Tuesday, October 31, 2017

Binks Mach 1 PCX Spray Gun



Robot Spray Gun

The next piece of the puzzle goes a long way toward being able to spray without mixing pre-catalyzed batches of material.  Factory and robotic production of fiberglass resin products have been using external catalyzation.  This is where the resin and catalyst are mixed in the airstream after leaving the sprayer.







Binks 2100GW
Binks makes a few external catalyzing hand spray guns.  I initially considered using the 2100GW.  This gun has a small catalyst bottle attached to the side of the gun.  It seemed to be fine for small repairs but one thing you don't want to do is run out of catalyst while spraying.  This would cause under or no catalyzation at all.  I also felt that it doesn't allow using the gun in all positions since the catalyst could be sloshing around in the bottle and the pickup tube may become uncovered and suck up air.




Binks Mach 1 PCX
Fortunately, Binks  also makes the Mach 1 PCX.  It is a very specialty product and since only a few are sold, the price is quite expensive.  Much more than I ever thought I would spend on a spray gun.  It is an HVLP (High Volume, Low Pressure) system.  The resin is routed to the gun by a hose from a pressure pot.  The catalyst is also routed to the gun through a second hose from it's pressure pot.  The air comes through a third hose to provide atomization.  This allows for spraying in any position and the catalyst quantity is only limited by the size of you tank.

 

The orifice size is 2.4 mm which is sufficiently large enough to spray high viscosity material like gelcoat.  Car paint orifices are half that size which is why those guns will not work unless the gelcoat is really thinned out.

Sunday, October 29, 2017

Catalyzation and Curing



Gelcoat is mixed with MEKP (Methyl Ethyl Ketone Peroxide) catalyst.  The MEKP bonds with the resin molecules and forms a hard polyester plastic.  The chemical reaction gives off some heat and in theory, all the MEKP is bonded and used up in the reaction.


The ratio of MEKP to resin is between 1 and 4% depending on the temperature.  The more MEKP, or the higher the temperature, the faster the resin will cure.
A fast cure is also not a good cure.  The reaction takes time and if the resin 'kicks' too fast, there will be unused catalyst in the polyester matrix. A 20-30 minute cure time is a good reasonable time to have.  As can be seen from this chart, 4% catalyzation at 5C will cure in 2 hours while at 20C it will cure in 5 minutes.

The daytime temperature here in Malaysia is around 32C (90F).  This does not give a lot of time for catalyzed resin to be applied.  If you mixed a batch, put it in a spray gun and started applying, it would probably turn into a hard chunk of plastic before you were done spraying.  This would ruin the gun and obviously this would make it very difficult to do a large area like an entire boat. 

Even if you were to apply early on the cool morning with 1% MEKP, you have to thoroughly clean the gun spray gun between each batch or the residue will still harden in the gun even though more material is added.


There are spray guns for small projects that use disposable cups. Even using a gun like this, the material sprayed in the beginning could have a cure time of 20 minutes while the material at the end may only have a few minutes, if that.  These guns are also more like spatter guns than spray guns.  There is not a fine misting orifice nor a controlled airflow pattern like you would find on a proper spray gun.



Friday, October 27, 2017

Duratec 904-001 Hi-Gloss Additive



Gelcoat will not harden if exposed to air.  When it is sprayed into a mold, the mold itself keeps the air away from that side and allows it to cure.  When the fiberglass cloth and resin is layed up on top of the gelcoat, it keeps the air away from that side.   

If you are using gelcoat in a layup like the picture above, you actually do not want the surface of the gelcoat to cure hard because the subsequent cloth layers will not have a molecular bond and stick very well, and delamination could occur.

To get gelcoat to harden when it is exposed to air such as an external repair of spray job, liquid wax is added or a mold release agent is sprayed over it to keep the air away.  While curing, the wax rises to the surface and forms a barrier to the air.  The key to getting this to work out well is to not add too much wax, which causes porosity, and not have the gelcoat cure too fast, giving enough time for the wax to rise.  It's a tough balancing act and if it fails, the gelcoat will be sticky and gum up the sandpaper.

A California company, Dura Technologies has created an additive that you mix 1:1 with gelcoat.  It slightly thins the mixture but best of all, it allows the gelcoat to air cure and not be sticky.  Since we will be spraying multiple layers to build up a sandable thickness, a layer of wax does not form on the surface between coats preventing adhesion of multiple layers.  They also claim that it allows a Hi-Gloss super hard surface and it makes spraying gelcoat like spraying paint.   

We'll see.

http://duratec1.com/pdf/DS 904-001.pdf

Thursday, October 26, 2017

Gelcoat vs. Paint




Gelcoat is the usually white layer that covers a fiberglass boat.  It's kind of like paint but much thicker.  It is actually just pigmented fiberglass resin. The same thing that the boat is made of.   Normally it is the first thing sprayed into the boat's mold and becomes the outer surface when the hull is removed from the mold.










Over time, gelcoat get oxidized and pitted from UV and the elements.  Sanding to deoxidize, compounding, and waxing only go so far.  Dirt and stuff sits in the porosity and the color just becomes dingy.   


One solution is to paint the entire boat with car paint.  Quite a few older boats have this done and it looks good for a few years but scratches easily, is hard to repair, and needs to be done again every 5 years.  The going price in the Caribbean and Mexico for a monohull was around $6,000 USD.  
$20K Paint Job
  
There is a catamaran here that was just painted for $20,000 and the guy thinks he got a pretty good deal.  Once you paint a boat, you can never go back to gelcoat unless you sand off all the paint.  




 In my opinion, the only reason to paint a boat is if it is constructed out of Epoxy or if you are selling it and don't care much about the future owner. To me, painting a boat is not something that you want to build into a continual maintenance schedule.  There's enough of that already.  My goal is to do it once and have it last for 15-20 years.

The Preval can cover about 2 square feet
I have done quite a few gelcoat repairs in the past.  Both gelcoat and paint surface preparation is extensive. Gelcoat, however, can bury small scratches whereas paint is so thin that the surface needs to be perfect before spraying.  With small repairs, a disposable spray bottle like the Preval is used.  The gelcoat is thinned down with styrene, extra wax additive, the material is catalyzed, and is sprayed like spray paint out of a can.  The real work comes after it dries.  Since gelcoat is thick, the surface has an orange peel texture that needs to be sanded to get to a smooth surface and then sanded with finer and finer grit sandpaper and compounded until it has a brilliant shine.

So my real challenge is to scale up what I have done on small areas with the Preval and make it work in the 90 degree heat of Malaysia.   No worries.

Tuesday, October 24, 2017

It's Not Always Hard Work, It's Also Social


Steve and Dave in Penang
It seems like we are always working on boat projects.  Boats require an incredible amount of maintenance and if you avoid doing it, you end up paying for your procrastination 3 times over.  Doing a boatyard refit is another thing completely.  It is just so much easier to do some things when the boat is on land.  Besides the obvious underwater work which would be impossible on a dock, the boat does not move when sitting on land and you can't drop your tools in the water.

Onion Biscut Tandoori
Living and working in a boatyard (on the hard) doesn't have to be so hard.  In our earlier days we stayed on the boat.  These days, especially in such a low cost country like Malaysia, we are happy to look at the boatyard as a day job, live like locals, and learn the local cultures.


Sundowners
Others in the yard are of a similar mind and we usually end up planning where to eat dinners together, group shopping, or just socializing somewhere.  There are usually 'Sundowner' get togethers, a monthly marina cookout and usually some other such excuse to have a party comes up.


The Family Size Dosai at our favorite Indian Restaurant
When someone discovers a new place to get materials or food or anything, word spreads quickly.  Our new favorite Tamil Indian restaurant quickly became the Cruiser Diner.  On any night of the week, cruisers could be found gathered around their Chapatis, Dosas, Masalas, and Kothu Parottas.

Coffee Hour after Yoga
We also spend alot of time helping, planning, and talking about each other's projects.  There is an incredible wealth of knowledge around a boatyard. 









Booker Getting Coiffed by Brian
If someone has a skill or trade from their before boating life, it can be very helpful in areas like this.  Brian was a hairdresser in Australia and did quite a few cuts and colors on the girls.





This area is now officially named the 'Yoga Park'
When someone has an interest, sometimes it becomes contagious.  Our Aussie friend Julie, was doing Yoga in the mornings.  All of a sudden, there were 15 of us laying on mats on the grass.  Even Akina from the office came in early to stretch and breathe.  




 

Riggers for the day
When a boat is stored in the large shed, it has to be dismasted.  This requires a knowledgeable crew which is usually made up of other cruisers.  When coming out of the shed, the mast must be re-stepped.  This is all good practice for everyone involved and lets us all be riggers for the day.




Barbeque in the 'Shed'
It's definitely more of a 9 to 5 work atmosphere here.  Most everyone rents a condo and has a car.  The great thing about Malaysia is a condo and rental car will cost $400/month.

One other thing, everybody is from far away.  The Australians, who are the closest to SE Asia, have an 8 hour flight.   Americans, Canadians, and Europeans have all traveled huge distances to get here. There really are no local Malaysian Cruisers.  No pun intended but this kind of "Puts us all in the same boat" living far away from home.

Monday, October 23, 2017

Back to the blog



I know it's been a while since I updated the blog but...

Surface Tension Problem with the Gelcoat
We left Malaysia in June in a very rushed and frustrated mode.  The gelcoat project did not was having issues and we needed to have a face to face in Singapore with the fiberglass resin supplier.  Their material was getting fish eye craters in it when it was sprayed.  Heaps of time was wasted trying to figure out where exactly the problem was.  We were running out of time and getting rushed.  They were avoiding emails and in general being unhelpful.


So we decided to wrap things up, deal with the resins guy, tour around Singapore, and then fly home out of Changi Airport.

The bus ride to Johor Bahru was a long 12 hours.  The following day, we showed up at the resins guy and got some things resolved.  The resolution was to add a thickener which is more of a band-aid solution instead of having a sprayable product from the beginning.






We then headed downtown to our hotel.  Singapore is an island country about 25 miles by 12 miles wide at the southern tip of the Malaysian Peninsula.  It is surrounded by Malaysia except for the south side which is the Singapore Strait.   It has a population of 5 million and is the 3rd most densely populated country in the world.  

They have an incredible subway and bus public transportation system.  It has to.  There is no way all those people could be driving on the roads without absolute chaos.  You can get just about anywhere for next to nothing.

We spent the next day historical touring in Little India.  We had a nice Curry lunch and did some shopping for things to take back home.  Our flight to Frankfurt was a midnight departure and of course the subway took us right to the airport.

It was a nice feeling to be heading home after 4 months of hard work.