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Nov 11, 2003, 04:19 PM
I told them, I was drunk.
temp_oct's Avatar
Question

How to fix a dent on foam?


Hi,
I brought my Spitfire into a tree due to bad hand launch and bad weather (believe me, it was not the pilot ). I got a dent on the LE of the main wing. It is around 1/2" deep and 3/4" wide. The foam is pretty stuck in there and I'm afraid to break it if I try to pull out.
Any suggestion on fixing this will be very appreciated.
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Nov 11, 2003, 04:23 PM
Closet Extrovert
Jim Poor's Avatar
I use light weight spackle mixed with micro balloons to fill dents, holes, and such in my EPP foam planes.

Where do you fly in/around LA?
Nov 11, 2003, 04:37 PM
Aerial Shutterbug
RMihara's Avatar
I've heard steam works to re-puff the foam cells.

Roger
Nov 11, 2003, 04:55 PM
I told them, I was drunk.
temp_oct's Avatar
Jim,
Where can I get micro-balloon in LA? I fly in several parks in Burbank and at the Sepulveda basin sometimes. Where do you fly?

Roger,
Could you give more detail? Stream like from boiling water?

Thank you guys
Nov 11, 2003, 05:59 PM
Registered User
RiBell's Avatar
Quote:
Originally posted by Wild Moose
I've heard steam works to re-puff the foam cells.

Roger
I've heard of this as well. Never tryed or done it.
But I think that the way to do it, was to use a needle and inject a very small amount of water into the foam.
Then use an iron to gently heat it up.
That or just use a regular clothes iron's steam, and work with gloves. and see if you can massage it back into shape.

Like I said I've never tryed it either way.
Just throwing out idea's that I would try, working with steam or even pouring hot water over it first.
Rick
Nov 11, 2003, 07:13 PM
Closet Extrovert
Jim Poor's Avatar
Temp_oct,
I got my last batch at Hobby People in Lawndale. The balloons only make it a bit lighter. If you can get the super super light epoxy at a hobby store, you can do it without the balloons. It's cheaper my way.

I flew (slope) quite a bit at Redondo, but people there got dangerous and I stopped going. I may go back.

I fly at El Dorado park when I am testing a new fast plane, or just need plenty of room.

There is a sports park near me on Van Ness just north of Rosecrans that I like. It's 4 baseball fields back to back with no fences.

There's anoter set of ball fields a little higher up Van Ness that I go to when I am desperate.

I also fly at a small little league field around the corner from my house.
Nov 11, 2003, 07:59 PM
Big 3D
jamin's Avatar
you could cut out the dent and glue in new foam and sand to shape
Nov 11, 2003, 08:13 PM
Closet Extrovert
Jim Poor's Avatar
Yep, done that too. Of course I had two identical sets of wings, and played canabal with one of them. You could cut a small rectangle out, glue one in the same size and sand. Actually this is my favorite option, and if you don't get the fit just right, you can go with a little filler/spackle.

Thanks for reminding me jamin.
Nov 11, 2003, 09:09 PM
Big 3D
jamin's Avatar
1 problem...many solutions....my geometry teacher could never see that...
Nov 11, 2003, 11:49 PM
I told them, I was drunk.
temp_oct's Avatar
Thank you again
I've tried hot water. It doesn't work; however, it does change the paint color (on the Tamiya paint).
I don't have time to get the supply @ the hobby shop so I cut out the dent part, put some balsa in and glue with PU. Soak with water and let the PU expand, then wipe out the excess part.
Nov 12, 2003, 12:24 AM
Aerial Shutterbug
RMihara's Avatar
IIRC the steam method uses a clothes iron, not touching the surface of the foam of course.

Injecting water most likely won't work on the large cell foam types as these have large channels which would 'leak' steam. the main idea is to re-inflate compressed foam cells back to their original shape (akin to blowing up a balloon).

I suspect that using steam actually causes outgassing of the foam material which causes the cells to re-expand, the heat softens the material enough to let that happen.

Roger