Making fibreglass nose cones

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PJR
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Making fibreglass nose cones

Postby PJR » Tue Dec 04, 2012 11:09 am

I am making a new nose cone mould for my LPR. Its a 65mm X 260mm 4:1 ratio nose cone. I have a lathe so I turned this up out of Delrin wood. But if you have an old nose cone you can use that or make one out of segments of wood or foam and sand/file it up.

I use Masonite hardboard for the mould, but you can use Melamine shelving board as well as long as the board is flat and smooth.

I will spend the rest of the day waxing the nose cone 6 times, I have to leave it an hour between coats. Before i can set it in the mould.(I didn't know how to write this below the pictures once they are down loaded?)
Attachments
DSC_0323.JPG
Cut a hole in the board the size of your nose cone and then tapper the edges out so that you can fill the gap with car body filler or plasticine. I do like the car body filler better because when you are waxing the mould 6 times before putting the glass on the plasticine gets pushed into the mould and you end up with a step in your mould.
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Glue some scrap timber under your mould to keep the nose cone off your bench and so that you can glue some cross members in between the timbers to hold the nose cone at the correct height

PJR
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Re: Making fibreglass nose cones

Postby PJR » Thu Dec 06, 2012 12:28 pm

Nose cone fitted. I filled the area around the board and nose cone with car body filler and a small amount of plasticine on top to smooth it out. The back board on the nose cone is not needed but it adds strength to the mould and stops resin flowing down the back of the nose cone
Attachments
nose cone mould 1.JPG

krusty
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Re: Making fibreglass nose cones

Postby krusty » Thu Dec 06, 2012 12:36 pm

Looking easy enough so far :)

What sort of wax are you using?

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Re: Making fibreglass nose cones

Postby PJR » Thu Dec 06, 2012 12:57 pm

krusty I am using TR regular mould release wax. It is a standard wax from any ship chandler,boat repair/supplier, and I always put PVA release agent over the top of that.

Phil

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Re: Making fibreglass nose cones

Postby PJR » Fri Dec 07, 2012 12:00 pm

again put 6 coats of wax onto the mould. The first time i waxed the nose cone was so that the car body filler wouldn't stick to it.

Then I brushed some PVA release agent over that as well, It just add insurance that the mould will separate. In the close up photo its hard to see but the PVA dosen't take to the wax will.

Then brush on a thick layer of gellcoat on the mould first and allow to almost set before the fibre glass go's on. I used natural gelcoat and add so royal blue die to the gelcoat. it dosen't matter what colour but it help when you lay up a nose come you can see that the matt is all wetted out. The gellcoat gives the mould a harder finish than just with glass. But again as you can see in the photo of the mould on the right it has just got a glass finish. The 1 litre tin cost $32.00 and one side I used 100ml of the gellcoat
Attachments
mould with PVA.JPG
Mould with gellcoat.JPG
Mould with gellcoat.JPG (104.75 KiB) Viewed 3902 times

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Re: Making fibreglass nose cones

Postby krusty » Fri Dec 07, 2012 12:33 pm

Does the PVA leave marks in the finished mould? It appears to be more lumpy than a film?

Or am I jumping too far ahead ;)

Oh! And another question - I know that you can buy PVA mould release, I was looking at my local fiberglass supplier online yesterday, but is it the same as the PVA glue, just really watered down??

Krusty

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Re: Making fibreglass nose cones

Postby PJR » Fri Dec 07, 2012 1:01 pm

Krusty I haven't had any problems with the marks left in the mould from the PVA. With a slight sanding for painting any mark in the finished product are gone. You don't have to use the PVA if you don't want to. The wax is the most inportant part of the process.
I am not shore if the PVA is watered down. I have a 1 litre bottle that i have had for ever so i haven't looked at any thing else.

If you want to do it cheaper leave the PVA and gellcoat out. I put gellcoat in the mould as I will be using this mould a lot as most of my LPR and MPR are 65mm in diameter which this mould is for.

Phil

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Re: Making fibreglass nose cones

Postby krusty » Fri Dec 07, 2012 1:10 pm

PJR wrote:Krusty I haven't had any problems with the marks left in the mould from the PVA. With a slight sanding for painting any mark in the finished product are gone. You don't have to use the PVA if you don't want to. The wax is the most inportant part of the process.
I am not shore if the PVA is watered down. I have a 1 litre bottle that i have had for ever so i haven't looked at any thing else.

I'm just trying to wrap my head around the products and the impact they have on the final outcome. You said that you brush on the PVA - is it thin enough to spray on? (via a spray bottle)

PJR wrote:If you want to do it cheaper leave the PVA and gellcoat out. I put gellcoat in the mould as I will be using this mould a lot as most of my LPR and MPR are 65mm in diameter which this mould is for.

Phil

It makes sense to do it right over doing it cheap :)

Krusty

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Re: Making fibreglass nose cones

Postby PJR » Fri Dec 07, 2012 2:37 pm

krusty you did catch me out. I like to spray it on, the thin coats are better they don't curdle as much. I was spraying in the shade and thought the setting on the gun was ok but when I was finished it was very lumpy so I bushed it out :oops:

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Re: Making fibreglass nose cones

Postby PJR » Fri Dec 07, 2012 4:10 pm

I placed 6 layer of glass on top of the gellcoat. I run a small bead of epoxy and micoballons around the nose cone as the glass matt forms a small radius and leaves a air pocket between the mould and glass. The micoballon mix fills this void. I didn't get any photo of this side as the wife was out and i make a mess and didn't want to touch my camera. I will get photos of the other side

Phil
Attachments
Mould glassed 1 side.JPG
Mould glassed 1 side.JPG (96.27 KiB) Viewed 3879 times

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Re: Making fibreglass nose cones

Postby PJR » Sat Dec 08, 2012 3:43 pm

Time to remove the top half of the mould.

Remove the back board first. Don't use metal scraper as you will scratch the finish of the mould. I use paddle pop sticks that I have sharpened with sand paper.

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work your way around the base board the same way but add a small amount of pressure to the nose cone as you want the nose cone to come out with the fibre glass section
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most of the PVA release agent will just peal off. But what dosen't just wash it off with water

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Tomorrow we have a launch day I hope. The weather dosen't look good for Doonside. I will get back into the mould on Monday

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Re: Making fibreglass nose cones

Postby PJR » Tue Dec 11, 2012 11:10 am

I washed the mould with water using a dish washing cloth and a toothbrush to remove the PVA glue.I cut another piece of masonite board to place at the back of the the mould to form the shoulder on the other side of the mould. I held it in place with 2 G clamps

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DSC_0347.JPG (90.29 KiB) Viewed 3795 times



When i clamped the board to the mould there was a gap between the board and the mould and a slightly bigger one between the nose cone and board. I placed plasticine between the board and the mould and used a plastic scraper i made from scrap material to get rid of the excess plasticine

DSC_0348.JPG


I will put 6 coats of wax on this side and finish the mould off tomorrow

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Re: Making fibreglass nose cones

Postby krusty » Tue Dec 11, 2012 11:19 am

That's looking really good!

Is there a particular size of mesh on the glass you're using? Or does it not matter since you've used the gell coat?

Krusty

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Re: Making fibreglass nose cones

Postby PJR » Tue Dec 11, 2012 12:05 pm

krusty it really dosen't matter what mat you use. I used to use chop strand when i was using polyester resin. On this mould I used a coulpe layer of 4 oz then 6oz and on top some really thick stuff that I had left over from a boat repair I did 5 to 10 years ago which is really had to wet out, you just have to be carefull that you get the matt to sit against the mould where the nose cone is sitting because the matt dosen't like sharp corner and it will leave a air gap at the point which is a weak point around it. That is why a run a small amount of resin and micoballoons around the nose cone to fill this area. You just have to be carefull that you don't then push it out when you are trying to wet the glass out. The best way is to put 1 or 2 layers on and let nearly set then lay the rest of the glass that way you want pust the micoballoons mix out, But if you are carefull it will come out fine. I will take photos tomorrow when i am finishing the mould off

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Re: Making fibreglass nose cones

Postby PJR » Wed Dec 12, 2012 10:07 am

This morning I sprayed 3 mist coats of PVA release agent onto the mould which came out a lot smoother them the other side and let set for 2 hours. I cut all the fibre glass ready for later. I was a bit rough on the mould and marked the PVA slightly in some spots, I should of cut the glass before I put the PVA on but it will be ok. Then painted a thick coat of gellcoat onto the mould 100ml again. I will let that set for 2 hours which will then be just tacky and I can start to glass it up. My wife got some work this morning so I will set the camera up on the tripod and try to get some photos of the glassing process


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