Coelan the barbarian

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nelsonmandela

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The next instalment ----You may have see my posting about re-starting coelan aplication after a long time.Well its not that great news for those of you who like us thought we could just pick up where we left off.
It seems to be possible to add new coats by sanding back with 60 to 80 grit as if you where just continuing on with a normal application ( not that you can get this info from Coelan) However the problem for us is that we had used the (red) so called mahogany coloured primer since the boat is to have "natural coloured" hull.THE PROBLEM IS--that the colour changes with time --both the wood and the Coelan stain/primer or what ever it really is.
As a result If you intend to do any new work on a previously coated hull it is difficult to predict whether there will be a colour match in due course or whether you will end up with an unaceptable patch work.
The lesson for us is to do EVERTHING we can to sort the varnished areas well before they are coated up because there appears to be no going back once you have started ,until of course you have sanded the boat to nothing!!! DISPITE THIS WE THINK THIS A BRILL PRODUCTas best as we can tell, its just that the preparation is all.
 
Hallo Nick and others:
I am a big fan of the Classic Boat magazine and I have been a long time reader of the CB forum althought up to now had not actively participated. I read your post regarding the Coelan application and the color mismatch of the primer and thought it high time to join up.
I have done several Coelan applications of various sizes and surfaces and have yet to experience any primer discoloration due to interrupted application.
Not that it should be an issue but how long did you wait between intervals?
Experience has shown me that all of the Coelan primers do tend to darken the wood surface. The mahogany primer more so than the yellowish primer used on teak and pine. Some small exceptions have been noticed when applying multiple primer coats that have not been equally mixed or shaken.
I have also found that the primers must be very, very vigorously shaken both prior to and during application as the coloring components do tend to settle in the tin.
My normal practice is to anticipate the use and required amount of the primer and store the tin/s upside down overnight and when ready given a good ten minute shake. Pour out the contents into a suitable sized clean container whilst watching for lumps and bits of coloring. Visually check inside the empty primer tins for sediment. If residue is found you will need to pour back some primer and re-shake. Repeat the process as necessary.
Then using a slow turning mixing rod carefully stir up the primer until all lumps are thoroughly dissolved. Do not strain out the primer at any point.
In addition; the US based Coelan distributor has incorporated extensive product and user application information and helpful tips on their web site. Suggest you give that data a read and perhaps email their technical support people whom I have found to be very knowledgeable and helpful. Their name is Premapro.
Their web site while slightly dated is more informative and more user friendly than the English version Coelan German factory web site.
Also as part of this thread; I see a question regarding “love affair” with 80 grit. It was explained to me that the use of 80 grit provides the optimum tooth in the surface to allow for a good mechanical bonding.
Hope this helps you.
 
This is a great thread as I am planning to apply the barbarian to my decks. I have couple of questions for the pro's:

1. I am only at the yacht at weekends and I don't think I will be able to do all the recommended coats in one weekend. I was planning to priming (using mahogany stained primer) first - two coats - and then leave for a further unspecified weekend to continue. I see nothing in the literature about leaving the primer for any lenghth of time before covering with the "real" thing. Do any of you with experience think I will get away with that or will I need to cover with atleast one coat of the real thing just to seal the deck in?

2. Coelan becomes considerably cheaper if you buy in large tins. I notice that the instructions say that the whole lot can "Go off" so I need to use the whole thing within the working time frame.

Anybody have any experience of quickly decanting a large tin into smaller ones for use later. Is this too risky or sound economic thinking?
 
1. I would not try leaving the primer without the top coat. I cannot quite say why, but I suspect that the primer reacts chemically with the top coat to ensure the bond. By (probably defective) analogy - Sikaflex DC290 deck caulking stuff is a polyurethane (and very happily compatible with the Barbarian) and it has a rather similar looking and smelling primer - which has a minimum and maximum time between application and application of the DC290.

2. I have not tried decanting, but I reckon it will work nicely, because I did have a part used tin that I did the hot air gun trick with and it was fine ONE YEAR later! You would need to be sure that the tin/bottles/whatever were airtight.
 
I thought as much for the primer. I see from the literature that once one "real" coat is on I can leave for upto two weeks before sanding back for next coat. I am now in the hands of a barbarian and what the God's dish out weather wise!

Not aware of the hot air gun trick - what does one do?
 
I can vouch for Mirelle's hot air gun trick as I believe it was the can I ended up buying from him and we had no problems with it. You simply waft a hot air gun into the tin before quickly reapplying the lid. I do this every time I move Coelan from the tin to a painting tub.

I say every time... anxious to get on with Crystal's brightwork, but at the moment, it's too cold indoors to do anything, let alone outside!!

/<
 
Re: Coelan a thin Barbarian?

Just one last question as I seem to have hit on a wealth of knowledge:

In users' experience was there a need to thin down the product at all and how much thinners were used if at all? I am intrigued as one supplier is says I need two litres of the stuff (overall order of five litres topcoat ) and another says that one litre will be fine, and I won't use more than 500ml of it.
 
Re: Coelan a thin Barbarian?

Yes you absolutely need to thin it.

Buy two litres of thinner - it' s cheap compared to the rest of the stuff and I reckon 10% is not always enough thinning.

Buy loads of cheap brushes and polythene pots.
 
Re: Coelan a thin Barbarian?

Thanks very much for the encouragement regarding my first post. I hope it was not too wordy but I feel specifics rather than vague references are important.
In response to the questions from Roach1948 and in agreement with the newer posts from Mirelle and Kristal I would offer the following.
Priming need only be a dual coat process when the wood surface is very dried out and the thoroughly mixed primer leaves little if any surface color. That said; I usually go with two coats for reasons of optimum UV inhibition. I would agree with others as to applying at least one layer of the clear coating as soon as the primer dries before any stoppage in work.
Therefore when working out of doors it is important to tackle only what available time and weather allow for.
The use of a hot air gun and the blowing of hot air into a larger opened and partially decanted tin is a nifty trick. After doing so I normally store these partially full tins in an upside down fashion so if there is any skinning it takes place at the bottom of the tin. Just make sure the lid is tightly attached.
I place a layer or two of clear plastic food wrap between the lid and the tin. For some reasons the lids and the container lip or rim appear to deform very easy so go easy with the mallet.
As others have suggested and for reasons of smoother flow and substrate absorption my standard application process also entails the thinning of the first two layers of the coating. Depending on air temperature I thin 10% up to 20% when warmer (+75F). BTW: If you run out of thinner I was told by Coelan that Xylol is a reasonable temporary substitute and there is a Coelan Retardation Agent to slow the coating cure during application in those really hot or tropical locations.
I have experimented with this in the direct hot afternoon sun and have found it works a treat. However; don't use thinner and RA in the same mixture.
Similar to the ongoing Classic Boat Varnish Test, I have constructed many coating and varnish test pieces both in accordance and some completely contrary to various coating manufacturers application guides. I have Coelan test bits from 2001 that are in brilliant shape and I am now thankfully becoming varnish free.
 
Re: Coelan a thin Barbarian?

Many thanks to all of you! I am now feeling more informed and eductated for this task then any of my previous jobs. My Coelan is on order, I am saving my old yoghurt pots up, and just bought my cheap stack of brushes - All I need now is a relatively warm dry spell of weather!
 
Re: Coelan a thin Barbarian?

When using Coelan is it necessay to remove all deck fitngs or can you apply up to the fitting with slight overlap?
 
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