Marelon vs. Bronze - Page 2 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #11  
Old 03-21-2002
Junior Member
 
Join Date: Mar 2000
Posts: 4
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
wingsofraven is on a distinguished road
Marelon vs. Bronze

Does it have to be a ski boot??
Reply With Quote Share with Facebook
  #12  
Old 03-24-2002
Junior Member
 
Join Date: Jan 2001
Location: Pensacola, FL
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
svPrimeTime is on a distinguished road
Marelon vs. Bronze

I had just one Marelon sea **** that was just 3 years old when, in the course of manipulating the handle to keep the unit working, freely, the handle broke off in my hand. No more Marelon for me.
Reply With Quote Share with Facebook
  #13  
Old 03-30-2002
Member
 
Join Date: Dec 2000
Posts: 60
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
Constantin is on a distinguished road
Marelon vs. Bronze

Marelon has a lot going for it. After all, it will not seize as readily as bronze sea-cocks, is usually cheaper, and doesn''t require grounding like bronze. If you''re not planning on doing a lot of maintenance, it may be the better option. Lastly, Marelon is not attacked by some substances like blackwater waste the same way as Bronze. Furthermore, it doesn''t interact galvanically if you were to attach it to a stainless tank.

Bronze sea-cocks are usually more solid and tougher than their marelon cousins. Reinforced plastic only goes so far. But "Marelon" is not only a brand name, it also assures some modicum of quality. The same cannot be said for a lot of "bronze" fittings which the layperson cannot distinguish from those actually fit for ocean service. Good Alloys cost money, and much of the stuff sold in discount stores is simply adapted from home use and sourced from the cheapest supplier they could find. Caveat Emptor!

Furthermore, bronze sea-cocks require monthly openenings and closings or they will seize hard and fast. Ideally, they should be taken apart and regreased yearly. That keeps corrosion to a minimum. In this sense, the bronze sea-cocks are no different from your average folding propeller which also usually needs a yearly greasing, cleaning, excercise, etc.

Having worked on the entire sanitation system in our boat, I see a role for both systems. Our stainless holding tank had no proper nipples to interface with hose - just a flat tube weldment which leaked invariably. A Marelon fitting might have been more appropriate because it has the barbs that keep the waste where it belongs. On the other hand, that presupposes access to the interior of the tank, etc.

I prefer bronze systems all around, but I''ve also had to deal with seized sea-cocks. They are no fun. One more reason to create a monthly/annual check-list for preventative maintenance. You either do it now or pay for it later. If interested, have a look at <a href=http://www.vonwentzel.net/Prout/>www.vonwentzel.net/Prout/</a> for more info on what we did to make our holding tank system work.
Reply With Quote Share with Facebook
  #14  
Old 03-31-2002
Senior Member
 
Join Date: Jan 2001
Posts: 114
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
Pangaea is on a distinguished road
Marelon vs. Bronze

thinredmohican,
I for one have never been sure about using marelon through hulls below the
waterline, but here''s what I think:
I picture hitting something like a rock (or that 12''" by 12''" by about 10'' long piece of wood that was floating in the water the other night) I would imagine objects like these would seriously damage marelon so, I, personaly don''t use or recomend them below the waterline.

Dennis L.
Reply With Quote Share with Facebook
  #15  
Old 03-31-2002
sailor
 
Join Date: May 2001
Location: North Dakota
Posts: 87
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
ndsailor is on a distinguished road
Send a message via Yahoo to ndsailor
Marelon vs. Bronze

I would imagine hitting something like that would damage your hull, much less the thru hulls. I think the marelon thruhulls are just as strong as the fiberglass surrounding them and the seacocks only weakness is the handle. If there is fire aboard, well, a lot of fiberglass is going to melt too, probably long before the thru hulls and seacocks melt.
Reply With Quote Share with Facebook
  #16  
Old 03-31-2002
Senior Member
 
Join Date: Jan 2001
Posts: 114
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
Pangaea is on a distinguished road
Marelon vs. Bronze

Hi Rick,
No I don''t think it would damage my hull.
When I passed the peice of wood it was lined up longitudally(spelling?) with the boat. If I''d have hit it like that, it might have slid along the under body in that position and hit a protruding through hull, it would tend to try to shear it off, Do you know if marelon is stronger than bronze? I really don''t know.

Dennis
Reply With Quote Share with Facebook
  #17  
Old 03-31-2002
sailor
 
Join Date: May 2001
Location: North Dakota
Posts: 87
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
ndsailor is on a distinguished road
Send a message via Yahoo to ndsailor
Marelon vs. Bronze

Goood question! I really don''t know. I wonder of any tests have been done regarding how much each would give before cracking. I would assume that the bronze, being a soft metal, would be less affected by cold water where the marlon would (I expect) be more susceptable to cracking if struck by a hard object. In warmer waters I don''t think it would make much difference.....just my feeling on the subject...an easy test would be to take a discarded bronze thru-hull and marlon thru-hull and squeeze both in a vise....waddaya think....Rick
Reply With Quote Share with Facebook
  #18  
Old 04-01-2002
Member
 
Join Date: Dec 2000
Posts: 60
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
Constantin is on a distinguished road
Marelon vs. Bronze

Fundamentally, the bronze units should be stronger and tougher than the Marelon ones. furthermore, they are usually more tapered (don''t need as much thickness for the same strength), so stuff is much less likely to catch on a protuding lip. However, once again it depends on the configuration, the type of impact, and the alloy used. Some are tougher than others.

If the bronze thru-hull is not properly bedded, the first thing to go is probably the hull around it. Any cantilevering action will exploit the 3x lower strength of the hull around the hole. Marelon would probably fail first. Either way, you have a leak to tend to.

Such a failure modes seems somewhat remote. I''d worry more about large logs hitting the bow/keel sections and causing damage the old fashioned way than shearing at the thru-hulls.

However, it hasn''t reduced my interest in common-box systems where one thru-hull/strainer feeds raw water for the whole boat much like a busbar feeds circuits on the electrical side. This minimizes thru-hulls, the associated maintenance, etc. but requires longer hose runs inside the boat.
Reply With Quote Share with Facebook
  #19  
Old 04-01-2002
Jeff_H's Avatar
Moderator
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 6,559
Thanks: 5
Thanked 92 Times in 69 Posts
Rep Power: 10
Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about Jeff_H has a spectacular aura about
Marelon vs. Bronze

I am not sure that the Bronze thru hulls really are all that much stronger than Marelon. While the properties of bronze are superior as a material [most bronze through hulls are cast Bronze, (Tensile strength 40-48 KSI)compared to Marelon which is glass reinforced nylon (27-33KSI)] Marelon Fittings are supposed to have heavier wall thicknesses so that they have the equivelient strength in bending and sheer. Marelon is however more flexible and so ''feels'' weaker.

I think the real choice is maintainability. Traditional bronze seacocks take more work to maintain, but no matter where in the world you happen to be, they can be maintained. It is relatively easy to plug the outside of the thru-hull and remove the tapered plug for maintenance. Most Marelon fittings are either not designed for disassembly or count on proprietary parts. Which is why I generally recommend marelon for coastal stuff and bronze if you going distance voyaging. While true marine bronze ball valves are a real favorite of mine and are really best in terms of operation, they lack the easily rebuildable qualities of a traditional tapered plug seacock. There are some neat (compact and easy to operate without freezing up) SS ball valves out there that are used in Europe but I have mixed feelings about those as I have one that is not sealing when closed and which I will replace at next haul out with a bronze ball valve.
Reply With Quote Share with Facebook
  #20  
Old 04-01-2002
Member
 
Join Date: Dec 2000
Posts: 60
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 14
Constantin is on a distinguished road
Marelon vs. Bronze

The one thing to consider with cast Bronze versus glass-fiber reinforced plastic is that cast Bronze has isotropic material strength while reinforced plastic does not.

That is, a cube of Bronze has the same strength in all directions, while a cube of Marelon should have higher tensile strength in the direction of fiber flow (while approximately having the tensile strength of the underlying resin in directions perpendicular to the flow of fibers).

Marelons compression strength is probably not enhanced that much by having glassfibers in the mix. The fiber flow profile would mimic the grain flow inside a forged part. The only difference is that fibers flow from where the injection occurs - this may or may not be in line with needs. I assume that the makers of Marelon fittings have this part figured out.

With proper design, Marelon is every bit as strong as Bronze - just add some thickness to make up for the lower strength and toughness. However, like any material that has unequal material qualities, reinforced plastics require careful engineering.
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Seacocks- Marelon or Bronze bidet Gear & Maintenance 2 11-03-2004 12:07 PM
sealer for bronze port twilk Gear & Maintenance 2 10-28-2003 09:48 AM
Cape Dory Bronze Portlights WLJarrell General Discussion (sailing related) 5 11-26-2001 08:28 AM
bronze stair hardware HeidiMills Gear & Maintenance 1 10-01-2001 09:27 AM
Testing the condition of bronze turnbuckles Sloop23_417 Gear & Maintenance 2 05-04-2001 03:38 PM


All times are GMT -4. The time now is 04:38 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.