Irokop decks

[MeritaII]

Hello to everyone .
This is my first posting , so be kind to me please !

I have almost completed the extensive renovation of our boat , it took two years.
After reading a lot of the letters here I seem to have commited all the sins !
For one reason or another , I guess we all do what we think is right , given the situation and what knowledge we have. ( and the advice we are given !)
The new deck is iroko 30mm , on ply, beded on sikaflex and all screwed through into the new 3 inch oak short beams , (one short beam to evey rib ) , one screw every other strip and beam , this I done with stainless 10's , two and a half inches long. Iroko plugs in the topping board and strip decking were put in with 'Bulkatan', makes a nice finnish and the colour is neutral, the topping board is to be varnished the strip deck left alone.
Right or wrong , ( there seems to be a difference of oppinion !) it's what is done and now I have to caulk it. There are a lot of seams as the strips are only 30mm wide ( as was the original ) .
I had intended to use "Sikaflex DC" complete with the bottom tape and the primer , the cost though is very high. So I am interested in the heated tar type I read about here, is it really as good as the sikaflex, given the type of deck we have . Seams by the way have a 5mm rebate.
What do you use to heat/pour it , and where can I get some ?
Other than the risk of being scared for life , what problems have you discovered when using it .
I would welcome all informed opinions , even unkind ones - I'll try to bear it all in mind ! Thanks




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[Mirelle]

If you want to try it, the stuff you need is Jeffrey's No 2 Deck Glue, obtainable from eg:

http://www.tradboats.com/index.html

Might I suggest leaving a sample of bare iroko to weather, to see if you like the results, before finally committing yourself to a bare iroko deck, though?

In the event that you would prefer a coating on the deck, I would be inclined to use clear Coelan, as quite a few people do, these days. In which case, you would be better off with the Sikaflex.






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[MeritaII]

Thanks for the advice, I'm listening ,

I know Trad Boats, I'll ring them tomorow.

Frankly I am not mad keen on the idea of leaving a totaly bare deck, I can see the pitfalls of that , andunderstand exactly what your saying.

After spending so much time on the boat I want to make a decent job of the decks , it could spoil the whole job or worse it could quickly return to the rot box it was before where the decks were through nailed which turned the strip deck into a rust sandwich and when it blew it rotted the sheer, ribs and short beams as well as just about everything else above the water line.
Its all new now , it took me thousands of hours and pounds , so I just want to get it right, or as right as I can so she will last at least another 63 years.
I am unfamilliar with "Colean", what is it ?
What are the advantages of using it rather than just bare wood ?


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[Mirelle]

The reason I am suggesting this is that in the case of the only boat I know which was built with bare iroko decks, the appearance was none too good after a year or two, because iroko weathers with a very large number of tiny surface checks, which hold the dirt, so the wood appears black.

Coelan is a rather interesting stuff; here is a link to the English language version of the website, which is far from user-friendly, but if you persist with it you will eventually find the "marine" bit which will in turn divulge a pdf file on Coelan boat coatings. Click on "sitemap" and then "marine protection":

http://www.coelan.de/englisch/html/products.html

I think it is a rather unusual moisture curing polyurethane, but I could be adrift there. I am a huge fan of the stuff since using it on my own (old, leaky, solid teak) decks some seven or eight years ago - I was expecting to replace them and I have not had a deck leak since! It is flexible, adheres very well and is very UV resistant.

It also costs a fortune, but if you want your new decks to last I would very seriously consider it. The stuff can be got from the bigger chandlers, eg Foxes in Ipswich if you are in this neck of the woods, and there is a first class English leaflet describing it in detail which chandlers stock.



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[ccscott49]

Two things, do not use jeffreys marine glue (the tar stuff you're talking about) use sikaflex, jeffreys was used before sikaflex became available and is still used, but IMHO sikalfex is better. Coelans, is wonderful stuff, do not allow your decks to weather first, put it on straight after the sikaflex, when the wood is new and unbleached, within 17 days of finishing the sika. Use plenty of primer (clear, yellow) It will then bond to the whole lot, wood, sika etc. You will then have a waterproof, non-slip, beautiful deck. again IMHO. Coelans, is basically thin clear sikaflex, but made by somebody else. I use it extensively on my wooden boat, as does my brother, we are very happy with it.

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[spark]

I recommend using Purflex instead of SikaflexDC. It appears to be exactly the same stuff (polyurethane sealant) at about half the price. I first used it in a re-decking job over 10 years ago and have had no complaints from any of the customers. I have just used it on my own new build.

I get it from a company called Aquafax (www.aquafax.co.uk), who may or may not deal directly with you. I'm sure you can get it retail if you ask around.

Use the primer and the bond breaking tape. Fill the seams slowly and carefully until the are overflowing. When cured, trim off with a broad bladed chisel and then sand with a belt sander. You will probably have to go over the job again to fill a few air holes and slump voids and give it a final sand.

As for finishing, I've had good success in the past using Deks Ojle #1 on iroko (the #2 will be too shiny for a deck) but on the new boat I am trying Varnol (www.varnol.com) - powerful stuff but I think I like it better than the Deks Ojle.



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[ccscott49]

Varnol is excellent stuff, but you will need to do it quite often on iroko, as this timber will not take much in, the grain is very tight, even pressurised baths dont work. teak is the same. I tried it on both and went away from it, it takes too long.

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[spark]

I should have added that the new boat is larch, doug. fir and oak so i haven't tried Varnol on iroko. I can believe what you say as it has more 'body' to it than Deks Ojle, even when thinned with turps.

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[ccscott49]

Oak is another timber which wont obsorb virtually anything, but varnol on fir and larch is brilliant! Soaks in a treat and stays there, I do believe it was originally designed for those and similar timbers, they use it extensively up here in Norway.

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[spark]

It seems to have worked well on the oak. I tried it on a test piece and left it out in the weather for a few months. The new boat hasn't been outside the shed yet so we'll have to wait and see.

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[ccscott49]

Then I stand corrected.

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[spark]

Don't stand yet ..... the outside test has been sitting in the yard, not on a mooring. I'll report back on the real thing in a year's time.

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[MapisM]

Iroko decks: varnish or not?

Hi everybody,

I've been away from the forum since months - luckily I must say, 'cause I was busy boating around !...
But it's nice to see what a useful source of qualified information it still is.
I also have a problem with Iroko, for which I would really welcome any experience-based opinion.

My boat has a teak deck, but many parts are in iroko (bulkheads, hand rails), and they are all varnished.
They look great, but since I don't have the time to repaint them myself, I always asked my shipyard to do that so far.
As a result, the boat is fine, but the maintenance expenses are driving me crazy.
A friend of mine suggested to leave also the iroko parts as bare wood (as the teak deck is), arguing that some oil is sufficient to protect the iroko planks and prevent them from splitting.

Apart from aesthetic evaluation, can anyone confirm if I should expect any damage/problem from bare-wood iroko, and if some oil now and then can effectively protect it?

Thanks in advance.

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[Peterduck]

You say that you have to go over the work again to remove air-holes and slump voids. It sounds as though you may be falling into the trap of drawing the gun towards you, instead of pushing it away from you. It works best if the gun is at a quite high angle so that you push the gunge down into the rebate, keeping a bulge of gunge ahead of the gun as you work your way forward along the seam.
Peter.

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[ccscott49]

Re: Iroko decks: varnish or not?

You can oil iroko, Also consider Coelans, remember iroko will probably split, anyway, as that is it's nature, small splits, so no real problem, large pieces of iroko get bigger splits.

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[spark]

No, I've done miles of mastic over the years, always pushing the gun.

I suspect the slumps come from working under fluorescent lights - the goo is shiny and reflects the light making it sometimes difficult to see if the seam has been fully filled. The air pockets seem to be in the stuff when its in the tube and, as such, are unavoidable. There aren't many of them (slumps and bubbles) but it is worthwhile going over the deck for a second time to fill them in.

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[MeritaII]

Re: Iroko decks

Hello to everyone, I posted the first question "Irokop decks" ( or iroko depending how thick your fingers are on the keyboard !) sorry but me' fingers were covered in 'Balakatan' it didn't help !
Firstly I would like to thank everyone for their opinions and experience, for which there is little substitute.
I have decided to go down the 'Sikaflex' route and then finish with Coelan, on balance this seems to be a good option. I would like to have left the deck plain, but it would appear, from what many of you have pointed out, that it would eventualy go dark. I also thought about the oil and so on and I have small areas of deck( same as the main decks) that I think I will try this on , these form steps to assorted parts of the boat , we shall see how it goes.

I have seen "Sikaflex" put into deck seams by first taping up either side and forcing the Sikaflex in, slightly proud of the seam, and then drawing the tapered side of a half inch chisel along the length of the seam . You then take the masking tape off whilst the Siakaflex is still wet ( try to do it in one go! I was told ) , the result was very impressive, the whole job only needed a light sand with a belt sander to clean things up . There didn't appear to be and voids or , but maybe time will tell.

This was my first posting on your notice board, the response has been very informed and interesting. There must be a lot of very valuable advice out there and I feel it was all worth listening to , Thanks again .





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[ccscott49]

Re: Iroko decks

You should not tape up either side, just the bottom of the groove, you want the sikaflex to stick to the sides of the groove/planks, otherwise, water will seep down the sides of the tape/sikaflex and you will end up rotting the deck out, also the sikaflex, can pull out of the seam. I hope I've explained myself properlyand I also hope you meant you taped the bottom of the groove!

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[MeritaII]

Re: Iroko decks

I think I did not explain myself clearlyin the first place, sorry. When I say 'tape' I was refering to simple masking tape, the kind you might use for spraying your car, not the 'Tape' as in the tape that goes in the bottom of the seam to allow for movement.It sounds as though you got the idea I was going to put this masking tape into the seam, Im not, only to the top edge of the seam.

The reason you put the masking tape along the length of the deck strip, up to the edges ( not in the strip deck grove) is simply to keep the Sikaflex off of the deck, after squeezing in the Sikaflex in the normal way , but slightly proud of the seam, you are able to force the Sikaflex down into the seam with the back of a chisel thus avoiding voids. Of course this means that some Sikaflex is pushed to either side, hence the masking tape. It takes a little time to put the masking tape down and you have to whip it off a bit sharpish after the seam is finished but it means you avoid a mess. The result I saw was good , Ill let you know when Ive tried it myself tomorow ! Ive got 16 seams 40ft long and 5mm wide to do , I make that about 640 ft of seam in all, should be a reasonable test . We shall see !

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[ccscott49]

Re: Iroko decks

That's the correct way to do it. I've payed a few deck seams in my day.

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