Osmosis treatment with homemade hotvac

[Crayfish]

Hi Roger,

Very nice piece of work! Congratulations. Haha it seems we went through the same steps of trials and tribulations. I tried one of those black electrical floor heating you apparently experimented with in picture 13, too. But the max. temperatures it reached were disappointing. My readings had been between 5-7 (d45 Greisinger, depth 10mm) when I started glassing the hull with epoxy, which appeared to be pretty dry compared to dry spots over the waterline. I have to add to that, though, that when I started hotvaccing there wasn't much moisture left as I'd already got rid of all the mats down to the roving. On average the readings dropped by another 2% and then stopped.
Did you finish your project by now?

Crayfish

[Crayfish]

Roger,

I've had a look on your website and I am deeply impressed!

Crayfish

[minaret]

Originally Posted by Crayfish

Roger,

I've had a look on your website and I am deeply impressed!

Crayfish

Likewise. Very nice work. This should put this in a more affordable price range for the dedicated amateur. Good stuff!

[HappyMdRSailor]

Wowsa...

You guys just stole my word..... OK... Uh... Beyond impressed then....

[rogerball0]

Cheers guys,

The projects on-going as i started it right at the beginning of what turned out to be the longest economic downturn (2008) so money's been tight the last few years but i will finish it as the difficult (hull) stuff is done now.

Just waiting for a weather window to spray the outside then engine and interior in, who knows may get the boat finished this year then save up and build a rig for it.

I was trying to post some pictures but dont seem to have had much luck, the reason why i posted here was to show a mate that people have made their own working hotvac systems. The other site is boatdesign.net which gives a good description of other peoples homebrew systems.

Basically i was trying to convince my mate he doesn't need to spend thousands of pounds as his boat is similar size to mine but he wants the job done but without the zero's.

I figured if you went with the heater cable mat, 2 stage pump, temperature control box and the fittings you can build the kit off of ebay for £250, to put that in context i was quoted £7000 to plane, dry then coat epoxy on the hull - just rediculous seeing as the boats worth £12000.

Yes the black electrical film was rubbish for me too, only 30 odd degrees c, the cable mat worked well but took a while to get upto temperature but the silicon mats were the daddy - they took under a minute to hit 100 degrees c.

Before i filled and faired the hull with wests i got the wetted area to match the topsides (green sector on a tramex) so should pass muster on a survey.

Thanks for taking the time.

cheers

roger

[minaret]

Originally Posted by rogerball0

Cheers guys,

The projects on-going as i started it right at the beginning of what turned out to be the longest economic downturn (2008) so money's been tight the last few years but i will finish it as the difficult (hull) stuff is done now.

Just waiting for a weather window to spray the outside then engine and interior in, who knows may get the boat finished this year then save up and build a rig for it.

I was trying to post some pictures but dont seem to have had much luck, the reason why i posted here was to show a mate that people have made their own working hotvac systems. The other site is boatdesign.net which gives a good description of other peoples homebrew systems.

Basically i was trying to convince my mate he doesn't need to spend thousands of pounds as his boat is similar size to mine but he wants the job done but without the zero's.

I figured if you went with the heater cable mat, 2 stage pump, temperature control box and the fittings you can build the kit off of ebay for £250, to put that in context i was quoted £7000 to plane, dry then coat epoxy on the hull - just rediculous seeing as the boats worth £12000.

Yes the black electrical film was rubbish for me too, only 30 odd degrees c, the cable mat worked well but took a while to get upto temperature but the silicon mats were the daddy - they took under a minute to hit 100 degrees c.

Before i filled and faired the hull with wests i got the wetted area to match the topsides (green sector on a tramex) so should pass muster on a survey.

Thanks for taking the time.

cheers

roger

Thanks for posting here! Nice system and your blog is a hoot.

[Francis Massin]

Volker
I have read your article. Very interesting.
I suppose the sheet is made of silicone. What I do not understand is how you apply vacuum between your sheet and the boat hull !
Can you explain a bot more
Regards

Francis

[rogerball0]

Hi Francis,

I'm not Volker but Roger the guy who built the other system, turns out we both came up against the same pitfalls and pretty much built similar systems having never met or seen each others work.

To answer your question; Butyl tape is what i put my silcone mats onto the hull with then evacuated all the area with a simple vac pump, have a look here:

https://picasaweb.google.com/1101828...eat=directlink

Any questions give us a shout although Volker just as knowledgable, my address can be found on my blog

A Gentleman's Yacht

cheers Roger

[mischief]

That's fantastic. I had hoped to get to this in a few months but the internal refit has run overtime. So likely I will be doing this on the next haul out.
Cheers


Sent from my iPhone using Cruisers Sailing Forum

[rogerball0]

Cheers Mischief go for it!

BTW just had a look at Volker's site for the first time; Hitch-Hike-Heidi.de | Lotterleben par excellence and have to say the guy's work is exemplary as i mentioned before its fascinating how we both tried similar approaches early on.

I have to admit i came quite close to scrapping the whole project when after nearly a year of hot-washing and heating the the moisture readings refused to budge. But by tweaking a couple of things and being more methodical i got there in the end.

Just goes to show with a little bit of knowledge and an ebay account anythings possible!!

Roger

[El_Fakir]

First of all, thank you to both Crayfish and Roger for making this info available and public, its been hugely instructive and cheering so far. I plan on trying this on my Annapolis 30 shortly.
One thing I have not been able to suss out yet:
Roger, between your initial heating pad model on the black backing, and the ones in the silicon mats: was there any change in the heating elements themselves, or was the difference purely in the insulation quality of the mat material?
Could either of you be just a tad more specific about the heat rating of the heating elements themselves?
Huge Thanks,
James

[rogerball0]

Hi James

Yes the black heater pads were experiements using domestic under-floor heater elements, the first one which was the huge black mat (1m square) utilised heater cable set in a mesh although later on i'd cut that away and tape the cable directly to the mat and make a smaller version.

The other iteration would utilse an under-floor element but unlike the first that used cables i went with a system that was 1mm thick which was a copper conductor set in plastic film.

I concluded the heater cable was far superior to the plastic film in terms of maximum heat (around 80 degrees c vs the film' max of around 35 degrees c and also the time taken to reach maximum heat output but i still wasn't impressed by the time taken with the heat cable tbh.

Hence the silicon rubber mats, these have tungsten elements running through them and were rated for 200 degrees c although the controller boxes i made were limited to 100 degrees c plus anymore than that and you'll start to change the chemistry of the resin.

In a nutshell the silicone mats would hit 100 degrees c almost instantly, obviously i'd dial in what i wanted temperature-wise via the controller boxes but overall they were way more practical as you could get alot more done over the course of a few days.

The 'ingredients' for the my mats were as follows (from outside to in):

So outer layer (the bit you see on the boats hull) edpm roofing rubber with butyl tape taped all around the edge to secure on the hull. Then a layer of 6mm depron with foil taped to it to reflect heat inwards towards the hull then the heater cables taped to that then breather cloth over that with a heat sensor taped inside to record temp and thats it.

The pictures tell you all this, importantly you'll need to build a thermostat control box to control temps as you dont want to fry the hull just dry it, google 'ATC 800' and thats the brain i built my control box around , very simple too.

Hope that helps

Roger

[GordMay]

Greetings and welcome aboard the CF, James.

[El_Fakir]

Cheers Roger, thanks a ton. And its good to have found you all; lots of detailed and highly valuable info seems to live here. I look forward to picking your brains in the future, as well as hopefully contributing to the knowledge heap.

[rogerball0]

No worries, give us a shout if you get stuck.

Just remembered with the silicone rubber mats (orange ones) i didn't bother with the depron sheet and also i forgot to get them made with a hole through the sheet placed in a corner to help drain any fluids as i had to make a rubber envelope that i butyl taped to the mat but everything else is as the early mats.

cheers

Roger