Post by atouchofglass on Apr 24, 2009 7:22:48 GMT 10
Hey Guys
In response to a question on V V a series of posts explaining how to make a mold and use it was posted
Thought they may be useful here
Post 1
Let me say from the beginning I'm no expert....
Possibly not even a talented amateur ;D ;D ;D
But here goes anyway
I've modified this thread progressively so if it doesn't flow as it did before.... sorry
The extra info was needed to get a better result ;D
You will need
A metre each of fibreglass matt.... 225gm and 450gm
100ml of a medium speed catalyst
squeeze measurement bottle for the catalyst
A couple of litres of resin
Mold release
A couple of litres of Acetone for clean up
a few 25mml cheap paint brushes (natural hair)
The container on the far right at the back is used to hold acetone to washout brushes and rollers
The container at the front is used to mix resin and catalyst
All of this will be available at your fibreglass supplier
The Plug
First of all fix up the originals by bogging or glassing or whatever means you have
They have to look (be the shape) as you want before taking the mold.
This is the "Plug"
If you make the plug as smooth and shiney as possible the mold will copy this.
Of course any defects will also be copied... so spend some time getting the plug to your satisfaction
Once that is done coat the plug with several layers/coats of mould release.
This is available at your local fibreglass supplier
The plug is now ready to use
Fibreglass/resin and catalyst
You will now need some fibreglass, resin and catalyst
The resin comes in a couple of types.... I'm not up with all the tech stuff so just ask for a resin to suit what you are doing
buy a couple of litres Polyester is the cheapest and a good all round resin
A catalyst that is not too fast
There are several speeds of catalyst available
About a 100ml should be plenty
We use M.E.K.P NP20 in Winter - it is a fast resin added at one percent
Summer we use a slower catalyst 100 - Better during the hot months
Always weigh your resin to know how much catalyst to add
The fibreglass chopped strand matt comes in many thicknesses
Buy a metres of thin and of thick ......
Again not up on the technical data bit
As I remember it.... 225gm/mtre and 450gm/mtre should do you well
That should be plenty of fibreglass to practice with
Making The Mold
If you haven't already waxed the plug
Wax the plug at least 3 times leaving 1/2 hour or more between waxes
This is done so the two will part cleanly when you want them parted
There is a product called "tooling gel"
Comes in black and red only it is harder than gelcoat
If you intend making lots of this product it is worth investing in it
If not.... ordinary gelcoat is good enough
Make the gelcoat a different colour to the product you intend making
Basically any colour except white ;D ;D ;D
Mix up the gelcoat with catalyst at 1%
Brush it onto the plug and allow it to tack off or go off
Same day put a layer of either tissue or 225 glass on to tie the gelcoat together
Put some of the resin in a plastic container of some sort
I use old clean cordial bottles or 2 ltre milk bottles with one side cut out
The instructions on how much catalyst to use will say 1%
This is not easy to work out unless you weigh it
I use a set of cheap plastic kitchen scales
You can safely use more, remembering that the more you use the faster it goes off
up to 3%
After that it could cause the resin to go off too fast and if you add way too much ...... you just may have a fire on your hands
The slower it goes off the less distortion in the mould and it gives you plenty of time to work with it
If it is a large mould .... stick to 1%
Using a stick stir the catalyst and resin..... they resin will start to change colour
Using a paint brush apply the resin to the gelcoat
Then use a piece or pieces of tissue or 225gm fibreglass to cover the gelcoated plug completely and leave a small amount over the edges
With more resin on the brush make sure the fibreglass is well soaked
The fibreglass matt will change from the white to clear/resin colour in a few minutes
Then a piece of 450 as a way of thickening the mould
As you get use to working the fibreglass you will see that not a lot of resin is needed... it binds the glass... the glass gives the strength
When you see the resin in the container start to gel... stop using it
Be careful not to mistake the glass that gets into the resin as geling
Place some acetone in an open container to clean up your hands and brush
USE GLOVES AS OFTEN AS POSSIBLE
It is less messy and you can just chuck them out after using them
Saves time and isn't that expensive
If you cover the container the acetone will last longer
Next post will discuss more of what to do
Cheers
Atog
In response to a question on V V a series of posts explaining how to make a mold and use it was posted
Thought they may be useful here
Post 1
Let me say from the beginning I'm no expert....
Possibly not even a talented amateur ;D ;D ;D
But here goes anyway
I've modified this thread progressively so if it doesn't flow as it did before.... sorry
The extra info was needed to get a better result ;D
You will need
A metre each of fibreglass matt.... 225gm and 450gm
100ml of a medium speed catalyst
squeeze measurement bottle for the catalyst
A couple of litres of resin
Mold release
A couple of litres of Acetone for clean up
a few 25mml cheap paint brushes (natural hair)
The container on the far right at the back is used to hold acetone to washout brushes and rollers
The container at the front is used to mix resin and catalyst
All of this will be available at your fibreglass supplier
The Plug
First of all fix up the originals by bogging or glassing or whatever means you have
They have to look (be the shape) as you want before taking the mold.
This is the "Plug"
If you make the plug as smooth and shiney as possible the mold will copy this.
Of course any defects will also be copied... so spend some time getting the plug to your satisfaction
Once that is done coat the plug with several layers/coats of mould release.
This is available at your local fibreglass supplier
The plug is now ready to use
Fibreglass/resin and catalyst
You will now need some fibreglass, resin and catalyst
The resin comes in a couple of types.... I'm not up with all the tech stuff so just ask for a resin to suit what you are doing
buy a couple of litres Polyester is the cheapest and a good all round resin
A catalyst that is not too fast
There are several speeds of catalyst available
About a 100ml should be plenty
We use M.E.K.P NP20 in Winter - it is a fast resin added at one percent
Summer we use a slower catalyst 100 - Better during the hot months
Always weigh your resin to know how much catalyst to add
The fibreglass chopped strand matt comes in many thicknesses
Buy a metres of thin and of thick ......
Again not up on the technical data bit
As I remember it.... 225gm/mtre and 450gm/mtre should do you well
That should be plenty of fibreglass to practice with
Making The Mold
If you haven't already waxed the plug
Wax the plug at least 3 times leaving 1/2 hour or more between waxes
This is done so the two will part cleanly when you want them parted
There is a product called "tooling gel"
Comes in black and red only it is harder than gelcoat
If you intend making lots of this product it is worth investing in it
If not.... ordinary gelcoat is good enough
Make the gelcoat a different colour to the product you intend making
Basically any colour except white ;D ;D ;D
Mix up the gelcoat with catalyst at 1%
Brush it onto the plug and allow it to tack off or go off
Same day put a layer of either tissue or 225 glass on to tie the gelcoat together
Put some of the resin in a plastic container of some sort
I use old clean cordial bottles or 2 ltre milk bottles with one side cut out
The instructions on how much catalyst to use will say 1%
This is not easy to work out unless you weigh it
I use a set of cheap plastic kitchen scales
You can safely use more, remembering that the more you use the faster it goes off
up to 3%
After that it could cause the resin to go off too fast and if you add way too much ...... you just may have a fire on your hands
The slower it goes off the less distortion in the mould and it gives you plenty of time to work with it
If it is a large mould .... stick to 1%
Using a stick stir the catalyst and resin..... they resin will start to change colour
Using a paint brush apply the resin to the gelcoat
Then use a piece or pieces of tissue or 225gm fibreglass to cover the gelcoated plug completely and leave a small amount over the edges
With more resin on the brush make sure the fibreglass is well soaked
The fibreglass matt will change from the white to clear/resin colour in a few minutes
Then a piece of 450 as a way of thickening the mould
As you get use to working the fibreglass you will see that not a lot of resin is needed... it binds the glass... the glass gives the strength
When you see the resin in the container start to gel... stop using it
Be careful not to mistake the glass that gets into the resin as geling
Place some acetone in an open container to clean up your hands and brush
USE GLOVES AS OFTEN AS POSSIBLE
It is less messy and you can just chuck them out after using them
Saves time and isn't that expensive
If you cover the container the acetone will last longer
Next post will discuss more of what to do
Cheers
Atog