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#1 T. van Vuuren Dec 02, 2012 06:26 AM

MD 500 fix
 
3 Attachment(s)
Hi all. Here is a 50 size MD 500 that a mate managed to "bend" a little. I will help him fix it as he has hassles working with glass.
I will also have to extend the boom by about 5" to fit the longer boom of the mechanics.

Theuns

#2 trucker41 Dec 02, 2012 10:40 AM

Quote:

Originally Posted by T. van Vuuren (Post 23418602)
Hi all. Here is a 50 size MD 500 that a mate managed to "bend" a little. I will help him fix it as he has hassles working with glass.
I will also have to extend the boom by about 5" to fit the longer boom of the mechanics.

Theuns

gel coat and alot of sanding ! i would start by finding gel coat at the local plastic suply "its cheaper there " and for the boom i dont have a clue other than finding anothe wrecked fuse and cutting what you need and grafting it on good luck .

#3 Keyrigger Dec 02, 2012 10:59 AM

On scalerchelis.com, there was a thread where a boom was repaired at a fly-in that was wrecked worse than that one. They make a tapered cone up to go inside the boom and I think it was covered with something like saran wrap so nothing stuck to it. They added glass over top and rebuilt it a layer at a time. I think the first step, however, was to use CA to get most of the large pieces back where they came from and then the glass was added over top. It was amazing to see how it was MacGivered together with litterally nothing, and flew on the last day of the weekend event. No get coat was used at the time, but the final rebuild was not shown. Take care.

Don

#4 T. van Vuuren Dec 03, 2012 02:36 AM

Thanx for the tips guys.
What I need to do firs is to somehow claen off the small rough epoxy bead tha holds the two halves of the boom together. There is no glass joiner tape and this is why it split open.

As soon as I have an even surface I will join with glass strip and when structural I can do all the rest.
I will extend the boom by installing a central stabilizing rod in the back of the boom and using high density foam shaped to the correct size.
This will then be epoxy glassed over onto the old boom and later with loads of sanding I hope to get a nice joint.

It is basically the same tecnique I used to make the dog box plug and molod for the 222.

The trick will be to lesten the amount of re-painting I will have to do. We will try not to repaint the entre heli if it could be helped.
Theuns

#5 T. van Vuuren Dec 07, 2012 09:27 AM

Hi. My idea of cleanig off the existing epoxy bead to get even surface for the join glass would not work ,so I made a paste of epoxy and flox that I spread either side of the bead. This gave me a flat surface I can glass over tomorrow.

As for the gapinghole in the rear of the boom ,I taped a piece of cardboard over it to give the basic shape and then glassed the inside of the boom. I am sure this will be good enough to get a backing for the filler to go on.

Pix to follow.

Theuns

#6 Keyrigger Dec 07, 2012 09:41 AM

I company that makes hobby resins was recommended to me to repair my Jet Ranger body. They recommended Z-Poxy finishing resin to do the outside final finish before primer and paint. That and a little fine glass cloth for deeper filling. They said that it sands very smooth and as such can be used as if it was a fine putty to fill in spots caused by chipped gelcoat or paint. I have not got to that project yet as there is still a chance of flying in the next couple of weeks before Winter really sets in here. Take care.

Don

#7 T. van Vuuren Dec 07, 2012 10:34 AM

I know the finishing epoxy well. I buy my resins from a place that supply to the full size aircraft industy. It is way cheaper than using hobby stuff and I get batch #'s and epiery dates with the epoxy. I also get my glass cloth and micro balloons/flox from them.

The hobby industry sometimes uses the exact same stuff in smaller qualtities for loads more $.

As for the small chips in the gelcaot, I usually just fill and sand them if they are small enough. The hassle comes in when trying to touch up the paint. It becomes rather hard to do and get an absolutely glass smooth finish.

I just had a look and it seems the epoxy in the boom has cured, always a good sighn LOL!

Theuns

#8 T. van Vuuren Dec 08, 2012 05:46 AM

2 Attachment(s)
Hi.

I have done the basic repair to the boom inside top with a glass tape over my epoxy base. It surely is far from pretty but it will do.

The hole in the boom has also been filled from the inside with 2 layups of epoxy glass and will be a base to fill against.

I will use the lost plag tecnique for the rear boom extention.

Theuns

#9 Keyrigger Dec 08, 2012 10:09 AM

That looks good and solid. Nice work.

Don

#10 T. van Vuuren Dec 09, 2012 02:23 AM

3 Attachment(s)
Solid but still light enough LOL!

Here is the plug I made for the 6" boom extention.
I made a 4 way spine and 1/4 round formers from 3mm balsa, planked it with 1,5 mm balsa and then filled and sanded the the shape I needed.

Put on some PVA to help get it out the glass and did a 2 layup of 63gr glass followed by a single layup of very fine cloth to help reduce the filler needed to smooth it out.

When cured I will fill.sand and prime ready for instenaltion on the rear boom. Luckly this shape could not be easier to make :-D

Theuns

#11 Keyrigger Dec 09, 2012 05:28 PM

You mean that 6" of the boom was missing? I know that with some chassis, you need to cut back the end of the boom but maybe an inch or so, not 6". Nice job making the plug and extension.

Don

#12 T. van Vuuren Dec 10, 2012 01:14 AM

Yea , the boom seems to be to short for the mechanics. Not exactlty sure why, but it should be better this time I hope.
More acurately it needs a 4" but I made a bit extra to give some thing to work with where I need to attach the the boom.

I will first do all the filling /sanding before removing the plug as it is more solid that way and less likely to get damaged.

Theuns

#13 T. van Vuuren Dec 10, 2012 08:04 AM

2 Attachment(s)
I got the extention sorted, I am pleased with it. Ity has been epoxied to the boom and now I will have to smooth it all out , that is going to be "fun" !

Theuns

#14 T. van Vuuren Dec 13, 2012 12:40 AM

2 Attachment(s)
Wow, eventually I can upload pix!

OK, the extention is glued on and mostly blended in, some small holes to still fill and sand. Same with the big hole in the rear dogbox.
Nearing the priming phase :-)

Theuns

#15 trucker41 Dec 13, 2012 09:52 AM

wow looks like you do some good work !!!


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