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Old Jul 28, 2008, 06:38 AM
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Malaysia, Federal Territory of Kuala Lumpur, Kuala Lumpur
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IOM Building

Just wanna know if anyone here ever built IOM before ? Mind to share few tips and tricks? I have built kits but not from scratch building and i would like to learn on how to build from plans. Which is the best method to start off? Planking or from foam core ?
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Old Jul 28, 2008, 09:41 AM
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http://www.rcgroups.com/forums/showthread.php?t=779699

I have built two. Both plank on shadows from plans. the first was a Vanquish, on the above link, and the second is a Vektor. The second hull was really a plug, as I made a mold from it, so I could make more than one.
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Old Jul 28, 2008, 09:43 AM
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I used 1/4" foamboard for the shadows, cause it was free (scraps from a local picture frame shop) but it did work great. Do you have some plans yet?
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Old Jul 28, 2008, 10:19 AM
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Hey thanks for responding well i did downloaded some plans but i'm thinking of noux2 but just dunno how to get my hands dirty ....
Foam board ey? Most of the people used ply or something more rigid or stronger, anyway if it worked for you why not. I don't know how hard is the planking job, but i think i need to get the balsa stripper to help me out
What kind of glue do you use to glue up all those strips?

I was thining of making a mould, FG the hull out of it.
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Old Jul 28, 2008, 10:27 AM
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I used CA glue to glue the balsa planks together. Do a few inches at a time, and pin to the shadows when you need to. The CA lets you build the whole thing in one sitting if you have all of the strips cut. Two days at most.

Then you can either finish the balsa and use as a plug, or fiberglass the outside, pop it off the shadows and glass the inside for a balsa core.

It's more work, but if you have friends that may want to sail an IOM too, the mold makes it easy to make two or more identical boats.
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Old Jul 28, 2008, 10:44 AM
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Yup .... we would like to have our fleet one day. I own a good old Nimbus i bought of from a friend but in our region, it's just too few of us keen in sail boats. And parts and accessories are hard to get. Well let me see if i can find the balsa then i can move on. At first i thought of using foam core, but in Malaysia they sell but bulk and the only way i can get them is from construction site, but i did not find any

So now i think i have to go with balsa planking if i still can't find any foam core by end of this month.

By the way did you make your own sail? how about the mast,jibs and deck accessories ?
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Old Jul 28, 2008, 01:54 PM
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I was going to suggest the Nimbus MKIII plans from sailsect , http://www.sailsetc.com/miscplans.htm because they are the most detailed plans you can buy for an IOM( a beginner can actually build a boat from the plans). It might not be competitve , but it would get you started. But you allready have one.

I have built a couple of US1 Meter hulls using balsa plank on frame. To keep the boats light you use very light weight contest balsa ( 7lb/ cu ft).

For the Nimbus and triple crown IOM's , I used cedar and redwood. Weight is not as much a problem because of the min weight limit for IOM's and you can still make it under the min weight using heavier, sturdier wood( looks good too).

I think balsa is much easier to work with though, because everything can be done with out power tools. If I was going to build an IOM with balsa I would use a much heavier density than for a US1Meter( like 10 -12 lb/cuft) its sturdier and its easier to find.

I have heard foam board works good , but whatever you use, make sure it is stiff enough to hold its shape with whatever type planking you are going to use. Harder woods put alot of strain on the formers.

The only real problem I had when planking with balsa ( and I was using very light soft stuff) was when I went to sand the hull smooth.The CA glue is much harder than the balsa and the hull sands unevenly.Thats not really a problem if your going to do alot of filling and sanding but it adds alot of unwanted time and weight.

Try to keep the glue off the outside of the hull. You can use thick CA and put it between the planks toward the inside of the hull so it doesnt squish to the outside of the hull or glue from the back for as long as you can( as you work your way up from the gunwhales to the bottom it gets harder to fit your hand in from behind).

I also used a glue called Sigment by SIG for one for one of the US1Meter hulls. Its softer than the softest basa so there is no problem with sanding. The only problem with it is, its slow to dry.

Dont worry about glueing the heck out of the planks, you will be glassing the outside and probably the inside( recomended) too.

I dont know if you have seen this but there is alot of good info for all R/C boats http://www.modelyacht.org/us1m/us1mcons.html

Here is a link to the triple crown http://www.mya-uk.org.uk/suppliers/triplecrown.html

Other good sites http://www.iom-nordic.org/index.php?...sk=view&id=131

http://navi.modelisme.com/article174.html you will have to run this through babblefish translater.

http://www.myrc.org/Library/Library.htm#SailMaking

http://rcboatbuilding.fotopic.net/c833706.html

http://woodenstars.net/50107693b3137...f08/index.html again babblefish.
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Old Jul 28, 2008, 10:47 PM
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I'll just try out with foam board first, may be a thicker ones, if it deform due to my silly handling i'll just get somebody to cut out the shadow from ply using scroll saw

If i want to make a complete fiber glass hull from the balsa hull, should i lay the fiber outside? It'll depend on the offset shadow that i've cut out right ?
Normally how many laters of fiber to lay to make the hull tougher? Should i use gel coating ?
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Old Jul 28, 2008, 11:11 PM
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Most of the plans I've seen have "3mm offsets" shown on the shadows. This allows you to plank with 1/8" balsa, then sand lightly and a layer of glass. I would remove the hull from the shadows, and build the deck right onto the hull, next. Once the deck is finished, glass the hull, and deck. The reason for building both halves is because you will need to wetsand the final layers of primer and/or paint and any balsa that can get water on it WILL mess up the finish! You will get to see all of your planking "print" through to the outer surface.

Try to get the balsa as smooth and ripple free as you can, before the glass. Use a single layer of medium glass, maybe 4-6 oz/yd2. If it is smooth enough, you can spray a coat of auto primer on it and sand to a "ready for paint" finish. Then a coat of finish paint, and you are ready to make a mold from it.

read the info on mold making in the "Composites" forum, unless you have done molds before.

Once your mold is ready, 2 layers of 6oz S Glass, or three of 4oz S Glass, with extra where the finbox and mast go, is what I have been using. I have a few photos posted on my flickr account, http://www.flickr.com/photos/hew_ham...7604340965096/ and a few on our IOM group, http://groups.yahoo.com/group/mbrciom
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Old Jul 29, 2008, 01:22 AM
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Btw, if you're going to build an IOM to the rules, you'll have to leave the hull unpainted.
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Old Jul 29, 2008, 02:02 AM
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Unpainted ? Are you sure ? All the hulls is saw on the net are in varieties of color.
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Old Jul 29, 2008, 04:46 AM
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Scrutineers need to be able to see that the hull has not been built with exotic material such as carbon by looking through the hatch, so its no paint on the inside. Some in the US who have ready access to it think that carbon is not exotic, but this is a worldwide international class, and the rules are formulated along those lines. If you are not going into formal racing, it doesn't really matter.
Paint on the outside is OK. If the hull is GRP, then it must not be self coloured.
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Old Jul 29, 2008, 04:51 AM
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Great stuff man ...... i wish i can make the plug nicely like yours.

So first step is to make the plug from balsa, then paint it ..... and then lay fiberglass to get the hull right? Or lay a thick fiber glass on the plug, paint the inside, and lay the fiber inside the painted fiber to get the hull ..... i'm so confused man ..... If i'm using the plans from the website, are they to scale or i have to scale them. I'm looking at the vanguish and it seems to have lots of details plan. Noux2 is just the shadow but i'm not too sure if that has been off set to 3mm


Quote:
Originally Posted by hew565
Most of the plans I've seen have "3mm offsets" shown on the shadows. This allows you to plank with 1/8" balsa, then sand lightly and a layer of glass. I would remove the hull from the shadows, and build the deck right onto the hull, next. Once the deck is finished, glass the hull, and deck. The reason for building both halves is because you will need to wetsand the final layers of primer and/or paint and any balsa that can get water on it WILL mess up the finish! You will get to see all of your planking "print" through to the outer surface.

Try to get the balsa as smooth and ripple free as you can, before the glass. Use a single layer of medium glass, maybe 4-6 oz/yd2. If it is smooth enough, you can spray a coat of auto primer on it and sand to a "ready for paint" finish. Then a coat of finish paint, and you are ready to make a mold from it.

read the info on mold making in the "Composites" forum, unless you have done molds before.

Once your mold is ready, 2 layers of 6oz S Glass, or three of 4oz S Glass, with extra where the finbox and mast go, is what I have been using. I have a few photos posted on my flickr account, http://www.flickr.com/photos/hew_ham...7604340965096/ and a few on our IOM group, http://groups.yahoo.com/group/mbrciom
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Old Jul 29, 2008, 07:17 AM
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Quote:
Originally Posted by mfr02
Paint on the outside is OK. If the hull is GRP, then it must not be self coloured.
Paint or coloured resin on the outside of any type of construction is OK, BUT, a coloured gel-coat applied into a femail mould is quite acceptable as long as the lay up is not pigmented. This is normal practice on most UK IOM's.

Ralph
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Old Jul 30, 2008, 12:00 AM
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The painting I am refering to is to the plug. The plug needs a layer or two of glass to make it durable enough to handle during the wetsanding/polishing. This is on the balsa, followed by primer and paint. THe plug must be as smooth and as polished as you want the final hulls to be. Primer and paint can be wetsanded and polished to a high gloss.

Once the plug is perfect, begin your molding process. 3-5 coats of wax to the plug. A coat of PVA mold release. Then a coat of tooling resin... thickened epoxy or polyester gel coat. Next is several layers of chopped strand FG mat, followed by several of 6oz cloth. Note, these are not all laid up at the same time. You have to watch the heat buildup if it is too thick a buildup at one time. The whole mold needs to be about 1/4" thick to prevent it from deforming over time, as the resin continues to harden. I added some feet to mine too, so it would sit nice and level on the table when ready to lay up a hull in it.

Another cool thing about having a mold, is that you can spray a coat of paint into the mold, then lay up your glass and resin. It will pop out of the mold with a nice glossy paint layer on it.
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