Author Topic: fibreglass question  (Read 4849 times)

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portside II

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fibreglass question
« on: October 19, 2008, 15:19:31 »
Thought i would have another go at a new hull, a pusher tug and would like to make a plug .
Now when the fibreglass is curing does it shrink or expand ? as this would determin whether i make the plug an inner or outer .
Or maybe there is someone on here who can make me one about 36"x 12" for twin screw ,not tripple .
daz
My boats look like i want them to ,well nearly

Stavros

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Re: fibreglass question
« Reply #1 on: October 20, 2008, 10:08:31 »
Right then simple answer it does not shrink
As I have been building moul;ds also for a living I think I can safely answer this one.
Construct hull out of whatever you desire,fill and fair it till you are happy,paint it,yes I am correct,polish it prefferably with mould release wax,paint pva mould release agent over plug 100% coverage.Lay up 1st mould 4oz is sufficient.Polish it around 5 coats then apply release agent,gell coat the mould,lay up new hull which in effect will be the PROPER PLUG  Now fill fair this first hull till 100% of all the imperfections have been removed,When I mean all imperfections have gone that is what I mean.Go down through the grades of wet dry till you get to 1500grit,yes dammed boring work but well worth it.Right then you should have one excellent hull which in fact is your PLUG.This is what is called the Master plug.Polish it with at least 5 coats of mould wax,then as above mould release agent,Give the plug a coat of gell coat ley it dry and lay up a mould of around 6oz stengething as necc leave to cure for at least 48hrs.Now remove mould from plug,you should now have a soouper smooth mould if not, you have cut corners.Right then you will now need to get hold of some 2000grit wet dry to rub down the mould then polish up with a good quality rubbing compound to a high gloss finish.Then polish up wiht mould wax and away you go.Now this process might to some seem exccessive but do you really want a hull that looks professional I think you will,there is no short cuts to mopulkd work believe you me,had the tee shirt and woirn it many times.
That little process If I was doing it would probably if I had a rough plug would take me at least a month if not longer to get to the first out of the mould hull,and that is working roughly 8hr days.Now is it worth it for a one off personal opinion NO,rough costing just on matterial to get a proper mould around 150-200 Maybee it would be better adapting a ready made hull.Put you off NO good lets see a thread on it then




Stavros
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portside II

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Re: fibreglass question
« Reply #2 on: October 20, 2008, 15:38:47 »
You realy are starting to scare me   :) Dave but i can see where your from and your advice is invaluable .I honistly did not think that there would be so much work involved but you have given me some great ideas . Just a few q's , you say lay up a mould of 6oz , how do i work out what 6oz is or is this the weight/type of cloth as i would have used tissue and matting and probably given myself too much work . as for adapting a ready made hull ,without breaching any copy-write when the hull has been polished waxed  and the gell coat put on is it normal to leave the plug for that length of time before applying the cloth/matting tissue,
oh and the other thing ,what about heating ,how much will it affect the resin / curing time .
daz
My boats look like i want them to ,well nearly

Stavros

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Re: fibreglass question
« Reply #3 on: October 21, 2008, 08:42:41 »
Matting is available in different weights 6oz is 3x2oz matting
I think you have missread what I said leave in mould for 24hrs,lay up as soon as gelcoat dried approx 2hrs at 20C
Heating will of course affect the curing time allarmingly,what I would suggest if you have not done this type of work before is to do it in a cold garage then introduce some heat but no more than 20c

Good place for supplies and probably the cheapest       http://www.glasplies.co.uk/


As this dammed metric poo poo is here a 2oz nmatt is roughly equivellent to 450gm



Stavros
« Last Edit: October 21, 2008, 09:42:42 by Stavros »
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tango

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Re: fibreglass question
« Reply #4 on: October 21, 2008, 09:38:55 »
Stav is right (you beat me to the answer mate).......Unfortunately there are no short cuts in mould making it's all in the preparation, poor plug = poor mould = poor hull. If you decide to carry on and make a mould just take your time and follow Stavs instructions you won't go far wrong.

Good luck, Mark.
I HAVE NOT FAILED, I HAVE JUST FOUND A 1000 WAYS THAT DON'T WORK.

portside II

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Re: fibreglass question
« Reply #5 on: October 21, 2008, 15:48:34 »
Sounds good to me , if i do decide to make a plug then i will have to do it over the winter and as i only have a portable gas heater in the shed then i will have to work in low temperatures , better find that bucket of elbow grease  :) .
As for supplies glasplies are realy good but its a pain having to pay for the courrier as its regarded as hazardus , i have found a good supplier in hull where i can collect and their prices are realy good , and as we go to hull once a week then its easy just to call in .
daz
My boats look like i want them to ,well nearly

Model Tug Man

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Re: fibreglass question
« Reply #6 on: October 22, 2008, 04:00:14 »
If you find the hull building task daunting, as I did, you can contact Karl at Microglass for reasonably priced custom work. He made a 1/32nd Foundation Franklin hull for me. Search under Microglass on the web.

TM
VGJQ

Franklin

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Re: fibreglass question
« Reply #7 on: October 23, 2008, 13:36:55 »
If you find the hull building task daunting, as I did, you can contact Karl at Microglass for reasonably priced custom work. He made a 1/32nd Foundation Franklin hull for me. Search under Microglass on the web.

TM

TM, Looking forward to following your progress as you build the Franklin.

Welcome to the Forum.


Lee  :)
« Last Edit: October 23, 2008, 16:11:24 by Franklin »

Franklin

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Re: fibreglass question
« Reply #8 on: October 28, 2008, 15:10:58 »
Welcome to the forum T.M


Lee  :)
« Last Edit: October 28, 2008, 15:12:53 by Franklin »

tango

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Re: fibreglass question
« Reply #9 on: October 28, 2008, 15:12:24 »
Topic now split Frisky/ Franklin thread moved here http://modeltugforum.com/index.php?topic=1029.0

Mark.
« Last Edit: October 28, 2008, 15:13:59 by tango »
I HAVE NOT FAILED, I HAVE JUST FOUND A 1000 WAYS THAT DON'T WORK.