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Removing nylon plug from carbon fibre tube

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John Baron22/05/2020 16:53:09
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471 forum posts
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Hi Guys,

Two things occur to me, assuming that you cannot get the plug to come out at all.

You have already drilled and threaded an M12 hole and said that the tenon is out of place ! It would be entirely feasible to make a screwed in piece to replace the tenon completely and use a thin washer to allow for alignment.

Or

You could remove as much of the old plug as possible by filling in the threaded hole that you have made, then using a hole cutter remove the bulk of the plug which should allow the remains to be extracted. It may be wise to tightly wrap the carbon fibre tube with something so that it cannot expand or crack whilst prising out the, what now should be a fairly thin wall of material.

A further thought is could the CF tube crack when putting in the new plug ?

Just my 2p worth.

 

Edited By John Baron on 22/05/2020 16:55:48

Ed Duffner22/05/2020 17:08:20
827 forum posts
94 photos

I would use a hole saw to core out the plug, then gently cut out the remaining ring with a pad-saw. Is it possible the plug could be pinned, preventing its removal?

Ed.

Edit: Just noticed I suggested the same as a previous poster (overlapped posting).

Edited By Ed Duffner on 22/05/2020 17:28:40

Sam Spoons22/05/2020 17:23:07
93 forum posts

No peg, there is a single retaining screw who's purpose is to prevent rotation (no chance.......) as the plug is under compression in use.

Rod Renshaw22/05/2020 17:46:32
286 forum posts
2 photos

Hi Sam

I noticed that the plug is thought to be stuck because it has absorbed water and swelled. Might very gentle heat over an extended period, perhaps several days, or even more, dry out the nylon, so that it shrinks, and thus loosens it? Perhaps use in conjunction with other methods of pulling it out. I am fairly sure this would help if the plug was wood but I have no experience of nylon.

Rod

Edited By Rod Renshaw on 22/05/2020 17:48:21

Edited By Rod Renshaw on 22/05/2020 17:49:06

Sam Spoons22/05/2020 17:48:34
93 forum posts

Posted by Ed Duffner on 22/05/2020 17:08:20:

Edit: Just noticed I suggested the same as a previous poster (overlapped posting).

Edited By Ed Duffner on 22/05/2020 17:28:40

Great minds yes

Sam Spoons22/05/2020 17:50:40
93 forum posts

Thanks John, The CF tube used in this application is pretty robust, roll wrapped pre-preg with walls in excess of 4mm thick so not prone to splitting.

Sam Spoons22/05/2020 17:55:47
93 forum posts
Posted by Rod Renshaw on 22/05/2020 17:46:32:

Hi Sam

I noticed that the plug is thought to be stuck because it has absorbed water and swelled. Might very gentle heat over an extended period, perhaps several days, or even more, dry out the nylon, so that it shrinks, and thus loosens it? Perhaps use in conjunction with other methods of pulling it out. I am fairly sure this would help if the plug was wood but I have no experience of nylon.

Rod

Yeah, not sure about that, just seems the most likely scenario as it is extremely well stuck and nylon is known for absorbing moisture and swelling slightly. Difficult to apply a useful amount of heat for a long enough period (several days I'd guess as the mast is over 6 metres long and impossible to get indoors (at least without accelerating the divorce proceedings beyond what I'm prepared to risk.....)

Thanks for all the ideas, keep them coming yes

John Baron22/05/2020 17:55:53
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471 forum posts
186 photos

Hi Sam,

When you mentioned how light the mast was, I thought that it was going to be thin, thinner than 4 mm anyway.

I would try my first suggestion since you now have a threaded hole there.

old mart22/05/2020 17:59:10
3185 forum posts
201 photos

An even simpler way would be to shorten the mast by 40mm, just cut it off. devil

Sam Spoons22/05/2020 18:32:39
93 forum posts

Yeah that would be easy..... But it's a strict one design so shortening the mast, even by a few mm is not allowed (strictly speaking even using a custom made plug is not legal as all parts must be sourced from the official supplier but I reckon I'll get away with that one).

The ally mast is 7.8 kg including rigging and fittings, probably about 5.7 for the bare tube. The carbon mast, with rigging and fittings is 5.3 so probably about 3.2kg for the bare tube, that suggests a wall thickness of around 2.5mm so I guess I'm wrong (just going off what I have been told) I cannot easily measure it without removing the damned plug......blush

Edited By Sam Spoons on 22/05/2020 18:33:32

Rod Renshaw22/05/2020 18:53:36
286 forum posts
2 photos

Sam

Gentle heat ideas?

Leave out in the sun during the day, pack around with pre dried silica gel at night?

Or, pierce a hole for the end of the mast in a tin can. Add another hole for an incandescent lamp holder and leave the lamp on 24 / 7.

Or, wind the end of the mast in gardeners' soil warming cable, (borrow from a keen gardner who will not need it now it's nearly summer.)

Or, see if anyone you know still has an old electric blanket in the loft.

Others might have other ideas!

Or, cut off the last 40 mm, as suggested above, and make a new plug, with 2 diameters, and which is 40mm longer than the old one to make up the lost lenght .

Regards

Rod

Sam Spoons22/05/2020 19:16:17
93 forum posts

Might wrap in in several layers of black bin bag and leave it 'till tomorrow evening then give it another go (I can move it so it gets the sun in the morning and back again after lunch). I like the idea of a longer plug but if I have to destroy it to remove it I may as well not alter the mast as well.

Trevorh22/05/2020 19:50:27
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303 forum posts
87 photos

Sam A simple but expensive option - Buy an Ent and come back from the dark side...

Hope you get it out without any damage to the mast Mate

cheers for now

Trevor

old mart22/05/2020 20:40:19
3185 forum posts
201 photos

I'm surprised that the rules are so strict that a shorter mast would be banned, I can see how a longer one might be frowned upon as it might add some speed. Drilling a number of holes lengthwise near the edge would tend to loosen the grip a little. Careful cutting of the bottom of the nylon would expose the end of the carbon fibre to find out exactly how thick it is.

Sam Spoons22/05/2020 21:20:03
93 forum posts
Posted by old mart on 22/05/2020 20:40:19:

I'm surprised that the rules are so strict that a shorter mast would be banned, I can see how a longer one might be frowned upon as it might add some speed. Drilling a number of holes lengthwise near the edge would tend to loosen the grip a little. Careful cutting of the bottom of the nylon would expose the end of the carbon fibre to find out exactly how thick it is.

It's a SMOD (Single Manufacturer One Design)* the idea is that anything that is not supplied by the manufacturer is not allowed, simply so that everybody has exactly the same kit. The Laser is probably the strictest SMOD, the Blaze (my boat) is pretty flexible in comparison. If you want a long diatribe/discussion on the merits and otherwise of SMODs please ask..... Hmm, thought not wink You are right, a shorter mast may be slightly less efficient and a longer one more.

Drilling near the edge to introduce some flexibility is the plan if I do decide to destroy it so if nowt else works that will be the next step.

Trevorh, I need a singlehander mostly so that's not an option though I will probably end up with another Ent before I retire (I'm 67 so not quite finished with sailboat racing yet but can only go on so long). I would love a Rondar Mk3 (I've done wooden boats, not going back there...) But I have this as well as the Blaze so my two hander needs are covered for now.

Edited By Sam Spoons on 22/05/2020 21:20:36

not done it yet22/05/2020 22:10:18
6078 forum posts
20 photos
Posted by Rod Renshaw on 22/05/2020 18:53:36:

Sam

Gentle heat ideas?

Leave out in the sun during the day, pack around with pre dried silica gel at night?

Or, pierce a hole for the end of the mast in a tin can. Add another hole for an incandescent lamp holder and leave the lamp on 24 / 7.

Or, wind the end of the mast in gardeners' soil warming cable, (borrow from a keen gardner who will not need it now it's nearly summer.)

Or, see if anyone you know still has an old electric blanket in the loft.

Others might have other ideas!

Or, cut off the last 40 mm, as suggested above, and make a new plug, with 2 diameters, and which is 40mm longer than the old one to make up the lost lenght .

Regards

Rod

In addition to my previous post, I’ve located some actual figures for ‘wet’ and ‘dry’ nylon. Looks like it can/might expand by as much as 2 1/2% and needs about 80 degrees Celsius drive off the moisture. Here

Enclosed, in a lump, may need quite some time to dry it out. I declined from making any heating suggestion as the insulation (presumably required) will affect the internal temperature considerably.

Edited By not done it yet on 22/05/2020 22:14:10

Sam Spoons22/05/2020 23:13:27
93 forum posts

Yes, on that basis I think I'll admit defeat and get the drill out. The effort to get the existing heel plug out undamaged compared to the cost/effort involved in fabricating to buying a replacement seems disproportionate.

Just to refer back to John Barron's concerns about the wall thickness and risk of splitting/damage. The mast is actually in three pieces (I knew this, can't think why I didn't occur to me when I answered your post John), two main sections, the upper being tapered (and possibly thinner walls at the top) and the lower being parallel and, presumably, equal wall thickness. The bottom few inches may be a repair where the base was damaged and a new section sleeved in* so all bets are off WRT it's inside diameter. Without being able to find out who the actual manufacturer of the mast tube was It's impossible to get any reliable info on older boats apart form the hulls. Add to that the 'builder/design rights holder**' has changed at least twice during the life of the class and it's fairly easy to get info on the hull (usually built in house by the 'manufacturer or, at least, farmed out to a specific builder) but finding info on the other bits is hard if the boat predates the current builder's tenure.

* Repairs are allowed to original components and carbon fibre masts are usually easily repairable, one of the selling points compared to aluminium masts which re pretty much impossible to repair successfully.

** The 'builder' is the guy who holds a licence to build and sell the boats, the design rights holder may be the same person or may be the guy who owns the IP related to the design and licences the 'builder' to build and sell the boats, but the 'builder' may not be the guy who actually 'manufacturers' the boats, he can subcontract that to another.... err, builder.... or.... errr.... manufacturer..... I give up......***

*** If you're still reading, google Laser Performance Europe vs Bruce Kirkby and 'International Laser Class Association' vs Laser Performance Europe. It's a long haul but you couldn't make it up.....

Edited By Sam Spoons on 22/05/2020 23:15:46

John Baron31/05/2020 17:56:29
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471 forum posts
186 photos

Hi Sam,

Did you get the plug out ?

Sam Spoons31/05/2020 18:21:15
93 forum posts

Hi John, No, It's not coming out intact and I haven't destroyed it until I have a new one made or sourced as it will still work. I'm waiting for a lump of 50mm Derlin round bar to fabricate a replacement before drilling it out.

Meanwhile I'm slowly removing the UV protective coating (probably two pack varnish given the difficulty I'm having sanding it off) as it's delaminating in places, but annoyingly stuck like a very sticky thing on most of the mast. Having spent the thick end of £200 on paint and consumables to refinish it I want to do a proper job So I won't have to do it again for a fair few years.

John Baron31/05/2020 19:26:48
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471 forum posts
186 photos

Hi Sam,

Thank you for your reply.

I did wonder. Unfortunately I don't have any large diameter Deralin bar or I would have offered you some. Sanding varnish off something is a right royal pain, particularly when you can't get a sander on it. Anyway I'm interested in how you get on.

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