PVC and DIESEL compatability

[cat man do]

I am wanting to use a heavy walled PVC tube as a deck filler on a cat i'm building and am wondering about compatability issues. Any comments????

[Alan Wheeler]

Hmmmmm, not sure thats a good idea. Strong solvents will attack the stuff. I doubt you are going to see any short term effects, but I think there are enough solvents in the Diesel to have some sort of long term detrimental affect. I would steer clear of the idea I think.

[cat man do]

Hi Wheels and thanks for the prompt reply.
I originaly was going to use a fiberglass tube, but because I have 6 fill points for 6 seperate tanks, and there 2m lengths, there was a bit of expense involved. Also I wanted large breathers to avoid overflow while filling, so had planned on 30mm pvc running up into a vented locker. Being a cat it would use up about 20 m of tube just for the breathers. more $$$$.

I found a site, http://www.coleparmer.com/techinfo/ChemComp.asp which reckons diesel/pvc had an excellent compatibility.

Did you have any reason in particular for not liking this idea??? I must admit I was unsure myself, but have heard of clear PVC tanks being made as custom jobs in Brisbane.

Comment please

Dave

[Alan Wheeler]

No I have no idea. I based my opinion on the fact that PVC is joint glued using a "glue" that's solvent melts the PVC and fuses it togther. So I figured that if a strong solvent can melt it, weaker or less concentrated solvents may pose a problem in the long term.
But if a Chemical company says it is OK, then it must be. Certainly a cheap way of going about it. But what about fuel capable hose? or is that too expensive.

[cat man do]

Hi , the fillers are positioned about 600mm in from the side , so the idea of the pipe was to tie it into the furniture and use it as handholds if required. Probably should add that i was going to give it a wrap of 440db and epoxy just to make us all feel a bit happier.

Thanks for the reply

Dave

[Rick]

I seem to recall that ABYC recommends only metal deck fillers yet another reader on this forum should be able to confirm/deny the validity of my memory.

[delmarrey]

The probem I see with PVC is it's adhesive factor. Neither polyester or epoxy bonds well to PVC. It has to be roughed up to stick and then under load I still wouldn't trust it.

It can be machine and screwed together but glueing is done by desolving the surfaces as Alan mentioned.

Another problem I see is with Biodiesel. I'm not sure they are compatible......_/)

[GordMay]

Excerpted from ABYC Section H-33 ~ Diesel Fuel Systems:

33.5.6
All individual components of the fuel system, as installed in the boat, shall be capable of withstanding a 21/2 minute exposure to free burning fuel (N-Heptane), or No 2 diesel fuel, without leakage ...
excepting
Fill and vent external fittings.

33.12.6
Fuel fill lines shall be hose or metal pipe...

3.14.4
Flexible hose shall comply with H-33.6 (wich requires UL 1114 or SAE J1527 certifications, and etc.)

3.14.5
Metalic fuel lines shall be aluminum or copper alloy pipe of no less than schedule 40
or
33.15.5.1
Copper or alloy tubing with a nominal wall thickness of at least .02 inches (.81 mm)

22.14.6
Rigid fuel distribution lines secured to hull members shall be connexcted to the engine by flexible hose.

[cat man do]

Just as well we're not building to ABYC standards, or else we'd suffer the same fate as most survey multihulls. Overweight and underperfoming.

These are deck fillers..... the plumbing to the engines will be flexible fuel hose and copper pipe.

And does'nt every thing have to get sanded before glassing to make it stick??

Dave

[Alan Wheeler]

OK so if you are wanting hand holds, why don't you use a SST pipe as the outer caseing and drop a smaller fuel hose down the center of it or even go SST all the way. Even epoxied, I would not trust a plastic/epoxy pipe for sufficient strength to hold onto in an emergency. You would be shocked as to the force something like this can sometimes be called upon to take. Many people have witnessed seemingly very strong fittings fail dramaticaly due to a body hitting or holding something when the "unlikely case of an emergency" happens.

[Pblais]

"unlikely case of an emergency"

Best to avoid things like that. Violates the number one rule of boating and most other potentially dangerous yet fun activites:

Don't hit anything!

[cat man do]

Just another point,
If PVC foam is OK as a core material in a diesel fuel tank, and Epoxy sticks fine to PVC foam, if PVC pipe is well prepped prior to glassing,surely it will be OK.
Alan we've seen this grab rail idea on other large cats where they used light wall PVC glassed and used to support cabin roof [tied in from bridgedeck panel to cabin roof]. Seemed more than strong enough, I'm a big fella and crashed into it when the skipper stuffed this forty footer into the back of a wave doin' 20+ knots. It was about the only bit of boat I did'nt break,a couple of hours later he did the same thing and I tore out some of his nice, light 3mm ply furniture. This guy did'nt seem to enjoy himself unless there was a damage bill after a race.

Again, this stuff we'll be using has a 50mm id and about 58mm od, so close enough to a 4mm wall thickness.It will also get a wrap of 440 double bias and the longest unsuported section will be around 1 meter long,so unless its getting flogged with a sledge hammer it should be fine.

Dave

[Brent Swain]

Throw a piece of PVC in diesel and leave it for a month.See how it makes out.
Brent

[markpj23]

Originally Posted by cat man do

the plumbing to the engines will be flexible fuel hose and copper pipe.

Dave

Many on this forum have warned against copper in diesel systems. Be careful with that too....

[cat man do]

Hi guys, I've been away for a few days.
Just wondering about the probs with copper pipe as I have seen it used before and have not heard of any problems, and the link to colepalmer I put in above gives copper and diesel compatabillity an excellent rating.

I'm confussed [ not hard ]

Dave