3D Demystifying Vacuum Bagging of foam wings!!

[Terryscustom]

Thanks Al,
That brings up a good point, I know when using a vacuum system you also don't have to edge glue sheeting when using resin since the resin get's sucked into the seams. Saves a TON of time and headache, thanks for mentioning that.

I know you can use resin without a vacuum but would have to edge glue the seams.

 

[Jetpainter]

Thanks Al,
That brings up a good point, I know when using a vacuum system you also don't have to edge glue sheeting when using resin since the resin get's sucked into the seams. Saves a TON of time and headache, thanks for mentioning that.

I know you can use resin without a vacuum but would have to edge glue the seams.

The fact that I dont have to edge glue is one of the main reasons I want to try bagging.

 

[IMAC FANATIC]

Great thread, I got more use out of the vac system by gluing on the LE and TE stock to every surface also. No yards of tape, just enough to hold in place, no clamps, no wondering, just slightly lower pressures. Used weldbond so it wouldnt foam and easier to sand the shape.

 

[Terryscustom]

Great thread, I got more use out of the vac system by gluing on the LE and TE stock to every surface also. No yards of tape, just enough to hold in place, no clamps, no wondering, just slightly lower pressures. Used weldbond so it wouldnt foam and easier to sand the shape.

NICE, but I have to say........This post is useless without pics!

If you have some, post 'em, that's a killer idea.

 

[jtec/radiowave]

Terry,

Only ever used resin with weight. I'll go ahead and skip the edge gluing on the next one. One of the interesting things to me is after you vacuum bag a wing it just has a more solid feel to it!!

Al

 

[Terryscustom]

Terry,

Only ever used resin with weight. I'll go ahead and skip the edge gluing on the next one. One of the interesting things to me is after you vacuum bag a wing it just has a more solid feel to it!!

Al

Very much, Dean always described it in his Carden Pro builds as "eggshell" feel. I think it also makes wings easier to sand, but maybe it's just me, with the surface tension they just seem to get smooth quicker.

 

[Terryscustom]

OK, using my video camera that is not super, and appologize for the CNC machine warming up in the background. Did not think it would pick that up quite that much!

Anyway, Part one, laying out the sheeting:

Edit, @thelaw says next time we're not using my POS camera

 

[Jetpainter]

When I was looking at your belly pan and turtle deck in your other thread, it dawned on me how much better bagging those parts would be over weighting then. The equal pressure in all directions has got to make that job better. I would think anyway.

Doug

 

[Terryscustom]

When I was looking at your belly pan and turtle deck in your other thread, it dawned on me how much better bagging those parts would be over weighting then. The equal pressure in all directions has got to make that job better. I would think anyway.

Doug

EXACTLY!!!

Some supporting pictures:
One other point I'd like to note is on longer parts like belly pans or wings on many planes you will need to scarf joint the sheeting. You DO NOT want to butt joint the sheets, you need to angle the joints at least 45 degrees. I have a 100 tooth fine blade in my miter saw so I cheat and simply cut them at a 45 and tape together. Make sure that any scarf joins are not connected, meaning the joints are offset from each other as you see here. Once done, tape the seams and cut out the final part.

 

[Terryscustom]

OK, couple of tidbits pertaining to sheeting in general. With quality hot wire cut foam there is very little surface prep to be done. Brush over the parts and make sure there are not any "fuzzy" stringies on the surface. Foam can cut differently from one batch to the next so check for any places where the wire could have left a divot or serrated type surface. This typically looks worse than it is and if vacuuming these will get smashed flat, if poly gluing the foam will fill the gaps. If they are deep enough you can lightly sand over the surface. If there are any small areas that are not flush (like if you dig in your finger nail like I did), use a motel room key and some lite-weight spackling to smooth over any holes or imperfections. This stuff weighs nothing and dries quickly. It also soaks up resin and poly so no adhesion worries.

Also backing up slightly to truing the edges of sheeting. Table saw clamp style jigs work well, I use a wide belt sander so I can do 50-60 sheets at one time and be done in about 4 minutes. This is the ideal way if you have any access at all to a sander, if not I recommend the table saw method. Worst case, the ol' straight edge and elbow grease. Anyone have methods on this please feel free to post so others can learn!!