine) - a guy who was at Dickinson years ago left to start his own heater company.  I bought one of these years ago because they had more BTU output than the similar Dickinson Newport.  Fast forward years later, I laid up the boat and didn’t drain the fuel from heater.  Valve float got ruined.  I bought a replacement two winters ago from Dickinson.  Now, Dickinson no longer sells the original Sig Marine spare valves (they used to).  They’re phasing them out.  I can, however, use the similar Dickinson valve, they said - unfortunately, it’s not at all “plug and play” as a replacement spare, requiring some diesel line re-plumbing to work as a spare...which Id like to avoid. 
 

So - if I can make a simple float and get this one working again, that would be ideal!  I’ll try polyethylene.  Question is, will it float in diesel?

Just looked the density figures up - almost certainly not. The density of diesel is approx 0.85 kg/litre. Polyethylene 0.857. So neutral buoyant or slightly negative buoyant if carved from a solid.

One suggestion - I have been making stuff from green polyurethane foam. New hard dodger. This stuff is very light closed cell foam. Doubt it'd like immersion in diesel but epoxy has no effect on it so doing an epoxy dip then diesel resistant paint might work.

Seems overly complex and elaborate though.

I've plenty of scraps and diesel, might toss a bit in a jar and see what happens.

FKT

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10 minutes ago, Fah Kiew Tu said:

Just looked the density figures up - almost certainly not. The density of diesel is approx 0.85 kg/litre. Polyethylene 0.857. So neutral buoyant or slightly negative buoyant if carved from a solid.

One suggestion - I have been making stuff from green polyurethane foam. New hard dodger. This stuff is very light closed cell foam. Doubt it'd like immersion in diesel but epoxy has no effect on it so doing an epoxy dip then diesel resistant paint might work.

Seems overly complex and elaborate though.

I've plenty of scraps and diesel, might toss a bit in a jar and see what happens.

FKT

Cool!  If you happen to be able to do a quick experiment and toss some scraps in a jar of diesel to see.

Polyurethane foam - interesting idea.  But I’m thinking using wood might be easiest, if the epoxy coating I put on it will resist diesel saturation.  (There’s always a bit of diesel left in the bottom of the valve, I learned, even when you shut off the fuel to the heater and burn off residual fuel in heater until flame goes out.). 

FYI, Dickinson told me the old valve floats used that white composite, as in my pic above, while newer ones are black, and made of a material which is apparently more resistant to diesel absorption.  

I don’t mind elaborate fussy work making something if it gets me a new valve float that I’ll have as a valuable very easy to change out spare...no choice, really! 

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I've made small custom-shaped containers out of fiberglass/epoxy (WEST) for water, fuel, soap, etc etc. I'm pretty sure that any commonly available commercial epoxy is diesel fuel resistant if not "proof." I'm do a small experiment to see, will take a couple days though.

Unfortunately the only piece that I know of for a fact that I made which has been used to contain diesel is on a boat that I no longer own and is far enough way that it would be troublesome to check.

FB- Doug

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Look online have seen used ones for sale, they are pretty common up in the frigid north, I have a spare on the boat I would give you but shipping would be spendy from Panama.

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2 hours ago, andykane said:

West say 20mil epoxy coat is fine for diesel tanks so would likely be ok for coating a wooden float (or foam). You'd want to make sure the buoyancy characteristics are close enough to the original to maintain the fuel at an appropriate level.

https://www.epoxyworks.com/index.php/epoxy-composite-tank-guidelines/

I can support this. Had to repair pinhole leaks in the bottom of 20 yr old aluminum

diesel tank at a very remote island in W. Panama. Had West epoxy on board so cleaned

inside of tank, sanded the surface hard, cleaned again, filled bottom to 2mm depth (all I had)

and wire brushed that into the aluminum by hand for a while before it kicked. 2 years and

10,000 miles later still no leaks and no visible signs of epoxy breaking down looking

into the tank. Still planning on replacing it - some day!

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PS: I recall West advice to go a little shy on the hardener and keep things warm.

Both of those instructions were easy when far from supplies in the tropics.

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My diesel fuel tank float is bare cork. 40 years and still floating. Drink some wine, make a float.

Either polyurethane foam or polyethylene foam in epoxy should work too. Or solder one up from copper sheet.

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1 minute ago, El Borracho said:

My diesel fuel tank float is bare cork. 40 years and still floating. Drink some wine, make a float.

Either polyurethane foam or polyethylene foam in epoxy should work too. Or solder one up from copper sheet.

Yes, cork seems pretty immune, and it's a good excuse to drink better wine.

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6 minutes ago, El Borracho said:

My diesel fuel tank float is bare cork. 40 years and still floating. Drink some wine, make a float.

Either polyurethane foam or polyethylene foam in epoxy should work too. Or solder one up from copper sheet.

That was my latest idea - solder up a small bit of sheet copper or brass - not sure of both are compatible with diesel (I think some metals react and alter the diesel).

But, damn - like the cork idea.  Easy, available.  

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1 minute ago, Jud - s/v Sputnik said:

That was my latest idea - solder up a small bit of sheet copper or brass - not sure of both are compatible with diesel (I think some metals react and alter the diesel).

But, damn - like the cork idea.  Easy, available.  

I knew girls like that, but I wouldn't put them into a diesel tank.

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carve a little block of foam and coat it in epoxy. Before they worried about liability, West system had instructions for making plywood/glass/epoxy diesel fuel tanks.

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Do a search on a basic carburetor float.  They are short money and may do the trick.

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Not to be chicken little but I have seen the results of two boats with failed metering valves that overfired the heater. One was a very near catastrophic fire on a wood boat, glowing metal, the other turned a aluminum one completely black with soot.  At $150+- for the valve plus some copper tube and fittings might be worth a retro and new valve.

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The correct modern material is Nitrophyl.  However it is difficult to purchase in small quantities except as a finished float.

https://www.rogerscorp.com/Elastomer Components/NITROPHYL

You may be able to get some from Restoration Supply.

https://restorationstuff.com/

They list three part numbers in their catalog:

6"x 6" x 1" Flat Block NIT001 $69.00
3"x 3" x 1" Flat Block NIT002 $20.00
2" round x 3" Long NIT003 $14.00

There may be other sources.  Floats are devilish hard to get right.  There's no extra space to work with.

I tried six times to patch a brass float with solder, for an old Jeep, and eventually gave up and sold the Jeep.  That was one of a handful of intractable problems it had that no amount of time and money could seem to fix, but that's a story for a different forum.

If you can't get nitrophyl you could try cork.  It has to be coated, and butyrate dope (as used on aircraft) was common when cork floats were still in widespread use.  Some people use epoxy or varnish.  Any coating will be heavier than the diesel so you would want to avoid gratuitous thickness as it will make the float sink.  There is usually not much reserve buoyancy in these systems.  Cork will eventually become saturated if the coating is compromised but it should stay intact rather than shedding little pieces to clog the orifice.

 

3 hours ago, SASSAFRASS said:

Not to be chicken little but I have seen the results of two boats with failed metering valves that overfired the heater. One was a very near catastrophic fire on a wood boat, glowing metal, the other turned a aluminum one completely black with soot.  At $150+- for the valve plus some copper tube and fittings might be worth a retro and new valve.

There is an overflow port that is supposed to go to a catch pan or back to the fuel tank.  I would suggest that it be connected and kept clear, and checked to ensure it is free from blockage periodically.  If the overflow is functional there is no risk of overfiring.

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Coking and airflow issues can cause the flame to drop into the burner and make all kinds of bad, even with a overflow tank working well it can be a bad day in a hurry especially at night when not monitored, hence going away from a harry home owner metering valve repair. Our dickenson stove ran more or less nonstop for several years before we left the PNW and even with diligent maintenance cleaning and metering valve calibration it could be a PITA sometimes.

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