Sheeting Foam Wings
03-10-2003, 07:43 AM
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Sheeting Foam Wings
This is my first kit where I actually have to sheet foam wings. I want to know what is the best technique out there. Any input well be gladly accepted.
Thanks in advance.
Thanks in advance.
03-10-2003, 03:02 PM
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Sheeting Foam Wings
Polyurethane glue is my choice!
First true the edges of the balsa sheeting and then tape the sheets together (flat) using masking tape. Then with the tape side down spread a very thin coat of Polyurethane glue, use a old credit card to spread it as thin as possible. Place wing core back in the foam that they came in (protect from gluing together with wax paper) dampen the wing core with a very light misting of water and put the skin on the wing cover with the remaining foam and weight it down.
Use a lot of weight, cover the foam with a flat board and the put on as mush weight as you can (sand bags, iron weight used for lifting can be found at garage sales, etc.) or if you know someone that can vacuum bag that is better.
The moisture helps cure the glue and you will find that Polyurethane expands (like a foam) and will not only glue the shins to the core but also glue the seperate pieces of balsa together. Repeat for the other side and wing.
After a few wings you may be able to do both sides at the same time but do not try it on your first attempt.
Some modelers like to use Epoxy using the same method.
First true the edges of the balsa sheeting and then tape the sheets together (flat) using masking tape. Then with the tape side down spread a very thin coat of Polyurethane glue, use a old credit card to spread it as thin as possible. Place wing core back in the foam that they came in (protect from gluing together with wax paper) dampen the wing core with a very light misting of water and put the skin on the wing cover with the remaining foam and weight it down.
Use a lot of weight, cover the foam with a flat board and the put on as mush weight as you can (sand bags, iron weight used for lifting can be found at garage sales, etc.) or if you know someone that can vacuum bag that is better.
The moisture helps cure the glue and you will find that Polyurethane expands (like a foam) and will not only glue the shins to the core but also glue the seperate pieces of balsa together. Repeat for the other side and wing.
After a few wings you may be able to do both sides at the same time but do not try it on your first attempt.
Some modelers like to use Epoxy using the same method.
03-10-2003, 04:05 PM
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Sheeting Foam Wings
Same as above with a few exceptions -
I sheet both sides at the same time. Not really hard to do and keep straight. One trick is to put building pins (the T pins you use) through the foam shuck, into the balsa and into the core). This keeps the sheeting from sliding around on you. As for misting the cores/wood. This is necessary in dry climates - i.e. Arizona, Nevada, utah, etc. OR in the north during the winter when the heat is runnig most of the time. Since you live in a very humid climate (Seattle), you do not need to mist the cores or wood.
What size plane are you doing? I just finished up a 40% Edge. I used about 400-500 lbs on each wing panel. Be sure that the base board and top board are flat. many building surfaces will bend under 500 lbs of weight. Even the floor in your basement or garage may have a slight curve to it so double check. I have two pieces of slate that I got from a pool table repair guy. They have chips out of them so they are useless for pool tables, but are great for sheting wings. perfectly flat, strong, and HEAVY. My bottom peice is thick and weighs about 250lbs. My top piece is only about 3/4" thing and weighs around 100 - 125lbs. Total cost for the two pieces was around $75. For weights, I used the slates, plus weights from an exercise set, plus I got some lead steel disks which are considered waste from a local manufacturing company. I have an engineering friend who is into large rC and got them for me for free. You can also use concrete pavers, sand bags (Play sand is around $3 for 50lbs), or anything else you can find. Leave the weights on a min. of 4-6 hrs. Overnight is better - a full day is overkill and wasting time.
I like the polyurethane glue (I use Pro-Bond found at home Depot and other hardware stores - Gorilla Gule is similar) better than epoxy because of the foaming described above. I am lazy and hate edge glueing sheets! Vacuum Bagging is nice, but unless you have someone who has done a few to show you how, I would avoid it (plus you are looking at around $300 in equipment). If you vacuum bag, count on using epoxy. polyurethane glue WILL work, but drying time goes up to more like 24-36hrs.
Check www.EDGE540.com for some good shots of sheeting foam.
Keith
I sheet both sides at the same time. Not really hard to do and keep straight. One trick is to put building pins (the T pins you use) through the foam shuck, into the balsa and into the core). This keeps the sheeting from sliding around on you. As for misting the cores/wood. This is necessary in dry climates - i.e. Arizona, Nevada, utah, etc. OR in the north during the winter when the heat is runnig most of the time. Since you live in a very humid climate (Seattle), you do not need to mist the cores or wood.
What size plane are you doing? I just finished up a 40% Edge. I used about 400-500 lbs on each wing panel. Be sure that the base board and top board are flat. many building surfaces will bend under 500 lbs of weight. Even the floor in your basement or garage may have a slight curve to it so double check. I have two pieces of slate that I got from a pool table repair guy. They have chips out of them so they are useless for pool tables, but are great for sheting wings. perfectly flat, strong, and HEAVY. My bottom peice is thick and weighs about 250lbs. My top piece is only about 3/4" thing and weighs around 100 - 125lbs. Total cost for the two pieces was around $75. For weights, I used the slates, plus weights from an exercise set, plus I got some lead steel disks which are considered waste from a local manufacturing company. I have an engineering friend who is into large rC and got them for me for free. You can also use concrete pavers, sand bags (Play sand is around $3 for 50lbs), or anything else you can find. Leave the weights on a min. of 4-6 hrs. Overnight is better - a full day is overkill and wasting time.
I like the polyurethane glue (I use Pro-Bond found at home Depot and other hardware stores - Gorilla Gule is similar) better than epoxy because of the foaming described above. I am lazy and hate edge glueing sheets! Vacuum Bagging is nice, but unless you have someone who has done a few to show you how, I would avoid it (plus you are looking at around $300 in equipment). If you vacuum bag, count on using epoxy. polyurethane glue WILL work, but drying time goes up to more like 24-36hrs.
Check www.EDGE540.com for some good shots of sheeting foam.
Keith
03-10-2003, 10:36 PM
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Sheeting Foam Wings
[QUOTE]Originally posted by Fly4Fun2
[B]Same as above with a few exceptions -
(plus you are looking at around $300 in equipment). If you vacuum bag, count on using epoxy. polyurethane glue WILL work, but drying time goes up to more like 24-36hrs.
Check out this sight....just got the $100.00 kit...
Have experimited with set up...does great.....
http://www.acp-composites.com/acp-vbs.htm
[B]Same as above with a few exceptions -
(plus you are looking at around $300 in equipment). If you vacuum bag, count on using epoxy. polyurethane glue WILL work, but drying time goes up to more like 24-36hrs.
Check out this sight....just got the $100.00 kit...
Have experimited with set up...does great.....
http://www.acp-composites.com/acp-vbs.htm
03-11-2003, 01:25 AM
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Sheeting Foam Wings
I'd stay with the 24 hour bit with Probond or Gorilla glue..
Put the glue on the skins and wet the core then put them on.......
Either way with the weights and pressed or VB is a good way to go...
Everyone has their way of doing things that they can get along with...I just don't have the room for a press...hanger is full.
2 1/2 cents worth...
Put the glue on the skins and wet the core then put them on.......
Either way with the weights and pressed or VB is a good way to go...
Everyone has their way of doing things that they can get along with...I just don't have the room for a press...hanger is full.
2 1/2 cents worth...
03-11-2003, 03:21 PM
#7
Sheeting Foam Wings
Well,
I used Epoxy for years, think I had to for strength. Then a freind that built and raced quickies for ever told me I was just wasting money and He for years has used plain old Carpenters glue
So I tried it, Works great and it's Cheap! Also I like the fact you have plenty of working time to get things positioned
What I do is cut it with about 30% water so it will spread out thinner. Then spread it out over the Foam, Not the balsa, as thin a layer as will still cover the panel.
I found if you spread it over the Balsa it has time to start warping before you get the weight on it.
Summer time it's ready over night, Cold and humid weather will slow the cure time. If you pull the weight off and it feels damp and cool, it's not dry yet. Usually you can feel it through the balsa
If you use water based glue make sure you have no dings or voids in the foam panel, the glue will be to thick in that spot and take longer to dry, Then if you pull the weight off before all the glue is dry the wet spots will cause the balsa to bubble a little in those spots. learned that the hard way on a not so perfect panel I cut.
Good luck.
I used Epoxy for years, think I had to for strength. Then a freind that built and raced quickies for ever told me I was just wasting money and He for years has used plain old Carpenters glue
So I tried it, Works great and it's Cheap! Also I like the fact you have plenty of working time to get things positioned
What I do is cut it with about 30% water so it will spread out thinner. Then spread it out over the Foam, Not the balsa, as thin a layer as will still cover the panel.
I found if you spread it over the Balsa it has time to start warping before you get the weight on it.
Summer time it's ready over night, Cold and humid weather will slow the cure time. If you pull the weight off and it feels damp and cool, it's not dry yet. Usually you can feel it through the balsa
If you use water based glue make sure you have no dings or voids in the foam panel, the glue will be to thick in that spot and take longer to dry, Then if you pull the weight off before all the glue is dry the wet spots will cause the balsa to bubble a little in those spots. learned that the hard way on a not so perfect panel I cut.
Good luck.
03-11-2003, 06:00 PM
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Sheeting Foam Wings
What about contact cement?
I seem to remember the sig couger and ace t-34 reccomending a product by dave brown I believe it was called sourgum or something like that. You applied it to the core and sheeting after letting it set then sorta rolled the sheeting onto the core.
I seem to remember the sig couger and ace t-34 reccomending a product by dave brown I believe it was called sourgum or something like that. You applied it to the core and sheeting after letting it set then sorta rolled the sheeting onto the core.
03-11-2003, 08:25 PM
#9
true
Originally posted by Crashem
What about contact cement?
I seem to remember the sig couger and ace t-34 reccomending a product by dave brown I believe it was called sourgum or something like that. You applied it to the core and sheeting after letting it set then sorta rolled the sheeting onto the core.
What about contact cement?
I seem to remember the sig couger and ace t-34 reccomending a product by dave brown I believe it was called sourgum or something like that. You applied it to the core and sheeting after letting it set then sorta rolled the sheeting onto the core.
I use Contact all the time in my buiness, I'm a Cabinet maker. Once the two surfaces touch you're comitted.
If the sheeting is a little off, you screwgied.
I'm good at it and I'd rather not have the stress of taking a chance I'll ruin the core. I'd rather wait over night and know it's going to be perfect.
03-12-2003, 07:15 AM
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Sheeting Foam Wings
If you insist on using Contact Cement, try this:
After applying contact cement on both the core and the sheeting, and letting it set for 10-20 min, while the core sits in the cradle, cover the core with wax paper (plain paper also works) leaving 1/2" to 1" exposed at the leading edge.
Place the sheeting on the paper being careful not to let the exposed portion of the core come in contact with it. Align everything carefully. When satisfied, roll the sheeting over the exposed part. Lift the other end of the sheeting, remove the paper, then carefully roll the rest onto the core moving from Leading Edge to trailing edge.
Contact Cement tends to get gummy which makes it more difficult to sand at the leading and trailing edges. I've also heard of wings delaminating in the sun. Personally, I prefer ProBond (no mixing involved).
I tried carpenter's glue once and was very happy with the results, but it took a few days to dry out.
After applying contact cement on both the core and the sheeting, and letting it set for 10-20 min, while the core sits in the cradle, cover the core with wax paper (plain paper also works) leaving 1/2" to 1" exposed at the leading edge.
Place the sheeting on the paper being careful not to let the exposed portion of the core come in contact with it. Align everything carefully. When satisfied, roll the sheeting over the exposed part. Lift the other end of the sheeting, remove the paper, then carefully roll the rest onto the core moving from Leading Edge to trailing edge.
Contact Cement tends to get gummy which makes it more difficult to sand at the leading and trailing edges. I've also heard of wings delaminating in the sun. Personally, I prefer ProBond (no mixing involved).
I tried carpenter's glue once and was very happy with the results, but it took a few days to dry out.
03-13-2003, 05:07 PM
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Add one more vote for the polyurethane glue. If the glue begins to turn a lighter color while you're spreading it out, then you don't need to apply any water to the core - it's already beginning to cure.
Edge gluing the sheeting is also unnecessary. As long as the edges are trued and taped together, they will "pinch" together when you apply the sheeting to the core. Then they get glued together with the poly glue that is attaching them to the core. Saves you alot of time!!
Edge gluing the sheeting is also unnecessary. As long as the edges are trued and taped together, they will "pinch" together when you apply the sheeting to the core. Then they get glued together with the poly glue that is attaching them to the core. Saves you alot of time!!
03-14-2003, 03:21 AM
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What is a good waterbased contact cement to use? I bought some stuff, applied to both surfaces, waited 30-40 min like the directions say, placed both together and it didn't want to stick. It took very little effort to pull the experimental pieces apart.
any suggestions??
BTW, I'm in a project that I am unable to use the poly glue so contact is my next choice.
Thanks.
(any one know why the url's on signatures don't work anymore?)
any suggestions??
BTW, I'm in a project that I am unable to use the poly glue so contact is my next choice.
Thanks.
(any one know why the url's on signatures don't work anymore?)
03-14-2003, 03:35 AM
#13
Sheeting Foam Wings
I've seen pattern plane builders use 24-hr epoxy (very low viscosity) from www.r-g.de to sheet their foam core wings. See the thread on enigma build in the pattern flying section.
03-14-2003, 06:57 AM
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Because it expands.
I will be sheeting a NWHT Corsair fuse soon and it does not come in the foam shucks.
I can not think of any other way (besides vac bagging) to glue the sheets to the fuse and keep constant pressure on them to adhere the sheets. Contact glue seems the only way to do this.
I've tried and failed misserably to use NWHT own foam bond (Le'Pages white glue) on the wings so I wanted to try something else. I've had great success in the past using 3M Super 77 spray but they've changed the formula and I've heard it eats foam now.
Any one have any other ideas or know of a good contact glue?
Thanks.
I will be sheeting a NWHT Corsair fuse soon and it does not come in the foam shucks.
I can not think of any other way (besides vac bagging) to glue the sheets to the fuse and keep constant pressure on them to adhere the sheets. Contact glue seems the only way to do this.
I've tried and failed misserably to use NWHT own foam bond (Le'Pages white glue) on the wings so I wanted to try something else. I've had great success in the past using 3M Super 77 spray but they've changed the formula and I've heard it eats foam now.
Any one have any other ideas or know of a good contact glue?
Thanks.
03-14-2003, 07:35 AM
#18
Sheeting Foam Wings
Originally posted by Goggles
What is a good water based contact cement to use? I bought some stuff, applied to both surfaces, waited 30-40 min like the directions say, placed both together and it didn't want to stick. It took very little effort to pull the experimental pieces apart.
any suggestions??
What is a good water based contact cement to use? I bought some stuff, applied to both surfaces, waited 30-40 min like the directions say, placed both together and it didn't want to stick. It took very little effort to pull the experimental pieces apart.
any suggestions??
Depending on humidity it should take at least 30-40 min to dry enough to make contact. If using it out in a cool garage or basement it could take hours to cure,
Once I think it's ready I leave it for another 10 -15 minutes just to be sure
DAP make a decent contact under the "weldwood" brand name Home depot carries it.
Some more porous material may need two coats to make proper contact
03-15-2003, 04:22 AM
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Thanks for the help guy's.
I do the work in my basement and have a thermometer that reads 68*-72* almost all of the time so temp shouldn't be a factor. I'll try 2 coats and see how well that works.
BTW, the brand I tried was Weldwood.
I do the work in my basement and have a thermometer that reads 68*-72* almost all of the time so temp shouldn't be a factor. I'll try 2 coats and see how well that works.
BTW, the brand I tried was Weldwood.
03-16-2003, 02:42 AM
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Goggles,
Get some 3" wide masking tape and wrap the fuselage after you put on the balsa sheeting. I'm sure that would work great to provide the compression you need for poly glue to work.
The poly glue expands, but not with enough force to break masking tape. . . . it will just push itself into the foam.
Get some 3" wide masking tape and wrap the fuselage after you put on the balsa sheeting. I'm sure that would work great to provide the compression you need for poly glue to work.
The poly glue expands, but not with enough force to break masking tape. . . . it will just push itself into the foam.
03-16-2003, 04:25 AM
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Sheeting Foam Wings
Personally, I would use nothing but Polyurethane glue on the fuse. I have been using it to sheet foam wings and I am absolutely astounded with the bond. It beats anything I have ever used, including epoxy. As already stated, use wide masking tape to secure the sheets to the fuse contour. The glue will expand, but not nearly enough to break masking tape. Masking tape is one of my most used tools.
Vince
Vince
03-16-2003, 05:42 AM
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Well KL & Vince, I will have to take that into consideration.
I was just afraid if I did that I would end up with 'waves' in the sheets where the tape was holding it into place. How far apart should I place the tape strips?
Kelvin.
I was just afraid if I did that I would end up with 'waves' in the sheets where the tape was holding it into place. How far apart should I place the tape strips?
Kelvin.
03-16-2003, 07:08 AM
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Goggles,
Here's how I sheet my wings using polyurethane glue, and after looking at the photo of your fuse, I don't see why this won't work the same way to sheet your fuselage.
Buy three rolls of 2" or 3" wide masking tape with a dispenser. You will be using alot of it!!
Next, true up the long edges of the 1/16" sheeting. This is really the only critical part. They have to butt together tightly along the whole length without bowing up.
Lay out the sheeting on a table and tape them together lengthwise while pinching the sheets together with your hands. You're trying to make the sheeting as airtight as possible while taping the sheets along their entire length.
Apply the polyurethane glue to the foam core (or fuselage). My technique is to apply the glue to the foam because of the little indentations in the foam make sure I have enough glue. The other technique, of course, is to apply the glue to the wood first. I guess it doesn't really matter, but my technique may end up applying more glue (weight). While you're spreading the glue, you will notice that it is changing to a lighter color and may even begin foaming a little if you mess around too long.
Apply the balsa sheeting to the foam core (or fuselage) tape side out, and whatever compression technique applies. Goggles, I would just apply the balsa sheeting to the fuse then wrap it with about 20 yards of masking tape until it cures.
Notice that nowhere above did I mention that the sheeting needs to be edge glued. As long as the individual sheets are trued up and taped together, they will "pinch" together when they are applied to the curved foam surface and the polyurethane glue will do a very nice job of adhereing them together as it glues them to the foam. Also, you do not get any glue joint lines when you sand it.
Another point, the poly glue will put brown stains on your fingers no matter what you do to try to wipe it off. If you have rubber gloves, I would recommend wearing them.
Once everything cures, you just remove all the masking tape and give the tape ball to your kids!!
Here's how I sheet my wings using polyurethane glue, and after looking at the photo of your fuse, I don't see why this won't work the same way to sheet your fuselage.
Buy three rolls of 2" or 3" wide masking tape with a dispenser. You will be using alot of it!!
Next, true up the long edges of the 1/16" sheeting. This is really the only critical part. They have to butt together tightly along the whole length without bowing up.
Lay out the sheeting on a table and tape them together lengthwise while pinching the sheets together with your hands. You're trying to make the sheeting as airtight as possible while taping the sheets along their entire length.
Apply the polyurethane glue to the foam core (or fuselage). My technique is to apply the glue to the foam because of the little indentations in the foam make sure I have enough glue. The other technique, of course, is to apply the glue to the wood first. I guess it doesn't really matter, but my technique may end up applying more glue (weight). While you're spreading the glue, you will notice that it is changing to a lighter color and may even begin foaming a little if you mess around too long.
Apply the balsa sheeting to the foam core (or fuselage) tape side out, and whatever compression technique applies. Goggles, I would just apply the balsa sheeting to the fuse then wrap it with about 20 yards of masking tape until it cures.
Notice that nowhere above did I mention that the sheeting needs to be edge glued. As long as the individual sheets are trued up and taped together, they will "pinch" together when they are applied to the curved foam surface and the polyurethane glue will do a very nice job of adhereing them together as it glues them to the foam. Also, you do not get any glue joint lines when you sand it.
Another point, the poly glue will put brown stains on your fingers no matter what you do to try to wipe it off. If you have rubber gloves, I would recommend wearing them.
Once everything cures, you just remove all the masking tape and give the tape ball to your kids!!
03-16-2003, 07:19 AM
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Goggles,
I would apply the masking tape over the entire sheeted surface one layer thick.
There is no need to apply any more compression than is needed to hold the wood firmly onto the foam without distorting it's shape. Any "force" from the glue expanding only results in the glue working it's way down into the foam.
I recommend the cheapest, widest masking tape you can find. I'd look at a dollar store. . . .
I would apply the masking tape over the entire sheeted surface one layer thick.
There is no need to apply any more compression than is needed to hold the wood firmly onto the foam without distorting it's shape. Any "force" from the glue expanding only results in the glue working it's way down into the foam.
I recommend the cheapest, widest masking tape you can find. I'd look at a dollar store. . . .