Not really,read the first post. Clear coat finish.
The pic of the rail tape is a different board I am working on.
I have sanded out some bubbles and creases in the high density foam. I will fill them. Hopefully get the bottom done this weekend.
I am thinking about doing the 2 layers on the bottom at once. Innegra then flax. I have worked with innegra once. You do not wont to sand it. It is difficult to wet out. Flax I have worked with a bit and it soaks up a lot of epoxy. I am thinking the extra epoxy in the flax will help wet out the innegra when vac bagged. If I lay the flax a little further than the Innegra it will cover the edge and I will not have to cut or sand it.
I would not use innegra with flax. Innegra has a very low modulus so it's tough as hell, but bendy. Thus it works well with carbon ..... well, it needs the carbon ......
Flax works well with carbon too
I'd consider one or the other.....or at least if you are doing flax and innegra, then do uni carbon up the middle for at least half the board.
I know what you are saying but with the composite bottom I was hoping to compensate for this. All the stuff I have read says flax has a higher modulus than glass.
The wooden deck and rails is where the stiffness will come from and a super tough bottom.
Looks good Tarquin, good to see peoples builds, I have one I'm working on at the moment and would like to know what amount of vacuum you are using to do the job without overdoing it?
The company I bought the blank off said around -0.1 -0.15. Or 850-900 mbar. Depends on your gauge. This is enough for light glass etc.
I hand layed 80g glass top and bottom so I could do more. -0.5 or 500 mbar.
I think leaving eps foam in the bag with the pump running just sucks the air out of the foam and it creases. You have to have both sides sealed or keep the pressure very low and in the bag for as short a time as possible.
I don't really think bagging is necessary unless you are using pvc,difficult fibers like flax or wood.
Thanks for that Tarquin, I'm vacuuming balsa down over glassed blank. I will do some tests also.
Balsa bends pretty easily so it should not take to much. Is the blank glassed both sides.
Filling,sanding. Probably sanded a little toooo much in some spots.
Take my time here to make sure it's all good. That's technical talk for the f'n innegra hasn't arrived yet.
Start looking at the wood for the deck.
Select to expand quotetarquin1 said..
Balsa bends pretty easily so it should not take to much. Is the blank glassed both sides.
Yes glassed both sides
Select to expand quote515 said..
Hi lukemin,
Balsa sounds I interesting.
What you building and lay up, any photos?
Hi 515, I'm building a surf SUP eight foot ten, EPS glassed with 4 oz then balsa - grooved on top.
rails from laminated balsa , then glass on top then 2 pac auto clear. Yes I like Sunovas
Nice one. That wont take much pressure at all. Will you glue all the balsa together first.
Select to expand quotetarquin1 said..
Nice one. That wont take much pressure at all. Will you glue all the balsa together first.
Yep laminate it together first then vac bag.
When I do pine deck (so not quite as porous as your balsa) I do 8"Hg (about 30kpa) vacuum and its more than enough to make it conform, and then it also draws resin through the wood in some places. Clearly enough if its sucking resin through wood!
Lots of vac bag pressures you read about are way too high as they are trying to bend thicker pvc foams and stuff.
Select to expand quoteMark _australia said..
When I do pine deck (so not quite as porous as your balsa) I do 8"Hg (about 30kpa) vacuum and its more than enough to make it conform, and then it also draws resin through the wood in some places. Clearly enough if its sucking resin through wood!
Lots of vac bag pressures you read about are way too high as they are trying to bend thicker pvc foams and stuff.
Sounds good Mark, I take it no problem with the EPS at that range. I will start off low
Mark do you ever get a perfect seal and turn the pump off or do you leave it running.
Luke not sure if you have glued up the balsa but there are some good ways on model aeroplane sites. Tape across as you have done then the whole length covering each join. You can then lay it flat on the edge of a table and glue each join as you slide it off the table. If that makes sense. There are loads of vids on YouTube.
I remove the tape before bagging. If epoxy pulls through the tape is a nightmare to get off.
Scubaste how did you do it.
Select to expand quotetarquin1 said..
Mark do you ever get a perfect seal and turn the pump off or do you leave it running.
Luke not sure if you have glued up the balsa but there are some good ways on model aeroplane sites. Tape across as you have done then the whole length covering each join. You can then lay it flat on the edge of a table and glue each join as you slide it off the table. If that makes sense. There are loads of vids on YouTube.
I remove the tape before bagging. If epoxy pulls through the tape is a nightmare to get off.
Scubaste how did you do it.
Clamp and glue on a flat table.
With the vac pump i used an old vacuum advance off a distributer,a micro switch, a 12volt relay and 12volt battery
So when she pulls full vacuum ( 3inch of mercury) then it pulls the vacuum advance into the point that it switches the micro switch which switches the 12v supply to the relay that swiches the neutral to the vac pump
When it looses vacuum the pump will switch back on.
Usually about 60 seconds off and a few minutes on.
Cheers
Scuba
Select to expand quotelukemin said..Mark _australia said..
When I do pine deck (so not quite as porous as your balsa) I do 8"Hg (about 30kpa) vacuum and its more than enough to make it conform, and then it also draws resin through the wood in some places. Clearly enough if its sucking resin through wood!
Lots of vac bag pressures you read about are way too high as they are trying to bend thicker pvc foams and stuff.
Sounds good Mark, I take it no problem with the EPS at that range. I will start off low
Sorry to clarify - I am bagging wood onto a shortboard with bottom lam done so its can;t bend much
any more vac or a longer board- rocker spine in wood so she can't move.
Select to expand quotetarquin1 said..
Mark do you ever get a perfect seal and turn the pump off or do you leave it running.
Luke not sure if you have glued up the balsa but there are some good ways on model aeroplane sites. Tape across as you have done then the whole length covering each join. You can then lay it flat on the edge of a table and glue each join as you slide it off the table. If that makes sense. There are loads of vids on YouTube.
I remove the tape before bagging. If epoxy pulls through the tape is a nightmare to get off.
Scubaste how did you do it.
scubaste method is how most do it.
For me - I got free pumps that will run for a long time so I do it a slightly naughty way - continuous running with a bleed valve I adjust so it maintains same vac. Takes a few mins of fiddling with the valve to get the vac to sit at same level.
Have a one way valve in the line to the pump so a temporary power failure will mean we at least retain vacuum in the reservoir / bag for a couple of mins.
Then I set a timer so it will turn off, and go do other things. I am often using fast resins in a warm workshop (30C plus) so only need 90mins in the bag Winter not so great.....
Many vac pumps are not designed to run continuously at part vacuum though...... still, I have not had one die on me yet.
That's what I have. I bought a pump that can run for a long time and a bleed valve, after I crushed a board! I have also snapped 6mm wood making skateboards. It's crazy how much pressure there is.
I think I will buy the cut off switch. Then I can set the pressure and it will turn on and off. And no FULL PULL. It's not that expensive and will save me money.
I am quite often working at 15? C so even with fast hardener things take a while.
Making up some test strips. 2mm foam then 1 layer of 2 oz innegra, wetted out easier than expected and went clearer than expected. Then 160 g woven flax and various glass overlapping to get different lay ups.
Cut into strips 5cm wide x 26cm long. That's 6kgs of weight. Like Jimmy says in his vid. Imagine putting that much weight on 2 layers of 6 oz glass.
Lukemin it would be interesting to see a similar test with the balsa if you have some scraps left.
Hows the board going?
Select to expand quotetarquin1 said..
Lukemin it would be interesting to see a similar test with the balsa if you have some scraps left.
Hows the board going?
Yes Tarquin, I have still to set up the vacuum gear but could do some similar test in the next couple of weeks.
I think the test you do is good but also a test to destruction would be interesting.
Oh who doesn't like destructive testing! I will get there. After a few beers of course!
A couple of things as expected, the just glass one is the weakest, it is a lighter weight. The ones with 2 layers are stiffer.
Something I was surprised about was the pieces had the same flex either way. I thought if you put the stiffer face down it would make the laminate stiffer as you have the bottom in tension.
A quick smack with a hammer showed results as I would expect as well. The just glass showed the damage the most. The flax showed the least. It doesn't shatter like glass.
So I think I will go ahead as planned.
I put 8 kgs of weight on the innegra flax one and it flexed 15mm.
I think shear failure between the sandwhich and EPS core will be a problem before the sandwhich breaks.
I learnt a lot from Grant Newby about vac bagging wood onto EPS blanks with PU glue. It is really strong because the PU glue goes so deep into the foam. Would you be better of vac bagging the high density foam onto the blank with PU to get better shear strength between the foams. You would loose the stiffness of the sandwhich but gain shear strength. Lighter ad cheaper as well.
Everything ready to go. Going to use the whole lot,peel ply perforated film then breather. Just to see if it makes a difference. Using slow clear epoxy this time.
Wet out table.
I have cut some strips of innegra to double up on the rails.
Seems to have worked well. I am going to leave the peel ply until the deck is done. Just to protect the bottom. Is there any problem with leaving it for a week or two.
Select to expand quotetarquin1 said..
Seems to have worked well. I am going to leave the peel ply until the deck is done. Just to protect the bottom. Is there any problem with leaving it for a week or two.
Its a mission getting it off the day after I would hate to leave it for a day or 2.
Impressed with the flax in photos and destruction testing is informative and good to learn flax handles impact better than glass but also fun to smash things
I liked to experiment with my own boards compared to building orders (development). Depending on purpose of board windsurf jumping and flat landing I only twice major board damage once under built deck and creased bottom.
The deck I broke was 2mm gaboon ply that wasn't glassed on top. It sounds like pu foam between wood and polystyrene foam is an awesome bond but your deck won't break so better to have sandwich.
Light/strong/material choice /method of construction and balancing material cost and labour is always has trade offs .
There are a lot of well designed and built production boards do custom is unique design and best construction.
I will build a multi purpose wave sup/ windsurf/ windfoil board. I have major life going on with starting business so project a year away. I have good ideas to suit the waves I sup and think more multipurpose boards from major brands will increase.
Can understand you want to keep peel ply on and haven't used it for while so may have become easier to get off but you will need to handle carefully with clean hands.
Nice work dude!
