dereklola
Aerospace
- Aug 7, 2014
- 8
Last year I had some lightweight epoxy-resin fiberglass panels made for a project - details below. They were in unheated, dry storage for about 12 months, sitting "on end" (which should have caused no external deforming forces) but have now warped to a small, but significant extent - presumably from residual internal stresses.
My question is would heating them while "blocked" to the right shape be successful in restoring them to their original "out of the mold" shape? Would this be a permanent fix or might it have to be repeated from time to time. (It would be possible to add some internal webbing if that would help.) What sort of heating arrangement is appropriate (heat lamps, fan heater blowing into an insulated box)? What sort of temperature? I've had one non-expert suggest 120-130degF should be about right - is it? Note that they were made from epoxy not polyester resin - and that they are foam sandwich construction which I presume means heat is needed on both sides.
Details: - each part is about 5ft x 5ft with some significant 3D shape and intermittent edge conditions - by that I mean there is not a consistent perpendicular wall all round - in some places it is a 12"-15" deep and in others almost non-existent. Construction is a 1/4" foam core covering about 90% of the full surface area - then skinned both sides with "thin" vacuum bagged epoxy/fiberglass - sorry I don't have exact details - I didn't make them myself - but as a guidance each part weighs only about 15 lbs.
The distortion is basically (1) one corner being about 1" low and (2) a central hump is now offset about 1" (was originally symmetrical).
Appreciate any help anyone can offer - Derek
My question is would heating them while "blocked" to the right shape be successful in restoring them to their original "out of the mold" shape? Would this be a permanent fix or might it have to be repeated from time to time. (It would be possible to add some internal webbing if that would help.) What sort of heating arrangement is appropriate (heat lamps, fan heater blowing into an insulated box)? What sort of temperature? I've had one non-expert suggest 120-130degF should be about right - is it? Note that they were made from epoxy not polyester resin - and that they are foam sandwich construction which I presume means heat is needed on both sides.
Details: - each part is about 5ft x 5ft with some significant 3D shape and intermittent edge conditions - by that I mean there is not a consistent perpendicular wall all round - in some places it is a 12"-15" deep and in others almost non-existent. Construction is a 1/4" foam core covering about 90% of the full surface area - then skinned both sides with "thin" vacuum bagged epoxy/fiberglass - sorry I don't have exact details - I didn't make them myself - but as a guidance each part weighs only about 15 lbs.
The distortion is basically (1) one corner being about 1" low and (2) a central hump is now offset about 1" (was originally symmetrical).
Appreciate any help anyone can offer - Derek