Oc-1 Lay up with Epoxy resin....
Aloha Mariano,
You can contact Vicente Dors, in Porto Alegre, Brazil (It´s not near but not so far anyway)
He is a rowing boat buider but he made a very nice OC-1 for me
He also teaches how to work with vacum bag
Here his web site http://www.vicentedors.com/
See ya,
#1 Wed, 04/14/2010 - 5:19am
Mariano,
Are you building with molds ?
Can you get any kind of foam or balsa for core material ???
What weight fiberglass are you using ??
35 pounds fully rigged ?
Without changing anything but your construction techniques and layup schedule your solid glass / polyester boats should be less than 30 pounds.
aloha,
pog
#2 Wed, 04/14/2010 - 9:17am
I remember the old days, when us guys would furnish the resin to make sure it was fresh and not the old stuff when time came to make our skis. It may not be economical, but there is big difference in the finished product.
#3 Wed, 04/14/2010 - 10:15am
Epoxys much better now but even sitting inside, the moisture can start to effect them if they sit around unused.
Hardeners worse IMO.
aloha,
pog
#4 Wed, 04/14/2010 - 12:05pm
O.K. cool ....
Are you spraying in the gelcoat ???
Don't worry too much about the Carbon for now ...
I would skip that "velo de superficie" ply entirely AND most importantly ...
Get some 1mm coremat ... The 2mm is killing you.
aloha,
pog
#6 Wed, 04/14/2010 - 2:47pm
It's time to invest in a vacuum pump. Ebay to the help.
There is also a company that refurbishes pumps - price for a $ 2500 pump is about $ 1200, including shipping you may get it for $ 1500 ?
I received it with USPS, they do services up to 70 pounds - it was surprisingly cheap.
I agree with Onno - having limited experience myself - I hand-laid-up my first boat, weight 25 lbs without ama.
I am just about to finish another attempt, this time with carbon/glass and coremat, vacuum bagged; much better.
Because it is a prototype I did not focus on light weight, but I will end up between 23 and 25 lbs and could have saved about 2.5 lbs.
Too much weight means too much resin obviously and that means less quality of the layup - of course, you all know that.
#7 Wed, 04/14/2010 - 2:52pm
If you're considering a vacuum pump, and don't plan on using it for production any old pump will do. Shouldn't run you more than $500 from an air conditioning supply store. Search for JB vacuum.
#9 Wed, 04/14/2010 - 8:59pm
Many variations ... Which one are you considering ?
http://www.spheretex.com/
aloha,
pog
#11 Thu, 04/15/2010 - 2:10am
Mariano, I think that the gel-time with polyester is kind of short for vacuum lay up.
I use a mix of a slow hardener and a regular hardener to extend the working time for epoxy resin to about 40 min.
With that mix you (I) need three people to lay up a boat with four layers. We did it with two people, got nervous half way and used too much resin for the final layer.
The resin pooled and pulled the sides of the part together while heating up and curing. It was correctable, but still.
Coremat is probably not the 'best' material, compared to divinicell etc., but is is very workable in a smaller setting.
We wet out the core mat, hang it on a line, do the fist layer(s) - after pre-wetting on the bench -, then take the coremat and apply it, then add the final inner layer dry, wet it out and apply the vacuum.
To distribute the vacuum evenly we have a central pvc pipe with holes cut into it every 1 1/2 foot. The holes are covered with breather material and peel ply. This way you get sufficient vacuum at bow and stern, too.
Vacuum is much more satisfying - that alone is worth the cost in my opinion - ; the same is true for epoxy and even for carbon - even though carbon is more difficult to apply. I am not sure a full carbon layup is necessary or even the best - it certainly is the stiffest. Kevlar is most break and puncture resistant, but quite difficult to repair, and, also more difficult to wet out, I heard.
Regarding layup/stiffness do a google book search: under kayak stiffness and carbon layup you can find an article that compares different layup schedules for a K1 - I posted the article here about two weeks ago.
The essence: carbon is stiffest, but with a carbon flange around the seam line you do very well, too. Stringers did not get good results, surprisingly. They are more for flotation, I guess.
"For every year lived, a man has to build a foot length of boat" ( some old English quote )
#14 Fri, 04/16/2010 - 7:47am
I would say the guy is pulling your leg ...
One might say to him ... same shit, different bag.
....... at least its 1mm ....
Different coremats in DO have slightly varied characteristics such as higher compression, better drapability or slightly stiffer parts yeilded but then these also end up being a little heavier even with the same process.
Eckhart ... to bust your balls ... I can do ( layup ) a coremat boat by myself in a day.
aloha,
pog
#15 Fri, 04/16/2010 - 12:38am
Onno, that sounds pretty stressful;
how do you organize mixing your resin while laying up ?
#17 Fri, 04/16/2010 - 7:47am
Slow hardener and have everthing layed out, physically and mentally.
Mariano, you are using the grooved rollers ? If not, order some a couple of these and play around with them.
aloha,
pog
#18 Fri, 04/16/2010 - 9:24am
what kind of gelcoat do you guys use? i heard polyester gelcoat is not working good with epoxy lay-ups and i saw many canoes, where the gel was peeling off. or is there any trick to make it work?
#20 Sun, 05/09/2010 - 1:30am
I think Ferro makes a polyester Gelcoat that epoxy can stick to ,otherwise you must use Hawkeyes duratec (either mixed with Gelcoat ,or coat the entire gelcoat with a different Duratec type later). In China they just vacuum lay up with no gelcoat and then sand/epoxy fill/sand/spray primer/sand/ topcoat. but you may not be able to afford that!
#21 Tue, 05/18/2010 - 1:06am
If you do want to stick to polyester i would spray a thin gelcoat (thinner than materials spec) one layer of woven carbon160-200 gm/m2 ,then a layer of 1mm core (tigercore,coremat,spherecore etc) and another layer of woven carbon (if you buy the carbon wide enough you will be able to get both hull layers from 1 length of fabric) you could use carbon/kevlar mixed fabric instead or try glass fabric 1st to perfect your technique (its see through when wet), glass comes in E (regular) or S/R (stiffer) but remember pure kevlar is not as stiff as regular E glass and its a pain to cut with scissors or repair later (kevlar should be next to the Gelcoat)(kevlar also works better with Vinylester resin but best with Epoxy resin)
as for the weight of things CSM(chopped strand mat) uses way more resin than woven cloth fabrics but the finished laminate will be thicker and stiffer.
#24 Tue, 05/18/2010 - 4:40am
latman, do you thin gelcoat to spray it? i had problems to spray it, because its so thick. it took me about 2kg for a canoe. i think that is to much!
#25 Tue, 05/18/2010 - 5:19am
How long is your canoe ? 2kg Gelcoat may be right if it is long or there is a complex footwell ,or try for a bit less.(the painting is lighter but the labour expensive,and 2 pack is more toxic) The Company you buy Gelcoat from is already thinning it with Styrene liquid , we thin it a bit more (no more than 10% maybe) with acetone (as the acetone evaporates as you spray) but this is never recommended by the company. If it is too thin it will tripe (alligatoring there) but we lay up by infusion and it seems the vacuum pushing the fabric against the Mould/Gelcoat stops this a bit. some colours like white and light blue and light grey need leess Gelcoat for opaque coverage.
#26 Tue, 05/18/2010 - 5:53am
Ahha! So that's why, in the past, many Aussie skis were light sky blue in color? Less gelcoat, less weight?
#28 Tue, 05/18/2010 - 6:38am
Yes , many light blue Hayden skis floating around the Islands.... Light blue is also a cooler (temperature) colour than many others so a few jobs are done by it (its not as boring as white) Ray Burton was more of a white fan. Some colours like yellow are very seethrough (translucent) and LOTS of gelcoat (weight) is needed for opaque coverage
#29 Tue, 05/18/2010 - 4:51pm
Aloha nui, i been building Oc-1 here in Argentina fo the past 2 years, using Poliester resin, stone age hand layups with a final weith of 35pounders.....and some times a bit more, the deal is, even though Epoxy-carbon fibers and foam core technilogies are very, very expensive here, i feel like making a prototype.
what you recomend? i was thinking building myself one with Epoxy resin and regular fiberglass layup for this first time, no carbon fibers, cause of its cost.
any help would be more than welcome since its gonna help improve a bit more our canoes, and finally our FUN in the waters.
mahalo in advance,
Aloha from Argentina.
Mariano.
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