How do you make fiberglass parts?
05-23-2005, 01:58 PM
#2
RE: How do you make fiberglass parts?
I use the "lost foam" method.
Carve/sand a block of pink or blue foam to the shape and size you need.
Cover the foam with a low temp film (Econokote, Towerkote) to insure the foam will not melt from the resin. (Some resins WILL eat/melt the foam)
I then either apply PVC mold release or put on a minimum of 10 coats of wax. (provided you want to save [or try to save] the plugs).
Cut your fiberglass cloth into strips about 2" wide and about 6" - 8" long. The weight of the fiberglass will depend on what you are using it for and the size of the part. For a 40 size cowl I normally use either 2 layers of 2 oz cloth or 1 layer of 4oz cloth with a layer of 2 oz over it. Again, this will depend on the overall size and shape.
LIGHTLY spray several strips with 3M #77 and apply them to the plug. You should have at least 1/2" of overlap on the edges/seams. Do this to all the strips before you apply them so they will adhere. You will want a minimum of 2 layers, again, depending on the size/shape of the part. I have found that 2 layers works well for 40 - 60 size cowls. It provides the rigidity and strength I want/need without being overly heavy.
I use laminating resin for mine. Mix up about 2 oz of resin (again, depending on the size of the part) for a 40 - 60 size cowl. You want to mix it so you have a 30 - 40 minute WORKING TIME. Now dilute this 10% BY VOLUME with acetone.
I use plumber's flux brushes to apply the resin. Apply the resin and be sure the cloth is COMPLETELY saturated. (if you see white spots, that area is not saturated) Once the cloth is saturated, CAREFULLY squeegee off any excess resin with a playing card (if you do not take the excess of now, you will be sanding it off later) . Let this dry for about 48 hours. NEATNESS COUNTS IN THIS STEP.
Once it is dry, you can look the part over and decide if you need to add another coat of resin to fill the weave or not. If you need to fill the weave, do it now with the resin. Do not dilute this batch.
When dry, sand the part as needed. I use spot putty to fill any low spots (comes in a tube in the automotive section and is red in color ).
When the part is sanded and filled, be sure you have nothing hanging over the back of the plug.
If you are going to try to reuse the plug, take the part and immerse it in water for about 30 - 45 minutes while GENTLY flexing the fiberglass part to allow the water to get between the fiberglass and the plug. The water will allow you to "pop" the part off the plug.
If you are not interested in saving the plug OR the part will not pop off (the RC Gods like to play jokes on us mortals
), take the part outside and make an X in the back of the covering. In the X pour a little gasoline (2 - 3 oz is plenty for a 40 - 60 size cowl ). Come back in 20 minutes and clean out the sludge and dispose of properly.
Thoroughly wash the part inside and out with soap and water. The part will be very soft and flexible. After the part is washed, do any final reshaping with your fingers and set the part aside. It will need about 72 hours to harden up.
It sounds hard, but it really isn't - just messy.
Carve/sand a block of pink or blue foam to the shape and size you need.
Cover the foam with a low temp film (Econokote, Towerkote) to insure the foam will not melt from the resin. (Some resins WILL eat/melt the foam)
I then either apply PVC mold release or put on a minimum of 10 coats of wax. (provided you want to save [or try to save] the plugs).
Cut your fiberglass cloth into strips about 2" wide and about 6" - 8" long. The weight of the fiberglass will depend on what you are using it for and the size of the part. For a 40 size cowl I normally use either 2 layers of 2 oz cloth or 1 layer of 4oz cloth with a layer of 2 oz over it. Again, this will depend on the overall size and shape.
LIGHTLY spray several strips with 3M #77 and apply them to the plug. You should have at least 1/2" of overlap on the edges/seams. Do this to all the strips before you apply them so they will adhere. You will want a minimum of 2 layers, again, depending on the size/shape of the part. I have found that 2 layers works well for 40 - 60 size cowls. It provides the rigidity and strength I want/need without being overly heavy.
I use laminating resin for mine. Mix up about 2 oz of resin (again, depending on the size of the part) for a 40 - 60 size cowl. You want to mix it so you have a 30 - 40 minute WORKING TIME. Now dilute this 10% BY VOLUME with acetone.
I use plumber's flux brushes to apply the resin. Apply the resin and be sure the cloth is COMPLETELY saturated. (if you see white spots, that area is not saturated) Once the cloth is saturated, CAREFULLY squeegee off any excess resin with a playing card (if you do not take the excess of now, you will be sanding it off later) . Let this dry for about 48 hours. NEATNESS COUNTS IN THIS STEP.
Once it is dry, you can look the part over and decide if you need to add another coat of resin to fill the weave or not. If you need to fill the weave, do it now with the resin. Do not dilute this batch.
When dry, sand the part as needed. I use spot putty to fill any low spots (comes in a tube in the automotive section and is red in color ).
When the part is sanded and filled, be sure you have nothing hanging over the back of the plug.
If you are going to try to reuse the plug, take the part and immerse it in water for about 30 - 45 minutes while GENTLY flexing the fiberglass part to allow the water to get between the fiberglass and the plug. The water will allow you to "pop" the part off the plug.
If you are not interested in saving the plug OR the part will not pop off (the RC Gods like to play jokes on us mortals
), take the part outside and make an X in the back of the covering. In the X pour a little gasoline (2 - 3 oz is plenty for a 40 - 60 size cowl ). Come back in 20 minutes and clean out the sludge and dispose of properly.Thoroughly wash the part inside and out with soap and water. The part will be very soft and flexible. After the part is washed, do any final reshaping with your fingers and set the part aside. It will need about 72 hours to harden up.
It sounds hard, but it really isn't - just messy.
05-23-2005, 05:00 PM
#3
Senior Member
Join Date: Aug 2004
Location: East Cobb County,
GA
Posts: 1,390
Likes: 0
Received 0 Likes
on
0 Posts
RE: How do you make fiberglass parts?
ORIGINAL: Campy
I use the "lost foam" method.
I use the "lost foam" method.
I use what The Redhead refers to as the VISA Felony method.
I find the part I need online and do bad things to a VISA card.
05-23-2005, 10:33 PM
#4
RE: How do you make fiberglass parts?
I need to make some parts too.
I'm building a stand-off scale Cessna Skymaster 337. It's a twin engine --push/pull setup.
When I say "stand-off scale"--I mean stand way the heck off about 20' away and it might ressemble a 337
I'm kit bashing/scratch building from 2 different planes and some scratch building. The fuse is from an LT-40 and the wing is from a 60 size Bingo. I'm increasing wingspan to 80" and adding removable wingtips 28" long. So- it's a 3-piece wing.
I want to make an air-scoop on the top of the center section of the wing----so that I can force air over the rear engine for good cooling. This scoop will stay permanently attatched to the wing. I want to glass it into the wing and paint it.
Picture a hood scoop on a hot rod.
I just want it to stick up about 1" and be 4" wide. It will basically be a hollow tunnel too allow air to "ram" through the tunnel and down onto the cylinder head.
I was planning on making a foam plug and using the lost foam method.
How can I make the LE of my scoop nice and rounded? I want it to have a nice radius--like a jet engine intake.
Thanks
I'm building a stand-off scale Cessna Skymaster 337. It's a twin engine --push/pull setup.
When I say "stand-off scale"--I mean stand way the heck off about 20' away and it might ressemble a 337
I'm kit bashing/scratch building from 2 different planes and some scratch building. The fuse is from an LT-40 and the wing is from a 60 size Bingo. I'm increasing wingspan to 80" and adding removable wingtips 28" long. So- it's a 3-piece wing.
I want to make an air-scoop on the top of the center section of the wing----so that I can force air over the rear engine for good cooling. This scoop will stay permanently attatched to the wing. I want to glass it into the wing and paint it.
Picture a hood scoop on a hot rod.
I just want it to stick up about 1" and be 4" wide. It will basically be a hollow tunnel too allow air to "ram" through the tunnel and down onto the cylinder head.
I was planning on making a foam plug and using the lost foam method.
How can I make the LE of my scoop nice and rounded? I want it to have a nice radius--like a jet engine intake.
Thanks
05-24-2005, 08:17 AM
#6
RE: How do you make fiberglass parts?
ORIGINAL: Rcpilet
I need to make some parts too.
I'm building a stand-off scale Cessna Skymaster 337. It's a twin engine --push/pull setup.
When I say "stand-off scale"--I mean stand way the heck off about 20' away and it might ressemble a 337
I'm kit bashing/scratch building from 2 different planes and some scratch building. The fuse is from an LT-40 and the wing is from a 60 size Bingo. I'm increasing wingspan to 80" and adding removable wingtips 28" long. So- it's a 3-piece wing.
I want to make an air-scoop on the top of the center section of the wing----so that I can force air over the rear engine for good cooling. This scoop will stay permanently attatched to the wing. I want to glass it into the wing and paint it.
Picture a hood scoop on a hot rod.
I just want it to stick up about 1" and be 4" wide. It will basically be a hollow tunnel too allow air to "ram" through the tunnel and down onto the cylinder head.
I was planning on making a foam plug and using the lost foam method.
How can I make the LE of my scoop nice and rounded? I want it to have a nice radius--like a jet engine intake.
Thanks
I need to make some parts too.
I'm building a stand-off scale Cessna Skymaster 337. It's a twin engine --push/pull setup.
When I say "stand-off scale"--I mean stand way the heck off about 20' away and it might ressemble a 337
I'm kit bashing/scratch building from 2 different planes and some scratch building. The fuse is from an LT-40 and the wing is from a 60 size Bingo. I'm increasing wingspan to 80" and adding removable wingtips 28" long. So- it's a 3-piece wing.
I want to make an air-scoop on the top of the center section of the wing----so that I can force air over the rear engine for good cooling. This scoop will stay permanently attatched to the wing. I want to glass it into the wing and paint it.
Picture a hood scoop on a hot rod.
I just want it to stick up about 1" and be 4" wide. It will basically be a hollow tunnel too allow air to "ram" through the tunnel and down onto the cylinder head.
I was planning on making a foam plug and using the lost foam method.
How can I make the LE of my scoop nice and rounded? I want it to have a nice radius--like a jet engine intake.
Thanks
The "hard" way is to mold your leading edge right into the plug. Of course, you will definitely have to destroy the plug to get all the foam out.
05-24-2005, 08:26 AM
#7
RE: How do you make fiberglass parts?
ORIGINAL: woops
Thanks for the help, but where do you get the fiberglass?
Thanks for the help, but where do you get the fiberglass?
05-24-2005, 03:57 PM
#8
RE: How do you make fiberglass parts?
That sounds much easier than making a glass intake scoop. I'll do it with balsa.
Can't figure out why I didn't think of that[:-]
Thanks
[/quote]
The "easy" way is to CA/epoxy some pieces of balsa to the leading edge and then sand them to shape. After the balsa is shaped, you can decide if you want to fill the balsa for painting or apply some .75 fiberglass cloth using water base poly to seal and harden the LE.
The "hard" way is to mold your leading edge right into the plug. Of course, you will definitely have to destroy the plug to get all the foam out.
[/quote]
Can't figure out why I didn't think of that[:-]
Thanks
[/quote]
The "easy" way is to CA/epoxy some pieces of balsa to the leading edge and then sand them to shape. After the balsa is shaped, you can decide if you want to fill the balsa for painting or apply some .75 fiberglass cloth using water base poly to seal and harden the LE.
The "hard" way is to mold your leading edge right into the plug. Of course, you will definitely have to destroy the plug to get all the foam out.
[/quote]
05-24-2005, 07:17 PM
#9
RE: How do you make fiberglass parts?
After the scoop is made and CA in place, I suggest applying some .75 oz fiberglass with water base poly over it and to fair it into the surface it is sitting on. The glass will stiffen the scoop and provide a good base for painting or covering with almost no additional weight gain.
05-24-2005, 11:23 PM
#10
RE: How do you make fiberglass parts?
Sounds good.
I figured out how to do it. I'll cut 1/16" ply formers to my shape and then add stringers. I'll sheet with 1/16" balsa inside and out. Add a balsa LE and sand it to a radius.
Glass it inside and out with some lite cloth--as you suggested. This is gonna be COOL.[8D]
Thanks a bunch Campy.
I figured out how to do it. I'll cut 1/16" ply formers to my shape and then add stringers. I'll sheet with 1/16" balsa inside and out. Add a balsa LE and sand it to a radius.
Glass it inside and out with some lite cloth--as you suggested. This is gonna be COOL.[8D]
Thanks a bunch Campy.
