How much pressure on the Iron?

[Ocean]

Hi there,

I don't usually frequent this part of the forum but glad to say I've starting building with balsa!

I was just covering a balsa elevator (the moving part) with solarfilm and was wondering how much pressure you are supposed to apply when you both stick and then shrink the film?

By the end of doing 1 elevator my hand was pretty sore from all the pressure.

If anyone has any advice on how much pressure to apply that would be much appreciated.

Thanks

 

[Joker 53150]

One of us! One of us! One of us!

You shouldn't need any real pressure when working with an iron. I normally just use the weight of the iron or just a tiny bit more than that for sealing edges. When it comes to using the iron to shrink the film (I usually use a heat gun and not the iron) I've seen people barely touch the film or even just over over it by a few millimeters.

I also use a "sock" over the iron to protect the film from scratches. Different color socks for different color films, so I don't leave streaks of different color on the plane when I change to a different color.

 

[hackofalltrades]

I usually use a sock as well, except for really sharp edges. As far as pressure, little more than the weight of the iron itself.

 

[planebreaker2000]

Usually, if I feel like I am pressing hard, it is because the iron is to cool

 

[Ocean]

Ok thank you everyone for the advice, I have raised my iron temps slightly and will not apply nearly as much force next time.

 

[Hai-Lee]

The pressure required is actually quite little. The iron is to heat the film, melt the glue, and bring the structure and the film into contact.

I normally just "Iron the leading Edges and trailing edges" then shrink the covering over the frame using the heel of the iron. When it has shrunk such that I can see the ribs contacting the film I iron the spar and the fiddly tip bit and check for warping.

 

[mikeporterinmd]

Can this type of covering be used on DTFB? How about the water resistant type?

Thanks,

Mike

 

[Hai-Lee]

I suppose you could but the FB is easily damaged by heat so the lowest temperature that works is required. I have used it on depron with the edges covered in a balsa frame to take impact damage and a little more heat for a good bond.

If it is just for a coloured covering you are considering this try just using coloured "Contact" which is an adhesive backed plastic sheet.

Just apply the plastic sheet before cutting it out and to eliminate the problems trying to use a big sheet of plastic and getting air bubbles and folds in the material try using a large mailing tube just roll the tube with the plastic film glue side out across the sheet.

Remove the protective covering on the plastic sheet as you go and not all at once and it should give a near perfect job every time.

When the aircraft is cut out and assembled just apply a few strips of clear packing tape along the seams and done.

The finished product will be water resistant/proof and have far greater impact resistance for a little added weight.

I hope this answers your question or gives you an idea which does.

 

[mikeporterinmd]

Thanks Hai-Lee, you have given me some good information. I am looking for color, sealed edges and a nice look.

This particular plane is built, so I suppose covering will be a little more difficult. You wouldn't happen to have a link to the product you mention? I found items such as:

https://www.amazon.com/dp/B01IFNOLF8?psc=1

and

https://www.amazon.com/dp/B0125FQD9Y?psc=1.

One is 2.5mil and the other 3mil.

I might try glued balsa on the open edges on my next plane. Yellow glue seems to bond pretty well to bare foam and of course it should bond to the balsa. It's also cheaper and lighter than hot glue. The vinyl would take care of the edges left by the A and B folds.

Thanks,

Mike

 

[Hai-Lee]

The stuff I referred to as 'Contact" is used a lot here for the covering of school books. I am sure that your local Kmart or similar will have your local equivalent.

As for the glue I use it is nothing more that a clear foam safe craft glue which is dirt cheap even here. the only problem is that it seems to soak into balsa before drying rock hard and so when used on balsa sheeting the sheeting must be clamped in place or it will bow and warp.

As for edges you could score cut the original outline and cut the piece out with a margin all round. Then peel off the foam on the extra margin so that the piece is now correct size but with a paper strip all round. Just fold up the paper over the bare foam edge and glue into place. This protects the Foam/Paper joint from transport damage trying to de-laminate the edges of your foamboard.

Just an other trick!! On a tail you can not only use balsa edge strips but you can also cut lightening holes in the tail (Symmetrically of course), and then plank both sides of the foamboard with either 1/32 or 1/64 balsa sheet. Done properly you can get a huge increase in strength without an increase in weight.

Just experiment, experiment, and EXPERIMENT!

Work out what works for you and pass the results on to others.

Thanks for your reply and please let us know how you go!