Mantua Bruma Build Log - RC Groups
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May 13, 2010, 06:05 AM
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Build Log

Mantua Bruma Build Log

As a newcomer to model boats and having chosen the Billings Nordkap kit as the place to start, I found LucidMonkey's build log and all the advice it attracted incredibly helpful. With Nordkap now finished and wanting to remain with plank on frame kits, I decided to have a go at the Mantua Bruma. Big Beesley's log on his build has already helped. My hope in starting my own build log is that it will attract advice and comment along the way, not only helpful to me but also to others who may have chosen to invest in this elegant kit. So here goes:

Two weeks in and the hull framework is completed, the motors and RC trial installed and planking of the deck now underway.

Mantua provide a motor kit with one motor driving both props but it is very expensive and the gear drive is apparently noisy. For a lower cost, and based on other recommendations, I have opted for two 385 motors and 35mm 3 bladed props, one RH and one LH.

I waterproofed the hull frame, deck underside and motor/RC mountings with diluted aliphatic glue. Remembering the amount of epoxy resin I coated the inside of Nordkap with, I hope this will be enough. It may depend on whether my planking skills have improved to the point that the hull does not leak.

Since Nordkap where I used model railway track pins to secure the planks whilst drying, I have come across the Miskin plank on frame clamps. Incredibly expensive though they are (9.95 for 10), they may prove to be worth their weight in gold. When it comes to planking the hull, they should hold the plank firmly onto the frames much better than pins.

Looking ahead to planking the hull, I aleady have a question. Should I but up the planks against the side of the keel at the prow end or run them over the keel to meet in front. If fitted against the side of the keel, do I have to leave space for the second planking to but in front of the first or does this then over lap the keel? I haven't explained this very well but someone may understand me!

Well that's it for now. Back to planking the deck.
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May 13, 2010, 03:02 PM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
The Nordkap looks great on the water, and it looks like you
have a good start on the Bruma.

Micro Mark has some similar clamps to your Miskin, probably cost the same .
May 19, 2010, 12:52 PM
Registered User
A week down the track and deck planking is now finished. Final sanding and two coats of sanding sealer still to do. Now for the hard part, planking the hull.
May 19, 2010, 03:35 PM
Sharky1dk's Avatar
Keep up the good work.

It looks stunning
Jun 01, 2010, 07:06 AM
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First planking underway - it's slow work! The balsa strips are brittle and, even with the Mantua curving tool, some have cracked at the stern. I will need filler over planks 2 and 3 working from the deck down to restore the required curve. The deck was sprayed with Humbrol acrylic varnish after sanding sealer had been applied. There are indentations where the clamps gripped too hard but I will have to live with these.
Jun 01, 2010, 03:24 PM
Sharky1dk's Avatar
Looks great Jeremy. thumbs up!!!

Im doing the Billing "Smit Rotterdam" so i know excactly what you mean about brittle balsa strips. But its worth it, its a compleatly different feeling to stand with a "chrispy" wooden hull than a "plastic bucket boat"

Cant you sand down the deck to get the indentations away?
Or is the strips to thin?

Jun 01, 2010, 05:02 PM
Registered User
Hi Sharky

I agree with you about all wooden boats - my Billings Nordkap was also plank on frame. It would be interesting to see photos of your "Smit Rotterdam" as you progress.

I think I'll live with the indentations on deck. The strips are very thin and I risk doing major damage if I try to sand them down too much. Thanks for the suggestion anyway.
Jun 05, 2010, 02:59 PM
can't beat an open mind
adrenaline's Avatar
Signing on.....interested in this kit so will be interested in your progress
Jun 13, 2010, 12:59 PM
Registered User
Welcome to the log Adrenaline....

Still planking....I decided to work up from the keel as well as down from the deck - not as per the instructions but it seems to me easier if you have a steadily reducing gap to fill. We shall see. The stern end presents a real challenge. I have been advised to let the planks decide where they want to fall. Prop shafts now in place and there is room for the propellor.
Jun 13, 2010, 02:48 PM
Registered User
Here is a trick I found works on the dried out (brittle) balsa strips in some of the kits that have been sitting on the shelves for a while, spray them down with H2O and leave them sit for a while before using. The moisture you put back into the balsa will make it more bendable.

This is nothing new, we have been doing the same thing in the real boat yards when we had to bend a piece of mahogany for a plank job or for trim for that matter. Sometimes we would tie the board with a line and soak it in the river for a day or so, then take it out bend it and clamp it to dry, and voile!! It works.
Jul 05, 2010, 12:24 PM
Registered User
First planking completed - not great but the second planking should hide a multitude of sins. Frankg's suggestion to soften the Balsa planks for curving with water worked well, much better than using the crimping tool. I used a lime plank for the first planking above the scuppers because the inner face will show above the deck. The crimping tool works much better on the lime than it does on the Balsa. I found cutting a 2mm high strip to create the drainage slot very difficult . The kit should ideally include some pre-cut 2mm strip. On the plus side, enough strips are supplied to do both plankings in Balsa or Lime which means there will be a lot to spare for use on future models . There is a small error in the instructions for the positioning of the 2mm strips at the prow - the strip should run to the inside face of frame 3, not as instructed frame 2. Since taking the photos, I have sealed the first planking with dilute aliphatic glue. Now on to the second planking in lime.
Aug 04, 2010, 08:57 AM
Registered User
A slow job but the second planking is now complete. If I were to do this again, I would have used the limewood strips for the first and second planking. The limewood planks were much easier to curve than the balsa planks. As can be seen in the photos, the line of the prow doesn't flow into the keel . Maybe I didn't sufficiently profile the leading edge? The question now is how to fill the gap - ideas welcomed. With the curves at the stern end more even on the second planking than on the first, there are some gaps between the two surfaces. Hopefully this won't cause problems later on. The finish overall is fairly smooth but I can still feel the joins between the planks. I could go on sanding but would run the risk of going right through the planking. Should the lines of the planking be totally invisible when painted? Now on to sealing the hull with epoxy resin followed by testing for water tightness before doing anything else.
Aug 04, 2010, 12:07 PM
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Jerome Morris's Avatar
Jeremy, Just use some wood filler paste that you should be able to find at any hardware store. Smear this paste on, let it dry, then sand that to fair the hull.
If you sand back to the wood, just add more wood filler.
I use a product by Elmer's that is a yellowish wood color, dry's quick and sand very easy.
Aug 04, 2010, 12:59 PM
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crazy yank's Avatar
Originally Posted by JeremyBB
Hi Sharky

I agree with you about all wooden boats - my Billings Nordkap was also plank on frame. It would be interesting to see photos of your "Smit Rotterdam" as you progress.

I think I'll live with the indentations on deck. The strips are very thin and I risk doing major damage if I try to sand them down too much. Thanks for the suggestion anyway.
Re: the indentations from clamping. I've had some problems with the same thing with other projects using balsa wood, like model airplane fuselages, and used a steam iron to moisten and expand the wood almost back to normal. I don't know what it might do to surrounding planking and the glue you're using, but you might try it in an area that doesn't matter as much, like below the water line.
Aug 22, 2010, 07:08 AM
Registered User
Hull completed and painted. Imperfections there for all to see. I used an auto body filler to try and smooth things up but with limited success . To be honest, I should have taken more time over this stage but I was getting fed up with filliing and sanding, filling and sanding..... Once sealed with epoxy resin and painted, there was no going back. At least the hull is watertight and doesn't look like it's made of ABS or GRP.

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