Repair & maintenance: Making a spare bit

Making a spare bit

Printed From: Yachts and Yachting Online
Category: General
Forum Name: Repair & maintenance
Forum Discription: Questions & tips on the subject
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=4561
Printed Date: 14 May 25 at 12:51pm
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Topic: Making a spare bit

Posted By: dics
Subject: Making a spare bit
Date Posted: 22 Aug 08 at 11:02am

On the older RS300 there is a mast chock. Although this is boat specific LDC in their usual manner do not supply this part any more so if you lose it you have to fork out £200 to have to new mast pot put in to keep your boat legal. Anyway, before I rant on about the difference between a hedgehog and the LDC factory I want to make one myself before I lose it.

So I have my old chock which is a little worn but in OK condition. It is obviously of a wedge shape in nature and there is a lip on the top that sits over the mast pot with two handy little holes in which are great for tying it to the boat. So how can I make another is my question?

Knowing nothing about the way that carbon works, I thought I might be able to wrap some carbon weave around this chock to get the shape and then "set" the carbon. Then take the chock out and fill the new hollow cardon chock with some epoxy and fibres. Then hey presto I have my new chock. Is this possible?

Also if I wanted to keep the hollow carbon chock as a template for making more than one, can I use something so that the epoxy filling can be extracted when set and used as the new chock leaving the carbon in tack for another chock to be made?

Or is there a better and easier way of solving this problem (other than selling the 300 and buying a MPS)?

Thanks

Replies:

Posted By: JimC
Date Posted: 22 Aug 08 at 11:57am

Ouch. One of my mates has indeed just lost that chock. Currently there's a bit of foam packing in there!

Yes, you could make a mould if the shape is suitable: there are various options. I think if you just wrap carbon round the current one you'll find, because epoxy laminates shrink slightly on curing, that you'll never get it off. You'll need a different technique. Its also awkward if there's sufficient wear on the current one to present a problem.

I've not played at taking moulds straight off components - I think some sort of rubber compound is normally used which gives you a bit of flex so that you can remove it easily. I did once have a job making the rubber compound though!

Materials wise I'd want to take a look at it, but probably I'd just use epoxy filled with microfibres, microballoons and some graphite to give a lower friction lightish, strongish lump. Proper fibres in there might well be unnecessary and certainly add hassle.

Where are you based: if you're round Surrey maybe we could do a deal where I borrow your chock as a pattern and make two, one a spare for you, one for my friend.

Posted By: dics
Date Posted: 22 Aug 08 at 12:24pm

Are that must be Peter who has been unfortunate. It was been my intention to get a spare for a while and Peter's situation highlights the need. As I will be using my boat shortly for a while i was thinking of ways of making a copies at home and certainly it was my intention to pass one to Peter.

May be it would be possible to sort something out over the winter months and get something knocked up if I have no success. Thanks for the advice about the "carbon wrap". I'll start searching to see if I can find some rubber moulding processes that I can use.

Regarding the foam - LDC suggested using a peice of nylon chopping board. The trouble is with this is I'm pretty sure the chock is tapered to give the correct mast rake, so LDC's fix would still leave me with an out of class boat! Not that 300 mast rake has bothered them before!

Posted By: tmoore
Date Posted: 22 Aug 08 at 2:15pm

there is a thread about this on the rs300 yahoo group, may be the same person(?)

RE class rules, aslong as you have something that does the same job as the chock nobody will care what material etc it is made from. we will just be glad to have you back on the water racing....

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Landlocked in Africa
RS300 - 410
Firefly F517 - Nutshell
Micro Magic RC yacht - Eclipse