Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Yachts and Sail => Topic started by: howie55 on June 28, 2009, 11:23:37 PM

Title: schooners ballast
Post by: howie55 on June 28, 2009, 11:23:37 PM
 %)its now time whilst the fibre glass is fully curing on the hull of the schooner to look at making the lead ballast, a wooden plug was produced to fit the hull  ( see photo ), a sturdy wooden box giving ample room for a good thickness of plaster when the plug is inserted. I made my box from 1/2 ply
Secure the plug to the top of the box, fill the box with plaster mix, reverse the lid with the wooden plug and gentle press it into the plaster mix removing any spillage then secure the lid as tight as possible to ensure the plug is fully immersed, place the box where it will slowly dry.
when dry remove the lid ,remove the plug and let the plaster dry completely, you need to make two holes in the lid one to pour the lead in the other to let the air out
The bolts you can see in the lid produce the holes in the lead ballast.
Title: Re: schooners ballast
Post by: Steamer on June 30, 2009, 03:08:38 AM
Not to sound too "nannyish", but do make sure that plaster is DEAD dry before putting any molten lead in it.   You will get one nasty explosive suprise otherwise.

I would consider baking at 200 F for a while...not hot enough to burn the wood, but enough to make sure the plaster is good and dry.

Great job on the hull by the way....that should be a beauty when she's done.

Title: Re: schooners ballast
Post by: tigertiger on July 13, 2009, 05:55:10 PM
Good technique

I will try that in the future.
Title: Re: schooners ballast
Post by: JayDee on July 13, 2009, 08:28:44 PM

Tiger Tiger,

I have used this method to SAFELY make Lead ballast bulbs.
A rather large Soldering Iron is used to melt the edges of Lead Flashing which are clamped between two pieces of wood.
Very easy to do, the Lead melts almost as soon as the Iron touches it.
Extra Lead can easily be added if required.

For extra security, brass screws can be fitted through the sides of the ballast, into the middle sheets and the heads
covered over with the Lead.
More Brass screws hold the Keel into the ballast.
MUCH, MUCH safer than pouring molten Lead !!!!!!!!!!!.

John.  :-))  :-))  :-))
( (
Title: Re: schooners ballast
Post by: nemesis on July 13, 2009, 08:48:10 PM
Having used Dental & Surgical plaster all my working life I can only confirm what Steamer( aptly named)
said about making sure its bone DRY before use. When dry it rings when you tap it. If you force dry it
it has a tendency to crack. Why not use casting sand instead, its a lot safer & quicker too. It can take months for a block of plaster to give up its moisture content. hope its a help,
Title: Re: schooners ballast
Post by: tigertiger on July 14, 2009, 06:31:15 AM
They don't use lead flashing in China unfortunatley.

I am reduced to buying fishing weights, and scraps. So melting and moulding is my only option I am afraid.