Split veneer repair

[John Minchell]

Hi all,

what is the best way to repair wrinkled and splits in the veneer on an old foam wing which has been in storage for 20+ years? 

I'm restoring a model to donate to a youngster or underprivileged person so they can get flying time in and learn in the hobby. 

It was a new wing but went into the loft and never covered with film or tex.

Thanks John M

[oipigface]

A photo would be useful.

[John Minchell]

All the splits are like these, 8" to 20" long also the whole length of the TE de-laminated.  Originally veneer glued down with Copydex which has now dried out.

[wookman]

If you have the shucks from which the cores were cut, strip the veneer off and replace with new, using the shucks to keep the wing straight on a flat surface.

[Stormeflyer]

I would just dilute some PVA glue and syringe or brush under the veneer, wipe off any excess with a damp cloth, then lay Mylar or grease proof sheet over the area and lay a sealed freezer bag with something like sugar or sand in it, just to follow the contour of the wing without deforming the veneer or foam.

[Mr_SMO]

As a flyer of Arthobby planes, I'll be very interested how you deal with this. 

My inclination would be, if the cracks are straight enough, to push the top down using the edge of a vertical ruler, then wicki some foam friendly CA in the crack. Sand the result as far as you dare. 

Another possibility would be to cut away the offending area, and scarf in similar veneer, or balsa sheet, and sand the best you can. 

Whatever you do, I'm looking forward to hearing what it was, and photos of the finished product. 

 

[oipigface]

Either of the two methods described above would probably do the job, but since you say that the original adhesive is probably giving way, and assuming that you are looking for something more permanent than a ‘quick fix’, I would go for Wookman’s solution. Pressing distorted veneer down will introduce new stresses into the skins, which could well cause new splits in them.

If you don’t have the original foam beds, I’d go for refinishing the wings with lightweight glass cloth. This method doesn’t stress the wing core the way veneering does. You can complete the job with heatshrink film, or, if you have the time, a nice epoxy paint job is good.

[Mr_SMO]

Just wondering, what happened in the end? 

[John Minchell]

Didn't have the the original foam beds the section was cut from.  Discussed with a couple of mates the remedies on here and one said the PVA method was best then proceeded to insist upon taking the model off me to do the job and my donated solarfilm to cover it with.  Its a 40 powered DB Mascot power trainer so is going to probably have a short life anyway.  So a quick fix to flying state is all that is needed so it helps a new modeller into the hobby.

We (the NW Area BMFA ) do one of these each year by collecting airframe, TX, RX, engine or motor, servos etc.

I'll report back once I have the model returned to me.  Thank you for all your suggestions.

John M