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Feb 23, 2002, 10:31 PM
Thread OP

Lost foam Fuse question

I'm starting my first Lost Foam Fuse project and need some advice.

1. When I glass it over, should I have the wing-hold-down pegs installed in the foam?
(I plan to use some CF arrow shaft).

2. Should I drill out the foam and install the (CF arrow shaft) Boom, and glass it in place?


As you can see, I've got a lot of sanding to do!
Last edited by rlt55; Feb 23, 2002 at 10:36 PM.
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Feb 23, 2002, 11:11 PM
Registered User
chlee's Avatar

Question 1: No, drill holes for your dowels after all the glass has cured and before you melt out the foam. This will make layup much easier.

Question 2: I describe my method for installing the carbon boom on the following thread:
Do tell me if anyone has a better method, though.

Feb 24, 2002, 05:18 PM
Registered User
Look at this has the lost foam method article in detail.You might find it very helpfull.
Mar 03, 2002, 02:36 PM
Thread OP

Sanding done!

It seems like the brown paper coating is the 'release agent' in this process.
Why can't the Blue foam Fuse form/plug just be coated in a few layers of wax?

If brown paper is the best option, what is the best way to apply it? Soak it in luke warm water with a Elmers glue mixed in?

Mar 03, 2002, 03:18 PM
Registered Lifeform
Paul Willenborg's Avatar

I've done several FG cowls with blue foam molds that were then covered with low temperature iron-on film like Econokote. It's very quick to get the mold ready, and once the foam is gouged and/or melted out the film can be pulled out cleanly just by grabbing a corner with needle nose pliers. One coat of wax makes it easier, but is not really needed.

Mar 03, 2002, 03:23 PM
Swedes don't grow on trees
Jonas Leander's Avatar
Packing tape also works well for covering the plug. It will even shrink if you heat it with a hot air gun.

/ Jonas
Mar 03, 2002, 04:24 PM

I converted a synergy 3 to electric and

bondoed the nosecone to make it larger for f27 aveox and 20 cell pack. I also made airscoop. I shaped until I liked it. Then I tightly wrapped the form with saran wrap. I then stretched a cf sleeve over it. The fact that it had a blunt nose now made it easy to do the glassing cleanly around the curves. I used a few rubberbands after it was hard enough to not sink in very far. I epoxied a motor mount plate on the front where the threads of the end of the sleeve wrapped around the front. I aplyed pressure against this to compress fibers and bond well. It was a relatively constant taper except for the airscoop so I stripped it off. I wanted a clean cf look so I added another layer of epoxy. I sanded this until smooth being careful not to go through to bare cf. I added one last thin coat of epoxy and voila. It is very stiff. It serves as my mount. I will paint it so windows of bare cf show through in a flame job sort of way. I just leave the saran wrap inside. I sanded the area where I then added another layer of cloth to build up to meet the new slightly larger dia. of cone. This is again on saran wrap on original surface that the cone slid on. Carefully slide the new cone over the cloth layup. This makes a perfect fit.

There is no way to get the sleeve to close down to a point. The range is about half.
Mar 04, 2002, 09:25 AM
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buckeyes1997's Avatar

just using wax

im fairly new to lost foam method but there is one large problem with not using brown paper or tape or iron on. the foam when it melts out will turn to a thick blue goo that is hard to remove and weighs enough to worry about. when you wrap the foam the idea is that when it melts you can pull out the wrap which will leave a very clean inside surface on it.

if you want to see how my first attempt turned out you can visit my projects page and see both my first mold try and lost foam try.
on the lost foam you can easily see the blue goo inside it. i also had problems with rigidity using the lost foam of luck. (click at the top on projects)
Mar 05, 2002, 11:57 AM
Thread OP
Thanks guys.
I'm going to try brown plastic packing tape.

Maybe I'll glass this weekend. If it's not too cold outdoors. If it comes out okay, I'll post some pictures.
Mar 07, 2002, 06:28 PM
Thread OP
It's actually 3M Mailing tape. The heat gun helped a lot.
The nose cone area was a little messy, may have to do it over.
With the saddle cut out for the wing, I don't see a good spot for the arrow shaft.
This is only a test run, but if it works out okay, I'll drill a hole for the boom and epoxy it to the bottom of the saddle.

I fear that the sides are have a little too much 'flat' to them and it will be too weak. Maybe I'll add some thin G10 between layers.

This Saturday is going to warm, I'll do the glass after I do some flying..


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